Metallurgy in Production

Transcription

1 In the Name of Allah University of Hormozgan Metallurgy in Production First semester Mohammad Ali Mirzai 1

2 Chapter 8 : Part 2 Metals - Nonferrous Alloys 2

3 Metals 3

4 4 Cu Alloys Brass: Zn is subst. impurity (costume jewelry, coins, corrosion resistant) Bronze : Sn, Al, Si, Ni are subst. impurity (bushings, landing gear) Cu-Be: precip. hardened for strength Ti Alloys -lower r: 4.5g/cm 3 vs 7.9 for steel -reactive at high T -space applic. Nonferrous Alloys NonFerrous Alloys Based on discussion and data provided in Section 11.3, Callister 7e. Al Alloys -lower r: 2.7g/cm 3 -Cu, Mg, Si, Mn, Zn additions -solid sol. or precip. strengthened (struct. aircraft parts & packaging) Mg Alloys -very low r: 1.7g/cm 3 -ignites easily -aircraft, missiles Refractory metals -high melting T Noble metals -Nb, Mo, W, Ta -Ag, Au, Pt -oxid./corr. resistant

5 Nonferrous alloys Aluminum alloys Copper alloys Magesnium alloys Nickel alloys Titanium alloys Refractory metals Superalloys 5

6 Aluminum alloys Low density gm/cc High electrical and thermal conductivities High ductility Low melting point and strengths Cast or wrought Aluminium alloys are widely used in engineering structures and components where light weight or corrosion resistance is required. 6

7 Aluminum alloys The main alloying elements in the AA system are as follows: 1xx.x series are minimum 99% aluminium 2xx.x series copper 3xx.x series silicon, copper and/or magnesium 4xx.x series silicon 5xx.x series magnesium 7xx.x series zinc 8xx.x series tin 9xx.x other elements 7

8 Aluminum alloys series are essentially pure aluminium 2000 series are alloyed with copper, can be precipitation hardened to strengths comparable to steel series are alloyed with manganese, and can be work hardened series are alloyed with silicon. They are also known as silumin series are alloyed with magnesium series are alloyed with magnesium and silicon. They are easy to machine, are weldable, and can be precipitation hardened, but not to the high strengths that 2000 and 7000 can reach alloy is one of the most commonly used general-purpose aluminium alloys series are alloyed with zinc, and can be precipitation hardened to the highest strengths of any aluminium alloy (ultimate tensile strength up to 700 MPa for the 7068 alloy) series are alloyed with other elements which are not covered by other series. Aluminium-lithium alloys are an example

9 Aluminum alloys 9

10 Aluminum alloys 10

11 Aluminum alloys 11

12 Copper alloys Soft, ductile, difficult to machine Highly resistant to corrosion Excellent electrical & thermal conductivity Can be alloyed to improve hardness Cold worked to get the maximum hardness Cu-Zn = brass; Cu-X = bronzes 12

13 Classification of copper alloys Family Classification of copper and its alloys Principal alloying element UNS numbers Copper alloys, brass Zinc (Zn) C1xxxx C4xxxx Phosphor bronze Tin (Sn) C5xxxx Aluminium bronzes Aluminium (Al) C60600 C64200 Silicon bronzes Silicon (Si) C64700 C66100 Copper nickel, nickel silvers Nickel (Ni) C7xxxx 13

14 Copper alloys 14

15 Copper alloys 15

16 Magnesium alloys Lowest density of all structural metals= 1.7 gm/cc Relatively soft and low elastic modulus (45 GPa) Have to be heated to be deformation processed Burns easily in the molten and powder states Susceptible to corrosion in marine environments Competing with plastics 16

17 Magnesium alloys Magnesium alloys names are often given by two letters following by two numbers. Letters tell main alloying elements (A = aluminium, Z = zinc, M = manganese, S = silicon). Numbers indicate respective nominal compositions of main alloying elements. Marking AZ91 for example coveys magnesium alloy with roughly 9 weight percent aluminium and 1 weight percent zinc. Exact composition should be confirmed from reference standards 17

18 Magnesium alloys 18

19 Titanium alloys Low density, high melting point High specific strength and elastic modulus superior corrosion resistance in many environments Absorb interstitials at high temperatures Highly reactive with other materials and hence nonconventional processing techniques have been developed Highly used in aerospace applications 19

20 Titanium Alloys 20

21 Superalloy 21 A superalloy, or high-performance alloy, is an alloy that exhibits several key characteristics: excellent mechanical strength, resistance to thermal creep deformation, good surface stability, and resistance to corrosion or oxidation. The crystal structure is typically face-centered cubic austenitic. Examples of such alloys are Hastelloy, Inconel, Waspaloy, Rene alloys, Haynes alloys, Incoloy, MP98T, TMS alloys, and CMSX single crystal alloys. Applications: structures at high temperature (T = 0.9 Tm) for example blades and bearing in the hot sections of turbine engines.

