Stainless Steel


Typical Analysis :

Grade
Carbon
Manganese
Phosphorous
Sulphur
Silicon
Chromium
AISI 410
0.10%
0.80%
0.030%
0.010%
0.20%
11.5%
0.14%
0.90%
max
max
0.40%
12.5%
AISI 420
0.17%
0.70%
0.030%
0.010%
0.20%
12.00%
0.20%
0.80%
max
max
0.40%
13.00%

Applications :
Capability of hardening and tempering makes this material suitable for applications like- Shafts, valve bodies requiring corrosion and heat resistance with a combination of strength and fatigue.

AISI 410/420- Supply condition -Ingot route material hot rolled to sizes up to 160 mm dia, followed by hardening and tempering. Peeling is done as per customer requirements. Blocks are used by Forging Industries for forging the components desirous of corrosion and heat resistance in the applications up to 815 °C.

Sections greater than 160mm dia are forged from bigger ingots (3T to 13T weight). Forging is done either at Bharat Forge or other forging units.

Heat Treatment :
Normalizing : Not recommended.

Annealing : Can be Process/Full/Isothermal annealed.

Heat Treatment
GradeAISI
Temp °C
Hardness
Remarks
Process Anneal
410
650/760
86/92 HRB
Controlled atmosphere
420
675/760
94/97 HRB
Isothermal
410
830/885
85 HRB
Slow cooling to 705 °C Hold for 6 hrs
420
830/885
95 HRB
Slow cool to 705 °C Hold for 2 hrs
Full Anneal
410
830/885
75/85 HRB
Controlled atmosphere Slow cool @ 17/23 °C/hr to 595 °C for severe  forming applications
420
86/95HRB
Hardening
410
925/1010
375/415HB
 As quench hardness
420
980/1065
448/564HB
 As quench hardness
Tempering
410
205/370
38/47HRC
 Stabilize at –76 to -195 °C
420
205/370
48/56HRC
 Stabilize at –74 °C
Nitriding
410
Not recommended
420
Can be to 0.203 mm max
case depth.

RECOMMENDED PROCESSING SEQUENCE :

  • Forging
  • Annealing
  • Rough machine
  • Stress relieve
  • Finish machine
  • Preheat
  • Austenitise
  • Oil quench
  • Stabilize optional
  • Temper (double temper for better impact properties)
  • Final grinding
  • Nitriding-if required

Note : The above two grades can be supplied through ESR (Electro Slag Remelting) route also.

Typical Analysis :

Carbon 0.15% max Manganese 1.25% max Silicon 1.00% max
Chromium 12.00/14.00% Molybdenum 0.060% max Sulfur 0.15% min.

Corrosion Resistance :
416 Stainless has been used for corrosion resistance to mild atmospheres, fresh water, steam, ammonia, many petroleum products and organic materials and several mild acid environments. A polished finish is not necessary, but a smoother surface is helpful in providing added corrosion resistance. For optimal corrosion resistance, surfaces must be free of scale and foreign particles and finished parts should be passivated.

Workability :
Hot Working : Although this grade can be forged, it is not recommended for upsetting operations. To forge, heat uniformly to 1149/1232 °C, then forge and cool in air. Cool large forging slowly in dry lime or ashes. Trim hot if possible; otherwise, anneal and trim cold. Do not forge below 927 °C.

Machinability : 416 Stainless has easy machining properties, with speeds comparable to 1144 and 8620 leaded.

Heat Treatment :
Annealing : Heat uniformly to 650 / 760 °C; soak, then remove from the furnace and cool in air. Brinell hardness approximately 187. For maximum softness anneal from a temperature of 816 / 00 °C and cool in furnace. Brineel hardness 155.

Hardening : Heat to 928 / 1038 °C, soak at heat at least ½ hour, quench in oil. Hardness as quenched will be RC 36 to 41. Air cooling yield about Rockwell C 35-39.

Tempering : Temper to secure the hardness and mechanical properties required.

Typical Mechanical Properties :
Typical Room Temperature Mechanical Properties

1” (25.4 mm) round bar, hardened 1800 °F (982 °C) ½ hour, oil quench, tempered two hours

Tempering

Temperature

0.2%Yield

Strength

Ultimate

Tensile

Strength

% Elongation

In 2’’
(50.8 mm)

% Reduction

Of Area

Hardness
Impact Strength
°F
°C
Ksi
MPa
Ksi
MPa
Brinell
Rockwell
Izod

Charpy

V-Notch

Ft-Ib
J
Ft-Ib
J
300
149
138
951
176
1213
10
20
363
C38
20
27
20
27
500
260
136
938
171
1179
11
32
352
C37
25
34
22
30
700
371
136
938
171
1179
14
45
352
C37
20
27
22
30
900
482
125
862
160
1103
15
45
331
C35
16
22
15
20
1000
538
110
758
137
945
16
50
285
C30
25
34
23
31
1100
593
95
655
114
786
17
54
235
C22
40
54
40
54
1200
649
83
572
103
710
21
57
207
B95
55
75
50
68
1300
704
75
517
95
655
21
60
187
B92
80
108
75
102

Typical Analysis :

Grade
Car
bon
Sili
con
Mang
anese
Phos
phorous
Sul
phur
Chro
mium
Nic
kel
Moly
bdenum
Cop
per
Nio
bium
Hydro
gen>
Oxy
gen
Alum
inum
17-4 PH

0.05

0.35

0.70

0.030 max

0.020 max

17.0

4.0

0.03 max

4.0
0.30
< 2 PPM
< 20 PPM
0.05 max
Grade
Car
bon
Sili
con
Mang
anese
Phos
phorous
Sul
phur
Chro
mium
Nic
kel
Moly
bdenum
Cop
per
Nio
bium
Hydro
gen>
Oxy
gen
Alum
inum
15-5 PH

0.05

0.35

0.70

0.030 max

0.020 max

15.0

5.0

0.03 max

3.5
0.30
< 2 PPM
< 20 PPM
0.05 max

Applications :

Components / Parts for nuclear power plants, compressors, load cells, rockets, missiles, air craft, hot forging dies, extrusion tooling, pressure vessels, boiler parts, Shock resisting parts at corrosive environment, valves & actuator parts etc.

Mechanical Properties (minimum) :

Grade
Condition
UTS MPa
0.2% Y.S MPa
% El in 4D
% R.A
Hardness HB

17-4 PH

H 925
1170
1070
10
44
375 – 429
H 1025
1069
1000
12
45
331 – 401

15-5 PH

H1025
1069
1000
12
45
331 – 401
H 1150
931
724
16
50
277 – 352

Heat Treatment :

SOLUTION ANNEALING: 1038°C, Air cool or oil Quench

AGING: 482°C to 621°C depending on the mechanical properties requirement.

RECOMMENDED PROCESSING SEQUENCE :

EAF – LF – VD – VCD – VD – INGOT – ESR – SR – FORGE – SR – PROOF M/C –  SOLN.ANN – STRAIGHTENING – FINISH M/C – AGING – GRINDING