Welding electrodes should be kept dry before use. Titanium-calcium type electrodes should be dried at 150℃ for 1 hour, and low-hydrogen type electrodes should be dried at 200-250℃ for 1 hour (repeated drying should be avoided, otherwise the coating will easily crack and peel off). Prevent the electrode coating from sticking with oil or other contaminants, as this will increase the carbon content of the weld and affect the quality of the weldment. During elbow welding, repeated heating causes carbide precipitation, reducing corrosion resistance and mechanical properties. Post-weld hardening is significant, making cracking more likely. If using the same type of electrode, preheating to above 300℃ and slow cooling to around 700℃ after welding are necessary. If post-weld heat treatment is not possible, chromium-nickel stainless steel electrodes should be used.
To improve the corrosion resistance and weldability of stainless steel elbows, adding appropriate amounts of stabilizing elements such as Ti, Nb, and Mo can improve weldability. When using the same type of chromium-stainless steel electrode, preheating to above 200℃ and tempering to around 800℃ after welding are required. If the workpiece cannot be heat-treated, then chromium-nickel stainless steel welding rods should be used.
