Cutting Edge Materials (ISO) 230

Transcription

1 Cutting Edge Materias (ISO) 230 Cass Outine Objectives The Importance of Too Materias High-Speed Stees Cassification of HSS Toos Appication of HSS Toos Powdered Meta HSS Toos Cemented Tungsten Carbides Carbide Composition Tungsten Carbide Grades Coated Carbides Chemica Vapor Deposition Physica Vapor Deposition Properties of Carbide Coatings ISO Carbide Cassification Cermet Cutting Toos Aumina Ceramics Pros and Cons of Aumina Ceramics Ceramic-Composite Materias Siicon Carbide Whisker Reinforced Aumina Siaon Ceramics Poycrystaine Cubic Boron Nitride (PCBN) Poycrystaine Diamond (PCD) Singe-Crysta Diamonds Summary Copyright 2009 Tooing U, LLC. A Rights Reserved.

2 Cass Outine Objectives The Importance of Too Materias High-Speed Stees Cassification of HSS Toos Appication of HSS Toos Powdered Meta HSS Toos Cemented Tungsten Carbides Carbide Composition Tungsten Carbide Grades Coated Carbides Chemica Vapor Deposition Physica Vapor Deposition Properties of Carbide Coatings ISO Carbide Cassification Cermet Cutting Toos Aumina Ceramics Pros and Cons of Aumina Ceramics Ceramic-Composite Materias Siicon Carbide Whisker Reinforced Aumina Siaon Ceramics Poycrystaine Cubic Boron Nitride (PCBN) Poycrystaine Diamond (PCD) Singe-Crysta Diamonds Summary Lesson: 1/24 Objectives Describe the significance of too materia seection. Describe the properties of high-speed stees. Identify HSS too cassifications. Describe common appications for HSS toos. Describe the properties of powdered meta HSS toos. Describe the properties of cemented tungsten carbides. Distinguish among the various compositions of carbide toos. Distinguish among the different grades of tungsten carbides. Describe the properties of coated carbides. Describe the characteristics of chemica vapor deposition (CVD). Describe the characteristics of physica vapor deposition (PVD). Distinguish among the properties of carbide coatings. Describe how ISO cassifies carbide grades. Describe the properties of cermet cutting toos. Describe the properties of aumina ceramics. Identify the pros and cons of aumina ceramics. Describe the properties of ceramic-composite materias. Describe the properties of siicon carbide whisker reinforced aumina. Describe the properties of siaon ceramics. Describe the properties of Poycrystaine cubic boron nitride (PCBN). Describe the properties of Poycrystaine diamond (PCD). Describe the properties of singe-crysta diamonds. Figure 1. Proper cutting too materia seection determines the quaity of the finished product. Figure 2. There are many variabes to consider when seecting a cutting too materia. Lesson: 2/24 Copyright 2009 Tooing LLC. A Rights Reserved. The Importance of Too U, Materias One of the most important characteristics of a cutting too is the type of too materia. Most peope in the meta cutting industry tend to think of too

3 Lesson: 1/24 Objectives Describe the significance of too materia seection. Describe the properties of high-speed stees. Identify HSS too cassifications. Describe common appications for HSS toos. Describe the properties of powdered meta HSS toos. Describe the properties of cemented tungsten carbides. Distinguish among the various compositions of carbide toos. Distinguish among the different grades of tungsten carbides. Describe the properties of coated carbides. Describe the characteristics of chemica vapor deposition (CVD). Describe the characteristics of physica vapor deposition (PVD). Distinguish among the properties of carbide coatings. Describe how ISO cassifies carbide grades. Describe the properties of cermet cutting toos. Describe the properties of aumina ceramics. Identify the pros and cons of aumina ceramics. Describe the properties of ceramic-composite materias. Describe the properties of siicon carbide whisker reinforced aumina. Describe the properties of siaon ceramics. Describe the properties of Poycrystaine cubic boron nitride (PCBN). Describe the properties of Poycrystaine diamond (PCD). Describe the properties of singe-crysta diamonds. Figure 1. Proper cutting too materia seection determines the quaity of the finished product. Figure 2. There are many variabes to consider when seecting a cutting too materia. Lesson: 2/24 The Importance of Too Materias One of the most important characteristics of a cutting too is the type of too materia. Most peope in the meta cutting industry tend to think of too materias as separate categories without considering other options. In fact, a the various too materias can be ranked or categorized according to the unique baance of hardness, toughness, and wear resistance, which enabe the too to effectivey resist heat, abrasion, and fracture. Primariy, the properties of a too materia directy resut from its chemica composition and structure. Figure 1 shows the reationship of a these too materias as they reate to each other on a graph. Proper too materia seection requires the consideration of severa key variabes summarized in Figure 2. These variabes incude the type of workpiece materia, production requirements, surface finish and toerances, the desired cost of the part, and the desired too cost per workpiece machined. You must consider the type of machine you are using, especiay if there are imitations with the setup. A these variabes create the need for too materias with the appropriate baance of hardness, toughness, and wear resistance. A too materias have an appropriate appication. The goa of a too engineer is to recognize the properties that each too materia offers and to seect the most appropriate too for the specific appication. This cass wi focus on the different types of cutting too materias and their characteristics. You wi earn how each materia heps you choose the best cutting too for a particuar appication. Copyright 2009 Tooing U, LLC. A Rights Reserved. Lesson: 3/24 Figure 1. The unique properties of each too materia determine the appropriate feed rate and speed. 1 PCD / CBN, 2 Ceramic, 3 Cermet, 4 Coated Carbide, 5 Compex Carbide, 6 Straight Carbide, 7 Tungsten HSS, 8 Cobat / Vanadium HSS, 9 Moybdenum HSS

