Duplex Stainless Steel Sheet / Plate Chapa Acero Inoxidable Duplex
Duplex Stainless Steel Sheet/Plate
Duplex Stainless Steel (DSS) refers to ferrite and austenite, each of which accounts for about 50%. Generally, stainless steel with a minimum phase content of 30% is also required. In the case of low C content, Cr content is 18%~28%, Ni content is 3%~10%. Some steels also contain alloying elements such as Mo, Cu, Nb, Ti, and N.
This type of steel has the characteristics of austenitic and ferritic stainless steel. Compared with ferrite, it has higher plasticity and toughness, no room temperature brittleness, and has significantly improved intergranular corrosion resistance and welding performance, while maintaining iron. The 475°C brittleness and high thermal conductivity of plain stainless steel are characterized by superplasticity. Compared with austenitic stainless steel, the strength is high and the resistance to intergranular corrosion and chloride stress corrosion is significantly improved. Duplex stainless steel has excellent pitting corrosion resistance and is also a nickel-saving stainless steel.
Duplex stainless steel has the following performance characteristics
(1) Molybdenum-containing duplex stainless steel has good resistance to chloride stress corrosion under low stress. Generally, 18-8 austenitic stainless steel is prone to stress corrosion cracking in neutral chloride solutions above 60°C. Heat exchangers and evaporators made of such stainless steel in trace chloride and hydrogen sulfide industrial media There is a tendency to produce stress corrosion cracking, but duplex stainless steel has good resistance.
(2) Molybdenum-containing duplex stainless steel has good pitting corrosion resistance. With the same pitting corrosion resistance equivalent value (PRE=Cr%+3.3Mo%+16N%), the critical pitting potential of duplex stainless steel is similar to that of austenitic stainless steel. The corrosion resistance of duplex stainless steel and austenitic stainless steel is equivalent to AISI 316L. The chromium corrosion resistance and crevice corrosion resistance of 25% Cr, especially nitrogen-containing high-chromium duplex stainless steel exceeds AISI 316L.
(3) It has good resistance to corrosion fatigue and wear and corrosion. Under the condition of some corrosive media, it is suitable for making pumps, valves and other power equipment.
(4) Good comprehensive mechanical properties. It has higher strength and fatigue strength, and the yield strength is twice that of 18-8 type austenitic stainless steel. The elongation in solid solution reaches 25%, and the toughness value AK (V-notch) is above 100J.
(5) The temperature range of duplex stainless steel containing low chromium (18%Cr) is wider than that of 18-8 type austenitic stainless steel, and its resistance is small. It can be rolled directly to produce steel plates without forging. Duplex stainless steel with high chromium (25% Cr) is slightly more difficult to heat than austenitic stainless steel, and can produce products such as plates, tubes and wires.
(6) The work hardening effect is greater than that of 18-8 austenitic stainless steel during cold working. In the initial stage of deformation of the tube and plate, large stress needs to be applied to deform.
(7) Compared with austenitic stainless steel, the thermal conductivity is large and the linear expansion coefficient is small, which is suitable for the lining of equipment and the production of composite plates. It is also suitable for making the core of the heat exchanger, and the heat exchange efficiency is higher than that of austenitic stainless steel.
(8) There are still various brittle tendencies of high chromium ferritic stainless steel, which should not be used in working conditions higher than 300°C. The lower the chromium content in duplex stainless steel, the less harmful the brittle phase such as σ.
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