Light big spiral steel pipe inside and outside after the first pre-welding process of welding (fine welding), welding can be in the best position to achieve less prone to the wrong side of the weld misalignment and lack of penetration defects such as welding quality, easy to control ---- I specializing in the production of thermal expansion of steel pipe, spiral steel pipe, high-frequency welded pipe, the annual distribution of the posterior wall of Baotou Steel, Tianjin Steel and other steel seamless steel pipe factory sided submerged arc welding process is second to none in North China, 35 technicians, thermal expansion pipe equipment machine units imported from Germany, the error is small, precise scale. Welcome to come to visit and negotiate.