4 Lesson: 2/24 The Importance of Too Materias One of the most important characteristics of a cutting too is the type of too materia. Most peope in the meta cutting industry tend to think of too materias as separate categories without considering other options. In fact, a the various too materias can be ranked or categorized according to the unique baance of hardness, toughness, and wear resistance, which enabe the too to effectivey resist heat, abrasion, and fracture. Primariy, the properties of a too materia directy resut from its chemica composition and structure. Figure 1 shows the reationship of a these too materias as they reate to each other on a graph. Proper too materia seection requires the consideration of severa key variabes summarized in Figure 2. These variabes incude the type of workpiece materia, production requirements, surface finish and toerances, the desired cost of the part, and the desired too cost per workpiece machined. You must consider the type of machine you are using, especiay if there are imitations with the setup. A these variabes create the need for too materias with the appropriate baance of hardness, toughness, and wear resistance. A too materias have an appropriate appication. The goa of a too engineer is to recognize the properties that each too materia offers and to seect the most appropriate too for the specific appication. This cass wi focus on the different types of cutting too materias and their characteristics. You wi earn how each materia heps you choose the best cutting too for a particuar appication. Figure 1. The unique properties of each too materia determine the appropriate feed rate and speed. 1 PCD / CBN, 2 Ceramic, 3 Cermet, 4 Coated Carbide, 5 Compex Carbide, 6 Straight Carbide, 7 Tungsten HSS, 8 Cobat / Vanadium HSS, 9 Moybdenum HSS Lesson: 3/24 High-Speed Stees Some of the most common too materias are high-speed stees (HSS), which are high-aoy too stees designed for use as cutting materias. These too materias are reativey inexpensive and have remained a mainstay in the industry. Figure 1 shows a HSS end mi on a manua mi. The key characteristic that HSS toos offer is exceent toughness. In other words, HSS toos can absorb the shock of interrupted cuts more effectivey than any other cutting too materia. HSS toos go through heat treating to increase their hardness to approximatey RC. High Speed Stees actuay consists of discrete categories of too materias with their own unique properties: Moybdenum grades offer improved toughness. Many moybdenum grades are exceent for genera-purpose appications. Tungsten grades offer increased hot hardness and provide exceent wear resistance. Vanadium grades incude the aoy vanadium to provide increased wear resistance. Within these categories, too manufacturers adjust the aoying content and heat treatment to find the best baance of too materia properties. Figure 2 shows the infuence that aoying eements have on the characteristics of the too materia. Toughness is increased in HSS by owering the carbon content, adding moybdenum, or tempering the too materia at 593 to 649 C. It shoud be noted that when toughness increases, hardness and wear resistance tend to decrease. Figure 1. HSS toos are often used on manua machines because of the too materia's exceent toughness. Copyright 2009 Tooing U, LLC. A Rights Reserved.

5 Lesson: 3/24 High-Speed Stees Some of the most common too materias are high-speed stees (HSS), which are high-aoy too stees designed for use as cutting materias. These too materias are reativey inexpensive and have remained a mainstay in the industry. Figure 1 shows a HSS end mi on a manua mi. The key characteristic that HSS toos offer is exceent toughness. In other words, HSS toos can absorb the shock of interrupted cuts more effectivey than any other cutting too materia. HSS toos go through heat treating to increase their hardness to approximatey RC. High Speed Stees actuay consists of discrete categories of too materias with their own unique properties: Moybdenum grades offer improved toughness. Many moybdenum grades are exceent for genera-purpose appications. Tungsten grades offer increased hot hardness and provide exceent wear resistance. Vanadium grades incude the aoy vanadium to provide increased wear resistance. Within these categories, too manufacturers adjust the aoying content and heat treatment to find the best baance of too materia properties. Figure 2 shows the infuence that aoying eements have on the characteristics of the too materia. Toughness is increased in HSS by owering the carbon content, adding moybdenum, or tempering the too materia at 593 to 649 C. It shoud be noted that when toughness increases, hardness and wear resistance tend to decrease. Figure 1. HSS toos are often used on manua machines because of the too materia's exceent toughness. Figure 2. Each aoy aters the characteristics of HSS toos differenty. Lesson: 4/24 Cassification of HSS Toos The American Iron and Stee Institute (AISI) cassifies HSS toos according to their composition. Each aoying ingredient added to HSS impacts the wear resistance of the specific grade of cutting edge materia, as iustrated in the chart in Figure 1. Each cass of HSS contains about 4% chromium, with varied amounts of vanadium and carbon. Generay, as the amount of vanadium in HSS increases, the amount of carbon increases as we. AISI recognizes two major groups of HSS, which are cassified as containing moybdenum (Mo) or tungsten (T). Moybdenum grades are identified with the prefix "M," and tungsten grades are identified with the prefix "T." Figure 1 shows aoy contents of these materias. There are 10 different types of moybdenum HSS, abeed M1 through M10. With the exception of M6, types M1 through M10 do not contain cobat. In HSS, the presence of cobat increases hot hardness. Most grades of M stees aso contain tungsten. Exampes of premium moybdenum HSS that contain tungsten and cobat are in the M30 and M40 series. Super high-speed stees range from M40 and up and can withstand heat treating to very high hardness. Tungsten grades that contain cobat are types T4 through T15, with varying amounts of cobat. T1 contains neither moybdenum nor cobat. Copyright 2009 Tooing U, LLC. A Rights Reserved. Figure 1. Each grade of HSS contains different additives to produce the desired characteristics.

