Steel for Fineblanking-Low Distortion

[mewhg]

I have an application for fineblanking a small part out of 9 gage (.149") carbon or alloy steel. The part is about .5x.7 inch with some precision holes and surfaces.

After the fineblanking process I want to heat treat the part to 55RC but I want to minimize distortion.

Any suggestions to my steel choice?

TIA

 

[NickE]

The problem here is that you will have a hard time getting 55HRc out of anything but alloy steel. 1075 might do the trick (with a low temp temper) 4130 is only going to give you ~48HRc after the proper temper. Did you design the part? Did a metallurgist see the print and the FEA. That will help you pick a material, the presence of impact loading will also give you a bit of trouble.

maybe try 4340 or something with a bit more carbon. (IS there a such thing as 4360?)

 

[mewhg]

I did design the part. There really is not any impact loading...just other parts of the mechanism contact to edges. If 8640 came in strip I believe this would work as 60RC is possible with this alloy. I may be able to live with 48 RC....just that the parts contacting this part are 60RC and I wanted to more closly match the hardness.

 

[Hydroformer]

Is the contact point static or dynamic ? I imagine dynamic because of the fine-blank edge. If so, kinda sounds like a cam and follower application. I can't remember the mat'l type but GM truck hinges with an internal checker use this set-up. Buy a service part and have the cam analyzed. I believe the followers are powdered/sintered.

*Without data, you're just another person with an opinion.*

Hydroformer

 

[TVP]

It might be better to case harden this part rather than through harden it. Have you considered SAE 1020 or similar low carbon steel and then carburizing (or nitriding, or carbonitriding) it to a surface hardness equivalent to 55 HRC?

 

[mewhg]

That might be a good idea, TVP....I have worked wth case hardened 1018 before and the surface became very hard and a bit slicker than the nickel based P6 alloy that was used on some previous parts. It is a type of cam and follower......if it was thicker I might consider the powder metal setup Hydro....

 

[TVP]

mewhg,

Since you are planning to use fineblanking, I think it would be best to investigate surface hardening. In order to quench and temper to that type of hardness, you will need a C content greater than 0.40%, which means that the flow stress is going to be quite high. Fineblanking companies are usually quite reluctant to form 3 mm thick steel with high flow stress. Good luck with your project.

 

[unclesyd]

I think if you give these people a call you will be well severed in your quest. They were a great help to me one time, got me out of terrible bind.

http://www.theis-usa.com/tpscabt.htm