4140 Steel Hardening Question

[FlinterNick]

Anyone harden 4140 steel on Rifle Shoppe kits ?

Working on some barrel bands for a French musket, the bands need to fitted to the stock

I’m trying to form the steel band to the barrel, has anyone heated these up and treated?

Do you get cracks ?

 

[dave_person]

Hi,
It is tough steel and often does not need to be hardened. I would form it when bright red under heat and then let air cool. That may surface harden the steel enough for barrel bands. However, it can be hardened by heating to bright red and quenching in oil. It may crack if you quench in water. If you harden it, you will need to temper the bands. I would definitely temper them to blue (590-600 degrees).

dave

 

[FlinterNick]

Thanks Dave !

 

[toadboy65]

"Bright red" is pretty subjective, although some people are wizards at estimating the temperature of hot steel in a forge.
I am not, so I heat treat steel in an electric kiln, exactly by the numbers.
The numbers for 1440 are- heat to 1550 degrees F, oil quench.
Temper to 400 F for 55 HRc
Temper to 500 F for 50 Hrc

 

[FlinterNick]

"Bright red" is pretty subjective, although some people are wizards at estimating the temperature of hot steel in a forge.
I am not, so I heat treat steel in an electric kiln, exactly by the numbers.
The numbers for 1440 are- heat to 1550 degrees F, oil quench.
Temper to 400 F for 55 HRc
Temper to 500 F for 50 Hrc

I do the best I can in my small shop.

I use a graphite crucible to moderate the temperature to 1600-2000 range, and I measure the temperature with a high range temp gun. I try to keep it between 600-700 for tempering springs of 1095 and 6150 steel.

The 4140 steel Im not used of working with, it seems mild to me. Italian gun makers use 1070 steel on their metal fittings and some type of harmonic spring steel on their springs.

 

[LRB]

4140 steel is a common modern gun barrel steel, often just called chrome-moly steel. I would consider it over kill for ML fittings. 1018 cold or hot rolled would be plenty enough. 1070 steel would make a spring, but again, over kill for fittings.

 

[toadboy65]

I do the best I can in my small shop.

I use a graphite crucible to moderate the temperature to 1600-2000 range, and I measure the temperature with a high range temp gun. I try to keep it between 600-700 for tempering springs of 1095 and 6150 steel.

The 4140 steel Im not used of working with, it seems mild to me. Italian gun makers use 1070 steel on their metal fittings and some type of harmonic spring steel on their springs.

Some of the projects I work on have pretty specific tolerances, so a pretty well controlled setup is required. The downside of that is that it is easy to get used to, and I would not do a very good job heat treating in a forge. I have done it in the past, but have never been confident in my results.