People often think that magnets absorb stainless steel wires to verify their quality and authenticity. If they don't attract, they are non-magnetic, so they think they are good ; if they attract, they are magnetic, so they think they are counterfeit. In fact, this is an extremely one-sided and wrong way of making a distinction. After all, stainless steel wires can also "rust" and become magnetic. Stainless steel wires are high-alloy steel with more than 60% iron as the base and adding alloying elements such as chromium, nickel, and molybdenum. Its biggest feature is its strong corrosion resistance. But stainless steel wire is not absolutely rust-free. In coastal areas or some places with severe air pollution, when the chloride ion content in the air is high, there may be some rust spots on the surface of the stainless steel wire exposed to the atmosphere, but these rust spots are limited to the surface and will not corrode the internal matrix of the stainless steel wire.
There are many varieties of stainless steel wires, most of which are magnetic. Therefore, using magnets to adsorb them is not a scientific method to identify stainless steel wires. Most of the stainless steel wire rods commonly used for decorative tube sheets are austenitic 304 materials. Generally speaking, they are non-magnetic or weakly magnetic. However, magnetism may also occur due to fluctuations in chemical composition due to smelting or different processing conditions, but this cannot be considered Is it counterfeit or unqualified. What is the reason?
As mentioned above, austenite is non-magnetic or weakly magnetic, while martensite or ferrite is magnetic. Due to component segregation or improper heat treatment during smelting, a small amount of martensite stainless steel wire will be produced in the austenitic 304 stainless steel wire or ferrite structure. In this way, the 304 stainless steel wire will have weak magnetism.
In addition, after cold working of 304 stainless steel wire rod, the organizational structure will also transform to martensite. The greater the degree of cold working deformation, the more martensitic transformation, and the greater the magnetism of the steel. Just like a batch of steel strips, the Φ76 tube produced has no obvious magnetic induction; the Φ9.5 tube produced has a more obvious magnetic induction due to the large bending deformation; the square rectangular tube produced has a larger deformation than the round tube, especially There are some folded corners, and the deformation is more severe and the magnetism is more obvious.

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