Material for Metal Spring 4

[adag1971]

Dear all,

I have been following many of the forums in here, however wasn't able to find the right answer to my specific question.

I am currently working on repairing a mechanical device whereby I have difficulties in finding the right material for a metal spring (L-Shaped) which needs be strong enough (46-50 hrc) without being too brittle (needs to be able to withstand slight squeezing pressure). The part itself is only 0.3mm thick, which adds to the problem.

I am actually thinking of using an AISI 1045 or 1065 and tempering/heat treating it. I was also informed that Mn65 does not seem to be applicable for heat treatment.

Highly appreciate your ideas & help on this matter!

Max

 

[dgallup]

1045 might have too little carbon depending on your requirements. 1050, 1065, 1074, 1095 all are common spring steels. Did you try googling "spring steel"? The thickness should not be a problem.

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[TVP]

I agree with dgallup, but would probably start with 1065 and not 1050/1055. We routinely use spring steel in that thickness and hardness range, most of it with the 1074 composition. 1095 is usually more in the 50-56 HRC range.

 

[adag1971]

Thank you for your initial feedbacks.

In fact, I also started with a 1065 however encountered problems with a distortion of my parts during the hardening/heat treatment, quenching and tempering process which eventually got me thinking about the material and thickness I am using.

Based on information received the parts were hardened at 1475 - 1550°F, oil quenched, then tempered at 650°F for 2 hrs, then oil quenched. After reading many forums about this matter I figured that there are many ways to approach this. However, I still don't seem to find the right one for my use which could also be because I might use the wrong time cycles.

Highly appreciate your further ideas & help!

Max

 

[dgallup]

Try austempering, it should lower distortion.

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[swall]

If your part is perfectly flat (which you imply), I would try tempering with the part(s) clamped between plates or otherwise held flat, perhaps with weights on a flat plate. Austenitize, oil quench, quick temper at 400F unclamped, then final temper at 650F with the parts clamped/weighted.

 

[TVP]

Both options suggested by dgallup and swall are good. Another would be to purchase pre-tempered spring steel and just cut/press/form the shape.

 

[pugheng]

You may want to try a precipitation hardened stainless like 17-7 PH. It will harden up to RC 49 and because it uses a low temp heat treatment, it doesn't warp when treated. Not sure if you can get the thickness you need however

See here

http://www.aksteel.com/pdf/markets_products/stainless/precipitation/17-7_PH_Data_Bulletin.pdf