Products Description
Product Specifications
| Standards |
GB/T 3077 |
| Steel Grades |
38CrMoAl |
| Equivalent Standards | 34CrAlMo5 (EN), 41CrAlMo7 (DIN), SACM645 (JIS),
NF 40CAD6.12, ISO 41CrAlMo74 |
| Outer Diameter (OD) | 5 mm - 630 mm |
| Wall Thickness (WT) | 0.5 mm - 55 mm |
| Length | 6/12 m, customized |
| Inner Surface Treatment | Honed, skived & roller burnished, polished |
| Production Process | Hot Rolled, Cold Drawn, Cold Rolled |
| Condition | BK, BKW, BKS, +N, +QT |
After nitriding, the surface hardness of 38CrMoAl Alloy Tubes can reach ≥850 HV. Traditional 40Cr steel, after nitriding, has a hardness of only HV 500~600, whereas 42CrMo can reach HV 550~700. The wear resistance of 38CrMoAl can be 2~3 times that of 40Cr.
During the reciprocating motion of the piston rod in a hydraulic cylinder, the high-hardness nitrided layer of 38CrMoAl Alloy Tubes tends to provide dry-friction self-lubrication, significantly reducing the risk of "cold welding" to seals or the piston.
Customized Services
- TORICH offers high-precision internal bore processing services, including deep-hole boring combined with roller burnishing or honing to meet customer specifications; achievable internal diameter tolerances range from H8 to H9, with surface roughness of Ra 0.2–0.4 μm.
- For piston rod tubing, we provide precision OD grinding services, achieving dimensional tolerances of ±0.01 mm and surface roughness of Ra ≤ 0.4 μm.
- We also offer surface treatments such as hard chrome plating (0.02–0.05 mm), electroless nickel-phosphorus plating (0.01–0.03 mm), and phosphating/saponification.
Chemical Composition
| Element | C | Si | Mn | Cr | Mo | Al | P | S |
|---|---|---|---|---|---|---|---|---|
| 38CrMoAl | 0.35–0.42 | 0.20–0.45 | 0.30–0.60 | 1.35–1.65 | 0.15–0.25 | 0.70–1.10 | ≤0.035 | ≤0.035 |
Mechanical Properties
| Property | Tensile Strength | Yield Strength | Elongation | Reduction of Area | Hardness |
|---|---|---|---|---|---|
| 38CrMoAl (+QT) | ≥980 MPa | ≥835 MPa | ≥14 % | ≥50 % | 229–269 HB |
| 38CrMoAl Nitrided | - | - | - | - | ≥850 HV Surface |
Possible Alternative Grades
- 42CrMo (AISI 4140) is the most commonly used alternative material when high strength and toughness are required. It offers excellent mechanical properties, though its nitriding hardness is lower than that of 38CrMoAl.
- E355 (ST52) is a cost-effective choice for standard hydraulic cylinders. It features good machinability and dimensional accuracy but is less suitable for environments involving severe wear.
- 20MnV6/STKM13C can serve as an alternative to 38CrMoAl and is suitable for medium-duty cylinders where low cost and high weldability are prioritized.
application areas
- Hydraulic cylinders for main booms and buckets of excavators, loaders, and bulldozers
- Lift cylinders for heavy-duty dump trucks
- High-temperature, high-pressure chambers and piston cylinders for die-casting and extrusion machines
- Hydraulic cylinders for marine steering gear and anchor winches
- Hydraulic outrigger and power tong cylinders for oil drilling and workover rigs
- Precision pneumatic components
- Cylinder bodies for impact crushing rods in mining machinery
Products Show
Testing Equipment
Factory Equipment
Pickling equipment
Polishing equipment
Cold drawing equipment
Products Package
FAQ
Q: What level of precision and surface roughness can be achieved for the inner bore?
A: We offer customized inner bore processing via roller burnishing or honing. We guarantee an H8 tolerance for the inner diameter upon delivery; precision roller burnishing consistently achieves a surface roughness of Ra 0.2–0.4 μm-producing a mirror-like finish suitable for direct use in sealing assemblies.
Q: Can 38CrMoAl tubing be welded? What are its welding characteristics?
A: 38CrMoAl has poor weldability. Due to its high carbon equivalent, the heat-affected zone is prone to forming hardened microstructures and cold cracks. For welded structural components such as hydraulic cylinder bases or flanges, it is generally recommended to use materials with better weldability, such as 42CrMo or 27SiMn.
Q: Is grinding required after nitriding 38CrMoAl?
A: One of the major advantages of nitriding 38CrMoAl is minimal deformation. Component distortion can typically be controlled within the range of 0.01–0.03 mm/m.
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