Why is the surface of stainless steel heating tube magnetic?

Some electric heating tube users don't know how to judge the material of the heating tube purchased, so they use magnetite to verify. Many verifications have shown that most of the stainless steel materials will absorb iron magnets. At this time, they will come to the manufacturer and say that the material is fake. In fact, no matter whether it is stainless steel 304 or stainless steel 316 heating tube, its surface will be magnetic. Why? Let me explain to you why the surface of the stainless steel heating tube is magnetic?

         We all know that the electric heating tube heats the resistance wire in the tube, and then conducts heat conduction through the magnesium oxide powder. The resistance wire is relatively common and the most commonly used is the iron-chromium-aluminum wire. The iron-chromium-aluminum wire composition contains higher iron metal, so its thermal efficiency is very high, and its temperature resistance is particularly good.

        Seeing this, I think everyone should have understood why the surface of the stainless steel heating tube is magnetic, although it can still adsorb the magnet after the magnesium oxide powder because its resistance wire contains iron. However, the magnetism at this time is different from the magnetism of direct iron absorption. It is only very weak.

        Therefore, I tell my friends here that it is normal for the stainless steel electric heating tube to have weak magnetism, so please don't panic.