Influence and function of various elements on the performance and structure of square tube

2020-11-20 09:49:09

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1、 The decisive role of chromium in square tubes: only one element is needed to determine the nature of square tubes, which is chromium. Each square tube contains a corresponding amount of chromium. So far, there is no chromium free square tube. The basic reason why chromium has become the main element determining the performance of square tubes is that the addition of chromium as an alloying element in steel promotes its internal contradictory operation intention to be conducive to the development of corrosion resistance. This change can be explained from the following aspects:

Carbon is one of the main elements of industrial steel. The properties and microstructure of square tubes are largely determined by the carbon content in steel and its distribution mode, especially in square tubes. The influence of carbon on the structure in the square tube mainly shows two aspects as usual. On the one hand, carbon is an element that stabilizes austenite and has a great degree of effect (about 30 times that of nickel); on the other hand, because of the great affinity between carbon and chromium, it forms a series of complex carbides with chromium. Therefore, in terms of strength and corrosion resistance, the role of carbon in square tubes is contradictory.

The surface of fake and inferior square tubes is often pitted. The pitted surface is the irregular concave and convex defect on the surface of the square tube caused by the serious wear of the rolling groove. Because of hypocrisy Square tube manufacturer In pursuit of profit, it often appears that groove rolling exceeds the standard. 　； Fake square tubes are easy to fold. Folding is a variety of broken lines formed by the appearance of square tubes, and this defect often runs through the longitudinal direction of the whole product. The reason for folding is that the fake and inferior manufacturers pursue efficiency, and the reduction is too large, resulting in ears. The folding will occur during the next rolling. The folded product will crack after bending, and the strength of the square tube will drop greatly. The appearance of fake and inferior square tubes is easy to produce scars. There are two reasons: 1. The quality of fake and inferior square tubes is uneven and there are many impurities. 2。 The guide equipment of fake and inferior material manufacturers is rough and easy to stick steel, and these impurities are easy to produce scars after biting the rolls.