Custom Stamped And Heat-Treated 65Mn Spring Steel Retaining Clip

Material Specifications & Spring Properties

Grade: 65Mn (GB) / SAE 1065 modified, tensile strength after heat treatment 1300-1500 MPa, elastic limit ≥ 800 MPa.

Hardness: 42-46 HRC after tempering, with a fine tempered martensite microstructure free of decarburization.

Forming Process & Tooling Technology

Progressive stamping from coiled strip includes piercing, bending with over-bend compensation, and coining.

After stamping, clips are austenitized in a controlled-atmosphere belt furnace at 830°C, oil quenched, and tempered at 380°C. They are then constrained in a heat-setting fixture to correct spring-back.

A final stage coining in the tool refines critical radii to ±0.05 mm.

Surface Treatment & Performance Metrics

Electroplated zinc-nickel alloy (12-15% Ni) with trivalent passivation and anti-friction topcoat; no hydrogen embrittlement due to strict baking within 4 hours.

Clamping force at a defined deflection (e.g. 2.5 mm) is verified on a force tester to fall within a ±8% range. Fatigue life exceeds 5 million cycles at the specified working deflection.