Manufacturer Of Prepainted Aluminum Sheets

Standard level of stainless steel (in three grades)
y-level: international advanced level i-level: international general level h-level: domestic advanced stainless steel national standard

gb1220-84 stainless steel bar (grade i) gb4241-84 stainless steel welded disc (grade h) gb4356-84 stainless welded disc (grade i) gb1270-80 stainless pipe (grade i) gb12771-91 stainless Welded pipe (grade y) gb3280-84 stainless cold plate (grade i)

gb4237-84 stainless hot plate (i grade) gb4239-91 stainless cold belt (i grade)

Classification of stainless steel by tissue state
  Stainless steel is often divided into: martensitic steel, ferritic steel, austenitic steel, austenitic-ferritic (duplex) stainless steel and precipitation hardening stainless steel according to the structure state. In addition, it can be divided into: chromium stainless steel, chromium-nickel stainless steel and chromium-manganese-nitrogen stainless steel according to the composition.

1. Ferritic stainless steel: 12% to 30% chromium. Its corrosion resistance, toughness and weldability increase with the increase of chromium content, and its resistance to chloride stress corrosion is better than other types of stainless steel. Belonging to this category are crl7, cr17mo2ti, cr25, cr25mo3ti, cr28 and so on. Because of the high chromium content, ferritic stainless steel has good corrosion resistance and oxidation resistance, but poor mechanical properties and process performance. This kind of steel can resist the corrosion of the atmosphere, nitric acid and brine solution, and has the characteristics of good high temperature oxidation resistance and small thermal expansion coefficient. .

2. Austenitic stainless steel: contains more than 18% chromium, and also contains about 8% nickel and a small amount of molybdenum, titanium, nitrogen and other elements. It has good comprehensive performance and is resistant to corrosion by various media. The commonly used grades of austenitic stainless steel are 1cr18ni9, 0cr19ni9 and so on. The wc<0.08% of 0cr19ni9 steel is marked as "0" in the steel number. This type of steel contains a large amount of ni and cr, making the steel austenitic at room temperature. This type of steel has good plasticity, toughness, weldability, corrosion resistance and non-magnetic or weak magnetic properties. It has good corrosion resistance in oxidizing and reducing media. It is used to make acid-resistant equipment, such as corrosion-resistant containers and equipment. Linings, conveying pipes, nitric acid-resistant equipment parts, etc., can also be used as the main material of stainless steel watch accessories. Austenitic stainless steel is generally solution treated, that is, heating the steel to 1050-1150 °C, and then cooling it with water or air to obtain a single-phase austenite structure.

3. Austenitic-ferritic duplex stainless steel: It has the advantages of both austenitic and ferritic stainless steels, and has superplasticity. Austenitic and ferritic structures each account for about half of stainless steel. In the case of low c content, the cr content is 18%~28%, and the ni content is 3%~10%. Some steels also contain alloying elements such as mo, cu, si, nb, ti, n. This type of steel has the characteristics of both austenitic and ferritic stainless steels. Compared with ferrite, it has higher plasticity and toughness, no room temperature brittleness, and significantly improved intergranular corrosion resistance and welding performance. The 475 ℃ brittleness and high thermal conductivity of element stainless steel have the characteristics of superplasticity. Compared with austenitic stainless steel, it has high strength and significantly improved resistance to intergranular corrosion and chloride stress corrosion. Duplex stainless steel has excellent pitting corrosion resistance and is also a nickel-saving stainless steel.

4. Martensitic stainless steel: high strength, but poor plasticity and weldability. The commonly used grades of martensitic stainless steel are 1cr13, 3cr13, etc. Due to the high carbon content, it has high strength, hardness and wear resistance, but the corrosion resistance is slightly worse, and it is used for high mechanical properties and corrosion resistance. Some general parts are required, such as springs, turbine blades, hydraulic valves, etc. This type of steel is used after quenching and tempering.

5. Precipitation hardening stainless steel: the matrix is ​​austenite or martensite structure, and the commonly used grades of precipitation hardening stainless steel are 04cr13ni8mo2al and so on. It is capable of hardening (strengthening) stainless steel by precipitation hardening, also known as age hardening.