Straight seam steel pipe with rolled plate submerged arc welding technology

According to the estimates of the volume weight and actual weight per unit length of the coil, the budget of the long steel rolls, cut the whole rationale for determining the length and the number of qualified steel sheets; same time as the on-site inspection volume Kaiping head and capuchin defects, real serious for straightness excessive volumes and revenue from coil cut; straightness exceeded for larger volume header plate and capuchin board, increase milling capacity. Since coil slitting not been easy rolling defects and shortcomings exist side panels, such as heavy leather, folding, scarring, indentations, scratches, etc., this way the first time artificial material strengthening checks on the plate. In addition, because the steel billet is after hot-rolled into plate, then became the coil winding, coiling temperature of 500-600 degrees Celsius, and therefore it can not be stratified UT flaw in the steel mills, coil quality can not be guaranteed. So pipe technical requirements "shall be 100% of all steel tiered testing, carried out 100% of the scan." Domestic steel plant in the feed production lines are equipped with ultrasonic flaw detection stratification processes, thus online testing can be layered plate, just different scanning area, the general scanning area can reach more than 25%. To improve the scanning coverage, it will walk straight probe packet is changed to slow swing back and forth scan, the scan area can be increased to more than 40%, to ensure internal quality online steel. Collage class after roll milling and molding, in the pre-welding and welding inside and outside, to strengthen the welds and weld inspection is the best way to the edge of the board edge defects eliminated. Strengthen the edges on both sides of the weld 20-50mm base metal pipe weld inspection X-ray industrial TV or X-ray film inspection, pipe weld seam edge of the base metal increased stratification automatic UT flaw detection testing, can be very ensure good quality steel pipe weld edge. Strengthen steel exterior inspection of defects found in time. Using coil manufacturing SAW straight seam steel pipe into the boards after facing Kaiping low, steel head, there is a difference in the performance of the tail, roll slitting plate board which has not been easy flawed and can not be stratified UT flaw in rolling mills, Bauschinger Effect unknown trends and other issues. By volume header, volume and capuchin steel and steel tensile test and fracture toughness test analysis showed that the volume is relatively weak performance of steel and steel pipe. It is recommended to measure the position of the steel roll into the performance, the most representative of the volume and the ratio of the stove pipe performance. To improve the coverage of steel tiered testing, the grouping of the probe walking straight to the slow swing back and forth scan, the scan area can be increased to more than 40 percent, Paul let the intrinsic quality of the online steel. JCOE technology used in the steel coil made of steel pipe yield strength than an average of about 30MPa, yield than the average increase of about 0.02; description of the specification coil manufacturing process using JCOE straight seam submerged arc welding pipe smaller Bauschinger effect, far less than the molding process deformation strengthening, mainly in material deformation strengthening based. Coil made using UOE process pipe, steel pipe base metal transverse Bauschinger effect is more obvious, with an average of 24MPa; steel base metal vertical Bauschinger effect is not obvious, mainly for the vertical steel yield strength increased on average than 36MPa, the same also lead to material deformation strengthening.