JIANGSU MITTEL STEEL INDUSTRIAL LIMITED
Jiangsu Mittel Steel Industrial Limited Supply all kinds of Stainless Steel Sheet/Plate/Coil/Round ,Flat ,Angle Bar/Stainless steel Seamless pipe /welded pipe /Elbow/Flange /Galvanized Steel sheet
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31CrMoV9 is a nitriding steel which has at least 2.3%Cr,0.15%Mo,0.1%V as strengthening alloy elements.
Due to its high wear resistance,it is mainly used in the automotive industry and general components mechanical engineering.30CrMoV9 is difficult to weld and therefore should not be used in weld constructions.It can attain surface hardness of 800 HV after nitriding.31CrMov9 is directly involved the nitriding steel 30CrMoV9 (DIN1.7707).
1.Supply Form & Size & Tolerance
Hot rolled bar:Φ6-Φ130mm,Length:3000-10000mm
Hot Forged round bar:Φ130-Φ1000mm,Length:3000-10000mm
Flat bar/Blcoks:Thickness :120-800mm xWidth:120-1500mm,Length:2000-6000mm
| Surface Finish | Tolerance |
| Black For Forged condition | (0,+5mm) |
| Black For Rolled condition | (0,+1mm) |
| Rough Turned | (0,+3mm) |
| Grinding | Best h9 |
| Polished | Best h11 |
| Peeled | Best H11 |
| Cold Drawn | Best H11 |
2.Chemical Composition
| Grade | C | Mn | P | S | Si | V | Cr | Mo |
| 31CrMoV9/1.8519 | 0.27-0.34 | 0.40-0.70 | ≤ 0.025 | ≤ 0.035 | ≤ 0.4 | 0.1-0.2 | 2.3-2.7 | 0.15-0.25 |
3.Physical Property
Density ,g/cm3: 7.85
Specific heat capacity, J/(kg.K):460
Thermal conductivity ,W/(m.K):42
Electric resistivity,Ohm.mm2 /m:0.19
Modulus of elasticity ,Gpa: 210
4. Mechanical Property
| Diameter d mm | 16-40 | 40-100 | 100-160 | 160-250 |
| Yield Strength Mpa | ≥900 | ≥800 | ≥700 | ≥650 |
| Tensile Strength Mpa | 1100-1300 | 1000-1200 | 900-1100 | 850-1050 |
| Elongation, % | ≥9 | ≥10 | ≥11 | ≥12 |
| impact,J | ≥25 | ≥30 | ≥35 | ≥40 |
| Hardness,HB | 331-380 | 298-359 | 271-331 | 253-319 |
5.Forging
Heat the temperature between 1050℃-1150℃,hold suitable time for the steel to be thoroughly heated.Reheat the steel once temperature below 850°C. Crack is easily occured when improper cooling way after forged,so it should be cooled as slowly as possible in the furnace or in sand after forged.
6.Heat Treatment
| Hold time,h | Hardness,HV | ||||||
| 30 | 750 | 540 | 430 | 410 | 400 | 380 | 380 |
| 90 | 830 | 750 | 640 | 530 | 430 | 410 | 410 |
| 120 | 790 | 730 | 660 | 600 | 540 | 460 | 400 |
| 180 | 800 | 760 | 700 | 640 | 580 | 550 | 420 |
| Depth,mm | 0.15 | 0.25 | 0.35 | 0.45 | 0.55 | 0.65 | 1 |
7.Jominy Test -Distance from quenched end mm
| mm | 2 | 8 | 12 | 16 | 20 | 30 | 40 | 50 | 60 | 70 |
| HRC | 51 | 50 | 50 | 49 | 48 | 46 | 44 | 42 | 41 | 41 |
8.Application
31CrMoV9 nitriding steel is used in mechanics automotive and general mechanics, which must be nitrided for very high wear forces, for example, gears, rods or axes.Structural parts of medium and large cross sections and high surface hardness, e.g., valve and gate valves, cylinders for combustion engines, superheated steam valves and fittings.