Impact of Heat Input on Mechanical Properties

The mechanical properties of a welded joint significantly depend on the cooling rate of the joint, and this in turn is influenced by the heat input (welding energy), plate thickness and working temperature (interpass temperature). The most significant microstructure changes from the viewpoint of the properties of the weld metal and the heat-affected zone take place during the cooling of the joint within the temperature range of 800-500°C. It is usually the cooling time t8/5, i.e. the time required for this temperature range to be passed, which is used to describe the cooling rate.