OVER VIEW ON

METALLIC MATERIALS-1

PART 1: PROPERTIES & APPLICATIONS

ALLOY SYSTEMS

• STEELS• ALUMINUM ALLOYS• TITANIUM ALLOYS• NICKEL BASE SUPERALLOYS

TYPES OF STEELSSTRUCTURAL STEELS 

• Carbon Steels• Free Cutting Steels• Case Hardening Steels• Spring Steels• High Temperature Steels• Nitriding Steels• Bearing Steels• Valve Steels•  

TOOL STEELS• Carbon tool steels• Shock resisting steels• Deep Hardening steels• Cold work steels• Hot Die Steels• File steels

 

HIGH SPEED STEELS• Tungsten base• Molybdenum base

STAINLESS STEELS• Austenitic• Ferritic and martensitic

HEAT RESISTANT STEELS• Super Austenitic• Super Ferritic

SPECIAL STEELS• PH stainless steels• Maraging steels

ALLOYING ELEMENTS AND IMPURITIES

Any alloy containing Fe & C is called Steel. Other Alloying elements are Mn, Si, Cr, Mo,

Ni, V, W, Al. Cu, Ti, Nb are added in small quantities. S, P, AS, Bi and Sb are present as impurities.Sometimes Sulphur is added intentionally.

EFFECT OF ALLOYING ELEMENTS Al Strongest deoxidizer, combines with N, reducing susceptibility to

strain ageing. Used as alloying addition in Nitriding steels.(Nitriding – increases surface hadrness like in case carburizing)

B Improves through hardening, thus increases core strength of case hardening steels.

Ce Strong De-oxidant, promotes desulphurising. Promotes non-scaling properties of heat resistant steels.

Co Restricts grain growth at high temperatures. Helps retain hardness at high temperature, so used as alloying element in HSS, hot work tools etc. Increases magnetism, Coercive force and thermal conductivity. Therefore serves as base element for high grade permanent magnet steels.

Cr Increases strength but small reduction in elasticity. Improves resistance to heat & non scaling properties. Higher amount of Cr (>11%) makes steel highly corrosion resistant (stainless steel). Strong carbide former. Weldability is reduced.

Contd…

EFFECT OF ALLOYING ELEMENTS

Cu Strength and hardenability increase. Decreases modulus. Improves corrosion resistance to atmospheric corrosion when added in small quantity (≈ 1.1.)

Mn Good deoxidizer. Reduces deleterious effect of sulphur. Improves hardenability and slightly lowers modulus. Improves forging and welding.

Mo Improves strength, heat resistance and welding properties, strong carbide former, improves cutting efficiency.

Ni Stabilizes the austenite phase, increases impact strength, so added to case hardening steels (like gears). Cr-Ni steels very popular and resistant to corrosion. Also increases hardenability.

Nb & Ta

Strong carbide formers. Added to Boiler steels to enhance creep resistance of austenitic steels

Contd…

EFFECT OF ALLOYING ELEMENTS Si Acts as a deoxidizer. Increases strength and wear resistance.

Increases elastic limit and hence suitable as alloy constituent in spring steels. It resists scaling, so added to heat resistant steels.

Ti Strong affinity for O, N, S and C. Also has grain refining effect. Used to form carbides in austenitic and duplex steels to prevent inter granular corrosion.

W Strong carbide former. Carbides of W are very hard. Increases life of cutting edge. Used in high speed and heat treating steels.

V Small additions of V improve hot hardness and reduce grain growth. Used in combination with Cr in structural and heat resisting steels and with W in hot work steels.

Zr Strong carbide former. Improves high temperature strength and creep strength.

EFFECT OF IMPURITY ELEMENTS Sb Reduces toughness, narrows γ range

As Strong tendency for segregation which is difficult to remove by homogenization, causes temper embrittlement, reduces toughness and weldability, narrows γ range

Be Strong de-oxidiser and strong affinity for sulphur, narrows γ range

H Produces hydrogen embrittlement and promotes hair line cracking

N In elemental form reduces toughness, causes blue brittleness and causes inter granular stress corrosion cracking.forms nitride and allows obtaining high surface hardness.

P causes heavy segregation during solidification. Causes cold shortness.

S Produces most severe segregation and red shortness. Reduces impact properties. Sulphur is added in free cutting steels because of its lubrication effect on the cutting edge.