6 Lesson: 4/24 Cassification of HSS Toos The American Iron and Stee Institute (AISI) cassifies HSS toos according to their composition. Each aoying ingredient added to HSS impacts the wear resistance of the specific grade of cutting edge materia, as iustrated in the chart in Figure 1. Each cass of HSS contains about 4% chromium, with varied amounts of vanadium and carbon. Generay, as the amount of vanadium in HSS increases, the amount of carbon increases as we. AISI recognizes two major groups of HSS, which are cassified as containing moybdenum (Mo) or tungsten (T). Moybdenum grades are identified with the prefix "M," and tungsten grades are identified with the prefix "T." Figure 1 shows aoy contents of these materias. There are 10 different types of moybdenum HSS, abeed M1 through M10. With the exception of M6, types M1 through M10 do not contain cobat. In HSS, the presence of cobat increases hot hardness. Most grades of M stees aso contain tungsten. Exampes of premium moybdenum HSS that contain tungsten and cobat are in the M30 and M40 series. Super high-speed stees range from M40 and up and can withstand heat treating to very high hardness. Tungsten grades that contain cobat are types T4 through T15, with varying amounts of cobat. T1 contains neither moybdenum nor cobat. Figure 1. Each grade of HSS contains different additives to produce the desired characteristics. Lesson: 5/24 Appication of HSS Toos Despite the increased use of cutting too materias such as carbides, HSS toos are sti used extensivey in industry because of their toughness and versatiity. Figures 1 show a range of soid HSS toos. HSS toos are aso ow in cost and easy to produce. Most dris, taps, reamers, end mis, thread chasers, broaches, and gear cutting toos are made from HSS. Cutting toos that require compex shapes and sharp cutting edges, such as many form toos and cutoff toos, are aso often made from HSS. HSS toos are preferred for operations performed at ow cutting speeds and on ess rigid, ow horsepower machine toos. As with a cutting too seection, you must understand the characteristics of the different grades of HSS. For genera production, M2 and T1 grades of HSS are preferred for appications requiring increased abrasion resistance, M3, M4, and M10 are good choices and T5 and T15 are best suited for operations requiring high hot hardness. M42 and M44 grades are appropriate for operations that require high hot hardness and high abrasion resistance. Figure 1. The tap, reamer, and dris are made from HSS too materias. Lesson: 6/24 Powdered Meta HSS Toos Powdered meta high-speed stee toos offer properties that ink traditiona HSS and carbide tooing. Figure 1 shows an exampe of both powdered meta HSS and HSS toos. Powdered meta HSS toos have a uniform microstructure, consistent grain distribution, and a fine carbide formation. Powdered meta HSS aows press and sinter technoogy, simiar to carbide, which aows the economica production of compex too shapes with minima finish grinding. Traditionay, high-performance HSS toos, such as T15, were avoided because they were expensive and difficut to produce. Today, powdered meta HSS toos offer design fexibiity. They aow the use of higher aoy stees that woud otherwise be difficut or uneconomica to produce with conventiona production methods. Miing cutters, gear cutting toos, and other compex too forms can be produced easiy and economicay using powdered meta HSS. Using aoys such as vanadium and high amounts of tungsten with powdered meta HSS aows manufacturers to create toos with greater speed and feed capabiities. The meta remova rate for these toos in many appications Copyright 2009 Tooing U, LLC. A Rights Reserved. Figure 1. Powdered meta HSS toos combine

7 Lesson: 5/24 Appication of HSS Toos Despite the increased use of cutting too materias such as carbides, HSS toos are sti used extensivey in industry because of their toughness and versatiity. Figures 1 show a range of soid HSS toos. HSS toos are aso ow in cost and easy to produce. Most dris, taps, reamers, end mis, thread chasers, broaches, and gear cutting toos are made from HSS. Cutting toos that require compex shapes and sharp cutting edges, such as many form toos and cutoff toos, are aso often made from HSS. HSS toos are preferred for operations performed at ow cutting speeds and on ess rigid, ow horsepower machine toos. As with a cutting too seection, you must understand the characteristics of the different grades of HSS. For genera production, M2 and T1 grades of HSS are preferred for appications requiring increased abrasion resistance, M3, M4, and M10 are good choices and T5 and T15 are best suited for operations requiring high hot hardness. M42 and M44 grades are appropriate for operations that require high hot hardness and high abrasion resistance. Figure 1. The tap, reamer, and dris are made from HSS too materias. Lesson: 6/24 Powdered Meta HSS Toos Powdered meta high-speed stee toos offer properties that ink traditiona HSS and carbide tooing. Figure 1 shows an exampe of both powdered meta HSS and HSS toos. Powdered meta HSS toos have a uniform microstructure, consistent grain distribution, and a fine carbide formation. Powdered meta HSS aows press and sinter technoogy, simiar to carbide, which aows the economica production of compex too shapes with minima finish grinding. Traditionay, high-performance HSS toos, such as T15, were avoided because they were expensive and difficut to produce. Today, powdered meta HSS toos offer design fexibiity. They aow the use of higher aoy stees that woud otherwise be difficut or uneconomica to produce with conventiona production methods. Miing cutters, gear cutting toos, and other compex too forms can be produced easiy and economicay using powdered meta HSS. Using aoys such as vanadium and high amounts of tungsten with powdered meta HSS aows manufacturers to create toos with greater speed and feed capabiities. The meta remova rate for these toos in many appications approaches that of carbide. Lesson: 7/24 Cemented Tungsten Carbides Cemented tungsten carbides, shown in Figure 1, contain a cass of hard, wearresistant refractory metas in which the hard metas are bound together or cemented by a soft and ductie meta binder. The binder is usuay cobat or nicke. D. Widia deveoped these materias in Germany in the eary 1920s. The first tungsten carbide (WC) toos were produced with a cobat binder. Cemented carbide is often referred to as hard metas. Carbide manufacturers vary the microstructures and compositions in the powder mixture to gain the desired baance of hot hardness, toughness, and wear resistance. In particuar, the grain size of the tungsten carbide partices directy impacts these properties. Larger grains offer improved toughness, and smaer grains provide better wear resistance. The grain size, in tungsten carbide mixtures, range from sub-micron to approximatey 7 microns. The quaity of cemented tungsten carbides is dependent on the consistency of the formua and the proper distribution of the tungsten carbide partices. Copyright 2009 Tooing U, LLC. A Rights Reserved. Figure 1. Powdered meta HSS toos combine characteristics of carbide and HSS tooing.

