Product Details
I. Basic Materials
II. Chemical Composition of Base Material (Mass Fraction wt%)
III. Mechanical Properties (Quenched and Tempered)
IV. Processing Technology & Surface Roughness
V. Coating & Physical Properties
VI. Application Scenarios
Hydraulic piston rods, cylinder shafts, valve fittings, shafts for food processing machinery, wear-resistant precision pin shafts, general high-strength corrosion-resistant transmission components.
| Item | Technical Parameters |
| Base Material Grade | 420 |
| National Standard Grade | 20Cr13 |
| Surface Treatment | Chrome Plated |
| Chrome Plated Coating Thickness | Diameter ≤φ20: 15μm; Diameter＞φ20: 20μm, thickness can be customized as required |
| Surface Hardness after Chrome Plated | HV800～1100 |
| Common Diameter Range | φ3.0mm～φ300mm |
| Diameter Tolerance | Conventional: h8, h9; High Precision: h7, f7, g6, h6 |
| Roundness | ≤1/2 of diameter tolerance |
| Straightness | ≤0.10mm/1000mm |
| Standard Length | Fixed length of 3 meters for φ40mm and below; fixed length of 6 meters for sizes above φ40mm; customized fixed lengths available for large specifications |
| End Face Requirements | Flat ends with chamfering and burr removal |
II. Chemical Composition of Base Material (Mass Fraction wt%)
| C | Si | Mn | P | S | Cr |
| 0.16～0.25 | ≤1.00 | ≤1.00 | ≤0.040 | ≤0.030 | 12.00～14.00 |
III. Mechanical Properties (Quenched and Tempered)
| Item | Mechanical Properties |
| Tensile Strength Rm | ≥735 MPa |
| 0.2% Proof Strength Rp0.2 | ≥540 MPa |
| Elongation after Fracture A | ≥12% |
| Base Material Hardness | 217～241 HB |
IV. Processing Technology & Surface Roughness
| Process Type | Complete Process Flow | Surface Roughness |
| Process 1 | Hot-rolled base material → Precision drawing → Centerless precision grinding → Polishing → Chrome Plated → Polishing | Ra ≤0.2μm |
| Process 2 | Hot-rolled base material → Peeling and straightening → Centerless precision grinding → Polishing → Chrome Plated → Polishing | Ra ≤0.2μm |
| Process 3 | Forged round bar → Turning finishing → Centerless precision grinding → Polishing → Chrome Plated → Polishing | Ra ≤0.2μm |
V. Coating & Physical Properties
| Item | Parameter Description |
| Coating Adhesion | No peeling or flaking; passes bending resistance test |
| Corrosion Resistance | High hardness, rust-proof and wear-resistant; corrosion resistance greatly improved after Chrome Plated |
| Friction Coefficient | Dense and smooth surface with low friction, wear resistance and scratch resistance |
| Magnetism of Base Material | Magnetic |
VI. Application Scenarios
Hydraulic piston rods, cylinder shafts, valve fittings, shafts for food processing machinery, wear-resistant precision pin shafts, general high-strength corrosion-resistant transmission components.
