4130 Application and Heat Treatment 1

[mewhg]

We have a .120" thk sheet metal pawl type part that has traditionally been stamped from 1050/1060 steel, milled to produce a sharp edge and then heat treated to 50 HRC.

Volumes are increasing and we want to look at a fineblanking.

The fineblanking people want to use 4130 as its easier for them to blank. They say they can get 4130 to 50 HRC but in my search on heat treatment 4130 is usually used at lower hardness (40-45 HRC). As quenched, the hardness of 4130 is published as 52 HRC.

This part is like a pawl to a ratchet. Not a lot of load but another component snaps past the sharp edge (so there is a bit of low intensity impact). The sharp edge will round over a bit on the 1050 steel parts but then the rounding stablizes during use. The part dimensions are about 1" x 1/2".

The manufacturing process would be to fineblank out of .156" thk 4130, heat treat, then grind the sides to .120" thk, then form a sharp edge by a gang grinding operation.

I guess my questions are will 4130 hold up like the 1050 parts?

Is it a good idea to run 4130 at 50 HRC?

What kind of a temper will produce 50 HRC on 4130?

I have always selected steels that would give the required hardness after a "good temper" and that using a steel at the very top of it's hardness range is not a good idea.

Thanks in advance....

 

[swall]

How were the 1050/1060 parts heat treated? Through hardened, induction hardened? You might want to look at carburizing and use 4118 or 4120 instead of 4130. You can easily get a Rc 55 case while retaining a tough core. Might even be able to get by with carburized 1020.

 

[israelkk]

Swall:

To my opinion and experience the edge of the "pawl" will be completely case hardened and will be brittle and will break if induction hardening, carburizing or nitriding or any other similar process will be used. The part should be through hardened with enough toughness.

 

[unclesyd]

Here is a procedure for getting your hardness range with fairly good impact values.

Normalize @ 1600F air cool
Reheat to 1575F Quench in water.
Temper @ 400F
The Elongation is 10%

This will give you a Rc 49 with an IZOD of (32).
The IZOD number seems high for such a low drawing temperature but I have the same number from two sources.

Even with this material you need to watch your radii and section changes. If you have any problem with cracking you might try an oil quench from 1600F with the same tempering temperature

 

[mewhg]

The 1050 part was through hardened. Carburizing or nitriding is not an option as the secondary operation that makes a sharp edge has to be performed after heat treat due to some really close tolerances.

Thank you everyone and thanks especially to Unclesyd. I will prototype and test with that heat treat.

 

[wbrokow1]

Unclesyd:

Is the the heat treatment process you describe for 4130 or 1050?

 

[unclesyd]

The heat treatment given was for 4130.