Material Name: Alloy Steel
Grade: 30CrMnSiNi2A
● Features and application:
After heat treatment for high strength, good ductility and toughness, good fatigue resistance and fracture toughness, fatigue crack growth rate low. High hardenability, machinability and weldability is still good, but the gap and hydrogen embrittlement (including environmental embrittlement) more sensitive. Appropriate for high-strength connectors and shaft parts and other important structural components of the force.
● Chemical Composition:
Carbon C: 0.27 ~ 0.34
Si Si: 0.90 ~ 1.20
Manganese Mn: 1.00 ~ 1.30
Sulfur S: ≤ 0.020
Phosphorus P: ≤ 0.020
Chromium Cr: 0.90 ~ 1.20
Ni-Ni: 1.40 ~ 1.80
● Mechanical Properties:
Tensile strength σb (MPa): 1) 1767; 2) 1627
Elongation δ5 (%): 1) 12; 2) 13
Reduction of area ψ (%): 50
Impact toughness αku (J/cm2): 1) 79; 2) 90
Specimen size: bar
● Heat treatment and microstructure specifications:
Heat treatment specifications: 1) 890 ~ ​​900 ℃ oil quenched, 200 ~ 300 ℃ tempering, air-cooled; 2) 890 ~ ​​900 ℃ heating, quenching into 210 ~ 280 ℃ isothermal nitrate bath 1h, cooled, and then 200 ~ 300 ℃ tempering, air-cooled.
Microstructure: 1) high-temperature tempering after hot or cold for the pearlite; 2) for the high-temperature tempering normalizing plus tempering sorbite; 3) after isothermal annealing
Flake pearlite and ferrite; 4) normalizing the status of martensite and bainite; 5) the use of state tempered horse