ASSAB 8407 SUPREME UDDEHOLM ORVAR SUPREME

Transcription

1 ASSAB 8407 SUPREME UDDEHOLM ORVAR SUPREME

2 REFERENCE STANDARD AISI WNr. JIS ASSAB DF-2 ARNE O1 (1.25 (SKS 3 ASSAB DF-3 O1 (1.25 (SKS 3 ASSAB XW-5 SVERKER 3 D6 (D3 ( (SKD 2 ASSAB XW- RIGOR A SKD 12 ASSAB XW-41 SVERKER 21 D SKD 11 ASSAB XW-42 D SKD 11 CARMO CARMO CALMAX CALMAX CALDIE ASSAB 88 CALDIE SLEIPNER ASSAB PM 23 SUPERCLEAN VANADIS 23 SUPERCLEAN (M3: SKH 53 ASSAB PM 30 SUPERCLEAN VANADIS 30 SUPERCLEAN (M3:2 + Co SKH 40 ASSAB PM 60 SUPERCLEAN VANADIS 60 SUPERCLEAN ( VANADIS 4 EXTRA SUPERCLEAN VANADIS 6 SUPERCLEAN VANADIS SUPERCLEAN VANCRON 40 SUPERCLEAN ELMAX SUPERCLEAN VANADIS 4 EXTRA SUPERCLEAN VANADIS 6 SUPERCLEAN VANADIS SUPERCLEAN VANCRON 40 SUPERCLEAN ELMAX SUPERCLEAN ASSAB 518 P ASSAB 618 P20 Mod ASSAB 618 HH P20 Mod ASSAB 618 T P20 Mod Mod. ASSAB 718 SUPREME IMPAX SUPREME P20 Mod ASSAB 718 HH IMPAX HH P20 Mod NIMAX NIMAX MIRRAX 40 MIRRAX Mod. VIDAR 1 ESR VIDAR 1 ESR H SKD 6 UNIMAX CORRAX UNIMAX CORRAX ASSAB SUS 420J2 STAVAX ESR STAVAX ESR 420 Mod ESR SUS 420J2 MIRRAX ESR MIRRAX ESR 420 Mod. POLMAX POLMAX RAMAX HH RAMAX HH 420 F Mod. ROYALLOY ROYALLOY PRODAX ASSAB MM40 ALVAR 14 ALVAR SKT 4 ASSAB SKT 4 ASSAB M ORVAR 2M H SKD 61 ASSAB 8407 SUPREME ORVAR SUPREME H13 Premium ESR SKD 61 DIEVAR HOTVAR QRO 90 SUPREME DIEVAR HOTVAR QRO 90 SUPREME ASSAB SNCM8 ASSAB SCM4 ASSAB S50C ASSAB is a trademark of ASSAB Pacific Pte Ltd. The information contained herein is based on our present state of knowledge and is intended to provide general notes on our products and their uses. It should not therefore be construed as a warranty of specific properties of the products described or a warranty for fitness for a particular purpose. Each user of ASSAB products is responsible for making its own determination as to the suitability of ASSAB products and services. Edition D

3 General ASSAB 8407 Supreme is a chromium-molybdenumvanadium alloyed tool steel which is characterised by: High level of resistance to thermal shock and thermal fatigue Good high-temperature strength Excellent toughness and ductility in all direc tions Good machinability and polishability Excellent through-hardening properties Good dimensional stability during hardening Typical analysis % Standard specification Delivery condition C 0.39 Colour code Orange Si 1.0 Mn 0.4 Cr 5.2 Mo 1.4 Premium AISI H13, WNr , SKD 61 Soft annealed to approx. 180 HB V 0.9 Applications DIE CASTING Part EXTRUSION Tin, lead zinc alloys HRC Aluminium magnesium alloys, HRC Dies Fixed inserts, cores Sprue parts Nozzles Ejector pins (nitrided Plunger, short-sleeve (normally nitrided Austenitising temp. Part Aluminium, magnesium alloys, HRC C Copper alloys HRC Stainless steel HRC Dies Backers, die holders, liners, dummy blocks, stems Austenitising temperature C C HOT PRESSING Material Aust. temp. HRC Aluminium, magnesium alloys C Copper alloys C Steels C PLASTIC MOULDING IMPROVED TOOLING PERFORMANCE The name SUPREME implies that by special processing techniques and close control, the steel attains high purity and a very fine structure. Further, ASSAB 8407 Supreme shows significant im provements in isotropic properties compared to con ventionally produced AISI H13 grades. These improved isotropic properties are particu larly valuable for tooling subjected to high mecha ni cal and thermal fatigue stresses, e.g., die casting dies, forging tools and extrusion tooling. In prac ti cal terms, tools may be used at somewhat higher working hardnesses (+1 to 2 HRC without loss of toughness. Since increased hardness slows down the formation of heat checking cracks, im proved tool performance can be expected. ASSAB 8407 Supreme meets the North American Die Casting Association (NADCA # for premium high quality H13 die steel. Part Aust. and tempering temp. HRC Injection moulds Compression/ transfer moulds OTHER APPLICATIONS Austenitising C Tempering 250 C Application Aust. and tempering temp. HRC Severe cold punching, scrap shears Hot Shearing Shrink rings (e.g., for cemented carbide dies Wear resisting parts Austenitising C Tempering 250 C Austenitising C Tempering 250 C Tempering C Austenitising C Tempering C Austenitising C Tempering 575 C Nitriding Core Surface ~00HV 1 3

