Products Description
Product Specifications
| Standards | EN 10297-1 |
| Steel Grades | 38Mn6(1.1127),41Cr4(1.7035),25CrMo4(1.7218),30CrMo4(1.7216),34CrMo4(1.7220), 42CrMo4(1.7225),36CrNiMo4(1.6511), 30CrNiMo8(1.6580),41NiCrMo7-3-2(1.6563),etc. |
| Equivalent Standards | ASTM A519: 4130 / 4135,4137 / 4140; JIS G3441: SCM430 / SCM435 / SCM440; GB/T 8162: 30CrMo / 35CrMo / 42CrMo |
| Outer Diameter (OD) | 6 mm - 630 mm |
| Wall Thickness (WT) | 2.0 mm - 8.0 mm |
| Length | 6/12m, or customized |
| Surface Treatment | Bright annealed |
| Production Process | Cold drawn/ Cold Rolled |
| Condition | +C, +SR , +A, +QT |
After undergoing quenching and tempering (+QT) treatment, 1 chromoly tubing can easily achieve a tensile strength of 800–1000 MPa, 1.1-2.8 times that of standard E355 carbon steel. Through the cold-drawing process, the tubing achieves high dimensional precision on both its inner and outer surfaces, with an outer-diameter tolerance of ±0.08 mm and a wall-thickness tolerance of ±10%.
Automotive tubing must withstand millions of cycles of alternating torsional loads during vehicle operation. The combination of chromium (0.9–1.2%) and molybdenum (0.15–0.3%) in the steel refines the grain structure and forms a stable tempered sorbite microstructure, thereby significantly enhancing the fatigue limit.
Customized Services
- TORICH offers custom precision sizing and non-standard dimension services, covering outer diameters of 6–630 mm and wall thicknesses of 0.5–50 mm, with tolerances as tight as ±0.05 mm.
- TORICH provides precision internal bore processing, including ID honing (achieving Ra ≤ 0.2 μm) and hard chrome plating (customizable layer thickness of 20–30 μm) for components such as shock absorber cylinders and hydraulic valve bodies.
- Additional machining services include high-precision OD grinding (h8), internal and external tube-end chamfering, specialized sealing thread turning (e.g., M24x1.5), C-clip groove machining, flanging, tube end reduction, drilling, and pin hole machining.
Chemical Composition
| Element | C | Mn | Si | Cr | Mo | P | S |
|---|---|---|---|---|---|---|---|
| 30CrMo4 | 0.26–0.34 | 0.50–0.80 | ≤0.40 | 0.90–1.20 | 0.15–0.30 | ≤0.035 | ≤0.035 |
| 34CrMo4 | 0.30–0.37 | 0.60–0.90 | ≤0.40 | 0.90–1.20 | 0.15–0.30 | ≤0.035 | ≤0.035 |
| 42CrMo4 | 0.38–0.45 | 0.60–0.90 | ≤0.40 | 0.90–1.20 | 0.15–0.30 | ≤0.035 | ≤0.035 |
Mechanical Properties
| Property | Tensile Strength (MPa) | Yield Strength (MPa) | Elongation (%) | Hardness (HB) |
| 30CrMo4 | 750–900 | 600–750 | ≥12–15% | 220–280 |
| 34CrMo4 | 850–1000 | 700–850 | ≥10–14% | 240–300 |
| 42CrMo4 | 950–1100 | 800–950 | ≥9–12% | 260–320 |
Possible Alternative Grades
- 25CrMo4 offers lower costs, superior toughness, and better weldability than 30CrMo4, making it suitable for low-load structural components, standard fasteners, and non-critical drive shafts.
- For environments requiring corrosion resistance, 410 stainless steel is a suitable choice; it offers three times the salt-spray corrosion resistance of 30CrMo4 and is ideal for chassis components and exhaust systems in coastal regions.
- 30CrNiMo8 features significantly higher hardenability than 42CrMo4, making it suitable for high-performance race cars, extreme low-temperature environments, and heavy-duty components with large cross-sections.
application areas
- Chassis and Suspension: Hollow stabilizer bars, torsion bar springs, control arm sleeves, subframe reinforcement tubes
- Steering and Braking: Steering rack tubes, steering columns, brake pedal sleeves
- Powertrain: Driveshaft tubes, half-shaft sleeves, CV joint cage blanks, transmission gear sleeves
- Engine and Fuel System: High-pressure common rail tubes, fuel injection pump plunger sleeves, hydraulic tappet tubes
- Shock Absorption and Body: Shock absorber working cylinders/reservoirs, door impact beams, seat frame tubes
Products Show
Testing Equipment
Factory Equipment
Pickling equipment
Products Package
fAQ
Q: How do you quickly choose between 30CrMo4, 34CrMo4, and 42CrMo4?
A: The primary criteria are the required strength and processing method. Choose 30CrMo4 for the best weldability and moderate strength; choose 34CrMo4 for high strength and good machinability; and choose 42CrMo4 for ultra-high strength and wear resistance-ideal for heavy-duty torsion bars or axle tubes. Our engineers can assist with verification.
Q: What are the outer diameter and wall thickness tolerances for this Chromoly tubing?
A: In the bright annealed or stress-relieved annealed condition, the standard tolerance for a 25.4 mm outer diameter is ±0.08 mm, with a wall thickness tolerance of ±10%. Tolerances can be upgraded to the h8 class (0/-0.033 mm) upon request.
Q: Can these tubes be bent using CNC machining?
A: Yes. These chromoly alloy tubes are fully suitable for CNC bending in the annealed (+A) or stress-relieved (+SR) condition. We recommend a bending radius of at least 2.5 times the tube diameter. After bending, stress-relieving or quench-and-temper heat treatment can be performed as needed to eliminate residual stresses and restore strength.
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