STEEL GRADES COMPOSITIONS

AND APPLICATIONS

STRUCTURAL STEELS Carbon SteelsFree Cutting SteelsCase Hardening SteelsSpring SteelsHigh Temperature SteelsNitriding SteelsBearing SteelsValve Steels

PLAIN CARBON STEELS

C Si Mn S P0.1-1.0 0.25  0.4-0.8 0.035max 0.035 max

Condition BHN UTS, MPa

%El

Annealed 200-205 620-682 15-30

Hardened & Tempered

240-500 800-1882 5-21

Process Temp C

Forging  1100-850

Normalising 820-850

Annealing 650-700

Hardening 800-850

Tempering 530-670

APPLICATIONSHeat treated condition - automotive and general engineering applications; parts requiring better wear resistance such as brakes, camshafts, axles, spring bolts, roller bearing etc.Higher carbon steels - for making fodder cutting blades, knives, plough etc.

FREE CUTTING STEELS

C Si Mn S P0.1-0.4 0.25  0.8-1.0 0.1-0.25 0.035 max

Condition BHN UTS, MPa

%El

Annealed 143-200 460-620 15-30

Hardened & Tempered

200-345 670-1130 10-32

Process Temp C

Forging  1200-850

Normalising 850-880

Annealing 650-700

Hardening 840-890

Tempering As required

APPLICATIONSMachine parts subjected to comparatively light loads

such as bolts, nuts screws intended for easy machining.

CASE HARDENING STEELSC Si Mn S P Cr Ni

0.15-0.22 0.25  0.5-1.25 0.035max 0.035 max 0.65-2.0 0.85-4.15

Condition BHN UTS, MPa

%El

Annealed 200-240 620-805 14-28

Hardened & Tempered

350-530 1180-1902 8-16

Process Temp C

Forging  1100-850

Normalising 860-880

Annealing 650-700

Hardening 800-850

Tempering As required

APPLICATIONSNi free steels are used for medium core strength and wear resistance – piston rings, bushes, drilling machine spindles and general engineering works.Ni containing steels have high tensile strength and toughness of core. Used for components in automobiles and aircrafts and general engineering where blows and shocks are involved. For heavy duty gearing such as transport vehicles and air crafts high Ni steels (>3.5%) are used.

GENERAL HARDENING AND TEMPERING STEELSC Si Mn S P Cr Ni Mo

0.2-0.5 0.25-1.25  0.5-1.75 0.035max 0.035 max 0-2.5 0-4.5 0.25-0.40

Condition BHN UTS, MPa

%El

Annealed 207-255 682-854 15-25

Hardened & Tempered

255-535 854-1902 7-15

Process Temp C

Forging  1200-850

Normalising 850-900

Annealing 680-720

Hardening 800-900

Tempering 670-530

APPLICATIONSGeneral engineering applications. For parts where high tensile and impact strengths are required such as crank shafts, stub axles, connecting rods etc., Ni, Mo steels are used.

SPRING STEELSC Si Mn S P Cr

0.5-0.65 0.25-1.65  0.4-1.85 0.035max 0.035 max 0.85-1.15

Condition BHN UTS, MPa

%El

Annealed 223-255 718-854 15-25

Hardened & Tempered

330-555 1096-2054 5-11

Process Temp C

Forging  1050-850

Normalising 850-900

Annealing 640-790

Hardening 840-870

Tempering 350-550

APPLICATIONSSpiral , Helical , Torsion, Leaf , volute , plate springs requiring good endurance , bending and fatigue strengths.

HIGH TEMPERATURE STEELSC Si Mn S P Cr V

0.15-0.25 0.25-0.40  0.5-1.1 0.035max 0.035 max 1.25-5.40 0.2-0.5

Condition BHN UTS, MPa

%El

Annealed 200-223 620-718 15-27

Hardened & Tempered

250-400 827-1392 10-17

Process Temp C

Forging  1100-850

Normalising 920-940

Annealing 680-700

Hardening 950-980

Tempering 650-760

APPLICATIONSSteam boiler plants, super heaters, receivers, superheated steam lines, up to 530-5500 C

NITRIDING STEELSC Si Mn S P Cr Mo Al Ni

0.30-0.35 0.25-0.30  0.5-0.6 0.035max 0.035 max 1.15-2.50 0.2-1.2 0.8-1.0 0-1.0

Condition BHN UTS, MPa

%El

Annealed 230-240 765-800 15-25

Hardened & Tempered

535-600surface

800-1200 8-15

Process Temp C

Forging  1050-850

Normalising 870-930

Annealing 680-720

Hardening 870-900

Tempering 580-630

APPLICATIONSConstruction members with high surface wear resistance; small ruling sections such as bolts, needle beds, precision measuring tools; parts of higher ruling section-cams, crank shafts, worms, big measuring tools.

