The production process of spiral pipes is similar to that of ordinary seamless pipes. For the welding of thick-walled seamless steel tubes, if strict welding techniques are not employed, cracks may appear in the welds. A reasonable welding process is determined through the analysis of the weldability of the base material. 1. Chemical composition of the base material: 45# steel is a medium-carbon steel, and the weldability of carbon steel changes significantly with increasing carbon content. As the wall thickness increases, so does the carbon content, leading to the formation of quenching tissues near the weld area under the action of the welding thermal cycle. This brittle state, combined with significant shrinkage stress, can cause cold cracks near the weld area. 2. Reducing the hydrogen content in the weld metal: During welding, the weld area absorbs hydrogen gas. Hydrogen is present in the moisture of the air and on the base material's oil污, iron锈, etc., which decompose into hydrogen atoms at the high temperature of the electric arc and dissolve into the welding pool. As the temperature drops, the solubility of hydrogen sharply decreases. Due to the rapid cooling speed of the joint area, the weld area can also be saturated with argon. Hydrogen precipitates at certain defects, and the residual hydrogen in the steel can also cause brittleness. 3. Welding preparation: It is essential to dry the bevel and use low-hydrogen welding rods before welding. The drying temperature should be 350 degrees Celsius, and the保温 time should be 2 hours. When in use, the welding rods should be stored in a rod tube and heated as needed to reduce the hydrogen content in the welding rods. Preheat the weld bevels by 250 degrees Celsius before welding. If cold cracks are clearly visible during the welding process, re-weld the area. Each joint must be welded continuously in one operation.