631 17-7PH Stainless Steel Bar | Compass Power Tech

Precipitation Hardening Stainless Steel Shafts

631 (17-7PH) Stainless Steel Bar AISI 631 | UNS S17700

Heat treatment conditions play a major role in the final performance of 631 (17-7PH) stainless steel. Through precipitation hardening, this chromium-nickel stainless steel can achieve high strength and hardness while maintaining good corrosion resistance for precision mechanical applications.

Its mechanical properties vary significantly according to the selected heat treatment condition. In the solution-treated condition, tensile strength can reach up to 1030 MPa. After aging at 565°C, tensile strength can increase to ≥1140 MPa, while aging at 510°C can further increase tensile strength to ≥1230 MPa. This gives customers flexibility when selecting a material condition for different strength, hardness, and toughness requirements.

Compass Power Tech manufactures 631 (17-7PH) precipitation hardened stainless steel precision ground bars for precision shafts, spring-related components, load-bearing parts, mechanical assemblies, and applications that require a combination of strength, corrosion resistance, and dimensional accuracy.

Mechanical Properties

Condition	Tensile strength (Rm)	Yield strength (Rp0.2)	Elongation (A5)	Reduction of area (Z)	Hardness
Cond A (Solution Treated)	≤ 1030 MPa	≤ 380 MPa	≥ 20%	-	≤229 HBW
Cond TH 1050	≥ 1140 MPa	≥ 960 MPa	≥ 5%	≥ 25%	≥363 HBW
Cond RH 950	≥ 1230 MPa	≥ 1030 MPa	≥ 4%	≥ 10%	≥388 HBW

Chemical Composition (%)

Grade	C	Si	Mn	P	S	Ni	Cr	Al
631 (S17700)	≤ 0.09	≤ 1.00	≤ 1.00	≤ 0.040	≤ 0.030	6.50–7.50	16.00–18.00	0.75–1.50

Specifications

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

Additional Custom Services

Cut-to-length service: Shaft length can be customized according to customer assembly requirements.
End chamfering: Both ends of the shaft can be chamfered to simplify downstream machining and installation.
Drawing-based machining: Shafts can be machined according to customer drawings and supplied as ready-to-assemble components.
Surface rolling treatment: Surface rolling can be applied to improve surface hardness when higher wear resistance is required.

Packaging and Storage

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.

Looking for Custom Metal Components for Your Application?

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.