What is the different between 304 stainless steel pipe and 321 stainless steel pipe?

What is the difference between the 304 stainless steel pipe and the 321 stainless steel pipe? There is a link between the 304 stainless steel pipe and the stainless steel that is produced according to the American ASTM standard. 304 stainless steel pipe is equivalent to China's 0Cr19Ni9 (0Cr18Ni9) stainless steel pipe. 304 contains chromium 19%, nickel 9%.
304 stainless steel pipe is widely used as stainless heat-resistant steel, food equipment, general chemical equipment, and equipment for atomic energy industry.
The 304 stainless steel tube is a versatile stainless steel tube that is widely used to make equipment and parts that require good overall performance (corrosion resistance and formability).
304 stainless steel pipe is the most widely used stainless steel, heat-resistant steel. For food production equipment, past chemical equipment, nuclear energy and so on.
304 stainless steel chemical composition specification C Si Mn PS Cr Ni (nickel) Mo
SUS304 ≤0.08 ≤1.00 ≤2.00 ≤0.05 ≤0.03 18.00-20.00 8.25~10.50 -
A high-alloy steel that resists corrosion in air or in chemically corrosive media. Stainless steel has an aesthetically pleasing surface and good corrosion resistance. It does not require surface treatment such as plating, and it exerts the inherent surface properties of stainless steel. A type of steel, usually called stainless steel. Representative performance of 13 chrome steel, 18-8 chromium nickel steel and other high alloy steel.

From the metallographic point of view, since the stainless steel contains chromium and forms a thin chromium film on the surface, this film separates and invades oxygen from the steel and acts as a corrosion resistance. In order to maintain the inherent corrosion resistance of stainless steel, steel must contain more than 12% chromium.
321 Stainless Steel Seamless Steel Pipe (GB3087-1999) is used to manufacture high-quality carbon for superheated steam pipes, boiling water pipes, superheated steam pipes for boilers of various structures, large smoke pipes, small smoke pipes, and arched bricks. Prime structural steel hot-rolled and cold drawn (rolled) seamless steel tubes.
321 stainless steel pipe: High-quality carbon structural steel, alloy structural steel and stainless heat-resistant seamless steel pipe for steam boiler piping, etc., which are mainly used to manufacture high pressure and above pressure, these boiler pipes are operated under high temperature and high pressure by the party. The tube will also be oxidized and corroded under the action of high-temperature flue gas and water vapor. Therefore, the steel pipe requires high endurance strength, high oxidation resistance, and good organization stability, and hydraulic pillar pipe.
321 stainless steel with steel number:
High-quality carbon structural steel steel 20G, 20MnG, 25MnG; 304 stainless steel.
Alloy structural steel grades 15MoG, 20MoG, 12CrMoG, 15CrMoG, 12Cr2MoG, 12CrMoVG, 12Cr3MoVSiTiB, etc.; rust heat-resistant steel commonly used 1Cr18Ni9, 1Cr18Ni11Nb high-pressure boiler tubes in addition to ensure chemical composition and mechanical properties, it is necessary to do root pressure test, to For flaring and flattening tests.
321 stainless steel pipes are delivered in heat-treated condition. In addition, there are certain requirements on the microstructure, grain size, and decarburization layer of the finished steel pipe. Geological drilling and seamless steel tubes for oil drilling control; use drilling rigs to drill wells for exploration of underground rock formations, groundwater, oil, natural gas, and mineral resources.

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