Welding of S31008 and Q345

When welding S31008 (i.e., 310S stainless steel) and Q345 low-alloy high-strength steel, conventional 304 welding parameters cannot be used directly due to the significant differences in their material properties. To ensure no cracks occur, the following guidelines should be followed: 1. Select appropriate welding materials: Use welding materials with good crack resistance, such as austenitic stainless steel electrodes with a high nickel content or nickel-based alloy electrodes. 2. Preheating: To reduce the cooling rate after welding, lower the hardness of the weld and heat-affected zone, and prevent the formation of cold cracks, Q345 steel should be preheated before welding. The preheating temperature is usually between 150°C and 300°C. 3. Control heat input: Maintain a low welding heat input to avoid overheating at the weld site; intermittent welding may be necessary during the welding process to control heat input. 4. Post-weld heat treatment: Appropriate post-weld heat treatment after welding can relieve residual stresses and prevent crack formation; the specific heat treatment temperature and holding time depend on the welding materials and the structure. These methods provide general guidance; specific welding parameters need to be determined through preliminary tests, taking into account the actual materials, structure, and process conditions. In actual operations, a Welding Procedure Specification (WPS) should be developed in collaboration with welding engineers to ensure the best welding results. .