1. Production of precision galvanized welded pipes with small internal burrs: One important aspect of the quality of precision galvanized welded pipe products is the removal of internal burrs in the weld seam. Due to spatial limitations, the removal of internal burrs in small-diameter welded pipes has always been a technical difficulty in the welded pipe manufacturing industry. Therefore, selecting suitable welding methods from the perspective of welding technology is an effective way to solve the problem. Welding methods with small burrs in production include DC welding and square wave resistance welding. The characteristics of these welding methods are uniform heating, smooth welds, good quality, and minimal formation of internal burrs, generally only 0.1-0.2mm. 2. Production of high-precision ultra thin wall welded pipes using micro beam plasma method: The micro beam plasma method is used to weld ultra thin wall welded pipes, with bright and smooth outer welds, flat and dense inner welds, and an average burr height of no more than 0.031-0.020mm. After welding, the outer diameter ovality of the steel pipe is 0.10-0.23mm, and the wall thickness difference is 0.020-0.034mm. After cold rolling, the excessive range of outer diameter ovality is effectively eliminated, and the wall thickness difference reaches 0.002-0.007mm. The quality fully reaches the level of precision seamless thin-walled pipes. After heat treatment, it has the same structure and properties as seamless pipes, but the economic superiority of producing ultra-thin pipes with seamless pipes is greatly inferior to ultra-thin pipes that are welded and then cold-rolled. 3. High strength welded pipes for the automotive industry: In recent years, the domestic and foreign automotive industry has promoted automotive lightweighting to save energy, and there is an urgent need to replace solid components with high-strength hollow parts. Developing high-strength welded pipes to replace seamless pipes to meet the needs of the automotive industry is technically feasible. In the development of high-strength welded pipes for the automotive industry, Japan has successively developed steel series such as C-Ti-B, C-Mn-Nb, C-Cr-AI-B, and adopted different heat treatment systems according to different usage purposes, such as annealing, normalizing, quenching, tempering, etc. Used for high-strength welded pipes in the automotive industry, their standard strength levels include 561MPa, 637MPa, 980MPa, etc. In addition to requiring high strength, welded pipes also require high plasticity, good processability, hardenability, strength, toughness, and fatigue strength.