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This box-beam production line is divided into semi-auto production line and automatic production line. The semi-auto line, which is composed of individual machines, has the advantages of flexible arrangement, low investment and small area. While, except the material loading at the beginning of line and unloading in the end where need the help of overhead crane, all the other stages of automatic line don't need the crane to conveying. Electro-slag welding prior to SAW welding technology , which can ensure the quality of electro-slag welding and SAW welding.