ERW (Electric Resistance Welding) steel pipe is referred to as ERW pipe or HF welded pipe, it has many advantages as following:
1) high production efficiency, low cost, its price is about the the UOE straight seam submerged arc welded steel, 85%;
2) high dimensional accuracy, its roundness (Roundenss) is superior to spiral welded pipe, the counterpart can save a lot of hours in the field;
3) smooth surface, beautiful appearance, which is conducive to inner and outer coating coated. In the past, poor reliability of ERW pipe welds, pipe there have been a large number of accidents, thus limiting the use of ERW pipe. Recently, Zhejiang Jinzhou Group has invested heavily, through the joint efforts of researchers and pipe manufacturer, this situation has changed substantially of ERW steel pipe weld quality can be compared with the LSAW comparable.
The process of ERW pipe to take the following measures:
1)control heat input in the process, many factors affect the heat input, the first is the convergence angle (Convergency Angle). The results showed that, in the case of other factors constant, the convergence angle is too large to cause cold welding, the convergence angle is too small will result in too burning. Another factor affecting the thermal input pipe in the forward speed of the forming line. The results show that in the case of other factors constant, the speed is too fast can cause cold welding, too slow, could easily lead to burn.
2)enhance the line automatic detection tube factory in Jinzhou, in order to ensure the quality of ERW pipe, additional multi-channel flaw detection in pipe technology. Unwinding strip on both sides of the ultrasonic testing, eddy current inspection after the completion of the welding. In addition, a number of visual inspection, and sampling for the flattening test and other mechanical properties test.
Post time: Oct-21-2019