Stainless steel precision tubing are generally used in precision instruments or medical devices. They are not only expensive but also commonly used in key equipment and instruments. Therefore, the material and precision requirements and surface finish requirements of
precision stainless steel tubing are very high.
Usually, there are 301 stainless steel, 304 stainless steel, 316 stainless steel, 316L stainless steel, 310S stainless steel for civil use. Traditionally, 201,202 will be called stainless iron, because it is magnetic, magnets have an attraction. 301 is also non-magnetic, but it is magnetic after cold processing and has an attraction to magnets. 304,316 are non-magnetic, non-suction and non-viscous to magnets.
The main reason for magnetism is that the stainless steel material contains chromium, nickel and other elements in different proportion and different metallographic structure. Combined with the above characteristics, using magnets to judge the quality of stainless steel is also a feasible method, but this method is not scientific, because, in the production process of stainless steel, there are cold-drawing, hot-drawing, good post-processing, then less or no magnetism, bad, then greater magnetism, can not reflect the purity of stainless steel. Users can also judge from the packaging of precision stainless steel pipes, appearance: rough, uniform thickness, whether there are stains on the surface and so on.
