生产大直径焊管或筒体时,一般工序是:备料、在卷板机上卷成筒形,然后再纵焊。如果管子或筒体直径绝对值小或D/S比值小(即筒壁较厚),则在一般卷板机上往往无法卷制。对于不重要的焊管,一般工厂是采用备料、压半圆、两半圆对焊在一起、校正管口圆度的方法生产。这种方法的缺点是:生产效率低,管子椭圆度 The production of large diameter pipe or tube, the general process is: preparation, rolled into a roll in the machine, and then longitudinal welding. If the tube or barrel diameter absolute value is small or D / S ratio is small (ie thick wall), then in the general coiler can not be rolled. For not important pipe, the general factory is the preparation of materials, pressure semicircle, two semicircle butt together, the method to correct the nozzle roundness. Disadvantages of this method are: low productivity, tube ovality