4 Properties All specimens are taken from the centre of a 407 x 127 mm bar. Unless otherwise indicated, all specimens were hardened 30 minutes at 25 C, quenched in air and tempered h at 6 C to 45 ± 1 HRC. Effect of time at high temperatures on hardness Hardness, HRC 50 PHYSICAL DATA Hardened and tempered to HRC C Temperature 20 C 400 C 600 C C Density kg/m C Modulus of elasticity MPa Coefficient of thermal expansion per C from 20 C Thermal conductivity W/m C x x C Time, h 0 00 Effect of testing temperature on impact energy Charpy-V specimens, short transverse direction. MECHANICAL PROPERTIES Approximate tensile strength at room temperature. Impact energy, J 0 Hardness 52 HRC 45 HRC Tensile strength, Rm Yield strength, Rp MPa 1420 MPa 1520 MPa 1280 MPa HRC 20 Approximate strength at elevated temperatures Longitudinal direction. Rm, Rp0.2 MPa Rp ºC Testing temperature Z A5 Rm A5, Z % ºC Testing temperature 4

5 Heat treatment SOFT ANNEALING Protect the steel and heat through to 850 C. Then cool in the furnace at C per hour to 650 C, then freely in air. STRESS RELIEVING After rough machining, the tool should be heated through to 650 C, holding time 2 hours. Cool slowly to 500 C, then freely in air. Hardness, grain size and retained austenite as functions of austenitising temperature Grain Size ASTM Hardness, HRC Grain size Hardness Retained austenite, % HARDENING Preheating temperature: C, normally in two preheating steps. Austenitising temperature: C, normally C. Temperature C Soaking time = time at hardening temperature after the tool is fully heated through. Protect the tool against decarburisation and oxidation during hardening. QUENCHING MEDIA Soaking time minutes Hardness before tempering ±2 HRC ±2 HRC High speed gas/circulating atmosphere Vacuum (high speed gas with sufficient positive pressure. Interrupted quench is recommended for distortion control, or when quench cracking is a concern. Martempering bath or fluidised bed at C, then cool in air Martempering bath or fluidised bed at approx C, then cool in air Warm oil Note 1: Temper the tool as soon as its temperature reaches C. Note 2: In order to obtain the optimum properties for the tool, the cooling rate should be fast, but not at a level that gives excessive distortion or cracks TEMPERING Choose the tempering temperature according to the hardness required by reference to the tempering graph. Temper at least twice with interme diate cooling to room temperature. The lowest tempering temperature which should be used is 250 C. The minimum holding time at tempering tem perature is 2 hours. To avoid temper brittleness, do not temper in the range C, see graph. Tempering graph Retained austenite C Hardness, HRC C Austenitising temperture Austenitising temp. 50 C 25 C Temper brittleness zone Retained austenite Retained austenite, % ºC Tempering temperature (2h + 2h

6 Approximate impact strength at different tempering temperatures Charpy-V specimens, short transverse direction. Impact strength KV Joule 0 DIMENSIONAL CHANGES DURING HARDENING Specimen size: 0 x 0 x 25 mm. Oil hardened from 20 C Min. Max. Width % Length % Thickness % ± Temper brittleness zone Air hardened from 20 C Vacuum hardened from 20 C Min. Max. Min. Max ± ºC Tempering temperature (2h + 2h Tempering within the range C is normally not recommended due to the reduction in toughness properties. DIMENSIONAL CHANGES DURING TEMPERING Dimensional change, % ºC Tempering temperature (1h + 1h Note: The dimensional changes in hardening and tempering should be added. CCT graph Austenitising temperature 25 C. Holding time 30 minutes. C Carbides Austenitising temperature 25ºC Holding time 30 minutes Pearlite A C3 = 940ºC A C1 = 840ºC Cooling Hardness Curve No. HV T (sec M S M f Martensite Bainite Seconds Minutes 1 0 Hours Air cooling of bars, Ømm 6