22 Refractory metals These are extremely high melting metals Nb, Ta, Mo, W (niobium, tantalum, molybdenum, tungsten, and rhenium). Very high strengths and hardness Very high elastic modulus W alloys used in x-ray tubes, filaments Ta & Mo used with stainless steels for corrosion resistance Ta is virtually immune to all environments below 150 C Some of their applications include tools to work metals at high temperatures, wire filaments, casting molds, and chemical reaction vessels in corrosive environments. Partly due to the high melting point, refractory metals are stable against creep deformation to very high temperatures. 22

23 Nickel alloys Quite ductile and formable Highly corrosion resistant, especially at high temperature Essential part of austenitic stainless steels Used in pumps, valves in seawater and petroleum environments 23

24 End-Good Luck This Semester Weblog: 24

25 Steels Classification of steels Non-alloy steels (carbon steels) Alloy steels Inclusions, % Non-alloy steels (carbon steels) Mn 1,65 > 1,8 Si 0,5 > 0,5 Cr 0,3 > 0,5 Ni 0,3 > 0,5 Alloy steels Ti 0,05 > 0,12 V 0,1 > 0,12 Chapter8-Lecture Metallurgy in Production University of Hormozgan, Mirzai, 95-96

26 Non-alloy and alloy steels classification Non-alloy steels (carbon steels) C content based Alloy steels Alloying degree based - low C-steels (<0,25%) - low alloy steels (<2,5%) - medium C-steels (0,3 0,6%) - medium alloy steels (<5%) - high C-steels (>0,6%) - high alloy steels (>5%) Alloying degree based - Cr steels - Mn steels - Cr-Ni steels etc. Chapter8-Lecture Metallurgy in Production University of Hormozgan, Mirzai, 95-96

27 Non-alloy and alloy steels (2) Non-alloy steels (carbon steels) Alloy steels Quality based (degree of purity): -ordinary quality - quality steels ( 0,035 S,P) - high quality steels ( 0,025 S,P) Deoxidation degree based - killed steels (Mn, Si) - semikilled steels (Mn, Si) - quality steels Quality based: - high quality steels Structure based: - in annealed condition - in normalized condition (ferrite, pearlite, martensite and austenitic steels) - rimmed steels (Mn) Chapter8-Lecture Metallurgy in Production University of Hormozgan, Mirzai, 95-96

28 Non-alloy and alloy steels classification (3) Non-alloy steels (carbon steels) Alloy steels Application based: C<0,7%C structural steels 0,2...0,7% C C>0,7%C tool steels 0,4...1,6% C corrosion resistant heat resistant high temperature strength magnetic cryogenic 28

29 Classification of structural steels Non-alloy steels (carbon steels) Alloy steels Heat treatment based: - case hardening steels ( 0,25% C) - quenching and tempering steels (0,3 0,6% C) - nitriding and carbonitriding steels (0,1 0,2 or 0,3 0,4% C) 29

30 Designation of steels (1) Steels (EN10027) Designations (1) Mechanical properties based on: R e steels for steel constructions S355J0 steels for pressure vessel P265B steels for machine constructions E295 steels for pipes L360QB concrete reinforcing steel B500N Based on: R m rail steels RO880Mn prestressing steels Y1770C Notch impact energy C KU, J JR J0 J2 J3 J4 J5 J6 KR K0 K2 K3 K4 K5 K6 LR L0 L2 L3 L4 L5 L6 Chapter8-Lecture Metallurgy in Production University of Hormozgan, Mirzai, 95-96

31 Chemical composition based C (non-alloy steels (carbon steels), ex free cutting steels C35E G-C35E (cast steel) 35 C%x100 (E max S-content) C, alloying elements (low- ja medium alloy steels, all. elem., 5%, non-alloy steels (carbon steels) Mn 1%, non-alloy free cutting steels) 28Mn6 G-28Mn6 C, all. elem. (high alloy steels, all. elem. >5%) X5CrNi18-10 All. elem. (high speed steels) HS W-Mo-V-Co Designations (2) Alloying element Cr, Co, Mn, Si, Ni, W Al, Cu, Mo, Nb, Ti, V, Zr Chapter8-Lecture Factor Metallurgy in Production University of Hormozgan, Mirzai, Ce, P, S 100 B 1000

