Quench Hardening Residual Stress State

Make sure the weld doesn't cool down too fast. If you quench the material too much, you'll get hard, brittle microstructures and internal stresses that can later lead to cracks. Especially with thick parts or when you're in a hurry, let the weld cool slower, for example by preheating or using a calm welding technique. This keeps the microstructure tough and the weld can withstand loads without residual stresses causing trouble.