Double-stranded stainless steel is divided into 4 grades.
1: Low alloy type: S31500, S32001, S32003, S32304
1) S31500 double-stranded stainless steel chemical composition: Carbon: ≤0.03, Chromium: 18.0~19.0, Nickel: 4.5~5.25, Molybdenum: 2.5~3.0, Nitrogen: 0.05~0.10, Tensile strength ≥630, Yield strength ≥630, Yield strength ≥4400, ELONGINIT, ELONGINTIAN, ELNONGINATION: eNONGINATION: eNONGINATION: eNONGINATION: eNONGINATION: ≥30.
2) S32001 double chain stainless steel chemical composition: carbon: ≤0.03, chromium: 19.5~21.5, nickel: 1.0~3.0, molybdenum: ≤0.60, ≤0.60, copper: ≤1.0, nitrogen: 0.05~0.17, 0.05~0.17, andile tensile strength ≥620, yield strength ≥450, Elong.450, Elong.
3) S32003 double-stranded stainless steel chemical composition: Carbon: ≤0.03, Chromium: 19.5~22.5, Nickel: 3.0~4.0, Molybdenum: 1.5~2.0, Nitrogen: 0.14~0.20 Elongation: ... 4) Chemical composition of S32304 double-stranded stainless steel: carbon: ≤0.03, chromium: 21.5~24.5, nickel: 3.0~5.5, molybdenum: 0.05~0.60, copper: 0.05~0.60, nitrogen: 0.05~0.20, 0.05~0.20, tensile≥600, yield≥600≥600≥600≥600≥600≥600≥600≥600≥450≥450≥450≥450.
2: Medium alloy type: S31803, S32205,
1) S31803 double strand stainless steel alloy composition: Carbon: ≤0.03, Chromium: 21.0~23.0, Nickel: 4.5~6.5, Molybdenum: 2.5~3.5, Nitrogen: 0.08~0.20, Tensile Strength ≥620, Yield Strength ≥400, ELOONONONGITION, ELOONONONGITION: eLONGINTIC: ≥255.
2) S32205 double strand stainless steel alloy composition: Carbon: ≤0.03, Chromium: 22.0~23.0, Nickel: 4.5~6.5, Molybdenum: 3.0~3.5, Nitrogen: 0.14~0.20, Tensile Strength ≥655, Yield Strength ≥655, Yield Strength ≥450, ELONTIM ≥450, ELONDITION: ELONTONONONGITIAN: ELONTONONONGITACT: ≥255.
3: High alloy type: S32550,
S32550 double chain stainless steel alloy composition: carbon: ≤0.04, chromium: 24.0~27.0, nickel: 4.5~6.5, molybdenum: 2.9~3.9, copper: 1.5~0.25, nitrogen: 0.25: 0.10~0.25, tension stregth stregth stregth stregth stregth stregth ≥760, yield ≥760, Elon grountion ～485;
4: Super DSS: S32750, S32760,
1) S32750 double chain stainless steel chemical composition: carbon: ≤0.03, chromium: 24.0~26.0, nickel: 6.0~8.0, molybdenum: 3.0~5.0, copper: ≤0.5, nitrogen: ≤0.5, nitro: 0.24~0.32, andile Stimile strength ≥550, Elongation ≥550.
2) S32760 DUPLEX STAINless Steel Chemical Composition: Carbon: ≤0.03, Chromium: 24.0 ~ 26.0, Nickel: 6.0 ~ 8.0, Mo: 3.0 ~ 4.0, copper: 0.5 ~ 1.0, nitrogen: 0.20 ~ 0.30, tensile stregth ≥750, yield strength ≥550, elongation: ≥25.
(Super) Duplex Stainless Steel Pipe
Duplex stainless steel has α+ and duplex structure, so its performance is similar to austenitic stainless steel and ferritic stainless steel. It is a stainless steel with the best high strength and corrosion resistance. Generally, when the C content is low, the CR content is 18%~28% and the NI content is 3%~10%. Suteels also contain alloying elements such as Mo, Cu, Nb, Ti and N., and are fixed with ferrite, have high plasticity and touch resistance, no room temperature brittleness, and have significantly higher intergranular corrosion and welding performance. At the same time, it also maintains the 475° brittleness of ferritic stainless steel and high thermal conductivity, and has the characteristics of superplasticity.
Compared with austenitic stainless steel, the yield strength is significantly higher, and the resistance to intergranular corrosion, stress corrosion, corrosion fatigue and wear is meaningful.
Common standards for duplex stainless steel pipes:
ASTM A789 (ASME SA789) General purpose seamless and welded ferritic/austenitic stainless steel pipes,
ASTM A790 (ASME SA790) Seamless and welded ferritic/austenitic stainless steel nominal pipes,
ASTM A928 (ASME SA928) Standard specification for ferritic/austenitic (duplex) stainless steel pipes with filler metal,
GB/T 21832-2008 Austinite-Flotte duplex stainless steel welded steel pipe,
GB/T 21833-2008 Austinite-Flotte duplex stainless steel seamless steel pipe,
Performance characteristics of duplex stainless steel pipes:
1. Excellent resistance to overall and localized corrosion, especially stress corrosion, corrosive corrosion, crevice corrosion, corrosion fatigue and wear
2. Good weldability
3. Understanding mechanical properties
4. Good resistance to intergranular corrosion