7 Machining recommendations The cutting data below are to be considered as guiding values and as starting points for developing your own best practice. MILLING Face and square shoulder milling Condition: Soft annealed condition ~180 HB TURNING Cutting data parameters Rough milling Milling with carbide Fine milling Cutting data parameters Cutting speed (v c m/min Feed (f mm/r Depth of cut (a p mm Turning with carbide Rough turning Fine turning Turning with HSS Fine turning Cutting speed (v c m/min Feed (f z mm/tooth Depth of cut (a p mm Carbide designation ISO P20 - P40 Coated carbide P - P20 Coated carbide or cermet Carbide designation ISO P20 - P30 Coated carbide P Coated carbide or cermet - End milling High speed steel DRILLING High speed steel twist drill Drill diameter mm Cutting speed (v c m/min Feed (f mm/r * * * * Cutting data parameters Cutting speed (v c m/min Feed (f mm/tooth Carbide designation ISO Solid carbide Type of milling Carbide indexable insert High speed steel P20 - P30 - * For coated HSS drill, v c ~ m/min 1 For coated HSS end mill, v c ~ m/min 2 Depending on radial depth of cut and cutter diameter Carbide drill GRINDING Wheel recommendation Cutting data parameters Cutting speed (v c m/min Feed (f mm/r Indexable insert Type of drill Solid carbide Brazed carbide Type of grinding Soft annealed condition Hardened condition Face grinding straight wheel A 46 HV A 46 HV Face grinding segments A 24 GV A 36 GV Cylindrical grinding A 46 LV A 60 KV Internal grinding A 46 JV A 60 IV 1 Drill with interntal cooling channels and brazed carbide tip 2 Depending on drill diameter Profile grinding A 0 LV A 120 KV 7

8 Surface treatment NITRIDING AND NITROCARBURISING Nitriding and nitrocarburising result in a hard surface layer which is very resistant to wear and erosion. The nitrided layer is, however, brittle and may crack or spall when exposed to mechanical or thermal shock, the risk increasing with layer thickness. Before nitri ding, the tool should be hardened and tempered at a temperature at least C above the nitri ding temperature. Nitriding in ammonia gas at 5 C, or plasma nitriding in a 75% hydrogen/25% nitrogen mixture at 480 C, both result in a surface hardness of about 10 HV 0.2. In general, plasma nitriding is the preferred method because of better control over nitrogen potential. Particularly, plasma nitriding can readily avoid the formation of so-called white layer, which is not recommended for hot work service. However, careful gas nitriding can give perfectly acceptable results. Electrical discharge machining If spark-erosion is performed in the hardened and tempered condition, the white re-cast layer should be removed mechanically by grinding or stoning. The tool should then be given an additional temper at approx. 25 C below the highest previous tempering temperature. Welding Welding of tool steel can be performed with good results if proper precautions are taken regarding elevated temperature, joint preparation, choice of consumables and welding procedure. The following guidelines summarise the most important welding process parameters. ASSAB 8407 Supreme can also be nitrocarburised in either gas or salt bath. The surface hardness after nitrocarburising is HV 0.2. Welding method TIG MMA Depth of nitriding Preheating temp ºC ºC Process Time h Depth* mm Filler material QRO 90 TIG-WELD DIEVAR TIG-WELD QRO 90 WELD Gas nitriding at 5 C Maximum interpass 475 C 475 C temp. 2 Plasma nitriding at 480 C Cooling rate 20-40ºC/h for the first 2 to 3 hours and then freely in air Nitrocarburising in gas at 580 C in salt bath at 580 C Hardness after welding Heat treatment after welding HRC HRC * Depth of case = distance from surface where hardness is 50 HV 0.2 over base hardness Nitriding to case depths >0.3 mm is not recommended for hot work applications Supreme can be nitrided in the soft annealed condition. The hardness and depth of case will, however, be reduced somewhat in this case. Hardened condition Soft annealed condition Temper at 25 C below the original tempering temperature. Soft anneal the material at 850 C in protected atmosphere. Then cool in the furnace at C per hour to 650 C, then freely in air. HARD CHROME PLATING After plating, parts should be tempered at 180 C for 4 hours, within 4 hours of plating, to avoid the risk of hydrogen embrittlement. 1 Preheating temperature must be established throughout the die and must be maintained for the entire welding process, to prevent weld cracking 2 The temperature of the tool in the weld area immediately before the second and subsequent pass of a multiple pass weld. When exceeded, there is a risk of distortion of the tool or soft zones around the weld. 8

