Mastery of Tianjin Steel Trade Co., Ltd. specializes in the supply of various types of spiral pipe, pipe, seamless tube, reasonable price and stock. Hydrostatic test should be done each pipe hydrostatic test without leakage, the Hunan spiral, test pressure press Calculate P = 2ST / D formula S- hydrostatic test of test stress Mpa, coil specifications, hydrostatic test stress test strip according to the corresponding standard of the minimum specified yield (Q235 to 235Mpa) of 60% selection. Regulators time: D <508 Test pressure holding time of less than 5 seconds; D≥508 test pressure holding time less than 10 seconds 4 non-destructive testing of steel welding seam, strip end weld and circumferential joints should be X-ray or ultrasound test. Mastery of Tianjin Steel Trade Co., Ltd. specializes in the supply of various types of spiral pipe, pipe, seamless tube, reasonable price and stock. Also known as spiral or helical spiral steel pipe, q345b spiral, is the low carbon steel or low alloy steel strip according to certain helix angle (called molding angle) rolled into a tube and then the tube seam welding made up, it can produce a large-diameter steel pipe with a narrow strip. Mastery of Tianjin Steel Trade Co., Ltd. specializes in the supply of various types of spiral pipe, pipe, seamless tube, reasonable price and stock. If the spiral pipe extrusion pressure is too small, large diameter spiral form crystals on a small number of common weld metal strength decreases, the force generated after cracking; squeeze if the pressure is too big, it will cause molten metal to be extrusion welding, not only reduces the weld strength, and will generate a lot of internal and external burrs, or even result in welding seam defects ride. Spiral plant, spiral Hunan, accessible from the Tianjin Steel Union Steel Union Co., Ltd. Mastery. Mastery of Tianjin Steel Trade Co., Ltd. (www.tjtdgl.com) (www.tdglgt.com) strong, credible, Liaocheng in Shandong steel industry has accumulated a large number of loyal customers. The company better work attitude and constantly improving access innovative ideas will lead VAI into the brilliant and you work for a better future!