High-Temperature Strength
Hot strength is the ability of a material to withstand mechanical loads at high temperatures without deformation or fracture. It's critical for the safety and service life of weld joints.
Physico-chemical mechanism of action
Hot strength describes how well a material withstands mechanical loads at elevated temperatures. At high temperatures, the crystal structure and the bonding capabilities of the atoms in the material can change, affecting its mechanical properties.
Metallurgical relevance & risks when welding
Poor hot strength can cause a material to suddenly deform or fracture at high temperatures. This leads to safety risks and can drastically shorten the service life of weld joints. An example is the loss of toughness in steels when they are subjected to temperatures above their hot strength limit.
Workshop practice & instructions
To ensure hot strength, weld joints must be cooled at the correct temperatures and times. This requires careful control of the cooling rate and temperature profile. For steels with a high carbon content, the martensite phenomenon occurs when cooling is too fast. This results in a glass-hard, crack-sensitive structure, which reduces the hot strength and service life of the weld.