410 / 420 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.