Seamless Steel Pipe

    Hot rolling is relative to cold rolling. Cold rolling is rolling performed below the recrystallization temperature, and hot rolling is rolling performed above the recrystallization temperature.     Advantages     It can destroy the casting structure of steel ingots, refine the grains of steel, and eliminate the defects of micro-structure, so that the steel structure is dense and the mechanical properties are improved. This improvement is mainly reflected in the rolling direction, so that the steel is no longer an isotropic body to a certain extent; bubbles, cracks and looseness formed during casting can also be welded under the action of high temperature and pressure.     Disadvantages     1. After hot rolling, the non-metallic inclusions (mainly sulfides and oxides, and silicates) in the steel are pressed into thin slices, and delamination (interlayer) occurs. Delamination greatly deteriorates the tensile properties of the s...

　　The seamless tube for heat exchanger is one of the elements of the heat exchanger and is placed inside the cylinder for the exchange of heat between the two media. It has high thermal conductivity and good isothermal properties. It is a device that can rapidly transfer heat energy from one point to another, and has almost no heat loss, so it is called a heat-transfer superconductor and its thermal conductivity is several thousand times that of copper. 　　In addition to seamless tube, heat exchangers can also use a variety of enhanced heat transfer tubes, such as finned tubes, threaded tubes, spiral grooved tubes, and the like. When the heat transfer coefficient on the two sides of the inner diameter of the tube is greatly different, the fins of the fin tube should be arranged on the side with a low heat supply coefficient. 　　Commonly used sizes of heat transfer tubes (OD x wall thickness) are mainly Φ19mmx2mm, Φ25mmx2.5mm and Φ38mmx2.5mm seamless steel tubes and Φ25mmx2mm and Φ38m...