BEARING STEELSC Si Mn S P Cr

0.90-1.10 0.30  0.30 0.025 max 0.025 max 0.50-1.50

Condition BHN UTS, MPa

%El

Annealed 205-210 620-690 10-22

Hardened & Tempered

58-65Rc >2400 ≈1

Process Temp C

Forging  1100-850

Normalising ---

Annealing 750-800

Hardening 800-870

Tempering 150-200

APPLICATIONSBalls, rollers, cylinders, races etc

VALVE STEELSC Si Mn S P Cr Ni W

0.45-0.80

2.0-3.0  0.40-1.0

0.025 max

0.025 max

9.0-20.0

1.4-14.0

1.0-2.4

Condition BHN UTS, MPa

%El

Annealed 260-280 870-910 11-22

Hardened & Tempered

555-627surface

1620--2092 ≈1

Process Temp C

Forging  1100-900

Normalising ---

Annealing 720-820

Hardening 1000-1050

Tempering 700-750

APPLICATIONSScaling resistant, suitable for outlet and inlet valves in aircraft and high duty engines

Surfaces nitrided for good wear resistance

TOOL STEELSCarbon tool steelsShock resisting steelsDeep Hardening steelsCold work steelsHot Die SteelsDie block steelsFile steels

CARBON TOOL STEELSC Si Mn S P

0.75-1.30

0.25  0.3 0.025 max

0.025 max

Condition BHN UTS, MPa

%El

Annealed 198-204 650-675 10-17

Hardened & Tempered

550-650 1630-2100 ≈1

Process Temp C

Forging  1050-800

Normalising ---

Annealing 690-710

Hardening 760-780

Tempering As required

APPLICATIONSHeavy Forge hammers, sledge hammers, blanking tools, dies blacksmith, chisels, Scissors knife blades, hot and cold trimming tools, threading tools, cutting dies, milling cutters, boring tools taps, threading dies etc.

HOT WORK STEELS

Condition BHN UTS, MPa

%El

Annealed 234-255 750-850 10-20

Hardened & Tempered

455-650 1460-2480 1-2

Process Temp C

Forging  1050-900

Annealing 740-850

Spheroidized Annealing

234-280

Hardening 960-1050

Tempering 400-850

APPLICATIONSHeavy duty hot work tools, Extrusion mandrel dies, hot impact extrusion tools, forming dies, die inserts, hot shear blades etc. Austenitic PH steel of high strength used for extrusion dies.

C Si Mn S P Cr Mo V Ni W

0.30-0.55

0.30-1.10 

0.30-0.90

0.035max

0.035 max

1.60-10.0

0.50-6.20

0.20-1.10

0 -8.50

0.40-18.0

COLD WORK STEELS

Condition BHN UTS, MPa

%El

Annealed 219-234 737-799 11-23

Hardened & Tempered

48-67Rc 1578-2426 ≈1

Process Temp C

Forging  1050-800

Annealing 680-780

Spheroidzed Annealing

200-290

Hardening 780-830

Tempering 100-400

APPLICATIONSHighly wear resistant application such as spinning tools, bending rolls, punches and dies, spiral drills, center bits, cold upsetting and cold extrusion tools, Drawing tools, engraving tools, press tools, cold punches, knives, milling cutters, taps, Hacksaw blades, reamers etc.

C Si Mn S P Cr Mo V Ni W

0.20-1.2

0.20-0.3 

0.20-0.40

0.035max

0.035 max

0.20-2.0

0.20-0.30

0.10-0.35

0 -4.0

0.40-3.3

HOT DIE STEELS

Condition BHN UTS, MPa

%El

Annealed 240-250 820-850 11-23

Hardened & Tempered

53-58Rc 1834-2054 ≈1

Process Temp C

Forging  1050-900

Annealing 640-660

Hardening 870-890

Tempering 150-250

APPLICATIONSVery tough coining tools used for manufacturing cutlery and plastic moulding

C Si Mn S P Cr Mo Ni

0.40-0.5 --- --- 0.035max 0.035 max 1.0-1.4 0.20-0.30 0 -4.0

HIGH SPEED STEELS• Molybdenum base• Tungsten base

HIGH SPEED STEELS MOLYBDENUM BASED

Condition BHN UTS, MPa

%El

Annealed 217-255 710-855 8-18

Hardened & Tempered

60-63 Rc 2400-2510 ≈1

Process Temp C

Forging  1100-900

Annealing 770-850

Hardening 1180-1250

Tempering 530-580

APPLICATIONSExcellent cutting efficiency & tough. Twist Drills, Taps,

Profile Tools, Milling Cutters, Cold work tools and tool bits.

