Stress Relieving 1

[xr4titis]

Dear Forum,

I have a case of a stainless torsion spring (likely mat'l ASTM A313 Type 302 Class 2) of .10" wire diameter wrapped around a cast quenched and tempered Chromoly steel shaft.

The trick is the shaft has large heads on either side and must be cast in one piece so the torsion spring must be hand wrapped around the shaft.

The problem is stress relieving the spring while it's wrapped around the shaft. I was told from an individual in the spring manufacturing industry (who I am unable to reach anymore) that this spring would be stress relieved at 500 degrees F for 30 minutes, but the ASTM spec for that mat'l requires 850 degrees F for the same amount of time. While I don't think 500F will affect the properties of the shaft, I'm concerned that 850F will.

Can anyone provide additional info on stress relief?

Gracias

 

[TVP]

According to SAE J230 the recommended heat treatment following winding for this grade is 290-320 C (550-600 F). A temperature range of 230-510 C (450-950 F) is given in the SMI Handbook of Spring Design for austenitic stainless steels, but this is meant to cover a wide range of grades and operating environments. Stick with 500-550 F for 30 minutes and you should be fine.

 

[EdStainless]

What is your temper temperature for the shaft?
Slightly higher temp would be a bit better, but 500 will work.
You need enough time to make sure that then entire spring reaches temp.

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