SCM440 ALLOY STRUCTURAL STEEL- TJC STEEL.

​SCM440 is a commonly used steel for the production of high-strength fasteners. The product has the advantages of stable composition, low harmful elements, high purity[TJC STEEL] of steel, small decarburization layer, less surface defects, etc. It is easy to carry out spheroidizing annealing, low cold heading cracking rate, stable heat treatment quality and uniform hardness, and is widely used in engine, mold and other industries.
Chinese name SCM440 Material[TJC STEEL] name Alloy Structural Steel grade Japanese grade corresponding to 42crmo4
Catalogue
1 Product Introduction
2 Features and applications
3 Chemical Composition
4 Mechanical Properties
5 Heat treatment process
Product Introduction
Material Name: Alloy structural steel
Brand: SCM440(Japanese brand,[TJC STEEL] see standard JIS G4053-2008, similar to Chinese brand 42CrMo)
Corresponding to :42crmo4
Features and Scope of Application:
It is a medium hardenability steel, with good strength and comprehensive mechanical properties after heat treatment, good manufacturability and high yield. [TJC STEEL]The maximum operating temperature is 427℃. Can be used as turbine fastener.
Features and Applications
1. Good quenching, can be deep quenching, rather than the market anti-saw lock surface quenching
2. Less tendency to temper brittleness
3. Good high temperature processing, beautiful after processing
4. Good welding
5. Impact absorption performance is good, hammer hit will have a sense of rebound, can not carry[TJC STEEL] out violent destruction Advantages:
(1) Good processability
(2) Good shock absorption performance
(3). Easy welding
Chemical composition editing broadcast
C 0.38-0.43
Si 0.15-0.35
Mn 0.60-0.85
P ≤0.03
S ≤0.03
Cu ≤0.30
Ni ≤0.25
Cr 0.90-1.20
MO 0.15-0.30
Ni 0.25 or less[TJC STEEL]
Cu 0.30 or less
Mechanical Properties
Tensile strength σb (MPa) : ≥1080(110) Yield strength σs (MPa) : ≥930(95)
Elongation δ5 (%) : ≥12
Section shrinkage (%) : ≥45
Impact power Akv (J) : ≥63
Impact toughness value[TJC STEEL] αkv (J/cm²) : ≥78(8)
Hardness: ≤217HB
Specimen size: specimen blank size is 25mm
● Heat treatment specifications and metallographic structure:
Heat treatment specification: 880℃,1h oil quenching,650 ~ 680℃, 2h tempering, air cooling.
Metallographic structure: tempered martensite.
Heat treatment process
annealing No.1 "760±10℃ annealing, [TJC STEEL]furnace cooling to 400℃ air cooling.
HB220-230
normalize No.4 860±10℃ normalizing, air cooling out.
quenching water or oil at 840±10 ° C (depending on the complexity of the product), tempering at 680-700 ° C. HB<217
quenching oil at 840±10℃ and tempering at 470 ℃ is quenching according to quenching+tempering No.6. HRC41-45
quenching oil at 840±10℃ and tempering at 480 ℃. Quenching quenching+tempering No.7 HRC35-45
quenching oil at 850℃ +tempering No.8, then tempering at 510 ℃. HRC38-42
quenching oil at 850℃[TJC STEEL] +tempering No.9 and tempering at 500 ℃. HRC40-43
quenching oil at 850℃ +tempering No.10, then tempering at 510℃. HRC36-42
quenching quenching+tempering No.11 at 850℃ and tempering at 560℃. HRC32-36
quenching oil at 860℃ +tempering No.12 and tempering at 390 ℃. HRC48-52 42CrMo round rod[TJC STEEL]