Verify that stainless steel pipes contain iron without magnets correctly.

Release time:

2018-05-30

Verify that stainless steel pipes contain iron without magnets correctly. We often use magnets to absorb stainless steel pipes to verify their advantages and disadvantages.

Verify that stainless steel pipes contain iron without magnets correctly. We often use magnets to absorb stainless steel pipes to verify their advantages and disadvantages. Do not absorb no magnetism, think it is good, true price; suction magnetic, it is considered fake counterfeit goods. In fact, this is a one-sided, unrealistically discriminating method.

There are many kinds of stainless steel, which can be classified into several types according to their organizational structure at room temperature.

1. austenitic somatotype: 304, 321, 316, 310, etc.

2. martensite or ferrite type: 430, 420, 410, etc.

The austenite type is nonmagnetic or weakly magnetic, not magnetically adsorbed. Martensite or ferrite are magnetic and can be adsorbed by magnets.

Most of the stainless steel, usually used as a decorative tube, is 304 of the austenitic body. Generally speaking, it is non magnetic or weak magnetic, but it may be magnetic because of the chemical composition fluctuation or processing state, but it can not be considered as a fake or unqualified. What is the reason for this?

It is mentioned above that the austenite is nonmagnetic or weakly magnetic, while martensite or ferrite is magnetic. Due to improper segregation or improper heat treatment during smelting, a small amount of martensite or ferrite can be formed in Austenitic 304 stainless steel pipe. In this way, the 304 stainless steel tube will have weak magnetism and will be magnetically adsorbed.

In addition, after cold processing, the structure of 304 stainless steel tubes will be transformed into martensite. The greater the deformation degree of cold processing, the more martensite transformation, the greater the magnetic properties of the 304 stainless steel tube. For example, the same batch of steel strips, producing a diameter of 76 tubes, without obvious magnetic induction, producing 19 tubes. Because of the larger deformation of the cold bending, the magnetic sense is obvious. Because the deformation of the production rectangular tube is larger than that of the circular tube, especially the folding part, the deformation is more intense and the magnetism is more obvious.