Views:2 Author:Site Editor Publish Time: 2017-11-30 Origin:Site
People who are engaged in the steel pipe industry all know DIN 2391, which is the standard of steel tube in Germany. However, maybe some of our customers don’t know steel tube and this standard very much.
1.We must know that DIN 2391 is a standard for cold finished seamless precision steel tube. Cold finished refers to the delivery condition of steel tube, which can be divided into two kinds: cold drawing and cold rolling. According to the different requirements and uses of steel tube, there are 5 kinds of final supply conditions: BK, BKW, BKS, GBK, NBK. These five states are determined by the annealing temperature and the cooling time. The five states make steel pipe get softer and softer, the tensile strength is getting lower and the extension rate is getting higher.
2.Steel tubes of different materials have different physical properties. We can analyze from their chemical composition(table 1). In a nutshell, the higher the carbon content, the harder the steel pipe is. In China, the type of steel is based on the carbon content. For example, if the steel contains 0.2% carbon, it is No.20 steel. However, the material is not the decisive factor in determining the soft and hard degree of the steel pipe. The time of annealing and cooling determine the final delivery of the steel tube.
3.This standard is used for seamless precision steel tube. So it it has strict rules for dimensions and limit deviations of the steel pipe. People engaged in the steel pipe industry must know theses three terms: inner diameter, outer diameter and wall thickness. The limit deviation for wall thickness shall be equal to 10% of the mean wall thickness. Our company controls the tolerance of steel tubes within ±0.5mm. Besides, the straightness is also very important. The straightness of our steel tube can be controlled in 0.1%. So, if you need seamless precision steel tube, Ray steel tube company will give you qualified products.
Above is brief summary about DIN2391. As a manufacturer of seamless precision steel pipe, the salesmen of Ray steel tube keep learning this standard. Whether we are customers or manufacturers, we should be fully aware of this standard. Because from this standard we can know the main requirements of the steel tube whether we produce or buy steel tube.