The minimum tempering time is generally about 1 hour after the metal reaches the tempering temperature.
Larger or thicker components may require a longer tempering time.
Proper time ensures uniform properties and stress relief throughout the metal.
In this article:
What is the minimum tempering time?
The minimum tempering time is generally about 1 hour after the steel reaches the tempering temperature.
A common industrial guideline is:
- Minimum: 1 hour
- Often expressed as 1 hour per inch (25 mm) of section thickness
- Larger or thicker components may require longer holding times for uniform tempering.
The purpose of maintaining this time is to allow:
- Relief of internal stresses
- Carbon diffusion from martensite
- Formation of tempered martensite
- Uniform properties throughout the material
For many engineering and heat-treatment exam questions, the expected answer is simply:
Minimum tempering time = 1 hour.
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