Hard Chrome Plated Bars

Product Description

Technical Overview & Key Features

Hard Chrome Plated Bars (Rods) are carbon or alloy steel shafts electroplated with a micro-thin layer of chromium to achieve high wear resistance, low friction, and corrosion resistance.

• Low Friction Coefficient: Typically around 0.15–0.20 (dry vs. steel), extending seal and bearing life in dynamic sliding applications.

• Micro-Cracking Structure: Plating processes intentionally incorporate fine micro-cracks (300–800 cracks/cm) to retain lubricants and enhance sliding wear resistance.

• Surface Hardness: The electrodeposited chrome layer yields 850–1150 HV0.1 (equivalent to 65–72 HRC), far exceeding standard hardened base steels.

Plating Layer & Surface Specifications

Base Material Chemical Comparison

Mechanical Properties by Core Grade

Tolerances & Supply Range

• Diameter Range: 6 mm to 250 mm (Metric) | 1/4" to 10" (Imperial)

• Standard Dimensional Tolerances: ISO f7, f8, h7, h8

• Straightness Tolerance: Max 0.2 mm / 1000 mm (0.02%)

• Out-of-Roundness (Ovality): Max 50% of the diameter tolerance range

• Standard Stock Lengths: 3000 mm to 7500 mm

Processing Steps

1. Precision Centerless Grinding: Base bar is ground to exact OD tolerances and target surface finish.

2. Induction Hardening (Optional): High-frequency heating creates a hard outer casing beneath the surface to prevent denting from severe impacts.

3. Polishing: Pre-plating superfinish polishing to ensure consistent surface topology.

4. Hard Chrome Electroplating: Submerged in a chromic acid bath ($CrO_3$) under precise voltage/current density.

5. Post-Plating Superfinishing: Micro-polishing to achieve target $Ra \le 0.20\,\mu\text{m}$.