a. Remove the oil stain, rust, water and sundries from the welding wire, working groove and its adjacent surfaces.
c. DC reverse connection and short arc welding shall be adopted.
a. Reduce the content of harmful elements such as sulfur and phosphorus, and weld with materials with low carbon content.
c. The weld with shallow penetration shall be used to improve the heat dissipation condition so that the low melting point material floats on the weld surface and does not exist in the weld.
в. Welding specifications shall be reasonably selected, and preheating and afterheating shall be adopted to reduce the cooling rate.
е. Adopt reasonable assembly sequence to reduce welding stress.
a. Pay attention to the strengthening effect of metallurgical elements and their influence on reheat cracks.
c. Reduce residual stress to avoid stress concentration.
в. During tempering, avoid the sensitive temperature zone of reheat cracks or shorten the residence time in this temperature zone.
a. Low hydrogen type alkaline welding rod shall be used, dried strictly, stored at 100-150 ℃, and used when taking.
c. Select reasonable welding sequence to reduce welding deformation and welding stress.
в. Conduct hydrogen elimination heat treatment in time after welding