seamless steel pipe and ordinary steel pipe

The ordinary steel pipe, such as tap water pipes, It is usually welded by flat plate bending, you can find a weld above; the diameter is generally thick spiral welded seam. Seamless steel pipe is generally molten molten steel through the annular backlog out after the tensile and other processing technology molding, so there is no weld. In terms of performance, especially the pressure capacity is much higher than ordinary steel pipe, it is often used for high-pressure equipment, Such as hydraulic equipment, or pipe connections. The weld quality of ordinary steel pipe is also the main factor affecting the overall performance. People who have lived in the north generally experience the freezing of water pipes or heat pipes in winter, where the cracks are usually welded.

Seamless steel pipe for the use of hot-rolled or cold drawn, welded with welded sheet metal, weld straight seam, spiral weld. Conditions of use than seamless steel tube subject to more restrictions. Seamless steel pipe is a solid tube after piercing the rolling, according to different production methods can be divided into hot-rolled tube, cold-rolled tubes, cold drawn tubes, extruded tubes, etc. 

1.Hot-rolled seamless pipe is generally produced on automatic pipe rolling units. Solid tube after inspection and removal of surface defects, cut to the desired length, the center of perforation end of the surface of the tube, and then sent to the furnace heating, perforation in the piercing machine. In the perforation while continuing to rotate and forward, under the action of the roll and the head, the gradual formation of the hollow tube cavity, said the capillary. Then sent to the automatic rolling machine to continue rolling. Finally by the whole machine are the entire wall thickness, diameter sizing, to meet the specifications. The use of continuous rolling mill production of hot-rolled seamless steel pipe is a more advanced method. 

2.If you want a smaller size and better quality seamless pipe, you must use cold-rolled, cold drawn or a combination of both methods. Cold rolling is usually carried out on a two-roll mill. The steel is rolled in an annular groove of variable cross-section circular hole and an immobile tapered head. Cold drawing is usually carried out on a single or double chain cold drawing machine of 0.5 to 100T.

Seamless tube appearance of quality: the inner and outer surface of the pipe without cracks, folding, rolling off, from the layer, hair lines and scar defects exist. According to the chemical composition and mechanical properties of domestic seamless pipe, such as 10, 15, 20, 25, 30, 35, 40, 45 and 50 of the chemical composition of the steel should be consistent with the provisions of GB / T699-88. Imported seamless pipe according to the relevant provisions of the standard test. 09MnV, 16Mn, 15MnV steel chemical composition should be consistent with the provisions of GB1591-79.

Seamless pipe imports are large. The main importing countries are Germany and Japan. European countries such as Romania, Russia, Switzerland, France, Spain, the Czech Republic, Yugoslavia, Hungary and other countries have imports. There are a small amount of imports from South America, Argentina, Mexico and other countries. If you have any new plan of it, please do not hesitate to contact us at any time.