C Si Mn S P Cr Mo V Co W

0.8-1.25

0.20-0.30 

0.2-0.30

0.03max

0.03 max

3.75-4.30

5.0- 9.0

1.2-3.6

0.0-10.5

1.5-9.6

HIGH SPEED STEELS TUNGSTEN BASED

Condition BHN UTS, MPa

%El

Annealed 230-321 765-1055 8-17

Hardened & Tempered

64-67 Rc 2323-2482 ≈1

Process Temp C

Forging  1150-900

Annealing 770-870

Hardening 1200-1290

Tempering 550-590

APPLICATIONSMilling cutters, Taps, twist Drills, Reamers,

Planning tools. High strength and hard steels.

C Si Mn S P Cr Mo V W

0.75-1.5

0.20-0.30 

0.2-0.30

0.03max

0.03 max

4.30-5.0

0.8- 1.0

1.0-5.0

10.0-18.0

STAINLESS STEELS• Austenitic• Ferritic and martensitic

STAINLESS STEELSAUSTENITIC

Condition BHN UTS, MPa

%El

Annealed 140-160 490-560 30-40

Hardened & Tempered

NA

Process Temp C

Forging  1100-850

Annealing 680-720

Solution treatment

1020-1070

Stress relieving As required

APPLICATIONSCorrosion resistant, cold hardened, utensils, lining food processing industry, dairies and breweries, chemical industries, blunt surgical instruments (Good deep drawability) photo & film industry, Textile industry etc.

C S P Cr Mo Ni Ti

0.06-0.12 0.03-0.15 0.050 max 17.0-19.0 0-3.0 7.0-13.0 0.0-0.35

STAINLESS STEELSFERRITIC& MARTENSITIC

Condition BHN UTS, MPa

%El

Annealed                         

160-175 551-600 20-22

Hardened & Tempered

Martensitic410-610

1034-1793 5-8

Process Temp C

Forging  1150-750

Annealing 740-850

Hardening 900-1080

Tempering 600-750

APPLICATIONSFerritic steels used for spoons, forks, cutlery, steam turbine shafts, axles, screws, bolts, nuts, which are non-heat treatable. Martensitic steels used for corrosion resistant cutting tools, surgical instruments, knives, meat mincing components, needle valves, nozzle blades.

C S P Cr Mo Ni V Co

0.08-1.06 0.03-0.2 0.050 max 13.0-17.5 0-1.2 0.0-1.8 0.0-0.1 0-1.5

HEAT RESISTANT STEELS• Super Austenitic• Super Ferritic

SUPER AUSTENITIC STEELS

Condition UTS, MPa

PS, MPa

%El

Annealed 520-610 180-270 40

Process Temp C

Forging  1150-800

Annealing 900-980

Solution treatment 1100-1150

APPLICATIONSRequiring resistance to pitting corrosion . Rails, rams, roller axles, shafts, super heater suspensions, burner nozzles, valves, spindles, thermo couple protectors, nuts, rivets

C S P Cr Ni Mo

0.03-0.10 0.03 0.03 max 19.0-25.0 30.0-40.0 3.0-6.7

SUPER FERRITIC STEELS

Condition UTS, MPa

PS, MPa

%El

Annealed 450-550 275-415 20

Process Temp C

Forging  1150-800

Annealing 150-1100

APPLICATIONSFood handling equipment, heat exchangers, piping

systems, furnace parts, automobile exhausts etc.

