Hardness Measurement of Weld Tube

Welded pipe is made of steel plate or steel strip through bending forming, and then through welding. It can be divided into weld seam welded pipe and spiral welded pipe by weld form. According to the application, it is divided into general welded pipe, galvanized welded pipe, oxygen blowing metric welded pipe, welded pipe, wire casing, roller tube, deep well pump pipe, auto tube, transformer, electric welding thin wall pipe, welded pipe and spiral welded pipe. General welded pipe is working for low pressure liquid, is made of Q195A, Q215A and Q235A. Also, it can be manufactured with rigid steel conduit and other mild steel welding. Steel pipe should experiment with pressure, bending and flattening. There are several requirements of the surface quality. Usually, the delivery length is 4 to 10m. The specifications of the welded pipe is represented by nominal diameter (mm or inches), nominal diameter is different from the actual. According to welded pipe wall thickness, there are ordinary steel pipe and thickening steel pipe. According to the pipe end form, there are steel pipe with thread and steal pipe with no thread.

The following is the simple introduces of the application of several kinds of welded pipe.In usual, welded pipe is used to transport lower pressure fluid, such as water, gas, air, oil and heating steam.Common carbon electric wire conduit (GB3640-88) is a kind of steel pipe to protect electric wire which used in industrial, civil construction, machinery and equipment and other places to come on with electrical installation engineering.Straight electric welded pipe (YB242-63) is the pipe which weld and steel tube run parallel longitudinally. Commonly, it is divided into metric welded tube, welded thin-wall tube, transformer cooling pipe, etc.

Spiral submerged arc welded pipe with pressurized fluid convey (SY5036-83) is in hot rolled steel coil tube billet. Spiral shape and weld with double-sided submerged arc welding method. It is the spiral seam steel pipe to convey pressurized fluid. Spiral welded pipe is a strip coil as raw material, often warm extrusion molding, to automatically double-wire submerged arc welding process double-sided spiral welded pipe joints. Steel tube is strong in confined ability and welding performance, through strict scientific inspection and testing, the use of safe and reliable. Steel pipe diameter is big, high transmission efficiency, and can save laying pipelines. It is mainly used for conveying oil, natural gas pipeline. The edge milling process is widely used for manufacture of SSAW pipes. However, in case that proper control is not ensured, defects like welding misalignment ornon-through-welding may be caused.