Introduction to Stainless Steel and Stainless Iron
Stainless steel is generally a general term for stainless steel and acid-resistant steel. Stainless steel refers to steel that is resistant to corrosion by weak media such as atmosphere, steam, and water, while acid-resistant steel refers to steel that is resistant to chemical corrosion media such as acid, alkali, and salt. Stainless steel has a history of more than 90 years since it came out at the beginning of this century.
The invention of stainless steel is a major achievement in the history of world metallurgy. The development of stainless steel has laid an important material and technological foundation for the development of modern industry and technological progress. There are many types of stainless steel with different properties, and it has gradually formed several major categories in the development process.
According to the organization structure, it can be divided into four categories: martensitic stainless steel (including precipitation hardening stainless steel), ferritic stainless steel, austenitic stainless steel, and austenitic plus ferritic duplex stainless steel; according to the main chemical composition or Some characteristic elements in steel are classified into chromium stainless steel, chromium-nickel stainless steel, chromium-nickel molybdenum stainless steel, low carbon stainless steel, high molybdenum stainless steel, high purity stainless steel, etc.; according to the performance characteristics and use of steel, it is classified into nitric acid-resistant stainless steel,
Sulfuric acid-resistant stainless steel, pitting-resistant stainless steel, stress-corrosion-resistant stainless steel, high-strength stainless steel, etc.; according to the functional characteristics of steel, it is divided into low-temperature stainless steel, non-magnetic stainless steel, free-cutting stainless steel, superplastic stainless steel, etc. At present, the commonly used classification method is to classify according to the structural characteristics of steel and the chemical composition of steel, as well as the combination of the two. Generally divided into martensitic stainless steel, ferritic stainless steel, austenitic stainless steel, duplex stainless steel, and precipitation hardening stainless steel, etc., or divided into two categories: chromium stainless steel and nickel stainless steel.
The so-called “stainless iron” is made by reprocessing the recycled scrap iron, lead, steel, etc., through de-zipping. The traditional detection method is to use magnetite, but this product cannot be distinguished by traditional methods. Yes, it is naturally hiding from the sky, blindfolded by many engineering materials, so grandly entered one after another decoration construction site, boarded one after another luxurious curtain wall. This name was born after the “Focus Interview” was exposed, and it occupies about 65% of the market share, while the real national standard SUS304 stainless steel products have no market due to higher prices.
At present, the “stainless iron” products in the market can have 65% of the market because their price plays an important role. The current price of national standard stainless steel products is about 20,000 yuan per ton, and the price of national standard 7075 aluminum alloy is about 16,000 yuan per ton. The price of “stainless iron” is only 5000-7000 yuan per ton; then look at the tensile strength of these three materials: national standard stainless steel 530-620MPa, national standard 7075 aluminum alloy 540-560MPa, “stainless steel” Iron” 160-180MPa. Obviously, the tensile strength of “stainless iron” is still not up to 1/3 of the strength of stainless steel, which can easily lead to accidents.