JCOE焊管椭圆度和管径误差的控制

通过分析JCOE双面埋弧焊管的生产工艺特点，包括原材料性能、成型、预焊和扩径的工艺参数对铜管椭圆度和管径误差的影响，总结出：JCOE钢管管端椭圆度≤0．012D时。椭圆度指标会有明显提高，钢管平均椭圆度一次合格率从原来的85．4％提高到98．46％；钢管管端直径误差（D≥610mm）控制在±1．3mm，管端管径尺寸精度控制也能得到明显改善，管端管径一次合格率从原来的90．56％上升至现在的99-47％。指出了钢管椭圆度调整方案和铜管管端直径误差控制改进办法，以及常见问题产生的原因和改进措施，对提高铜管的椭圆度和管径精度有一定借鉴意义。

Control Ovality and Diameter Tolerance for JCOE Pipe

Through analysis on process characteristics of JCOE two-side submerged-arc welded pipe,including raw material performance,forming,tack welding,as well as the effect of expansion on ovality and diameter tolerance.The results indicated that when the ovality of pipe end is not more than 0.012D,the ovality index increases obviously,the one-pass conformity rate is enhanced from 85.4% to 98.46%;the diameter(D≥610 mm) tolerance of pipe end is controlled at ±1.3 mm,the accuracy of pipe end diameter is improved greatly,and one-pass conformity rate is enhanced from 90.56% to 99.47%.In the end,it pointed out the adjustment approach for steel pipe ovality,improved methods for controlling pipe end diameter tolerance,the reason for common problems and improvement measures,which delivers significant value for improving ovality and the accuracy of diameter.