Method for heat treatment of large-diameter straight seam steel pipe
The forming technology methods for manufacturing large-diameter straight seam steel pipes include UOE forming method, row roll forming method (CFE), CE forming and so on. For most of the forming processes, the last process is to weld the pipe diameter again to increase the welded steel pipe. Diameter expansion is a pressure processing technology that uses hydraulic or mechanical means to apply force from the inner wall of the steel pipe to expand the steel pipe radially outward. Diameter expansion has become a very important process in the production of large-diameter longitudinally welded pipes that can ensure the finished pipe. The device is simple and effective. The process: use mechanical expansion to divide the diameter section of the side portion to radially expand along the pipe in a stepwise manner along the longitudinal direction, and plastic deformation is achieved during the entire length of the pipe section. Let me introduce to you the method of treating heat treatment of straight seam steel pipe.
First of all, the mold planning must be reasonable, the thickness should not be too large, the shape should be symmetrical, the deformation rules should be mastered for the larger deformation mold, and the processing allowance should be reserved. For some messy precision molds, heat treatment, aging heat treatment, nitriding heat treatment and quenching and mold control accuracy can be selected in advance. When repairing defects such as blisters, pores, abrasion, etc., cold welders and other correction technology equipment with low thermal influence are used to avoid deformation during the repair process. The precision messy mold is pre-heated to eliminate the residual stress in the mechanical process. For precision messy molds, if conditions permit, try to quench and use cryogenic treatment after quenching by vacuum heating. On the premise of ensuring the hardness of our country's molds, pre-cooling, hierarchical cooling quenching or warm quenching treatment technology can be used as far as possible. Reasonable use of materials. The mold should be selected for precision and messy steel materials. Good micro-deformed carbide segregation. Serious mold cast steel. It should be reasonable and transfer of heat treatment. The mold cannot be large, and the steel can be refined. Double solution heat treatment. Choose a reasonable one. The heating temperature.
Large-diameter thick-walled spiral pipe refers to a spiral steel pipe with a diameter of 1000 or more and a wall thickness of 10 or more. It is superior to ordinary spiral steel pipe in terms of mechanical properties such as compression and tension. There is a high demand for spiral pipes in engineering. The reason for thick-walled spiral steel pipes is that the pressure needs to be transmitted by certain media. General spiral steel pipes will not be able to withstand them. Increasing the cost of the project, if it is a dangerous medium, it is inevitable that we will increase the cost. Spiral seam arc welded steel pipe for common fluid conveying system pipeline.
Note:The ASTM A500 specification covers cold-formed welded and seamless carbon steel tubing in round, square, rectangular, and “special” shapes for welded, riveted, or bolted construction applications, as well as for general structural purposes.