ASTM B696-00(2023) PDF

Overview

ASTM B696-00(2023) is the international standard specification for cadmium coatings mechanically deposited on metal products. Published by ASTM International, this standard establishes comprehensive requirements for the preparation, application, classification, and testing of mechanically deposited cadmium coatings. Mechanical deposition offers a viable alternative to electroplating, particularly for complex components and parts susceptible to hydrogen embrittlement, providing essential corrosion resistance and engineering properties.

Key applications of cadmium coatings include aerospace hardware, fasteners, electronic components, and other critical metal assemblies where corrosion protection and conductivity are important. The standard outlines classification based on thickness, supplementary treatments, and testing methods to ensure uniformity, quality, and safety of the coating.

Key Topics

• Coating Classifications

  • Class 12: 12 μm minimum thickness
  • Class 8: 8 μm minimum thickness
  • Class 5: 5 μm minimum thickness

• Coating Types

  • Type I: As-coated, no supplementary chromate treatment
  • Type II: Supplementary chromate conversion treatment for enhanced corrosion resistance and color identification

• Application and Process Guidelines

  • Mechanical deposition is ideal for coating bores, recesses, and features difficult to electroplate.
  • Process significantly reduces hydrogen embrittlement risk.
  • Requires meticulous surface preparation and, for high-strength steels, stress relief heat treatment prior to coating.

• Quality and Inspection

  • Coating must be uniform, free of blisters, flaking, pits, and other defects.
  • Thickness measured using recognized ASTM methods: microscopical, magnetic, and beta backscatter.
  • Coating must meet specified adhesion and corrosion resistance standards.
  • Corrosion resistance is validated through salt spray (fog) testing per ASTM B117.

• Safety and Health Considerations

  • Cadmium is toxic; coatings must not be used on food, beverage, or oral-contact articles.
  • Adequate ventilation is required during processes involving cadmium to manage harmful fumes, especially at temperatures above 320 °C.

Applications

Mechanically deposited cadmium coatings offer proven benefits in a variety of demanding environments:

• Aerospace and Defense: For components where reliability, corrosion resistance, and minimal risk of hydrogen embrittlement are critical.
• Fasteners and Connectors: Offers uniform protection on complex geometries, ensuring consistent performance in challenging conditions.
• Electronics and Engineering: Enhances conductivity and resists corrosion, extending the service life of parts.
• Automotive and Industrial: Protects vulnerable parts in harsh environments, reducing maintenance frequency and costs.

These coatings are especially advantageous for parts with bores, threads, and recesses that are hard to access with electroplating methods. The mechanical process ensures a thorough and consistent application without inducing hydrogen embrittlement, a significant issue for high-strength steel parts.

Related Standards

To ensure quality and consistency, ASTM B696-00(2023) references and works alongside numerous related ASTM standards, including:

• ASTM B117: Salt Spray (Fog) Testing for corrosion resistance
• ASTM B183: Preparation of Low-Carbon Steel for Electroplating
• ASTM B242: Preparation of High-Carbon Steel for Electroplating
• ASTM B322: Cleaning Metals Prior to Electroplating
• ASTM B487, B499, B567: Measurement of coating thickness
• ASTM B602, B697, B762, F1470: Sampling and inspection methods

These interrelated standards help producers and purchasers specify, measure, and assure the performance of mechanically deposited cadmium coatings across industries.

ASTM B696-00(2023) cadmium coating standard helps organizations achieve durable, high-quality corrosion protection for metal components, while focusing on safety, environmental, and quality requirements in accordance with internationally recognized best practices.