Briefly introduce: The difference between hot-expanded seamless steel pipe and seamless steel pipe The company wants to buy 100 tons of large-size (530*9) seamless steel pipe, call the steel pipe factory that it is in stock, but it needs to be hot-expanded. I can't understand it. Thermal expansion will not harm the quality of seamless steel pipes. What is the difference between thermal expansion and seamless heating? The price seems to be cheaper than thermal expansion.
Hot-expanded seamless steel pipe is a kind of seamless pipe, because you are buying 530mm pipe, there is no such model in China, the maximum is like 460MM, the manufacturer only reheat expansion (reprocessing), generally should damage The quality of the pipe, of course, see what you do with it. The price is certainly more expensive because of the two passes.
One is the thermal expansion on the bar, that is, piercing the middle of the bar, and slowly expanding it into a tube with a mandrel. The other is to expand after the tube has been heated, so that the defects on the original tube will be enlarged. In comparison, the first type of quality is better than the second type, and what you are talking about belongs to the second type. Compared with the original unexpanded seamless pipe, there is of course a gap between quality and chemical properties. The price will be cheaper.
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