C S P Cr Ni Mo Ti+Nb N

0.003-0.02 0.03 0.03 max 26.0-29.0 2.0-3.0 1.0-4.0 0.5 0.01-0.025

SPECIAL STEELSPH Stainless steelsMaraging steels

PH STAINLESS STEELS

Type UTS, MPa

PS, MPa

%El

Austenitic 600-1000 300-700 24-45

Martensitic 950-1400 750-1280 8-20

SemiAustenitic

1250-1350 950-1050 9-19

Process Temp C

Forging  1150-800

Solution treatment

925-1065

Aging 540-620

Type C Mn Cr Ni Mo Al Ti OthersAustenitic 0.08-

0.120.50-2.0

13.0-17.0

14.0-27.0

1.0-2.5

0-0.35

0.25-2.25

V-        0.1-0.5B-        0.001-0.003

Martensitic 0.05-0.07

0.10-1.0

12.5-17.5

3.0-8.5

0-2.50

0-1.35

Cu-       0-5.0Ta+Nb- 0.15-0.45

SemiAustenitic

0.07-0.15

0.50-1.25

15.0-18.0

4.0-7.75

0-3.25

0-1.50

-- N-         0-0.13

APPLICATONSJet engine parts like turbine buckets, discs fasteners, undercarriage parts, honeycomb panels ,chemical equipment, fluid control systems etc.

MARAGING STEELS

Type UTS, MPa

PS, MPa

%El

200 Grade 1450 1380 12

250 Grade 1760 1720 10

300 Grade 1930 1890 8

350 Grade 2340 2275 8

Process Temp C

Forging  1250-1000

Solution treatment

820

Aging 480-500

Type C Mn Ni Mo Co Al Ti200 Grade 0.03max  0.1max 17-19 3-3.5 8-9 0.05-0.1 0.1-0.25

250 Grade 0.03max 0.1max 17-19 4.6-5.2 7-8.5 0.05-0.15 0.3-0.5

300 Grade 0.03max 0.1max 18-19 4.7-5.2 8.5-9.5 0.05-0.15 0.5-0.8

350 Grade 0.03max 0.1max 17-19 3-4.5 12-13 0.12-0.2 1.5-2.0

APPLICATIONSLanding gears, rocket motor cases, engine shafts, cams , pistons, clutch discs, hot forging dies, springs, cold heading dies, gear box etc.

STRENGTHENING PRECIPITATESSteel type PrecipitateAustenitic PH Fcc γ’  - Ni3[Al,Ti]Martensitic PH Bcc NiAl

Fcc ε CuSemi Austenitic PH Bcc NiAlMaraging Hcp (Ni,Fe)3(Ti,Mo)

 Hcp (Fe,Ni,Co)2(Mo,Ti)

ALUMINIUM ALLOYSCOMPOSITIONS

PROPERTIES

CLASSIFICATION

WROUGHT ALLOYS• 1xxx : Pure aluminium• 2xxx : copper principal alloying

element+ other alloying elements like Si, Mg, Mn etc

• 3xxx : Mn principal alloying element• 4xxx : Si principal alloying element• 5xxx: Mg principal alloying element• 6xxx : Mg + Si principal alloying

elements• 7xxx : Zn principal alloying element+

other alloying elements like Cu, Mg, Cr, Zr etc

CAST ALLOYS• 1xx.x : Pure aluminium• 2xx.x : copper principal alloying

element+ other alloying elements like Si, Mg,Mn etc

• 3xx.x : Si principal alloying element +others like Cu, Mg etc.

• 4xx.x : Si principal alloying element• 5xx.x: Mg principal alloying element• 6xx.x : not used• 7xx.x : Zn principal alloying element+

other alloying elements like Cu, Mg ,Cr, Zr etc.

