2507 SDSS

Material

S32750, 1.4410, X2CrNiMoN2574, 022Cr25Ni7Mo4N

S32760, 1.4501, X2CrNiMoCuWN2574, 022Cr25Ni7Mo4WCuN

Overview

2507 SDSS contains 25% chromium, 4% molybdenum, and 7% nickel are designed for demanding applications which require exceptional strength and corrosion resistance, such as chemical process, petrochemical, and seawater equipment. The steel has excellent resistance to chloride stress corrosion cracking, high thermal conductivity, and a low coefficient of thermal expansion. The high chromium, molybdenum, and nickel levels provide excellent resistance to pitting, crevice, and general corrosion.

2507 SDSS like S32750 and S32760, is a mixed microstructure of austenite and ferrite (50/50) which has improved strength over ferritic and austenitic steel grades. The main difference is that Super Duplex has a higher molybdenum and chromium content which gives the material greater corrosion resistance than standard duplex grades.

Characteristics

  • ◇ Excellent resistance to stress corrosion cracking (SCC) in chloride-bearing environments
  • ◇ Excellent resistance to pitting and crevice corrosion
  • ◇ High resistance to general corrosion
  • ◇ Very high mechanical strength
  • ◇ Physical properties that offer design advantages
  • ◇ High resistance to erosion corrosion and corrosion fatigue
  • ◇ Good weldability

Application

  • ◎ Oil-gas
  • ◎ Chemical processing
  • ◎ Subsea control line
  • ◎ Heat exchangers
  • ◎ Offshore plateforms
  • ◎ Fire-fighting system
  • ◎ Injection & ballast water systems
  • ◎ Vessels
  • ◎ Desalination plants
  • ◎ Energy industry FGD system, industrial scrubbing system, absorption tower

Chemical composition

Material C Si Mn P S Cr
S32750 ≤0.03 ≤0.80 ≤1.20 ≤0.030 ≤0.020 24.0~26.0
S32760 ≤0.03 ≤1.0 ≤1.0 ≤0.030 ≤0.020 24.0~26.0
Material Ni Mo N Cu W
S32750 6.0~8.0 3.0~5.0 0.24~0.32 ≤0.50
S32760 6.0~8.0 3.0~4.0 0.20~0.30 0.50~1.00 0.50~1.00

S32750: PREN ≥ 41, S32760: PREN ≥ 40.

Corrosion resistance

Pitting corrosion resistance

Pitting and crevice corrosion resistance is generally a function of an alloy’s chromium, molybdenum and nitrogen contents. Calculated indexes have been devised to roughly predict and rank alloys for pitting resistance based on these elements (in weight-%). The higher the index the higher the predicted pitting corrosion resistance.

Stress corrosion cracking resistance

To achieve resistance to stress corrosion cracking in stainless steels, the nickel content must either be low as in the ferritic group of steels, or very high making them correctly nickel base alloys. The ferritic stainless steels are nearly immune to SCC, but are difficult to fabricate and are subject to brittle behavior at low temperatures. Nickel, and high nickel alloys also possess excellent SCC resistance but are costly due to their high nickel content. The low nickel austenitic stainless steels (304, 316, 317) have poor SCC resistance compared to ferritic stainless and high nickel alloys.

Mechanical property

Material Tensile strength
ksi (MPa)		 Yield strength
ksi (MPa)		 Elongation in 2”
% min.		 Hardness
HBW /HV max.
S32750 116 (800) 80 (550) 15 300 / 300
S32760 109 (750) 80 (550) 25 310 / 310

Heat treatment

  • S32750: 1880-2060 (1025-1125), rapid cooling in water or air.
  • S32760: 1960-2085 (1070-1140), rapid cooling in water or air.

Available Process

  • ◎ Hot formed, solution annealed, descaled
  • ◎ Cold worked and bright annealed
  • ◎ Cold worked, annealed and descaled
  • ◎ Cold worked, polished (MP, EP etc.)
  • ◎ Cold worked, bright annealed, polished (MP, EP etc.)

Common Tests

  • ◎ Chemical composition
  • ◎ Tension
  • ◎ Hardness
  • ◎ Flaring
  • ◎ Flange
  • ◎ Flattening
  • ◎ Micro structure
  • ◎ Hydrostatic
  • ◎ NDT
  • ◎ Intergranular Corrosion
  • ◎ Surface condition
  • ◎ Shape and dimension
  • ◎ Positive Material Identification

Product forms

Capillary tube

  • ◎ OD 0.08 ~ 6.0 mm
  • ◎ WT 0.015 ~ 1.5 mm

Micro ID and heavy wall seamless tube

  • ◎ OD 3.0 ~ 50.0 mm
  • ◎ ID 0.30 ~ 5.0 mm

Precision Conic Seamless Tube

  • ◎ OD 6.0 ~ 89 mm
  • ◎ WT 0.50 ~ 9.0 mm

Precision conic seamless tube

  • ◎ Bigger end: OD3.0 – 28.0mm
  • ◎ Smaller end: OD2.5 – 25.0mm
  • ◎ WT: 0.25 – 1.50mm

HP / UHP BA+ tube

  • ◎ OD 1.0 ~ 76 mm
  • ◎ WT 0.10 ~ 10.0 mm

Service

  • ◎ Precision cutting
  • ◎ Tube surface treatment, like ID surface super mirror polishing, best level could reach Ra0.0015um
  • ◎ Tube deep processing, like coiling, bending, end forming, body forming, laser processing, various needles processing, built to drawing and sample, etc.