ASTM B650-23 PDF

Overview

ASTM B650-23: Standard Specification for Electrodeposited Engineering Chromium Coatings on Ferrous Substrates establishes requirements for applying electrodeposited (electroplated) chromium coatings-commonly known as "hard" or "functional" chromium-onto ferrous alloys. Unlike decorative chromium plating, these engineering coatings are applied in greater thickness and aim to enhance the performance and longevity of critical steel components. Adherence to ASTM B650-23 ensures improved wear, abrasion, fretting resistance, and corrosion protection, as well as reduced friction and galling, alongside potential restoration of worn or undersized parts.

Key Topics

Chromium Plating for Engineering Use

ASTM B650-23 covers various technical aspects relevant to the electrodeposition of hard chromium on steel and iron substrates, including:

• Coating Classes: Coatings are classified by thickness to suit different engineering requirements, from light wear resistance and friction reduction to significant build-up for salvage applications.
• Testing & Quality Requirements: The standard specifies comprehensive sampling and testing methods, addressing:
  • Coating thickness (measured via microscopical, magnetic, coulometric, or X-ray spectrometric methods)
  • Adhesion (evaluated through bend, file, heat and quench, or push tests)
  • Porosity (verified using ferroxyl, neutral salt spray, or copper sulfate tests)
  • Workmanship and coating appearance
  • Stress relief and hydrogen embrittlement treatments to ensure safety and structural integrity
• Significant Surfaces: Only surfaces accessible by a 20-mm ball (unless otherwise specified) are generally required to meet the controlled thickness criteria.

Applications

Practical Value of ASTM B650-23

The use of ASTM B650-23 is essential for industries where component durability, reduced maintenance, and performance reliability are crucial. Typical applications include:

• Automotive and Aerospace Engineering: Enhancing wear and corrosion resistance of shafts, gears, pistons, and hydraulic rods.
• Heavy Equipment Manufacturing: Restoring worn or undersized steel components, thereby extending equipment life.
• Machinery Repair and Maintenance: Providing an economical solution to salvage high-value ferrous parts with precise dimensional control.
• Reducing Friction and Preventing Galling: Critical for moving parts operating under load or in hostile environments.

Implementing hard chromium coatings according to ASTM B650-23 supports regulatory compliance requirements and customer mandates, especially for components supplied to government or defense agencies.

Related Standards

Several ASTM standards and industry practices support or are referenced within ASTM B650-23:

• ASTM B117: Salt Spray (Fog) Testing for corrosion resistance validation
• ASTM B177, B183, B242, B320: Guidelines for preparing ferrous alloys before electroplating
• ASTM B487, B499, B504, B568: Methods for measuring coating thickness
• ASTM B571: Adhesion testing procedures
• ASTM B849, B850: Treatments to reduce hydrogen embrittlement in plated steel
• MIL-S-13165: Shot peening process for fatigue life improvement

Aligning processes with these related standards ensures best practices in electroplating, sampling, inspection, and component performance, helping manufacturers and engineers achieve reliable results with engineering chromium coatings.

Keywords: ASTM B650-23, chromium plating standard, electrodeposited engineering chromium, hard chromium coatings, ferrous substrates, wear resistance, corrosion resistance, friction reduction, hydrogen embrittlement, thickness measurement, adhesion testing.