Thermochemical Treatment

Heat treatment in which the chemical composition of the surface layer is intentionally altered through the diffusion of elements at elevated temperatures.

When welding, the heat can change the composition of the material at the surface – elements migrate in or out. This can harden the edge zone or affect corrosion resistance.

If you don't control this, brittle martensite can form in the structure, and the weld becomes cracky and loses toughness. Excessive hardening also coarsens the structure and worsens mechanical properties.

It's important to control the temperature cleanly and not cool the weld too quickly. Keep the exposure time short and let the part cool slowly, then you get a uniform edge zone without nasty surprises.

MetallurgieSchweißtechnik