Basic Knowledge of Stainless Steel Sheet

In the air or chemical corrosion medium can resist corrosion of a high alloy steel, stainless steel plate is a kind of steel with beautiful surface and good corrosion resistance, without surface treatment such as plating color, and play the inherent surface properties of stainless steel plate, used in many aspects of steel, commonly known as stainless steel plate.

• Here is the content:

• Corrosion resistance of various stainless steel plates

• Meaning and classification of stainless steel plate corrosion

• Causes of corrosion of stainless steel plate

Corrosion resistance of various stainless steel plates

304 is a kind of universal stainless steel, which is widely used in the production of equipment and parts requiring good comprehensive performance (corrosion resistance and formability). 301 stainless steel plate shows obvious work hardening phenomenon during deformation, which is used in various occasions requiring higher strength. In fact, the higher strength of 304 stainless steel plate can be obtained by cold rolling 302 stainless steel plate. 302B is a kind of stainless steel plate with high silicon content, which has high oxidation resistance at high temperature. 303 and 303se are free cutting stainless steel plates containing sulfur and selenium respectively, which are mainly used in the occasions requiring free cutting and high surface gloss. 303se stainless steel plate is also used to make hot upsetting parts, because under such conditions, this kind of stainless steel plate has good hot workability. 304L is a variant of 304 stainless steel plate with low carbon content, which is used for welding. Low carbon content reduces the amount of carbide precipitated in the HAZ near the weld to the minimum, which may lead to intergranular corrosion (welding erosion) of stainless steel plate in some environments. 304n is a kind of stainless steel containing nitrogen. The purpose of adding nitrogen is to improve the strength of the steel. 305 and 384 stainless steel plates contain high content of nickel and have low work hardening rate, so they are suitable for various occasions requiring high cold formability. 308 stainless steel plate is used to make welding rod. The nickel and chromium contents of 309, 310, 314 and 330 stainless steel plates are relatively high, in order to improve the oxidation resistance and creep strength of the steel at high temperature. However, 30s5 and 310S are variants of 309 and 310 stainless steel plates. The difference is that the carbon content is lower, so as to minimize the carbide precipitation near the weld. Type 316 and 317 stainless steel plates contain aluminum, so their resistance to pitting corrosion in marine and chemical industrial environment is much better than that of 304 stainless steel plate. Among them, type 316 stainless steel plate is a variety, including low carbon stainless steel plate, high strength stainless steel plate containing nitrogen and free cutting stainless steel plate with high sulfur content. 321, 347 and 348 are stainless steel plates stabilized with titanium, niobium plus tantalum and niobium respectively. They are suitable for welding components at high temperature. 348 is a kind of stainless steel plate suitable for nuclear power industry, which limits the amount of tantalum and drill.

The meaning and classification of stainless steel plate corrosion

In the corrosive environment, the damage caused by chemical or electrochemical interaction between metal and the surrounding medium is called corrosion. In the corrosive environment, when the stainless steel plate is not selected properly, corrosion will also occur. There are many ways to classify corrosion. According to the nature of the action, it can be divided into chemical corrosion and electrochemical corrosion. According to the form of corrosion, it can be divided into general (overall, uniform) corrosion. The so-called general corrosion and system corrosion are distributed on the whole surface of stainless steel plate, such as local corrosion, pitting corrosion, crevice corrosion, stress corrosion, corrosion fatigue, selective corrosion, erosion corrosion, etc. According to the environment and conditions of corrosion, it can be divided into atmospheric corrosion, industrial water corrosion and soil corrosion. Acid, alkali. Salt corrosion, seawater corrosion, high temperature corrosion (including liquid metal, molten salt, gas corrosion), etc.

Causes of corrosion of stainless steel plate

A recent study by British scientists shows that the tiny high concentration area of manganese sulfide in stainless steel plate can cause corrosion of stainless steel plate. Stainless steel plate is an alloy of iron, chromium and nickel, which first appeared in the early 20th century. Due to its excellent corrosion resistance, stainless steel plate is often used in the harsh working environment, or in the manufacture of tableware and medical appliances. The corrosion rate of stainless steel plate is very slow. Under ideal conditions, it can only corrode 1 cm every 1 million years. However, in practical application, corrosion often occurs and expands in a certain place, which eventually leads to the corrosion of the whole stainless steel plate. There are many theories that impurities in stainless steel plates lead to corrosion, but the specific mechanism of corrosion is not very clear. In the latest issue of the British journal Nature, a British research team reported their findings on the corrosion process of stainless steel plates. They found that the tiny high concentration area of manganese sulfide in stainless steel plate was the main culprit of corrosion. The corrosion sites are not random, they always occur in the area of hundreds of nanometers around small pieces of manganese sulfide. Scientists' research shows that in the manufacturing process of stainless steel plate, manganese sulfide produces high concentration accumulation in the local area, which leads to the decrease of chromium concentration in the surrounding area. Chromium and oxygen react to produce chromium oxide, which can prevent corrosion. The corrosion of low concentration chromium area first occurs, and then gradually extends to the whole stainless steel plate. In water with salt, the process becomes more rapid.

If you want to buy stainless steel plate, please find Jiangsu C.J.M Stainless Steel Group. The company has a variety of stainless steel products for customers to choose from. Tel. + 86-18092577236, post office postmaster@ssplatechina.com.