8 Lesson: 6/24 Powdered Meta HSS Toos Powdered meta high-speed stee toos offer properties that ink traditiona HSS and carbide tooing. Figure 1 shows an exampe of both powdered meta HSS and HSS toos. Powdered meta HSS toos have a uniform microstructure, consistent grain distribution, and a fine carbide formation. Powdered meta HSS aows press and sinter technoogy, simiar to carbide, which aows the economica production of compex too shapes with minima finish grinding. Traditionay, high-performance HSS toos, such as T15, were avoided because they were expensive and difficut to produce. Today, powdered meta HSS toos offer design fexibiity. They aow the use of higher aoy stees that woud otherwise be difficut or uneconomica to produce with conventiona production methods. Miing cutters, gear cutting toos, and other compex too forms can be produced easiy and economicay using powdered meta HSS. Using aoys such as vanadium and high amounts of tungsten with powdered meta HSS aows manufacturers to create toos with greater speed and feed capabiities. The meta remova rate for these toos in many appications approaches that of carbide. Figure 1. Powdered meta HSS toos combine characteristics of carbide and HSS tooing. Lesson: 7/24 Cemented Tungsten Carbides Cemented tungsten carbides, shown in Figure 1, contain a cass of hard, wearresistant refractory metas in which the hard metas are bound together or cemented by a soft and ductie meta binder. The binder is usuay cobat or nicke. D. Widia deveoped these materias in Germany in the eary 1920s. The first tungsten carbide (WC) toos were produced with a cobat binder. Cemented carbide is often referred to as hard metas. Carbide manufacturers vary the microstructures and compositions in the powder mixture to gain the desired baance of hot hardness, toughness, and wear resistance. In particuar, the grain size of the tungsten carbide partices directy impacts these properties. Larger grains offer improved toughness, and smaer grains provide better wear resistance. The grain size, in tungsten carbide mixtures, range from sub-micron to approximatey 7 microns. The quaity of cemented tungsten carbides is dependent on the consistency of the formua and the proper distribution of the tungsten carbide partices. Figure 1. Cemented tungsten carbides are aso known as hard metas and are avaiabe coated (1) and uncoated (2). Lesson: 8/24 Carbide Composition Cemented tungsten carbides are composed of the foowing materias: Tungsten carbide (WC). WC provides hard, wear-resistant properties. As the percentage of tungsten carbide increases, wear resistance increases. If the percentage of tungsten carbide is decreased to aow additiona aoys, wear resistance decreases. Titanium carbide (TiC). TiC is aoyed into the composition to provide resistance to faiure by cratering. Tantaum carbide (TaC). TaC is aoyed into the composition to provide resistance to faiure by therma deformation and therma cracking. Niobium carbide (NbC). NbC Some compositions incude NbC, which has characteristics simiar to TaC, as means to reduce costs. Cobat (Co). Co is the primary materia that serves as a binder. Cobat content can range anywhere from 4 to 15 percent. As the percentage of cobat in the tungsten Copyright 2009rises, Tooing U, LLC. A Rights Reserved. carbide toughness increases. However, increased cobat content aso makes the materia ess resistant to therma deformation. Figure 1. These cutting too materias are mainy composed of carbide.

9 Lesson: 7/24 Cemented Tungsten Carbides Cemented tungsten carbides, shown in Figure 1, contain a cass of hard, wearresistant refractory metas in which the hard metas are bound together or cemented by a soft and ductie meta binder. The binder is usuay cobat or nicke. D. Widia deveoped these materias in Germany in the eary 1920s. The first tungsten carbide (WC) toos were produced with a cobat binder. Cemented carbide is often referred to as hard metas. Carbide manufacturers vary the microstructures and compositions in the powder mixture to gain the desired baance of hot hardness, toughness, and wear resistance. In particuar, the grain size of the tungsten carbide partices directy impacts these properties. Larger grains offer improved toughness, and smaer grains provide better wear resistance. The grain size, in tungsten carbide mixtures, range from sub-micron to approximatey 7 microns. The quaity of cemented tungsten carbides is dependent on the consistency of the formua and the proper distribution of the tungsten carbide partices. Figure 1. Cemented tungsten carbides are aso known as hard metas and are avaiabe coated (1) and uncoated (2). Lesson: 8/24 Carbide Composition Cemented tungsten carbides are composed of the foowing materias: Tungsten carbide (WC). WC provides hard, wear-resistant properties. As the percentage of tungsten carbide increases, wear resistance increases. If the percentage of tungsten carbide is decreased to aow additiona aoys, wear resistance decreases. Titanium carbide (TiC). TiC is aoyed into the composition to provide resistance to faiure by cratering. Tantaum carbide (TaC). TaC is aoyed into the composition to provide resistance to faiure by therma deformation and therma cracking. Niobium carbide (NbC). NbC Some compositions incude NbC, which has characteristics simiar to TaC, as means to reduce costs. Cobat (Co). Co is the primary materia that serves as a binder. Cobat content can range anywhere from 4 to 15 percent. As the percentage of cobat in the tungsten carbide rises, toughness increases. However, increased cobat content aso makes the materia ess resistant to therma deformation. Figure 1. These cutting too materias are mainy composed of carbide. Lesson: 9/24 Tungsten Carbide Grades There are three basic groups of tungsten carbides; Straight grades (Figure 1) contain tungsten carbide with a cobat binder and are designed for high-abrasion workpiece materias such as cast iron, nonferrous aoys, and nonmetas. Due to their percentage of tungsten carbide, the straight grades of cemented tungsten carbide have the greatest resistance to fank wear. Kennameta s K6, K68, and K313 grades fa into this category. Compex grades (Figure 2) consist of tungsten carbide, titanium carbide (TiC), tantaum carbide (TaC), and often niobium carbide (NbC) with a cobat binder. Compex grades are designed for materias that produce ong chips, such as stees. Compex grades are produced by reducing the tungsten carbide content to aow the addition of aoying materias. This increases hot hardness in the cutting too materias but reduces abrasive wear resistance when compared to straight grades. In compex grades, each aoying Copyright 2009 specific Tooing U, LLC. A Rights Reserved. materia offers properties. TiC provides resistance to cratering and increases hot hardness. However, TiC aso reduces transverse rupture strength, compressive strength, and impact strength. TaC provides resistance to therma deformation and therma cracking. Figure 1. Straight grades are designed for high-

