The development prospects and facing issues of ERW pipe

Resistance welding is short of ERW steel pipe with number of advantages, such as high productivity, low cost, good dimensional accuracy, beautiful appearance. However, in the past, due to the poor reliability of the weld, great limitations on the use. The proportion of small pipe production.



ERW steel pipe welding mechanism made ​​gratifying achievements, and this theory as a guide to optimize. Automatic control technology to optimize the parameters given to ensure the weld quality greatly improved; due to the improvement of ultrasonic detection technology, ultrasonic flaw detector Wong stack trace detection can be achieved in the production line; due to the improvement of the level of automation. The annealing of the weld (normalizing) treatment step in the production line. The weld performance improvement.



Above several technical applications, greatly improved the reliability of ERW steel pipe welds. Making it increasingly wide range of applications. Currently, some of the world’s production of ERW steel pipes pipe plant can be applied in cold areas, and many countries have been building ERW pipe production line.



From countries ERW pipe production, in addition to the earlier high productivity, low into surgery, dimensional accuracy from the outside, the tensile strength of the weld. Elongation off and shrinkage, bending test at room temperature impact toughness values ​​can meet the specification requirements. But there are a lot of manufacturers of ERW steel pipe welds poor low-temperature toughness, which limits their use in cold areas.



The amount of heat input, the welding speed, the convergence angle and other factors are associated with the low temperature toughness of the weld, a large number of useful work has been done in this regard. Weld on both sides of the welding surface speed should be close to each other in the molding process, cold welding, and weld two, due to metal melt is poured to the surface separate speed, such as the former speed occurs if the latter speed is large will more foreign invasion FATT value increased, the literature recommended convergence angle of 5 to 6. Better welding speed to 20m/min specific circumstances specific analysis, I believe that after several tests to find the best welding process, thus improving the low temperature toughness of the weld.

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