4340 alloy steel is a high quality Quenched and Tempered Alloy Structural steel, It belong to the high quality medium carbon, Oil Quenched & Tempered Hardenss is 28-34 HRc.4340 Annealing delivery hardenss less than 250HB.
4340 steel properties is very similar with GB 40CrNiMo steel, JIS SNCM439 and DIN 1.6511 36CrNiMo4 Alloy structural steel. At most work environment,4340 is equivalent with 40CrNiMo, 1.6511 36CrNiMo4, SNCM439 steel.
| AISI 4340 Steel Round Bar Plate Sheet Supply Range |
| Type |
Specification |
Surface |
| Round Bar |
Diameter: 10mm – 1000mm; length: 2000mm-5000mm |
Black Surface/Bright Surface/ Grinded/Peeled/Turned |
| Sheet/Plate/Slab |
Thickness: 50-120mm; width: 2000mm-2300mm;
length: 3000mm-5800mm |
Black Surface/Bright Surface/ Grinded/Peeled/Turned |
S7 Steel Grade Equivalent Chart
| Country |
USA |
German |
| Standard |
ASTM A681 |
DIN EN ISO 4957 |
| Grades |
S7/T41907 |
1.2355/50CrMoV13-15 |
S7 Steel Chemical Composition
| Grade |
C (%) |
Mn (%) |
P (%) |
S (%) |
Si (%) |
Cr (%) |
V (%) |
Mo (%) |
| S7 |
0.45-0.55 |
0.20-0.90 |
0.030 |
0.030 |
0.20-1.00 |
3.00-3.50 |
≤0.35 |
1.30-1.80 |
AISI S7 Steel Physical Properties
| Physical Properties |
| Elastic Modulus |
207GPa |
| Density |
7.83 g/cm³ |
| Thermal Conductivity |
W/m- °K |
| at 95°C |
28.5 |
| Thermal Properties |
| Critical Temperature |
800°C |
| CTE, linear 20°C |
12.59µm/m- °C |
| CTE, linear 250°C |
13.33µm/m- °C |
| CTE,linear 500°C |
14.27µm/m- °C |
| Transformation Temperature |
785 °C |
S7 Tool Steel Mechanical Properties
| Mechanical Properties |
Metric |
| Hardness, Rockwell C (air cooled from 941°C, 649°C temper temperature) |
41 |
| Hardness, Rockwell C (air cooled from 941°C, 449°C temper temperature) |
53 |
| Hardness, Rockwell C (air cooled from 941°C, 149°C temper temperature) |
57 |
| Modulus of elasticity |
207 GPa |
| Charpy impact (V-notch; air cooled from 941°C; 425°C temper temperature) |
13.6 J |
| Charpy impact (V-notch; air cooled from 941°C; 649°C temper temperature) |
16.3 J |
| Charpy impact (V-notch; air cooled from 941°C; 200°C temper temperature) |
16.9 J |
| Machinability (1% carbon steel) |
70.0 – 75.0% |
| Poisson's ratio |
0.27-0.30 |
Applications
ASTM 4340 steel is a alloy structural steel, 4340 is used for engineering structural, Used as require good toughness, high strength, as well as the important conditioning of large size, heavy machinery such as high load of axial, turbine shaft, larger than 250 mm in diameter of helicopter rotor shaft, turbojet engine turbine shaft, blade, high load of transmission parts, fasteners of the crankshaft. Gear, etc.; Can also be used for operating temperature over 400 ℃ of rotor shaft and blade, etc.; And after nitriding processing can also be used to make special performance requirements of the important parts, after low temperature tempering or can be used for ultra-high strength steel after isothermal quenching.
Songshun Steel
Dongguan Songshun Mould Steel Co., LTD which is an industrial and trading company with 3500-7000ts hydraulic forging machine. We provide a great variety of steels, competitive price with good quality and keep the large stock are over 20000 tons.
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