10 Lesson: 8/24 Carbide Composition Cemented tungsten carbides are composed of the foowing materias: Tungsten carbide (WC). WC provides hard, wear-resistant properties. As the percentage of tungsten carbide increases, wear resistance increases. If the percentage of tungsten carbide is decreased to aow additiona aoys, wear resistance decreases. Titanium carbide (TiC). TiC is aoyed into the composition to provide resistance to faiure by cratering. Tantaum carbide (TaC). TaC is aoyed into the composition to provide resistance to faiure by therma deformation and therma cracking. Niobium carbide (NbC). NbC Some compositions incude NbC, which has characteristics simiar to TaC, as means to reduce costs. Cobat (Co). Co is the primary materia that serves as a binder. Cobat content can range anywhere from 4 to 15 percent. As the percentage of cobat in the tungsten carbide rises, toughness increases. However, increased cobat content aso makes the materia ess resistant to therma deformation. Figure 1. These cutting too materias are mainy composed of carbide. Lesson: 9/24 Tungsten Carbide Grades There are three basic groups of tungsten carbides; Straight grades (Figure 1) contain tungsten carbide with a cobat binder and are designed for high-abrasion workpiece materias such as cast iron, nonferrous aoys, and nonmetas. Due to their percentage of tungsten carbide, the straight grades of cemented tungsten carbide have the greatest resistance to fank wear. Kennameta s K6, K68, and K313 grades fa into this category. Compex grades (Figure 2) consist of tungsten carbide, titanium carbide (TiC), tantaum carbide (TaC), and often niobium carbide (NbC) with a cobat binder. Compex grades are designed for materias that produce ong chips, such as stees. Compex grades are produced by reducing the tungsten carbide content to aow the addition of aoying materias. This increases hot hardness in the cutting too materias but reduces abrasive wear resistance when compared to straight grades. In compex grades, each aoying materia offers specific properties. TiC provides resistance to cratering and increases hot hardness. However, TiC aso reduces transverse rupture strength, compressive strength, and impact strength. TaC provides resistance to therma deformation and therma cracking. TaC aso has ower hardness than TiC at room temperature but greater hot hardness at higher temperatures. The coefficient of therma expansion for TaC more cosey matches the same property in cemented carbide. Consequenty, TaC has good resistance to therma shock. Kennameta s K42 and K420 grades fa into this category. Figure 1. Straight grades are designed for highabrasion resistance using carbide partices (1) with a cobat (2) binder. Cobat-enriched grades (Figure 3) contain arger amounts of cobat concentrated at the surface of the cutting too edge. They are used intended for genera -purpose and roughmachining operations. Cobat-enriched grades maintain a higher degree of resistance to therma deformation and exhibit a significant increase in cutting edge strength. However, cobat-enriched grades require an un-ground cutting edge that may not be as sharp as other grades. As a resut, cobat-enriched grades may require an increased feed rate to maintain the reationship between the cutting edge (edge preparation) and the feed rate. Figure 2. Compex grades are made up of tungsten carbide (1), aoyed with Titanium Carbide and Tantaum Carbide (3) with a cobat binder (2). Copyright 2009 Tooing U, LLC. A Rights Reserved.

11 Lesson: 9/24 Tungsten Carbide Grades There are three basic groups of tungsten carbides; Straight grades (Figure 1) contain tungsten carbide with a cobat binder and are designed for high-abrasion workpiece materias such as cast iron, nonferrous aoys, and nonmetas. Due to their percentage of tungsten carbide, the straight grades of cemented tungsten carbide have the greatest resistance to fank wear. Kennameta s K6, K68, and K313 grades fa into this category. Compex grades (Figure 2) consist of tungsten carbide, titanium carbide (TiC), tantaum carbide (TaC), and often niobium carbide (NbC) with a cobat binder. Compex grades are designed for materias that produce ong chips, such as stees. Compex grades are produced by reducing the tungsten carbide content to aow the addition of aoying materias. This increases hot hardness in the cutting too materias but reduces abrasive wear resistance when compared to straight grades. In compex grades, each aoying materia offers specific properties. TiC provides resistance to cratering and increases hot hardness. However, TiC aso reduces transverse rupture strength, compressive strength, and impact strength. TaC provides resistance to therma deformation and therma cracking. TaC aso has ower hardness than TiC at room temperature but greater hot hardness at higher temperatures. The coefficient of therma expansion for TaC more cosey matches the same property in cemented carbide. Consequenty, TaC has good resistance to therma shock. Kennameta s K42 and K420 grades fa into this category. Figure 1. Straight grades are designed for highabrasion resistance using carbide partices (1) with a cobat (2) binder. Cobat-enriched grades (Figure 3) contain arger amounts of cobat concentrated at the surface of the cutting too edge. They are used intended for genera -purpose and roughmachining operations. Cobat-enriched grades maintain a higher degree of resistance to therma deformation and exhibit a significant increase in cutting edge strength. However, cobat-enriched grades require an un-ground cutting edge that may not be as sharp as other grades. As a resut, cobat-enriched grades may require an increased feed rate to maintain the reationship between the cutting edge (edge preparation) and the feed rate. Figure 2. Compex grades are made up of tungsten carbide (1), aoyed with Titanium Carbide and Tantaum Carbide (3) with a cobat binder (2). Figure 3. Cobat-enriched grades have an area with high cobat content (1) with provides high edge strength. Lesson: 10/24 Coated Carbides Coated carbides are cemented carbide cutting toos coated with wear-resistant compounds for increased performance and onger too ife. Coated carbides are the fastest-growing segment of cutting too materias. The use of coated carbide can increase cutting speeds up to five times that of uncoated carbide for some workpiece materias. In fact, coated carbide is often credited as the most significant advance in cutting too materias since the deveopment of cemented carbide tooing. Figures 1 and 2 show coated carbide inserts and a magnification of their coating ayers Tooing U, LLC. A Rights Reserved. Copyright The first coated carbide cutting toos consisted of a thin ayer of titanium carbide (TiC) on a conventiona cemented tungsten carbide substrate. These toos exhibited increased wear