• 8xx.x : Sn principal alloying element

AGE HARDENABLE ALLOYSAlloy Si Fe Cu Mn Mg Cr Zn Others

2014 0.5-1.2 0.7 3.9-5.0 0.4-1.2 o.2-0.8 0.1 0.25

2219 0.2 0.3 5.8-6.8 0.2-0.4 0.02 0.1 V:0.05-0.15Zr:0.1-0.25Ti:0.02-0.1

2618 0.1-0.25 0.9-1.3 1.9-2.7 - 1.3-1.8 0.1 Ni:0.9-1.2

6061 0.4-0.8 0.7 0.15-0.4 0.15 0.8-1.2 0.04-0.35 0.25 Sn:0.15

7021 0.25 0.4 0.25 0.1 1.2-1.8 0.05 5.0-6.0 Zr:0.08-0.18

7075 0.4 0.5 1.2-2.0 0.3 2.1-2.9 0.18-0.28 5.1-6.1 Ti :0.2

203.0 0.3 0.5 4.5-5.5 0.2-0.3 0.1 0.1 Ni:1.3-1.7Ti: 0.25-0.5

705.0 0.2 0.8 0.2 0.4-0.6 1.4-1.8 0.2-0.4 2.7-3.3 Ti: 0.25

SOLID SOLUTION ALLOYSAlloy Si Fe Cu Mn Mg Cr Zn Others

3204 0.3 0.7 0.1-0.25 0.8-1.5 0.8-1.5 - 0.25

4010 6.5-7.5 0.2 0.2 0.1 0.3-0.45 - Be:0.04-0.07Sn:0.04-0.2

5083 0.4 0.4 0.1 0.4-1.0 4.0-4.9 0.05-0.25 0.25 Sn: 0.15

5456 0.3 0.4 0.1 0.5-1.0 4.7-5.5 0.25 Ti: 0.05-0.2

AMГ6 0.4 0.4 0.1 0.5-0.8 5.8-6.8 0.2 Ti: 0.02-0.1

302.0 9.5-10.5 0.25 2.8-3.2 - 0.7-1.2 NI: 1.0-1.5

408.2 8.5-9.5 0.6-1.3 0.1 0.1 - 0.1

511.0 0.3-0.7 0.5 0.15 0.35 3.5-4.5 0.15 Ti: 0.25

850.1 0.7 0.5 0.7-1.3 0.1 0.1 Sn=5.5-7 Ni:0.7-1.3Ti:0.2

Effect of Solute Concentration on Yield Strength

SOLID SOLUTION STRENGTHENING IN AL ALLOYS

MECHANICAL PROPERTIES OFSOME Al ALLOYS

Alloy Desig-Temper UTS(MPa) P S(MPa) %Elongation

1100(pure Al)-O 90 34 35

2219(Al-Cu-Mn)-T87 476 393 10

3004(Al-Mn-Mg)-O 180 70 20

5456(Al-Mg-Mn)-O 310 159 24

6061(Al-Mg-Si)-T6 310 276 12

7075(Al-Zn-Mg-Cu)-T6 572 503 11

EFFECT OF ALLOYING ELEMENTSCu : One of the most important alloying additions. Appreciable solubility.

Strengthening through solution treatment and aging when added as principal alloying element, and through solid solution strengthening in secondary additions

Mn: It has limited solubility. It is added in the limit of about 1% in non heat treatable wrought alloys(3xxx). It is used as supplementary addition in both heat treatable and non heat treatable alloys

Mg: Provides substantial strengthening and improvement of work hardening characteristics of Al. High solubility in solid solution but not amenable to heat treatment.

Zn: Zn is added in conjunction with Mg in wrought alloys to make it suitable for heat treatment(7xxx). Mg produces the highest solid solution strength among all Al alloys

Contd…

EFFECT OF ALLOYING ELEMENTSSi: It lowers the melting point and increases fluidity of Al. Some

increase in strength is also achieved

Mg+Zn :Mg and Zn are added in appropriate proportions to form Mg2Si precipitate which is the basis for age hardening in both wrought(6XXX) and cast(3XXX) alloys.

Sn : Improves the anti friction characteristics of Al. Cast Al-Sn alloys(8XX.X) alloys are used for bearings.

Li : added to some Al alloys in concentrations approaching 3wt% to decrease density and increase elastic modulus. Eg. Al-Cu-Li alloys (2091) , Al-Cu-Li-Mg alloys(8090).

• Introduction• Extraction and melting of titanium• Classification of titanium and its alloys• α+β titanium alloys• β titanium alloys• Properties of titanium alloys

TITANIUM AND ITS ALLOYS

APPLICATIONS

+ 4% efficiency+ 4% efficiencyClappered Wide-chord fan+ 4% efficiency+ 4% efficiency+ 4% efficiency+ 4% efficiencyClapperedClappered Wide-chord fanWide-chord fan

APPLICATIONS

SPONGE PRODUCTION (KROLL PROCESS)

ALLOY PRODUCTION

ALTERNATE REFINING PROCESS

ALLOY CLASSIFICATION

NEAR a TITANIUM ALLOYSPROPERTIES

• Moderately high strength and ductility at RT

• High toughness and good creep strength at HT

• Good weldability• Good resistance to

salt water environment

APPLICATIONSAirframe andjet engine parts

Composition Condition Type of Application

8%Al-1%Mo1%V Duplex Annealed

Air frame and jet engine parts requiring high strength up to455o Good creep toughness and weldability

