1.4532, X8CrNiMoAl15-7-2, 15-7PH, AISI 632 - stainless steel

1.4532, X8CrNiMoAl15-7-2, 15-7PH, AISI 632 - martensitic stainless steel according to EN 10088-1:2014 and ASTM A693.

1.4532, X8CrNiMoAl15-7-2, 15-7PH, AISI 632 – description

Steel used for valve parts, tanks, CNC parts and tooling in aerospace industry. Resistant to acids and chlorides commonly occuring in river water. Sufficiently resistant to ammonia and nitrogen tetroxide in mild temperature. Rust may occure in a marine atmosphere.

The steel has better stress corrosion cracking resistance and resistance to reducing acids and chloride containing pleas than 1.4568 steel. It also has limited resistance to crevice corrosion and pitting.

Weldable, but less weldable than 17-4 PH, which is caused by high Al content.

Physical and mechanical properties

1.4532 physical properties:

• In ambient temperature:
  • Density: 7.79 g/cm³
  • Specific heat capacity: 0.5 kJ/(kg*K)
  • Thermal conductivity: 16 W/(m*K)
  • Young's modulus E: 200 GPa
• At 100°C:
  • Linear expansion coefficient: 41.0 * 10^-6/K
  • Young's modulus E: 195 GPa
• At 200°C:
  • Young's modulus E: 185 GPa
• At 300°C:
  • Linear expansion coefficient: 14.4 * 10^-6/K
  • Young's modulus E: 175 GPa
• At 400°C:
  • Young's modulus E: 170 GPa

AISI 632, 15-7PH, S15700 Alloy mechanical properties:

• Annealed:
  • Yield strength Re: > 450 MPa
  • Tensile strength Rm: > 1035 MPa
  • Hardness HRB: < 100
  • Elongation A: > 25 %
• Precipitation Hardened TH1050 (760°C + 15°C + 566°C):
  • Thickness: 0.038 - 0.124 mm
    • Yield strength Re: > 1170 MPa
    • Tensile strength Rm: > 1310 MPa
    • Elongation A: > 2 %
    • Hardness HRC: > 40
  • Thickness: 0.127 - 0.251 mm
    • Yield strength Re: > 1170 MPa
    • Tensile strength Rm: > 1310 MPa
    • Elongation A: > 3 %
    • Hardness HRC: > 40
  • Thickness: 0.251-0.505 mm
    • Yield strength Re: > 1170 MPa
    • Tensile strength Rm: > 1310 MPa
    • Elongation A: > 4 %
    • Hardness HRC: > 40
  • Thickness: 0.51 - 4.76 mm
    • Yield strength Re: > 1170 MPa
    • Tensile strength Rm: > 1310 MPa
    • Elongation A: > 5 %
    • Hardness HRC: > 40
  • Thickness: 4.762 - 15.880 mm
    • Yield strength Re: > 1170 MPa
    • Tensile strength Rm: > 1310 MPa
    • Elongation A: > 4 %
    • Hardness HRC: > 40
    • Hardness HB: > 40
    • Percent reduction of area Z: > 20 %
• Precipitation Hardened RH950 (954°C + 73°C + 510°C):
  • Thickness: 0.038 - 0.124 mm
    • Yield strength Re: > 1380 MPa
    • Tensile strength Rm: > 1550 MPa
    • Elongation A: > 1 %
    • Hardness HRC: > 46
  • Thickness: 0.127 - 0.251 mm
    • Yield strength Re: > 1380 MPa
    • Tensile strength Rm: > 1550 MPa
    • Elongation A: > 2 %
    • Hardness HRC: > 46
  • Thickness: 0.251 - 0.505 mm
    • Yield strength Re: > 1380 MPa
    • Tensile strength Rm: > 1550 MPa
    • Elongation A: > 3 %
    • Hardness HRC: > 46
  • Thickness: 0.51 - 4.76 mm
    • Yield strength Re: > 1380 MPa
    • Tensile strength Rm: > 1550 MPa
    • Elongation A: > 4 %
    • Hardness HRC: > 46
  • Thickness: 4.762 - 15.880 mm
    • Yield strength Re: > 1380 MPa
    • Tensile strength Rm: > 1550 MPa
    • Elongation A: > 4 %
    • Hardness HRC: > 45
    • Hardness HB: > 429
    • Percent reduction of area Z: > 20 %
• Cold rolled at mill CH900 = 900F (482°C):
  • Thickness: 0.038 - 0.130 mm
    • Yield strength Re: > 1585 MPa
    • Tensile Strength Rm: > 1655 MPa
    • Elongation A: > 1 %
    • Hardness HRC: > 46

Heat treatment and working

Recommended working and heat treatment parameters for 1.4532 alloy:

• Forging: 1100-800 °C
• Rolling: 1100-800 °C