1. Definition of stainless steel

Stainless steel is a kind of high alloy steel that can resist corrosion. It has a beautiful surface and does not need to go through surface treatment such as plating color or paint. Therefore, many machinery factories often do not do any paint treatment to show that they are stainless steel, and black material (the so-called black material is the name of general steel and iron) must be treated with rust prevention.

2. Simple classification of stainless steel

Stainless steel can be roughly divided into 200 series, 300 series and 400 series, of which 300 series is the most commonly used, 200 series and 400 series are certain substitutes for 300 series, while strictly speaking, 400 series is not called stainless steel or stainless iron, because there is no nickel element in it, so it can be attracted by magnets. But 200 series and 300 series have nickel, so they are non-magnetic and cannot absorb iron.

304 is the most common variety in 300 series, so the price trend of the whole stainless steel can be judged from the price change of 304. 200 series contains less nickel, 400 series does not contain nickel, 300 series contains the most nickel, so 300 series is the most affected by nickel price.

300 series can be simply divided into 304, 304L, 316, 316L, 321, 309S, 310S and so on. The basis of differentiation is that the content of various metal elements is different, and the characteristics of stainless steel with different content are also different. The difference between 304 and 304L lies in the difference of carbon (c) content. With L, it means low carbon, also known as low carbon. The difference between 316 and 316L is the same.

3. Shape classification of stainless steel

Stainless steel can be divided into five categories: rolling plate, plate, profile, steel pipe and parts. The most important is rolling plate. Profiles are various shapes of materials made of plates, including angle steel, flat steel, I-beam and channel steel. The steel pipe mainly refers to the seamless steel pipe, and the welded pipe is the opposite of the seamless steel pipe, the difference is whether it is formed at one time. Parts mainly refer to elbows and flanges and other small things.

In fact, coil and plate are the same, but the delivery form is different. Coil is rolled one by one, and plate is one by one. If the delivery is plate, it is also called original plate, generally thick plate, because it is very thick, it can not be rolled, generally more than 16 mm can not be rolled

There are rolls, there are boards, many times it is boards, the prices of rolls and boards are also different. If it is a purchase roll, it is calculated according to the actual weighing, so the price is high, the price of boards is calculated according to the theory, the price is low, because there is a difference, for example, the actual thickness of 10 mm may be 9.6 mm, and there will be a price difference in the middle.

Stainless steel plate is divided into hot rolling and cold rolling according to the different rolling process of rolling mill (rolling mill is the machine name of rolling plate). Hot rolling is usually marked as No.1 cold rolling marked as 2B or BA (BA is better and brighter than 2B's surface, close to the mirror, the best is the mirror, and the mirror is not available in stock, so it needs to be processed). For example, 304 is often purchased plate, which means that the coil must be opened and leveled into plate by machine. This kind of machine It's the Kaiping machine. It can be cut into different lengths through the leveling machine. If it is not a regular length, it is called fixed opening, which means fixed opening size. Because customers often put forward different length requirements according to the actual needs, at this time, the roll is important, and the conventional board can not meet the requirements.