Tempering and re-tempering 1

[leizhou]

I have a component been quenched and tempered at 580C
The material did not pass the impact test, would a 650C retempering make any difference?

What is the difference between a direct tempering at 650C and tempering at 580C and retempering at 650C?

It is a low carbon steel, very low alloy elements.

Thanks for any advise!

 

[metengr]

leizhou;
A second temper treatment performed at a higher temperature will reduce strength, reduce hardness, increase elongation and should increase notch toughness (impact energy).

Can you provide the chemical composition of the steel and desired mechanical properties and threshold impact requirements? This may help to fully answer your question.

Typically, carbon is the main driver for notch toughness; higher carbon results in lower notch toughness. However, other parameters come into play like grain size and alloy elements. This is the reason for my question.

 

[stanweld]

The higher tempering temperature may or may not increase absorbed energy values. More info is required; e.g., size/thickness of part, austenitizing temperature, quench medium, steel chemistry, existing microstructure, absorbed energy requirements at the test temperature.

 

[Neubaten]

Double tempering is not uncommon for some steels, due to some precise reasons.

The point is double tempering is commonly for tool steel, with high carbon content. What is the carbon content of your steel?