heat treat vs strength

[downwash]

does the heat treatment of steel increase its elestic limit,ultimate strength, endurance limit? im mainly curious about bending loads. thanks

 

[CoryPad]

It depends on the alloy. In general, heat treatment increases all of those.

Regards,

Cory

Please see FAQ731-376 for tips on how to make the best use of Eng-Tips Fora.

 

[downwash]

thanks CoryPad the part in question would be a feathering spindle for a helicopter. i think 4140 would be the best but im not sure thanks again

 

[CoryPad]

4140 is a heat treatable alloy, so it will have higher yield, ultimate, and fatigue strengths after heat treatment.

Regards,

Cory

Please see FAQ731-376 for tips on how to make the best use of Eng-Tips Fora.

 

[TVP]

Just to clarify the yield, ultimate and fatigue strengths will be increased after hardening heat treatments such as 1) quenching and tempering or 2) austempering. Annealing, spheroidizing, etc. are heat treatments but they do not result in increased strength.

 

[downwash]

so if i understand corectly to increase its srength, yeild, fatiuge it will need to be heated to appropriot temp quench "oil quench"? drawn or drawn twice just like 01 type tool steel but at diffrent temps thanks again

 

[TVP]

downwash,

You have the correct understanding. Tool steels that have retained austenite upon quenching need to be tempered (drawn) multiple times in order to convert the retained austenite into martensite. Relatively low alloy steels like 4140 will only require one tempering treatment after oil quenching.

 

[davefitz]

some high temperature creep resistant steels have a critical need to properly N+T following bending to ensure proper crystal structure is maintained. So, in addition to YS, UTS, endurance, there are issues related to creep strength and notch toughness.

 

[downwash]

thanks much