What is the difference between stainless steel and stainless iron?

Stainless steel is the abbreviation of stainless acid-resistant steel. It is resistant to weak corrosive media such as air, steam, water or stainless steel. The term “stainless steel” not only refers to a single type of stainless steel, but also refers to more than one hundred kinds of industrial stainless steel. Each type of stainless steel developed has good performance in its specific application field.

Stainless steel is often divided into martensitic steel, ferritic steel, austenitic steel, austenitic-ferrite (dual phase) stainless steel, precipitation hardening stainless steel, etc. according to the organization state. In addition, it can be divided into: chromium stainless steel, chromium nickel stainless steel and chromium manganese nitrogen stainless steel.

Stainless steel pipe fittings

Stainless steel pipe fittings

The so-called “stainless iron” refers to the processing of recycled scrap iron, lead, steel, etc. by secondary recycling and demagnetization treatment. The traditional detection method is using magnetite, which is indistinguishable by traditional methods. Of course, it is natural to hide from the sky and cover a lot of engineering materials, so it has entered a decoration site one after another, and boarded a luxury curtain wall after another.

At present, the “stainless iron” products in the market have a 65% share, mainly because their prices play an important role. The current price per ton of national standard stainless steel products is about 20,000 yuan, the price per ton of national standard 7075 aluminum alloy is about 16,000 yuan, and the price of “stainless iron” is only 5000-7000 yuan per ton.

Inconel Flange and Incoloy Flange

Inconel Flange and Incoloy Flange

Look at the tensile strength of these three materials respectively: National Standard Stainless Steel 530-620MPa, National Standard 7075 Aluminum Alloy 540-560MPa,”Stainless Iron” 160-180MPa. Obviously, the tensile strength of “stainless iron” is less than 1/3 of the strength of stainless steel,which is very easy to cause accidents.Therefore, in the construction engineering industry, we must resolutely ban “stainless iron” products.

Compared with stainless steel, the main difference between stainless steel and stainless iron is whether it contains nickel,and stainless steel contains both chromium and nickel. Since nickel is a relatively stable element,its corrosion resistance is naturally much stronger than that of stainless iron. Because the price of nickel is more expensive, stainless steel is higher than stainless iron in cost,plus the difference in corrosion resistance,the price of stainless steel is usually 1/4 ~ 1/3 higher than that of stainless iron.