12 Lesson: 10/24 Coated Carbides Coated carbides are cemented carbide cutting toos coated with wear-resistant compounds for increased performance and onger too ife. Coated carbides are the fastest-growing segment of cutting too materias. The use of coated carbide can increase cutting speeds up to five times that of uncoated carbide for some workpiece materias. In fact, coated carbide is often credited as the most significant advance in cutting too materias since the deveopment of cemented carbide tooing. Figures 1 and 2 show coated carbide inserts and a magnification of their coating ayers. The first coated carbide cutting toos consisted of a thin ayer of titanium carbide (TiC) on a conventiona cemented tungsten carbide substrate. These toos exhibited increased wear resistance and speed capabiity but reduced toughness at the cutting edge. Today, coated carbides combine the characteristics of the coatings and the substrate to provide edge strength, wear resistance, and speed capabiity. Aso, coated carbides offer resistance to fank wear, cratering, and rake face buid-up-edges. Most importanty, coated carbides aow for higher cutting speeds than uncoated toos, which means that they yied increased productivity and reduced workpiece manufacturing costs. Figure 1. A face mi containing coated carbide inserts. Figure 2. Coated carbides can have mutipe coating (1) ayers. Lesson: 11/24 Chemica Vapor Deposition Carbide coatings are categorized based on the process used to create them and the characteristics that each provides. There are three major categories of carbide coatings: chemica vapor deposition (CVD), moderate temperature chemica vapor deposition (MTCVD), and physica vapor deposition (PVD). CVD is the most common coating process used for carbide cutting toos. This process produces a significant heat shied which increases speed capabiity, but requires a honed cutting edge to avoid excess coating buidup at the edge. The deposition temperature for CVD coatings is C, and they have a thickness of between 5-25 microns. CVD coating materias incude TiC, TiCN, TiN, and A2O3. CVD materias are appied in mutipe ayers to gain the benefits of different coating materias at different ayers. There is an unavoidabe tendency for CVD coatings to therma crack on their surface, due to the therma expansion differences between the substrate and the coating materia as shown in Figure 1. MTCVD, which is shown in Figures 2 and 3, provides good coating adhesion whie minimizing the deveopment of eta phase, the unavoidabe formation of carbon pockets between the coating and the substrate. MTCVD is used primariy with cobat-enriched substrates to enhance coating adhesion without adversey affecting the cobat zone. MTCVD is typicay used with TiCN and ZrCN coatings as a sub-coating in conjunction with high-temperature CVD. The deposition temperature is moderate at approximatey 850 C, and it aso has a faster deposition than conventiona CVD. MTCVD minimizes eta phase formation as we as therma cracks on the surface of the toos. CVD-coated cutting edges require a arger edge preparation than do other coating processes. This arger edge preparation often requires an increased feed to obtain satisfactory too performance. The combination of ayered coatings and engineered substrates provides greater versatiity, simpifies too seection, and reduces inventory. Copyright 2009 Tooing U, LLC. A Rights Reserved. Figure 1. This magnified view shows the therma cracks that appear on a CVD surface.

13 Lesson: 11/24 Chemica Vapor Deposition Carbide coatings are categorized based on the process used to create them and the characteristics that each provides. There are three major categories of carbide coatings: chemica vapor deposition (CVD), moderate temperature chemica vapor deposition (MTCVD), and physica vapor deposition (PVD). CVD is the most common coating process used for carbide cutting toos. This process produces a significant heat shied which increases speed capabiity, but requires a honed cutting edge to avoid excess coating buidup at the edge. The deposition temperature for CVD coatings is C, and they have a thickness of between 5-25 microns. CVD coating materias incude TiC, TiCN, TiN, and A2O3. CVD materias are appied in mutipe ayers to gain the benefits of different coating materias at different ayers. There is an unavoidabe tendency for CVD coatings to therma crack on their surface, due to the therma expansion differences between the substrate and the coating materia as shown in Figure 1. MTCVD, which is shown in Figures 2 and 3, provides good coating adhesion whie minimizing the deveopment of eta phase, the unavoidabe formation of carbon pockets between the coating and the substrate. MTCVD is used primariy with cobat-enriched substrates to enhance coating adhesion without adversey affecting the cobat zone. MTCVD is typicay used with TiCN and ZrCN coatings as a sub-coating in conjunction with high-temperature CVD. The deposition temperature is moderate at approximatey 850 C, and it aso has a faster deposition than conventiona CVD. MTCVD minimizes eta phase formation as we as therma cracks on the surface of the toos. Figure 1. This magnified view shows the therma cracks that appear on a CVD surface. CVD-coated cutting edges require a arger edge preparation than do other coating processes. This arger edge preparation often requires an increased feed to obtain satisfactory too performance. The combination of ayered coatings and engineered substrates provides greater versatiity, simpifies too seection, and reduces inventory. Figure 2. MTCVD coating is used primariy with cobat-enriched substrates. Figure 3. MTCVD provides coating adhesion whie minimizing the deveopment of the eta phase. Lesson: 12/24 Physica Vapor Deposition The third common coating process is physica vapor deposition (PVD), which is shown in Figure 1. PVD coatings are appied thinner than other processes and are appicabe to reativey sharp cutting edges.. PVD coatings tend to sea porosity adding ubricity and inertness in the cutting too, which keeps the workpiece materia from penetrating the too surface. PVD is a "ine of sight" process. In other words, the PVD coating tends to grow at different thicknesses on different surfaces within the reactor. PVD coatings are fixture dependant for producing the desired thickness of coating materia on the desired cutting edge surface. They are appied at approximatey 500 C, significanty ower than CVD or MTCVD coatings. PVD coatings contain finer grains and are aso smoother than CVD coatings. PVD coatings can be appied over sharp edges, and there is compressive residua stress with no eta phase. PVD coatings are aso thinner and tend to be crack free. The atest exampe of coated tooing combines the most desirabe characteristics of both CVD and PVD. 2 shows exampe of this combination. For exampe, a PVD TiN coating is Copyright Figure 2009 Tooing U, an LLC. A Rights Reserved. appied over an A2O3 CVD coating to produce a seaed surface that is easier to identify the wear and so that fank wear can be measured more easiy. Typica coating combinations incude CVD TiN-TiCN pus a PVD TiN or TiAN top coat. The CVD ayers provide wear resistance and Figure 1. PVD coatings are often used for finishing operations.