6%Al-2%Sn-4%Zr-2%Mo

Annealed Parts and cases for jet engine compressors: airframe skin components

5%Al-5%Sn-2%Zr-2%Mo-0.25%Si

975 ½ hr air cooled +600 2hr air cooled

Jet engine parts: high creep strength up to 54o C

6%Al-1%Mo-2%Nb-1%Ta

As rolled High toughness: moderate strength, good resistance to sea water and hot salt stress corrosion, good weldability

APPLICATION OF a+b ALLOYSAlloy composition Condition Typical Applications

6%Al-4%V Annealed:Solution+ age

Rocket motor cases: blades and disks for aircraft turbines and compressors: structural forgings and fasteners: pressure vessels gas and chemical pumps: cryogenic parts: marine parts: steam turbine blades

6%Al-4%V(lowO2)

Annealed High pressure cryogenic vessels operating down to -100 C

6%Al-6%V 2%Sn AnnealedSolution +age

Rocket motor cases : ordnance components; structural aircraft parts, landing gears

7%Al-4% Mo Solution +age Aircraft and jet engine parts for operation up to 430 C; missile applications

Solution +age 6%Al-2%Sn-4%Zr-6%Mo

6%Al-2%Sn-2%Zr-2%Mo-2%Cr-0.25%Si

Solution +age Strength, fracture toughness in heavy sections, landing -gear wheels

10%V-2%Fe-3%Al Annealed Heavy airframe structural components requiring toughness at high strengths

8%Mn Annealed Aircraft sheet components, structural sections

3%Al-2.5%V Annealed Aircraft hydraulic tubing

APPLICATIONS OF b TITANIUM ALLOYSAlloy composition Commercial

nameCategory Application

Ti-35V-15Cr Alloy C Beta Burn resistant alloy

Ti-6V-6Mo-5.7Fe2.7Al TIMETAL125 Metastable Beta High strength fasteners

Ti- 13V-11Cr-3Al B 120 VCA Metastable Beta Air frame, Landing gears, springs

Ti-4.5Fe-6.8Mo-1.5Al TIMETAL LCB Metastable Beta Non aerospace applications, low cost high strength alloy

Ti-8v-8Mo-2Fe-3Al 8-8-2-3 Metastable Beta High strength forgings

Ti-10V-2Fe-3Al 10-2-3 Metastable Beta High strength forgings

TI-13Nb-13Zr Beta rich Orthopedic implants

PROPERTIES

CONVENTIONAL CASTINGRammed graphite is used instead of sand

since graphite has very little reactivity with titanium

Produces intricate shapes with good surface finish

INVESTMENT CASTINGExtensively used for titanium alloys

Precise dimensional control

Expensive but cost effective for Ti alloys

TITANIUM ALLOY CASTING TECHNOLOGIES

MECHANICAL PROPERTIES OF SOME Ti ALLOYSAlloy a Morphology/

Processing methodYield strength(MPa)

Fracture toughnessMPa√m

Ti-6Al-4V EquiaxedTransformeda+b rolled, annealed

9108751000

44-6688-11032

Ti-6Al-6V-2Sn EquiaxedTransformed

1085980

33-5555-77

Ti-6Al-2Sn-4Zr-6Mo EquiaxedTransformed

11551120

22-3333-55

Ti-6Al-2Sn-4Zr-6Mo forging

a+b, forged, ST+aged b forged, ST+aged

903895

8184

Ti-17 a+b, forged, b forged,

1035-11701035-1170

33-5053-88

SUPERALLOYS

CHARACTERSTICS OF SUPER ALLOYS

• Ability to withstand loading at an operating temperature close to its melting point

• A substantial resistance to mechanical degradation over extended periods of time.

• Tolerance of severe operating environments

Superalloys are high-performance materials designed to provide high mechanical strength and resistance to surface degradation at high temperatures of 1200°F (650°C) or above.

They combine high tensile, creep-rupture, and fatigue strength; good ductility and toughness, with excellent resistance to oxidation and hot corrosion.

Furthermore, superalloys are designed to retain these properties during long-term exposures at the elevated temperatures

Room temperature strength properties are good but not outstanding

“Superalloys as a class constitute the currently reigning aristocrats of the metallurgical world. They are the alloys which have made jet flight possible, and they show what can be achieved by drawing together and exploiting all the resources of modern physical and process metallurgy in the pursuit of a very challenging objective.” by Cahn.

