Comparison of 4140 to 41L40 2

[fastline12]

We currently use 4140 CDA for a part and quench/temper to about HRC55. It has worked very well for us. I believe we temper at 200* for 2 hrs. Anyway, I did not realize 41L40 existed until recent and wondering if this would have much structural deduction operating below 200*F? It seems it might help a bit with tooling for us which would be nice. However, I have not yet priced it and I know Lead is getting up there.

 

[redpicker]

In my opinion, leaded steels are not a good idea. In addition to the health and environmental effects and liabilities, there is the detrimental effect on mechanical properties. At 55 HRC, the SME effects could also result in unexpected failures.

rp

 

[CoryPad]

Agreed, very little reason to consider lead these days when modern steels can offer the same benefits with respect to machining.

 

[fastline12]

I think it would be pretty hard to argue that a non Lead alloy machines as easy as a Leaded alloy. However, if there would be sacrifice in structural properties, it may not be worth it.

 

[Metaldealer]

The Different Between 4140 and 41L40, Is that 41L40 has lead in for machining. They still have some in Southern Calif and Up in the Northwest.

 

[tbuelna]

Attached is a page from the Jorgensen Steel book about the relative machinability difference between 4140 and 41L40. The added lead does not appear to make a big difference.

 

[EdStainless]

At high hardness it will make less difference, and you will give up toughness and fatigue resistance.

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