LR gr.A marine steel plate processing and manufacturing industry began scientific research and application of welding technology since the beginning of the 20th century. In 1920, the US shipyard first selected welding technology to build ocean-going ships as a sign, making LR gr.A marine steel plate welding technology slowly Shipyards get application promotion and quickly replace riveting technology.
Because the alloy content of LR gr.A marine steel plate is relatively high, the hardening tendency of steel is relatively large. During welding, the hardness near the fusion line is the largest, which reduces the ductility and toughness of LR gr.A marine steel plate. Due to the heat of welding, a hardened structure is generated. At the hardened structure, the stress or strain exceeds a certain limit, and the hydrogen exceeds a certain limit. , Prone to welding cold cracks.
Therefore, certain welding process measures must be adopted for LR gr.A marine steel plates to ensure welding quality.