14 Lesson: 12/24 Physica Vapor Deposition The third common coating process is physica vapor deposition (PVD), which is shown in Figure 1. PVD coatings are appied thinner than other processes and are appicabe to reativey sharp cutting edges.. PVD coatings tend to sea porosity adding ubricity and inertness in the cutting too, which keeps the workpiece materia from penetrating the too surface. PVD is a "ine of sight" process. In other words, the PVD coating tends to grow at different thicknesses on different surfaces within the reactor. PVD coatings are fixture dependant for producing the desired thickness of coating materia on the desired cutting edge surface. They are appied at approximatey 500 C, significanty ower than CVD or MTCVD coatings. PVD coatings contain finer grains and are aso smoother than CVD coatings. PVD coatings can be appied over sharp edges, and there is compressive residua stress with no eta phase. PVD coatings are aso thinner and tend to be crack free. The atest exampe of coated tooing combines the most desirabe characteristics of both CVD and PVD. Figure 2 shows an exampe of this combination. For exampe, a PVD TiN coating is appied over an A2O3 CVD coating to produce a seaed surface that is easier to identify the wear and so that fank wear can be measured more easiy. Typica coating combinations incude CVD TiN-TiCN pus a PVD TiN or TiAN top coat. The CVD ayers provide wear resistance and exceent adhesion to the substrate. The PVD outer ayer offers a smooth, crack-fee surface with compressive residua stress. The bend of positive traits from these coatings eads to exceent performance in miing and tough turning appications. Figure 1. PVD coatings are often used for finishing operations. Figure 2. A coating that combines both CVD (2) and PVD (1) characteristics. Lesson: 13/24 Properties of Carbide Coatings Each carbide coating materia has different properties. Figure 1 shows an iustration of some of the coatings used on carbides. The foowing is a ist of some of these coating materias and their characteristics. Titanium carbide (TiC). TiC is appied using the CVD process. It has high hardness at ower temperatures, but its hardness decreases rapidy as temperatures increase. TiC has exceent abrasive wear resistance. Titanium Nitride (TiN). TiN is appied using CVD or PVD. It is not as hard as TiC and is often used as a top coating ayer for cosmetic appea and for easier identification of too wear. TiN is often used as an interayer between other coatings to refine grain size and enhance adhesion. TiN is chemicay more stabe than TiC. Titanium carbonitride (TiCN). TiCN is appied using CVD with norma temperatures. At moderate temperatures, it is appied using MTCVD or PVD. TiCN offers an intermediate hardness between TiC and TiN. TiCN provides a good baance of abrasion resistance and toughness. Auminum oxide (A2O3). A2O3 coatings are not as hard as TiC-based coatings at ower temperatures, but they are harder at higher temperatures. A2O3 has good chemica stabiity and exceent resistance to cratering. Copyright 2009 Tooing U, LLC. A Rights Reserved.

15 Lesson: 13/24 Properties of Carbide Coatings Each carbide coating materia has different properties. Figure 1 shows an iustration of some of the coatings used on carbides. The foowing is a ist of some of these coating materias and their characteristics. Titanium carbide (TiC). TiC is appied using the CVD process. It has high hardness at ower temperatures, but its hardness decreases rapidy as temperatures increase. TiC has exceent abrasive wear resistance. Titanium Nitride (TiN). TiN is appied using CVD or PVD. It is not as hard as TiC and is often used as a top coating ayer for cosmetic appea and for easier identification of too wear. TiN is often used as an interayer between other coatings to refine grain size and enhance adhesion. TiN is chemicay more stabe than TiC. Titanium carbonitride (TiCN). TiCN is appied using CVD with norma temperatures. At moderate temperatures, it is appied using MTCVD or PVD. TiCN offers an intermediate hardness between TiC and TiN. TiCN provides a good baance of abrasion resistance and toughness. Auminum oxide (A2O3). A2O3 coatings are not as hard as TiC-based coatings at ower temperatures, but they are harder at higher temperatures. A2O3 has good chemica stabiity and exceent resistance to cratering. Figure 1. Each of these coatings adds specific characteristics to the cutting too materia. Lesson: 14/24 ISO Carbide Cassification The Internationa Organization for Standardization (ISO) cassifies cutting toos according to the appication and workpiece materia. There are six workpiece materia cassification groups, which are isted in Figure 1: P: stees M: stainess stees K: cast irons N: nonferrous metas S: hi-temp aoys H: hardened materias Figure 2 shows how cutting toos are cassified according to their toughness. Numbered from 01 to 50, the ower-numbered toos are the most wear resistant, and the highernumber toos are the toughest and most fracture resistant. Figure 1. ISO cassifies carbide toos according to appication and workpiece materia. For exampe, a P10 grade of carbide is designed to cut stees in finishing-type operations at higher speeds, whie a P25 woud be designed for genera-purpose machining of stees at moderate speeds. A P40 grade is designed for heavy roughing of stees at ower speeds. The graph in Figure 3 shows the reationship of different materias to each other based upon their characteristics. Figure 2. ISO cassifies carbide too toughness through a numbering system. Copyright 2009 Tooing U, LLC. A Rights Reserved.

