4140 Tempering Curve 2

[paras99]

Hi,
does anyone know if there is data available for a hardness vs temperature curve for 4140 steel at a certain time. I have been looking everywhere and cant seem to find it.

Your help would be much appreciated.

thank you

Paras

 

[dbooker630]

The ASM Heat Treater's Guide has a hardness vs. tempering temperature chart but my version does not show any time reference. What time are you looking for?

 

[paras99]

Anywhere between 2 and 72 hours will work. Another thing I forgot to mention was that is the 4140 material air cooled instead of quenched

 

[metman]

Here you go.

it is on page 148

http://www.akronsteeltreating.com/images/ast-book.pdf

As for the time: 2 hours at temperature.

As for cooling from tempering temperture:
Air cooled is best. However, if it is not complex geometry or very thin it can be quenched. This won't affect the microstructure but will induce some residual stresses.

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