Heating HT steel

[Peter CaswellParticipant @petercaswell93233]

Hi all hoping for some info as to whether heating an 8.8 HT bolt to cherry red will effect it's tensile strength.

[Peter CaswellParticipant @petercaswell93233]

[HopperParticipant @hopper]

Could make it brittle if you cool it too quickly.

[AdrianRParticipant @adrianr18614]

I would say it would be very unlikely to not affect its strength. The 8.8 specification is for medium carbon steel, quenched and tempered.

You also don't say if the red heat is under load or is how you are operating it.

Personally I would bin it. If it is for something critical you cant trust it, and if it is in your bits box you may end up using it for something critical. An accident waiting to happen.

Adrian.

[SillyOldDufferModerator @sillyoldduffer]

Impossible to predict without knowing what the steel is. The 8.8 strength specification can be met by many different steels – carbon, stainless, or alloy types. How each behave after being heated cherry red varies, but it can be assumed it's unlikely to make them stronger unless followed by suitable heat treatment!

If strength or safety matters, I'd assume an 8.8 bolt made red-hot was junk, perhaps considerably weaker than an ordinary unmarked bolt.

Dave

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