It should be said that all austenitic stainless steel fluid pipes have the characteristics of corrosion resistance, high temperature resistance and high pressure resistance. Only relatively speaking, they have different obvious characteristics and functions:
304: Ordinary corrosion resistance and high temperature resistant stainless steel seamless pipe, 304 has good resistance to intergranular corrosion, excellent corrosion performance, cold working and stamping performance, and can be used as heat-resistant stainless steel. At the same time, the mechanical properties of the steel are still good at -180°C. In the solid solution state, the steel has good plasticity, toughness and cold workability; it has good corrosion resistance in oxidizing acids, air, water and other media.
304L is a variant of 304 stainless steel with a lower carbon content and is used where welding is required. The lower carbon content minimizes the precipitation of carbides in the heat-affected zone near the weld, which can lead to intergranular corrosion (weld attack) in stainless steels in some environments.
The corrosion resistance of 316/316L stainless steel pipe is better than that of 304 stainless steel pipe, and it has good corrosion resistance in the production process of pulp and paper. Due to the addition of Mo, it has excellent corrosion resistance, especially pitting resistance; high temperature strength is also very good; excellent work hardening (weak magnetic after processing); non-magnetic in solid solution state. It also has good resistance to chloride corrosion, so it is usually used in marine environments or construction projects by the sea.
321 stainless steel is a Ni-Cr-Ti type austenitic stainless steel industrial pipe, its performance is very similar to 304, but due to the addition of metal titanium, it has better intergranular corrosion resistance and high temperature strength. Due to the addition of metal titanium, it effectively controls the formation of chromium carbide. 321 stainless steel has excellent high temperature stress rupture (Stress Rupture) performance and high temperature creep resistance (Creep Resistance) stress mechanical properties are better than 304 stainless steel. Ti in 321 stainless steel pipe exists as a stabilizing element, but it is also a heat-strength steel grade, which is much better than 316L in terms of high temperature. It has good corrosion resistance in organic and inorganic acids of different concentrations and temperatures, especially in oxidizing media, and is used to manufacture linings and pipelines for wear-resistant acid containers and wear-resistant equipment. It has a certain high temperature resistance, generally around 700 degrees, and is often used in power plants. Applied to field machines in the chemical, coal and petroleum industries that require high resistance to grain boundary corrosion, heat-resistant parts of building materials and parts that are difficult to heat treat.
310S: The most widely used oxidation resistance, corrosion resistance, high temperature resistant industrial stainless steel seamless pipe and industrial welded pipe. Common uses: materials for furnaces, materials for automobile purification devices. 310S stainless steel pipe is an austenitic chromium-nickel stainless steel with excellent high temperature oxidation resistance, acid and alkali resistance, and corrosion resistance. Because of the higher content of chromium (Cr) and nickel (Ni), it has much better creep strength. It can work continuously at high temperature and has good high temperature resistance. When the temperature exceeds 800, it begins to soften, and the allowable stress begins to decrease continuously. The maximum service temperature is 1200°C, and the continuous use temperature is 1150°C. High temperature resistant steel pipes are specially used in the manufacture of electric furnace tubes and other occasions. After increasing the carbon content in austenitic stainless steel, the strength is improved due to its solid solution strengthening effect. The chemical composition of austenitic stainless steel is based on chromium and nickel. Elements such as molybdenum, tungsten, niobium and titanium are added as the basis. Because its organization is a face-centered cubic structure, it has high strength and creep strength at high temperatures.
Post time: Jan-31-2023
