Standard: GB / T 1220-1992
● Features and application:
Adding copper precipitation hardening steel types. For the manufacture of shafts, turbine parts.
● Chemical Composition:
Carbon C: ≤ 0.07
Si Si: ≤ 1.00
Manganese Mn: ≤ 1.00
Sulfur S: ≤ 0.030
Phosphorus P: ≤ 0.035
Chromium Cr: 15.50 ~ 17.50
Ni-Ni: 3.00 ~ 5.00
Cu Cu: 3.00 ~ 5.00
Niobium Nb: 0.15 ~ 0.45
● Mechanical Properties:
Tensile strength σb (MPa): 480 ℃ aging, ≥ 1310; 550 ℃ aging, ≥ 1060; 580 ℃ aging, ≥ 1000; 620 ℃ aging, ≥ 930
Conditions yield strength σ0.2 (MPa): 480 ℃ aging, ≥ 1180; 550 ℃ aging, ≥ 1000; 580 ℃ aging, ≥ 865; 620 ℃ aging, ≥ 725
Elongation δ5 (%): 480 ℃ aging, ≥ 10; 550 ℃ aging, ≥ 12; 580 ℃ aging, ≥ 13; 620 ℃ aging, ≥ 16
Reduction of area ψ (%): 480 ℃ aging, ≥ 40; 550 ℃ aging, ≥ 45; 580 ℃ aging, ≥ 45; 620 ℃ aging, ≥ 50
Hardness: solid solution, ≤ 363HB and ≤ 38HRC; 480 ℃ aging, ≥ 375HB and ≥ 40HRC; 550 ℃ aging, ≥ 331HB and ≥ 35HRC; 580 ℃ aging, ≥ 302HB and ≥ 31HRC; 620 ℃ aging, ≥ 277HB and ≥ 28HRC
● Heat treatment and microstructure specifications:
Heat treatment specifications: 1) solid solution 1020 ~ 1060 ℃ rapid cooling; 2) 480 ℃ aging, after solution treatment, 470 ~ 490 ℃ air-cooled; 3) 550 ℃ aging, after solution treatment, 540 ~ 560 ℃ air-cooled; 4) 580 ℃ aging, after solution treatment, 570 ~ 590 ℃ air-cooled; 5) 620 ℃ aging, after solution treatment, 610 ~ 630 ℃ air-cooled.
Microstructure: the organization is characterized by precipitation hardening.
