UN. Remove the oil stain, rust, water and sundries from the welding wire, working groove and its adjacent surfaces.
B. Alkaline welding rods and fluxes shall be used and thoroughly dried.
C. DC reverse connection and short arc welding shall be adopted.

Crepitio

UN. Reduce the content of harmful elements such as sulfur and phosphorus, and weld with materials with low carbon content.
B. Certain alloy elements are added to reduce columnar crystals and segregation. For example, aluminum and iron can refine grains.
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.
D. Welding specifications shall be reasonably selected, and preheating and afterheating shall be adopted to reduce the cooling rate.
e. Adopt reasonable assembly sequence to reduce welding stress.

UN. Pay attention to the strengthening effect of metallurgical elements and their influence on reheat cracks.
B. Reasonably preheat or use afterheat to control the cooling rate.
C. Reduce residual stress to avoid stress concentration.
D. During tempering, avoid the sensitive temperature zone of reheat cracks or shorten the residence time in this temperature zone.

UN. Low hydrogen type alkaline welding rod shall be used, dried strictly, stored at 100-150 ℃, and used when taking.
B. The preheating temperature shall be increased, the post heating measures shall be taken, and the interpass temperature shall not be less than the preheating temperature. The reasonable welding specification shall be selected to avoid brittle and hard structures in the weld.
C. Select reasonable welding sequence to reduce welding deformation and welding stress.
D. Conduct hydrogen elimination heat treatment in time after welding