Heating HT steel

Heating HT steel

This topic has 4 replies, 4 voices, and was last updated 18 July 2020 at 13:02 by SillyOldDuffer.

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18 July 2020 at 12:24 #486423
Peter Caswell
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@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.
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18 July 2020 at 12:24 #27522
Peter Caswell
Participant
@petercaswell93233
18 July 2020 at 12:43 #486425
Hopper
Participant
@hopper
Could make it brittle if you cool it too quickly.
18 July 2020 at 12:57 #486427
AdrianR
Participant
@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.
18 July 2020 at 13:02 #486429
SillyOldDuffer
Moderator
@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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