Influence of different welding currents on the cold cracking susceptibility of the high-performance special steel

Abstract Because high-performance special steel often exhibits cold cracking with different welding processes, research on the susceptibility of this steel does not only provide technical support but also enriches its theoretical knowledge. Therefore, the influence of welding currents on the cold cracking sensitivity of high-performance special steel was investigated in this paper by microstructural observation, impact toughness, residual stress, and hardness measurement. The result shows that the microstructure is composed of martensite and retained austenite in the heat-affected zone (HAZ) of the high-performance special steel with various welding currents, the toughness decreased from 23.3 to 20.1 J with increasing welding currents (180, 200, 220, and 240 A). Simultaneously, the residual stresses increased from 356 to 396 MPa, and the cold cracking sensitivity gradually increased with increasing welding currents. When the welding current is increased to 240 A, quench-hardening cold cracks appear in the HAZ near the arc crater.