Pure Iron Relay Yoke Plate

Precision Progressive Die Stamping

Utilizing multi-station progressive dies, multiple processes for Relay Iron Yoke Bracket-including blanking, deep drawing, bending, embossing, and punching-are completed within a single die set. Dimensional tolerances are controlled within ±0.02 mm, and flatness is maintained at ≤0.1 mm/100 mm. For critical areas (such as the air-gap surface interfacing with the armature), a dedicated finishing station is incorporated to ensure exceptional surface flatness.

Dual-Stage Copper Plating Process

Employing either rack plating or barrel plating techniques for the Electromagnetic Relay Yoke Frame, a base layer of copper (3–5 μm thick) is applied first. This coating is uniform, dense, and exhibits excellent adhesion. The copper layer serves not only to provide corrosion protection but also acts as a lubricating layer to minimize friction during subsequent assembly.

Protective Atmosphere Annealing

Following the stamping process, Pure Iron Stamped Relay Yoke undergo stress-relief annealing in a protective atmosphere furnace (using hydrogen or nitrogen gas) at temperatures ranging from 650°C to 700°C, with a holding time of 4 to 6 hours. This process thoroughly eliminates internal stresses induced by work hardening during stamping, thereby restoring the material's soft magnetic properties. After annealing, the yoke exhibits a uniform, silvery-gray metallic luster, and its coercivity is reduced by 30% to 50%.