32 Designations (3) Materials numbers (EN 10027) Material group Steel class Order in class Additional numbers 1. XX XX (XX) Pos. 2 and 3 Ordinary grade steels Tool steels High quality grade Special steels spec. phyc. prop. steels (stainless and heat resistant. etc.) 11 construction and machine construction steell 12 machine contruct. steels 13 spec. constr. and ja machine constr. steels High quality structural steels non heat treatable structural steels high P- ja S-cont. steels Pos. 4 ja 5 Order no. in class Chapter8-Lecture Metallurgy in Production University of Hormozgan, Mirzai, 95-96

33 Structural steels (1) Non-alloy structural steels (C = 0,2...0,65%) ordinary (quality) steels quality steels C15E (max S), C15R (S range) high quality steels (S, P 0,025%) Free cutting steels (C = 0,12...0,4%; g 0,2% S) 10S20, 35S20 Cast steels (C = 0,15...0,55%) GE250, G28Mn6 33

34 Structural steels (2) 34 Alloy structural steels (C = 0,2...0,7%, wear resistant steels 0,9...1,3%) low alloy steels (all. elem. g 2,5%) structural steels cold forming steels spring steels (C = 0,5...0,7%, Si = 1...2%) ball bearing steels (C 1%, Cr = 0,5...0,6%) medium alloy steels (all. elem. 2,5...5%) cementizing steels quenching and tempering steels nitriding steels high alloy steels (leg. el. > 5%) steels with specific properties corrosion resistant steels high temperature strength steels wear resistant steels

35 Low alloy steels (1) 35 Structural steels (3) Steels for structural construction Low alloy carbon steels C 0,22%; 1...2% Si, Mn Requirements: Cold brittleness: low T BCT, T 50 high toughness (h impact energy KU, KV) Weldability CE%=C%+Mn%/6+(Cr%+Mo%+V%)/5+(Ni%+Cu%)/15 CE 0,40% - satisfactory weldability CE 0,40% - special means: preheating, low annealing. Alloying principles: ip,s gi T BCT Simultaneous alloying with V,NgT BCT -80 C

36 36 Steels Structural steels (4) Low alloy steels (2) Cold forming steels Requirements low yield strength ratio (R p0,2 /R m = 0,5...0,65) high plasticity (A 40%) Principles of alloying: C and Si%h R p0,2 gi formability; Mn% h R m, R p0,2 g good formability Preferred: rimmed steels (Si 0%) dual phase steels (F % M or B) (C = 0,06...0,12%, partial-hardening g R p0,2 /R m = 0,5) g good deep drawability at 10% degree of deformation R p0,2 /R m = 0,8...0,9 Ballon steels Pressure vessel steels Seamless pipes Welded pipes

37 37 Steels Structural steels (5) Low alloy steels (3) Spring steels high R e, σ R, modulus of elasticity E C = 0,5...0,7% Mn-steels (1...2% Mn) Si-steels (2...3% Si) Cr-V-steels TT: Hardening + mid. temp. ( C) g Trostite structure Ball bearing steels High hardness ( 62 HRC) C 1%; Cr = 0,6...1,5% 105 Cr6 Ball races ( HRC), balls ( HRC)

38 Cementizing (case hardening) steels (0,1...0,25% C) Cr-steels Cr-Mn-steels Cr-Ni-steels B-steels Steels HT: T cem + hard. + low. temp. Surface (Cg0,8) HRC Core (C = 0,1...0,25) HRC Structural steels (6) Medium alloy steels (1) Chapter8-Lecture Metallurgy in Production University of Hormozgan, Mirzai, 95-96

39 Steels Structural steels (7) Medium alloy steels (2) Quenching and tempering steels Requirements: Reliability ( R m, R p0,2 ; acceptable KU and T BCT ) High hardenability (D 50, D 95, T 50 ) Principles pf alloying: Alloying hardenability ( M a, M l ) (all exc. Al and Co) At solution in F, R m and T BCT, alloying degree as low as possible (for D 50 ) 39

40 Steels Structural steels (8) Medium alloy steels (3) Quenching and tempering steels (0,3...0,5% C; 3...5% all.elem.) I gr non-alloy steels (carbon steels) D 95, mm T 50, C II gr Si-Mn/Cr-steels (~1%) III gr Mn-Cr-steels IV gr Ni-Mo-steels V gr Ni-refractory. (W, Mo, V jt.) R m g1200 N/mm 2 ; R p0,2 g 1100 N/mm 2 ; A = %; KUg40J 40

41 Steels Structural steels (9) Medium alloy steels (4) 41 Nitriding steels (C-, all. elem. same as in hard. and temp. steels) T nitr C (differently from cem.) All. elem. Cr, Mo, Al + N g CrN, MoN, AlN Properties: Hardness: surface alloy steels HV, non-alloy steels (carbon steels) HV Core HB High fatigue strength ( by comp. stresses induced nitrides)

