The Characteristics of Thermal Expansion Steel Pipe

Thermal expansion pipe is a steel pipe with special processing method, which is a hot expanding use of hydraulic or mechanical forcing the steel pipe from the pipe wall bulged radially outward pressure of the molding process. Mechanical way than hydraulically, simple and more efficient equipment in the world's most advanced system of several large-diameter welded pipe diameter pipeline expansion processes have been adopted. Thermal expansion of steel production process is a continuous rolling process without a hollow base metal mandrel. In ensuring the quality of the premise of the mother pipe welding, pipe tension reducing the overall process is the pipe is heated to 950 degrees Celsius, and then stretch reducing mill (tension reducing Machine has 24 times) rolled into a variety of outside diameter and wall thickness of the finished pipe produced using this process with the ordinary thermal expansion of high-frequency welded steel pipes are essentially different, heated by the furnace microstructure and mechanical properties of the weld and the parent can reach exactly the same addition, through a multi- passes stretch reducing mill makes steel rolling and automatic control of dimensional accuracy (especially the tube wall thickness and roundness accuracy) than similar seamless. Developed countries produced fluid pipe, seamless pipe has been widely adopted technology. Two-step thermal expansion pipe used to promote the expansion of the machine set-type cone mold expanding technology, digital intermediate frequency induction heating technology, hydraulic technology in one machine, with its reasonable process, lower energy consumption, lower capital investment, good product quality, a wide range of raw materials and product specifications applicability, flexible variable low-input production batch adaptability replace the traditional steel industry pull Dial expanding technology. Limited to steel pipe specifications are limited, according to the needs of the end consumer thermal expansion pipe so it was born, thermal expansion pipe specifications randomness is relatively large, generally based on customer needs and production, thermal expansion pipe is, we often say The thermal expansion, the density is relatively low but strong contraction pipe, (seamless pipe) can be referred to as thermal expansion. The thermal expansion characteristics of the pipe after the thermal expansion, the non-metallic inclusions inside the steel (mainly sulfides and oxides, and silicates) is pressed into the sheet, delamination (interlayer) phenomenon. Layered in the thickness direction of the steel tension performance deteriorated significantly, and there may be an interlayer tear weld shrinkage. Weld local strain-induced contraction of the yield point strain often reach several times larger than the load caused by the strain; residual stresses caused by uneven cooling. Residual stresses in the absence of external forces from the equilibrium of the internal stress of the thermal expansion of various cross-beam has such residual stresses, the greater the cross-sectional size generally of steel, the residual stress is larger. Although the residual stress from equilibrium, but still has some influence on the performance of the steel members under loads. Terms such as deformation, stability, anti-fatigue effects may adversely.