SSAW Pipe

　 　Induction welding 　　The two main aspects of HF welding are processes and power supplies. Each of these can be broken down further into subcategories. Processes. The two HF welding processes are HF contact and HF induction. In both processes, the equipment that provides the electrical current is independent from the equipment that supplies the forge pressure. Also, both HF methods can employ impeders, which are soft magnetic components located inside the tube that help to focus the weld current in the strip edges. 　　Contact welding description 　　HF Induction Welding. In the case of HF induction welding, the weld current is transmitted to the material through a work coil in front of the weld point. The work coil does not contact the tube--the electrical current is induced into the material through magnetic fields that surround the tube. HF induction welding eliminates contact marks and reduces the setup required when changing tube size. It also requires less maintenance than con...

　 　Boiler tubes 　　Defect localization and analysis, mainly for the defect depth 0.2 ~ 0.5mm, the length of 20 ~ 50mm superficial cracks, which causes the piercing of minute defects generated in the process, or rolling the first and second plurality of specifications by trauma, Four planes during rolling 20g high-pressure boiler tube by the inner surface of the oxide residue effects formed in the slide and scarring defects, these defects after rolling reduction of squash and stretch Zhang aggravated. 　　Through the high-pressure boiler tube double length number tracking found that injury concentrated in the steel tube end report first, twice-foot (from the pipe end within 25m), is closely related to the capillary head borax oxide accumulation, small-diameter steel pipe defect in the front of the capillary the higher the ratio of the rolling zone appears. Through the above analysis we can draw the following conclusions: 　　(1) the presence of perforated capillary end in addition to ...

　　Hot rolling, as the name suggests, the temperature of rolled piece is high, so the deformation resistance is small to achieve large deformation. Take rolling of steel plate for example, the general thickness of continuous casting slab is about 230mm, and after roughing mill and finishing mill, the final thickness is 1~20mm. At the same time, due to the small thickness ratio of steel plate, the dimension accuracy is relatively low, it’s not easy to cause shape problem. 　　 Advantage 　　It can destroy the microstructure of ingot casting, grain refinement of steel and eliminate microstructure defects, so that make steel structure compact and improve the mechanical properties. This improvement is mainly reflected in the rolling direction, so that the steel no longer is isotropic; Formation of bubbles, cracks and loose when pouring can also be welded under high temperature and pressure. 　　The technological process of hot-rolled seamless pipe 　　round billet→heating→perforation→extrus...

　　 Seamless steel pipe wall thickness inspection 　　Micrometer is the main tool that is adopted. When you check, left hand holds the micrometer stand, with right hand rotation induced wheel, and the wire rod should be coincident with the diameter of the measuring point. Once found that the wall thickness is not qualified, it should be marked in time. 　　Outside diameter, ellipse of seamless steel pipe inspection 　　Calipers, vernier caliper should be taken. The caliper should be perpendicular to the axis of the steel pipe in checking, measuring the maximum and the minimum point when the pipe rotated slowly. Founding the outer diameter of large or small, you should mark it in time. 　　Seamless steel tube length inspection 　　The steel tape can be measured directly by metallic tape. 　　Bending inspection of seamless steel tubes 　　With the tools of level, feeler and line. 　　End profile inspection 　　At two ends of the steel tube should be cut into specified angle and remove bu...

　　 Cold rolling seamless pipe 　　Cold rolled seamless pipe is a seamless steel pipe for high dimensional accuracy and good surface finish. Cold rolled seamless pipe in addition to include the general steel, low and medium pressure boiler tube, high-pressure boiler tubes, alloy steel pipe, stainless steel pipe and oil cracking tube, also includes carbon thin wall steel pipe, alloy thin wall steel tube, thin-walled stainless steel pipe and special-shaped steel tube. The diameter of cold rolled seamless steel pipe is 6mm, wall thickness is 0.25mm, while the diameter of thin-walled tube can be 5mm, wall thickness can less than 0.25mm. The dimensional accuracy of cold rolling is higher than that of hot rolling. 　 　Hot rolling seamless pipe 　　Hot rolling is relative to the cold rolling. Cold rolling carries on rolling below the temperature of recrystallization, and hot rolling is above the recrystallization temperature. Hot rolled seamless steel pipe is generally divided into low, medi...

　　There are three common methods for forming welded steel pipes: 　　1. Single radius forming method 　　The single-radius roll forming method has three methods: a circumferential bending forming method, an edge bending forming method, and a center bending forming method. The single radius forming method is: the hole type is composed of a single radius, and the forming machine horizontal roller and vertical roller are alternately arranged, and the strip is formed. From the middle of the horizontal roller and the vertical roller, the flat plate is gradually bent into a circular tube. 　　2. Circular bending forming method 　　The strip is bent and deformed at the same time in the whole width direction, and the bending radius of each frame is gradually reduced; the edge bending forming method starts from the edge of the strip, the bending radius is constant, and the deformation angle is gradually increased to reduce the middle portion of the strip. Width until the steel strip is rounded;...

　　The so-called seamless steel tube yield strength refers to the yield limit when the seamless steel tube yields, that is, the stress against the slight plastic deformation. External forces greater than this limit will permanently disable the part and will not recover. 　　The external factors that affect the yield strength of seamless steel tubes are: temperature, strain rate, and stress state. As the temperature decreases and the strain rate increases, the yield strength of the material increases, especially the body-centered cubic metal is particularly sensitive to temperature and strain rate, which leads to low temperature embrittlement of the steel. The effect of the stress state is also important. Although the yield strength is an essential indicator of the intrinsic properties of the material, the stress state is different and the yield strength values are different. 　　The intrinsic factors affecting the yield strength of seamless steel tubes are: bonding bond, organization, s...