42 Steels Structural steels (10) High alloy steels (1) Corrosion resistant steels (1) Cr-steels, C min (0,08...0,2%) 0,1...0,4% for hardenability Cr = 13, 17 or 27% C corrosion resistance, C 0,1 %C ferritic steels For hardness/ wear resiatance 0,1...0,4 %C martensitic steels 42

43 43 Steels Structural steels (11) High alloy steels (2) Cr-Ni steels C 0,12% 18% Cr, % Ni, Ti/Nb 1% R m = N/mm 2 R p0,2 = N/mm 2 Intergranular corrosion (at t o o C): C corr. resist, i, especially in welds g Cr 3 C 2 g Cr % reduction in A. To avoid: g Ti, Nb (0,1...0,2%) g Ci (<0,03%)

44 44 Steels Structural steels (12) High alloy steels (3) High temperature strength steels High temperature strength = heat resiatance + high temp. strength Heat resistance = oxidation resistance High temp. strength: endurance limit σ t T creep strength σ ε/t T C boiler steels 0,1...0,15% C, 0,5...1% Mo, W või V 0,5...1% Cr (pearlite steels) 2...6% Cr (martensite steels) - silchrome 0,5...0,6% C, 1,5...3% Si, % Cr C austenitic steels % Cr; % Ni T, C % Cr; g37% Ni + Al, W, Nb, Ti, Mo 500 > 700 C - Ni- ja Co-alloys (superalloys) mittekuumuspüsiv kuumuspüsiv

45 45 Steels Structural steels (13) High alloy steels (4) Wear resistant steels Requirements: High surface hardness Principles of alloying: through alloying (uneffective 2...3% /Ø100mm) surface alloying Non-alloy- and alloy steels (Cr, Mn, W jt.) Cementizing steels Mn-steels (Hadfield steel) (1,1...1,3% C, % Mn) HT: H ( C) g A-structure R m = , R p0,2 = N/mm 2, A = %, HB In cold worked conditions g HRC self hardening

46 Steels Requirements: hardness and wear resistance strength and toughness heat resistance Tool steels (1) Non-alloy tool steels (C = 0,7...1,3%) Alloy steels (C = 0,4...1,6%) non-heat resistant (g200 C) semi heat resistant (g C) coldwork tool steels hot work tool steels Heat resistant steels (g C) Carbide induced tempering hardness, Intermetallics induced tempering hardness Chapter8-Lecture Metallurgy in Production University of Hormozgan, Mirzai, 95-96

47 Steels Tool steels (2) 47 Non heat resistant steels ( C) non-alloy tool steels (0,7...1,2% C) low alloy steels (Cr, W, Mn) Semi heat resistant steels ( C) Cold work tool steels ( C) Cr-steels (1,2...2,3% C; 12% Cr + Mo, V) Structure: M % carbides C = 0,6...0,7 cutting- ja impact tools Hot work tool steels Requirements: high temperature strength, heat resistance ja thermal resistance high hardenability and not prone to tempering brittleness low adhesion Steels 0,5...0,6% C g good toughness 1,5...2% Ni, Mo g high hardenability

48 Steels Tool steels (3) Heat resistant steels ( C) Steels with carbide induced tempering hardness ( C) Alloying elements: W (18 or 9%) + Mo, V, Co HS HS (P6M5K5) HT: H ( C); 3x T ( C) gi A rest ; g HRC Steels with intermetallics induced tempering hardness ( C) Alloying elements: Co, W, Mo g Co 7 W 6 ; (Co,Fe) 7 W 6 etc. (0,1...0,3% C, % Co, % W, ca 7% Mo) HT: Hard. ( C) g 68 HRC; T ( C) g 60 HRC 48

49 Steels Special steels ja -alloys (1) Magnetic steels Soft magnetic materials pure Fe (C < 0,05%) electrotechnical (1...4% Si) Hard magnetic materials High C-content Non-alloy tool steels (1,1...1,3% C) Cr-steels (ca 1% C; 1,5...3% Cr) Co-steels (ca 1% C; 1,5...3% Cr; % Co) Fe-Ni-Al-alloys (alniko) ( % Al; % Ni) 49

50 50 Steels Special steels ja -alloys (2) Cryogenic steels Requirements: low transition temperature T BCT Steels for low temperature applications 60 C (non-alloy- ja low alloy steel) 100 C low C-content Ni-steels 2...5% Ni + Cr, V, Ti 190 C (liquid N 2 ) austenitic stainless steels) below 190 C (liquid H 2, O 2 ) high alloy corrosion resistant steels Cr > 10%; Ni > 20%