201 Grade Annealed Stainless Steel Coil
Production introduction Austenitic stainless steel refers to stainless steel having an austenite structure at normal temperature. When the steel contains about 18% Cr, Ni 8% to 25%, and C about 0.1%, it has a stable austenite structure. Austenitic chrome-nickel stainless steel includes the...
Austenitic stainless steel refers to stainless steel having an austenite structure at normal temperature. When the steel contains about 18% Cr, Ni 8% to 25%, and C about 0.1%, it has a stable austenite structure. Austenitic chrome-nickel stainless steel includes the famous 18Cr-8Ni steel and high-Cr-Ni series steel which is developed by adding Cr, Ni content and adding elements such as Mo, Cu, Si, Nb and Ti. Austenitic stainless steel is non-magnetic and has high toughness and plasticity, but its strength is low. It is impossible to strengthen it by phase transformation. It can only be strengthened by cold working. For example, adding elements such as S, Ca, Se, Te has good Easy machinability.
Annealing of cold-rolled strips recrystallizes cold-rolled coils, eliminating cold-rolling work hardening, restoring plasticity to achieve expectations. This special steel has a beautiful surface and excellent corrosion resistance. It is a high-value-added steel product that can be used in various applications without any separate treatment.
Chemical Composition of Stainless Steel Coil
What is the cold working hardening phenomenon of metal?
In engineering, steel parts are sometimes cold worked, such as forging, rolling, bending, stamping, etc. When the cold working produces plastic deformation, not only the shape changes, but also the internal grain shape changes, and the crystal grains are elongated in the direction of the force. When the cold working plastic deformation is large, a large internal stress is also generated. This phenomenon is called cold work hardening.
The use of cold work hardening has a limited increase in the strength of use of steel, while the reduction in plasticity due to cold work hardening and residual internal stress are detrimental. Therefore, after cold working, it is still eliminated by tempering.
What is bright annealing?
The surface achieved in a protective atmosphere is oxidized and non-decarburized cold rolled strip annealed. The protective atmosphere has a single inert gas of argon or helium, and also a mixed gas of CO-H2-N2-CO2 (DX), N2-H2 (HNX), N2-CO2-H2 and the like. The composition of these mixed gases is adjusted to equalize the oxidation and reduction, decarburization and carburization speeds during annealing of the strip, thereby achieving oxidation-free and decarburization-free annealing of the strip. After annealing, the surface of the strip has an invisible oxide film to protect the metallic luster.
According to the chemical reaction between furnace gas and steel and its changing law, a protective atmosphere is prepared and applied to determine the conditions for preventing oxidation and decarburization. CO2 and H2O can oxidize and decarburize the surface of the strip; CO and CH2 can reduce the oxide layer on the surface of the strip and carburize the surface of the steel; although H2 can reduce the oxide layer, it can also decarburize the steel surface. Bright annealing depends on the H2O, CO2, H2 atmosphere and the redox reaction of Fe. N2 and other inert gases are neutral protective atmospheres for steel, of which N2 is the most widely used, but the oxygenation atmosphere must be removed to provide good protection. Commonly used mixed protection atmosphere of N2 and H2.
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