Difference between seamless and seam pipe

无缝管is formed at one time during rolling. Welded steel pipes need to be welded after rolling, generally with spiral welding and straight welding. The performance seamless tube is better, and of course the price is higher.

Steel pipe is a kind of hollow long steel, which is used as a pipeline for conveying fluids, such as petroleum, natural gas, water, gas, steam, etc. In addition, when the bending and torsional strength are the same, the weight is light, so it is also widely used. Used in the manufacture of mechanical parts and engineering structures. Also used to produce a variety of conventional weapons, barrels, shells and so on.

同心度：制造过程无缝管is a hole punched out in a stainless steel billet temperature of 2200 ° f the, in this high temperature, the tool steel by stamping and drawing softens and spirally from Kongzhong Cheng-shaped out. So that the wall thickness of the pipe is not uniform and high eccentricity. Thus astm allows seamless pipe wall thickness than a slit tube wall thickness difference. Precision cold-rolled plate (width of 4-5 feet per roll) made a slit tube. These cold rolled sheet is usually the largest wall thickness difference is 0.002 inches. The steel sheet was cut into a width πd, where d is the outer diameter of the pipe. Seam pipe wall thickness tolerance is very small, and the entire circumference of the wall thickness is very uniform.

Welding performance:Average seam pipe and seamless pipe the chemical composition has a certain difference. The production of seamless steel component is only astm the basic requirements. Produce seamless tube steel with the chemical composition suitable for welding. For example, silicon, sulfur, manganese, oxygen and triangle ferrite and other elements can be mixed according to a certain proportion in the welding process with an easy transfer heat weld, so that the entire weld penetration. The lack of the above chemical composition of the steel, seamless, for example, in the welding process will produce a variety of factors of instability, is not easy to weld and welding impervious.

晶粒尺寸：usually, the grain size of the metal and the heat treatment temperature and to maintain the same temperature for the time. Therefore, annealed seam and seamless pipes are the same grain size. If the slit pipe with minimum cold treatment, grain size smaller than the grain size of the weld metal of the weld, and otherwise, the grain size is the same.

力量：管子的强度取决于合金组合物，其含有相同的合金，无缝和缝合管强的热处理本质上是相同的。在拉伸试验和三维振动试验之后，撕裂缝管几乎完全发生在远离焊接点或加热区域的地方。这是因为焊接杂质较少，氮含量较高，因此焊缝的强度在其他部位更好。然而，ASME锅炉和压力容器关联，狭缝管只能提供85％的许可证压力，这主要是由于今天使用的焊接设备提高了数据收集。通过超声波试管接头100％的ASME要求可以完全暴露在许可证压力下。同样，欧洲和亚洲还通过涡流试验管接头来保证焊接质量的性能，涡流检测需要批准法律程序和许可机构。经过瑞典能源部许可的特伦特涡流测试。ASME认为电流损失较小的质量性能是基于狭缝管。

耐腐蚀性能：corrosion resistance, good or bad is also vary depending on the composition of the alloy. The same chemical composition fully heat-treated seamless and the seam pipe corrosion resistance. ASTM provide supplementary test can prove the corrosion resistance of the weld is equal to or better than the metal being welded. Incomplete seam tube welding heat treatment in acidic chloride environment, corrosion will be accelerated, but only need corrosion test is, in fact, their environment is not so bad. Bending and extension: extension of the welding at the following tests can be specified by ASTM Verification: bend 45 °, then bent to 90 °, then flattened along the weld seam pipe Repeat the above steps; then turned so that the weld bending diameter up to 180 °. Weld quality standards adopted by the tear or intergranular separation are not allowed in the case of 40 times magnification. Pipe bending radius is controlled by the composition of the alloy, the general minimum bend radius for 2d. Conditions of the welding seam in a neutral or a state of compression. Moreover, the piping should be annealed to reduce its hardness, thereby improving the bending performance.

价钱：Price seam pipe is usually only half of the seamless.

壁厚和直径：小薄壁管的厚度和直径值优选通过焊接生产。厚度和直径大的厚壁管最好用冲压法制成。