420SS Heat Treatment 1

[forging82]

I have some forgings that need to be heat treated to the following properties:
Hardness [HBN] 223-255
Tensile strength [ksi] 121 min
Yield strength [ksi] 100 min
Percentage elongation 20 min
Percentage reduction in area 60 min
Charpy impact [Ft lbs] 23 min



I have checked the ht ASM handbook and some other online sources(mills, matweb, ASM ht data sheet) but I want to get some feedback on here as I haven't worked with 420SS before. I am thinking they should be hardened at 1900F for 2 hours, oil quenched, and tempered at 1125F for 2 hours. Does this heat treat seem like it will work?
Thanks.

 

[Maui]

I'd suggest following the recommended practices outlined in Latrobe's data sheet for this grade:

http://customer.cartech.com/assets/documents/datasheets/LSS_420_MQ.pdf

Maui

 

[EdStainless]

What is your carbon level?
That could change the temper temperature.
Do you really think that you make 23 lb-ft impact? notched or un-notched?

First, you must anneal, follow the Latrobe instructions.

We used this for molds, we used two furnaces for hardening.
We would put parts into a furnace at 1200F, stabilize, then slowly ramp up to 1500F.
Then we moved them to the other furnace at 1825F and soaked.
Make sure that you oil isn't too cold and remove from oil when the parts are below 1000F.
Allow to still air cool, once they are down to 150F put into tempering, don't wait overnight.
You need a temper over 1050F, but how high depends on you C levels.
Still air cool and re-temper.

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Plymouth Tube

 

[arunmrao]

Ed, I liked your comments .

I'm just one step away from being rich, all I need now is money.
( read somewhere on the internet)

 

[forging82]

I'm not sure what the carbon level will be. We were originally told just to order it to ASTM A473 and to heat treat it. ASTM A473 only says that the C is .15 min. I plan to do some ht trials to figure out the process. Thanks for the input!