ASTM B200-22

Overview

ASTM B200-22 is the internationally recognized standard specification for electrodeposited coatings of lead and lead-tin alloys on steel and ferrous alloys. Developed by ASTM International, this standard outlines the requirements for the composition, thickness, adhesion, corrosion resistance, hydrogen embrittlement, workmanship, finish, and appearance of these specialized coatings. ASTM B200-22 is widely referenced for quality control in electroplating processes where enhanced atmospheric corrosion resistance is critical. It is particularly relevant for fabricated parts and does not apply to unfabricated sheet, strip, or wire forms.

Key Topics

• Coating Types and Composition

  • Covers pure lead coatings and lead-tin alloys with up to 15% tin content.
  • Includes terne coatings (3-15% tin) for specific applications.
  • Emphasizes use of high-purity materials to ensure coating consistency.

• Coating Requirements

  • Minimum coating thickness levels: 6, 12, 25, or 40 μm.
  • Strict criteria for uniformity, lack of defects, and appearance.
  • Optional copper or nickel undercoating to enhance corrosion resistance.

• Performance Testing

  • Adhesion and thickness verified using standardized ASTM test methods.
  • Corrosion resistance evaluated through salt spray tests, with required performance levels based on coating thickness.
  • Procedures for managing and reducing the risk of hydrogen embrittlement in high-strength steels.

• Inspection and Sampling

  • Provides guidance for lot-based sampling and inspection protocols.
  • Quality is ensured through both destructive and nondestructive testing, as specified in the order or contract.
  • Allows for use of separate test specimens plated concurrently with production parts when direct testing is impractical.

• Workmanship

  • Finished surfaces must be free from blisters, pits, nodules, cracks, and other defects.
  • Superficial staining from post-plating treatments such as baking is permitted and not grounds for rejection.
  • Purchasing requirements include clear designation of coating type, thickness, and any supplementary tests.

Applications

ASTM B200-22 is widely utilized in several industries for its practical value in providing corrosion protection and functional surfaces, including:

• Chemical Processing Equipment: Components exposed to dilute sulfuric acid and other corrosive chemicals frequently require lead or lead-tin plating for extended durability.
• Brine Refrigeration Tanks: Coatings prevent aggressive brine solutions from attacking the underlying metal structure.
• Electrical and Storage Battery Parts: Lead’s electrical properties and corrosion resistance make it ideal for battery grids and connectors.
• Bearing and Mechanical Surfaces: Lead-tin alloys, such as 93% Pb–7% Sn, are used for their low-friction, wear-resistant qualities. Indium layers may be diffused for specialized performance.
• General Metal Fabrication: Any fabricated steel or ferrous alloy component requiring atmospheric corrosion resistance and enhanced longevity can benefit from these coatings.

Related Standards

Numerous ASTM standards are referenced within ASTM B200-22 to guide surface preparation, coating application, and laboratory testing:

• ASTM B117: Salt Spray Testing for corrosion resistance.
• ASTM B183, B242, B320, B322: Procedures for preparing steel and ferrous surfaces for electroplating.
• ASTM B374: Electroplating terminology.
• ASTM B487, B499, B504, B567, B568: Standard methods to measure metallic coating thickness.
• ASTM B571: Test procedure for coating adhesion.
• ASTM B602, B697: Sampling plans for inspecting metallic coatings.
• ASTM B849, B850: Guidelines for pre- and post-coating treatments to reduce hydrogen embrittlement.

By specifying ASTM B200-22, manufacturers and purchasers ensure reliable, documented performance and compliance for electrodeposited lead and lead-tin coatings on steel and ferrous alloy components. This standard supports safety, longevity, and quality across critical applications in multiple industries.