TYPES OF SUPERALLOYS 1. Iron based alloys‑    in some cases iron is less than 50% of total composition‑2. Nickel based alloys‑    better high temperature strength than alloy steels ‑

– Other elements: Cr, Co; also: Al, Ti, Mo, and Fe 3. Cobalt based alloys‑    ‑  40% Co and  20% chromium

– Other alloying elements include Ni, Mo, and W • In virtually all superalloys, including iron based, strengthening is by precipitation 

hardening• Nickel Base Super alloys are dominant in aeroengines

Nickel Base alloy Ni Cr Co Mo W Ta Cb Al Ti Fe CAlloy-713C 74 13 4 2 6 1 0.12MAR-M-247 60 8 10 1 10 3 6 1 0.14Inconel-718 53 19 3 5 1 1 19 0.04Nimonic-263 51 20 20 6 1 2 0.06Udimet-720 55 18 15 3 1 3 5 0.03

Cobalt Base alloyHaynes -188 22 22 39 0 14 3 0.10

L-605 10 20 53 0 15 0.05MAR-M-918 20 20 53 0 0 8 0.05

Iron Base alloyA-286 26 15 0 1 2 54 0.05

Haynes -556 20 22 20 3 3 1 29 0.10

Turbine blade

Compressor and Turbine disc

Combustor chamber

COMPOSITIONS OF SOME SUPERALLOYSAlloy Ni Cr Co Mo W Ta Nb Al Ti Fe C B Zr

713LC 75 12 - 4.2 - - 2.0 5.9 0.6 - 0.05 0.01 0.1

CMSX2 66 8.0 4.6 0.6 7.9 5.8 - 5.6 0.9 - - - -

IN100 60 10 15 3.0 - - - 5.5 4.7 - 0.18 0.014 0.06

IN939 48 22.5 19 - 2.0 1.4 1.0 1.9 3.7 - 0.15 0.009 0.9

MAR-M 302

0 21.5 58 - 10 9 - - - 0.85 0.005 0.2

A-286 26 15 - 1.3 - - - 0.2 2.0 54 - - -

Incoloy MA 956

0.0 20 - - - - 4.5 0.5 74 - 0.5Y2O3

VARIATION OF MECHANICAL PROPERTIES WITH TEMPERATURE

Alloy Ultimate tensile strength(Yield strength)MPa

RT 650 C 760 C 870 C 980 C

713LC 895(750) 1080(785) 955(760) 750(580) 470(285)

CMSX 1185(1135) - 1295(1245) 1020(860)

IN738LC 1035(895) - - - -

IN100 1015(850) 1110(890) 1070(860) 885(695) 565(370)

1N939 1050(800) 985(695) 915(635) 640(400) 325(205)

MAR-M 302 930(690) 785(485) 705(450) 450(290) 275(165)

A-286 1005(725) 905(605) 720(605) 440(430)

INCOLOY MA956

645(555) 370(285) 230(170) 160(140)

Strengthening by particles of g’

1. Dislocations dissociate in the g'-phase, leading to the formation of an anti-phase boundary. It turns out that at elevated temperature, the free energy associated with the anti-phase boundary (APB) is considerably reduced if it lies on a particular plane, which by coincidence is not a permitted slip plane.

2. One set of partial dislocations bounding the APB cross-slips so that the APB lies on the low-energy plane, and, since this low-energy plane is not a permitted slip plane, the dissociated dislocation is now effectively locked.

Anomalous yielding effect in gamma prime alloysBy this mechanism, the yield strength of g'-phase Ni3Al actually increases with temperature up to about 1000 °C, giving superalloys their currently unrivalled high-temperature strength.

STRENGTHENING OF NICKEL BASE SUPERALLOYS

Superlative combinations of properties– Nickel-based alloys– Other alloying elements: Nb, Mo,

W, Ta, Cr, and TiApplications: aircraft turbine components– Turbine blades and discs, high

creep and oxidation resistance at elevated temperatures (1000°C)

– Density is an important consideration because centrifugal stresses are diminished in rotating parts when the density is reduced

NI-BASE SUPERALLOYS

Superalloys develop high temperature strength through Solid solution , precipitate strengthening.

Oxidation and corrosion resistance is provided by the formation of a Protective oxide layer which is formed when the metal is exposed to oxygen and encapsulates the material protecting the rest of the component