9 Polishing ASSAB 8407 Supreme exhibits good polishability in the hardened and tempered condition. Polishing after grinding can be effected using aluminium oxide or diamond paste. TYPICAL PROCEDURE 1. Rough grinding to grain size using a wheel or stone. 2. Fine grinding with abrasive paper or powder, down to grain size. 3. Polish with diamond paste grade 15 (15µm grain size using a polishing tool of soft wood or fibre. 4. Polish with diamond paste (8 6 3µm grain size using a polishing tool of soft wood or fibre. 5. When demands on surface finish are high, grade 1 (1µm grain size diamond paste can be used for final polishing with a fibre polishing pad. Photo-etching ASSAB 8407 Supreme is particularly suitable for texturing by the photo-etching method. Its high level of homogeneity and low sulphur content ensure accurate and consistent pattern reproduction. The ESR Tool Steel Process The starting material for our tool steel is carefully selected from high-quality recyclable steel. Together with ferroalloys and slag formers, the recyclable steel is melted in an electric arc furnace. The molten steel is then tapped into a ladle. The deslagging unit removes oxygen-rich slag. Then deoxidation, alloying and heating of the steel bath are carried out in the ladle furnace. Vacuum degassing removes elements such as hydrogen, nitrogen and sulphur. Electroslag remelting (ESR ESR PLANT In uphill casting, a controlled flow of molten steel from the ladle filled the prepared moulds, and solidfies into ingots. Subsequently, the steel can go directly to our rolling mill or to the forging press. Our premium steel grades go to our ESR furnace, where they are melted once again in an electroslag remelting process. This is done by melting a consumable electrode immersed in an overheated slag bath. Controlled solidification in the steel bath results in an ingot of high homogeneity, thereby removing marcrosegregation. Melting under a protective atmosphere gives an even better steel clealiness. HOT WORKING From the ESR plant, the steel goes to the rolling mill or to our forging press to be formed into round or flat bars. Prior to delivery, all bar materials are heat treated to either soft-annealed condition, or hardened and tempered condition. 9

10 MACHINING Before putting into stock, flat-bar profiles are machined to the required size and exact tolerance. Whilst larger round dimensions are turned in lathe, where the steel bars rotate against a stationary cutting tool. Peeling is performed on smaller round dimensions via cutting tools that revolve the bars for removal of surface defects. To safeguard the quality and integrity of our tool steels, we perform surface inspection and ultrasonic testing on all bars. We then cut off and discard the bar ends and any defects that are found during inspection. Further information For further information, i.e., steel selection, heat treatment, application and availability, please contact our ASSAB office nearest to you. Relative comparison of ASSAB hot work die steels QUALITATIVE COMPARISON OF CRITICAL DIE STEEL PROPERTIES ASSAB grade Temper resistance Hot yield strength Creep strength Coefficient of thermal expansion Heat conductivity Ductility ALVAR 14 ASSAB M ASSAB 8407 SUPREME DIEVAR HOTVAR QRO 90 SUPREME QUALITATIVE COMPARISON OF RESISTANCE TO DIFFERENT DIE FAILURES ASSAB grade Heat checking Gross cracking Hot wear / Erosion Plastic deformation Corrosion (Al ALVAR 14 ASSAB M ASSAB 8407 SUPREME DIEVAR HOTVAR QRO 90 SUPREME

11 ASSAB 8407 SUPREME Ningbo ASSAB Tooling Technology (Ningbo Co., Ltd. Tel : Fax: info.ningbo@assab.com Cikarang* PT. ASSAB Steels Indonesia Tel : Fax: / info.cikarang@assab.com MALAYSIA Kuala Lumpur - Head Office ASSAB Steels (Malaysia Sdn. Bhd. Tel : Fax: /55 info.kualalumpur@assab.com Tel : Jiangxi* ASSAB Tooling (Dong Guan Co, Ltd., Jiangxi Branch Tel : Fax : info.jiangxi@assab.com 11

12 Choosing the right steel is of vital importance. ASSAB engineers and metallurgists are always ready to assist you in your choice of the optimum steel grade and the best treatment for each application. ASSAB not only supplies steel products with superior quality, we offer state-of-the-art machining, heat treatment and surface treatment services to enhance steel properties to meet your requirement in the shortest lead time. Using holistic approach as a one-stop solution provider, we are more than just another tool steel supplier. ASSAB and Uddeholm are present on every continent. This ensures you that high-quality tool steels and local support are available wherever you are. Together we secure our position as the world's leading supplier of tooling materials. For more information, please visit