When a precision shaft requires high strength, good hardness, and stainless steel corrosion resistance in the same material, 630 (17-4PH) offers a strong solution. This martensitic precipitation hardening stainless steel achieves its performance mainly through copper precipitation hardening, giving customers a reliable material option for demanding mechanical and industrial components.
630 (17-4PH) provides high strength, high hardness, good weldability, and good corrosion resistance after proper heat treatment. These properties make it suitable for precision shafts, hydraulic components, valve parts, pump components, aerospace parts, mechanical parts, and other applications where load-bearing performance and corrosion resistance must be considered together.
Compass Power Tech manufactures 630 (17-4PH) stainless steel precision ground bars according to customer requirements and applicable ASTM A564 material standards. For projects requiring specific heat treatment conditions, strength levels, hardness, or dimensional tolerances, our team can support material selection and customized processing for ready-to-use precision components.
| Condition | Tensile strength (Rm) | Yield strength (Rp) | Elongation (A) | Reduction of area (Z) | Hardness |
| |
- | - | - | - | ≤ 363 HBW |
| |
≥ 1310 MPa | ≥ 1175 MPa | ≥ 10% | ≥ 40% | ≥ 375 HBW |
| |
≥ 1070 MPa | ≥ 1000 MPa | ≥ 12% | ≥ 45% | ≥ 331 HBW |
| |
≥ 1000 MPa | ≥ 860 MPa | ≥ 13% | ≥ 45% | ≥ 302 HBW |
| |
≥ 930 MPa | ≥ 725 MPa | ≥ 16% | ≥ 50% | ≥ 277 HBW |
| Grade | C | Si | Mn | P | S | Ni | Cr | Cu | Nb |
| 630 (S17400) | ≤ 0.07 | ≤ 1.0 | ≤ 1.0 | ≤ 0.04 | ≤ 0.03 | 3.50–5.00 | 15.00–17.50 | 3.00–5.00 | 0.15–0.45 |
| Diameter | Tolerance | Roundness | Straightness | Standard Length | Surface Roughness |
| Φ3-Φ25 | 0.1mm/m | g6, h6, f7 | ≤1/2 | 2m 3m | Ra≤0.4 |
| Φ25-Φ40 | 0.1mm/m ≤ | g6, h6, f7 | ≤1/2 | 3m, 6m | Ra≤0.4 |
| Φ40-Φ80 | 0.1mm/m ≤ | g6, h6, f7 | ≤1/2 | 3m, 6m | Ra≤0.4 |
| Φ80-Φ150 | ≤0.05mm/m | g6, h6, f7 | ≤1/2 | 3m, 6m | Ra≤0.4 |
| Φ150-Φ180 | ≤0.05mm/m | g6, h6, f7 | ≤1/2 | 3m, 6m | Ra≤0.4 |
To protect stainless steel precision ground shafting during sea freight and storage, Compass Power Tech uses anti-rust paper tube packaging. Before wrapping, anti-rust oil is applied evenly to the shaft surface, and anti-rust wax is applied inside the paper tube. This protection process helps reduce corrosion risk during transportation and ensures customers receive shafts in stable, ready-to-use condition.
We manufacture precision ground shafts, stainless steel tubing, piston rods and aluminum alloy cylinder tubes for hydraulic, pneumatic, machinery, energy and transportation applications. Contact us for material selection, specifications and customization support.
