A heat treating includes a series of thermal processes carried out on metals or metal alloys in order to achieve a particular metallurgical structure and specific final properties.
The steps consist of a heating at a suitable and predetermined temperature, keeping the piece at this T for enough time and cooling down to the ambient conditions in accordance with definite procedures.
The most important scopes of heat treatments are:
- Increasing the mechanical properties of the constituent material of the item;
- Improving the creep resistance;
- Reducing the hardness in the fusion and heat affected zone (HAZ);
- Removing states of strain hardening due to plastic deformation;
- Reducing the residual stress within the welding;
- Bringing back the material to the initial properties of corrosion resistance (for example, Cr-Ni and high nickel content alloys).
Metalprove S.r.l. chiefly carries out heat treatments of welding, by using electrical resistances as heating source. The main types of heat treatment performed are preheating, preheat maintenance and Post Welding Heat Treatment (PWHT).