16 Lesson: 14/24 ISO Carbide Cassification The Internationa Organization for Standardization (ISO) cassifies cutting toos according to the appication and workpiece materia. There are six workpiece materia cassification groups, which are isted in Figure 1: P: stees M: stainess stees K: cast irons N: nonferrous metas S: hi-temp aoys H: hardened materias Figure 2 shows how cutting toos are cassified according to their toughness. Numbered from 01 to 50, the ower-numbered toos are the most wear resistant, and the highernumber toos are the toughest and most fracture resistant. Figure 1. ISO cassifies carbide toos according to appication and workpiece materia. For exampe, a P10 grade of carbide is designed to cut stees in finishing-type operations at higher speeds, whie a P25 woud be designed for genera-purpose machining of stees at moderate speeds. A P40 grade is designed for heavy roughing of stees at ower speeds. The graph in Figure 3 shows the reationship of different materias to each other based upon their characteristics. Figure 2. ISO cassifies carbide too toughness through a numbering system. Figure 3. This graph shows how specific carbides reate to each other based upon their characteristics. Lesson: 15/24 Cermet Cutting Toos Cermet is the coective name given to cemented carbides that have repaced tungsten carbide hard partices with hard partices based on TiC, TiCN, or TiN. Figure 1 shows an exampe of a cermet substrate. The name "cermet" is used because these cutting too materias are a combination of ceramic and meta. The ceramic partices are combined in a meta binder of nicke or cobat. Like carbide toos, cermet toos are avaiabe as either coated or uncoated. Cermet toos offer distinct advantages. have high fank wear, good crater resistance, Copyright 2009 Tooing U, LLC. A Rights They Reserved. high chemica stabiity, and hot hardness. Cermets aso resist rake face buit-up edge. When working with stees, stainess stee, and ductie irons, cermet toos can be used at high speeds for finishing, precision turning, boring, and miing. When accuracy and finish are

17 Lesson: 15/24 Cermet Cutting Toos Cermet is the coective name given to cemented carbides that have repaced tungsten carbide hard partices with hard partices based on TiC, TiCN, or TiN. Figure 1 shows an exampe of a cermet substrate. The name "cermet" is used because these cutting too materias are a combination of ceramic and meta. The ceramic partices are combined in a meta binder of nicke or cobat. Like carbide toos, cermet toos are avaiabe as either coated or uncoated. Cermet toos offer distinct advantages. They have high fank wear, good crater resistance, high chemica stabiity, and hot hardness. Cermets aso resist rake face buit-up edge. When working with stees, stainess stee, and ductie irons, cermet toos can be used at high speeds for finishing, precision turning, boring, and miing. When accuracy and finish are required for your appication, cermets may be used if the appication cas for high cutting speeds but aso has a ow chip oad and ight depth of cut. Figure 1. Cermets contain ceramic partices hed together by a metaic binder. Cermets have a narrower appication range than carbides: from P01 to P20, M05 to M15, and K01 to K10 in turning and from P01 to P30 and M01 to M25 for miing. Demanding profiing operations are not normay recommended for cermets. They are more sensitive to therma shock than uncoated or coated carbides. Therefore, cooant is not generay used with cermet cutting toos. However, there are exceptions. For exampe, in ight-finish turning and boring appications, using cooant can be beneficia to the surface finish of the workpiece. Lesson: 16/24 Aumina Ceramics Aumina ceramics are indexabe inserts, such as the ceramic cutting too shown in Figure 1, consisting of neary 100% aumina (A2O3). They have been commerciay avaiabe for machining stee and cast iron since the 1960s. Aumina ceramics contain fine-grained (<5µm) A2O3 of high reative density. There are severa different methods used to manufacture these cutting toos to combine the essentia structura features of indexabiity and disposabiity. Some toos are produced by cod pressing and sintering inserts simiar to the process used for cemented carbide. Because sintering occurs in the air, it produces a white coor. A white ceramic too has the best wear resistance, but is not very strong. Another production method invoves hot pressing arge cyinders of aumina in graphite mods resuting in a dark gray coor. Gray is stronger, but it has ess speed capabiity. The cutting edges are then cut from the soid using diamond-sitting saws. At room temperature, the hardness of aumina is 1600 HV, which is simiar to the hardness of cemented carbide at 1500 HV. The compressive strength of aumina at room temperature is 3000 Mpa, which is approximatey 50% of that of carbide, which is 5500 Mpa. Figure 2. A ceramic insert hed in its toohoder. Lesson: 17/24 Pros and Cons of Aumina Ceramics Aumina ceramics have both advantages and disadvantages, which are summarized in Figure 1. To their advantage, aumina toos are non-metaic with ow therma conductivity, and they retain their hardness and compressive strength at higher temperatures than carbides. They aso exhibit a ower soubiity in stee than carbide. In fact, aumina is practicay inert when machining stee up to its meting point. The hot hardness characteristics of aumina aow significant increases in cutting speed with potentia speeds three to four times that of carbide. This can ead to increased meta remova rates and productivity, simiar to what was gained from converting from high-speed stee to carbide. Aumina cutting toos produce the best resuts when used for high-speed finish machining of cast irons. Aumina ceramics aso have their disadvantages. The transverse rupture strength of aumina is approximatey 30% of cemented carbide's TRS. Aso, cemented carbide has better fracture toughness than aumina. These poor strength characteristics of aumina too materias neary Copyright 2009 Tooing U, LLC.rake A Rights Reserved. mandate the use of negative geometry or heavy edge preparations. For workpiece materias with onger chips and higher cutting forces, the poor toughness of aumina too materias has ed to unreiabe performance. Figure 1. You must evauate the needs for your workpiece to decide if aumina is the best choice.