螺旋钢管将带钢送入焊管机组，经多道轧辊滚压，带钢逐渐卷起，形成有开口间隙的圆形管坯，调整挤压辊的压下量，使焊缝间隙控制在1~3mm，并使焊口两端齐平。
1.如间隙过大，则造成邻近效应减少，涡流热量不足，焊缝晶间接合不良而产生未熔合或开裂。
2.如间隙过小则造成邻近效应增大，焊接热量过大，造成焊缝烧损;或者焊缝经挤压、滚压后形成深坑，影响焊缝表面质量。
将管坯的两个边缘加热到焊接温度后，在挤压辊的挤压下，形成共同的金属晶粒互相渗透、结晶，终形成牢固的焊缝。螺旋钢管若挤压力过小，形成共同晶体的数量就小，焊缝金属强度下降，受力后会产生开裂;如果挤压力过大，将会使熔融状态的金属被挤出焊缝，不但降低了焊缝强度，而且会产生大量的内外毛刺，甚至造成焊接搭缝等缺陷。
螺旋钢管主要工艺特点：
1.成型过程中,钢板变形均匀,残余应力小,表面不产生划伤。加工的螺旋钢管在直径和壁厚的尺寸规格范围上有更大的灵活性,尤其在生产高钢级厚壁管,特别是中小口径厚壁管方面具有其他工艺无法比拟的优势, 可满足用户在螺旋钢管规格方面更多的要求。
2.采用先进的双面埋弧焊的工艺，可在佳位置实现焊接，不易出现错边、焊偏和未焊透等缺陷,容易控制焊接质量。
3.对钢管进行百分之100的质量检查,使钢管生产的全过程均在有效的检测、监控之下，有效地保证了产品质。
4.整条生产线的全部设备具备与计算机数据采集系统联网的功能,实现数据即时传输,由中间控制室对生产过程中的技术参数。
The spiral steel pipe will send the strip steel to the welded pipe unit, and the strip steel will gradually roll up after rolling by multiple rollers to form a circular tube blank with an opening gap. Adjust the reduction of the extrusion roller so that the weld gap is controlled at 1-3mm and the two ends of the welded joint are flush.
1. If the gap is too large, the proximity effect will be reduced, the eddy current heat will be insufficient, and the poor intergranular joint of the weld will result in incomplete fusion or cracking.
2. If the gap is too small, the proximity effect will increase, the welding heat will be too large, which will cause the weld to burn; or the weld will form a deep pit after extrusion and rolling, which will affect the weld surface quality.
After heating the two edges of the tube blank to the welding temperature, under the extrusion of the extrusion roller, the common metal grains infiltrate and crystallize with each other, finally forming a solid weld. If the extrusion pressure of spiral steel pipe is too small, the number of common crystals will be small, the strength of weld metal will decline, and cracks will occur after the stress; if the extrusion pressure is too large, the molten metal will be extruded out of the weld, which not only reduces the strength of the weld, but also produces a large number of internal and external burrs, and even causes defects such as weld overlap.
Main process features of spiral steel pipe:
1. During the forming process, the steel plate has uniform deformation, small residual stress and no scratch on the surface. The processed spiral steel pipe has greater flexibility in the size and specification range of diameter and wall thickness, especially in the production of high-grade thick wall steel pipe, especially in the small and medium-sized thick wall steel pipe, which has advantages that other processes can not match, and can meet more requirements of users in the specification of spiral steel pipe.
2. The advanced double-sided submerged arc welding technology can realize welding in a good position, and it is not easy to have defects such as wrong edge, welding deviation and incomplete penetration, and easy to control the welding quality.
3. Conduct 100% quality inspection on steel pipes, so that the whole process of steel pipe production is under effective detection and monitoring, and effectively ensure the product quality.
4. All equipment of the whole production line has the function of networking with the computer data acquisition system to realize the real-time data transmission, and the intermediate control room is responsible for the technical parameters in the production process.
