440C Stainless Precision Shaft | Compass Power Tech

Martensitic Stainless Steel Hardened Shafts

440C Stainless Steel Precision Shaft AISI 440C | UNS S44004

High-hardness shaft applications require a material that can resist wear while maintaining reliable strength after heat treatment. 440C martensitic stainless steel contains a higher carbon level than many stainless steel grades, allowing it to achieve high hardness and strong mechanical performance when properly heat treated.

With good rust resistance and hardness up to 58 HRC, this grade is widely used where surface durability, cutting performance, and wear resistance are critical. It is commonly selected for high-strength tool steel applications, precision shafts, wear-resistant mechanical parts, cutting components, bearings, and other parts exposed to repeated friction or contact stress.

Compass Power Tech manufactures 440C stainless steel precision shafts for customers who need a balance of hardness, corrosion resistance, and dimensional accuracy in demanding mechanical applications.

Mechanical Properties

Hardness	Hardness (after Q&T)	Hardness (after Q&T)	Tensile Strength (Rm)	Yield Strength (Rp0.2)	Elongation (A)	Impact Energy (KV)
≤ 269 HBW	≥ 58 HRC	≥ 633 HV	760–850 MPa	450–600 MPa	≥ 14 %	12 J

Chemical Composition (%)

Grade	C	Si	Mn	P	S	Ni	Cr	Mo
440C (S44004)	0.95–1.2	≤ 1.00	≤ 1.00	≤ 0.035	≤ 0.030	≤ 0.600	16.00–18.00	≤ 0.75

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.