This guide provides information on the deposition of engineering chromium by electroplating. This is sometimes called "functional" or "hard" chromium and is usually applied directly to the basis metal and is usually thicker than decorative deposits. This guide is not intended as a standardized procedure, but as a guide for obtaining smooth, adherent coatings of a desired thickness while retaining the required physical and mechanical properties of the base metals. Engineering chromium may be plated directly to the surface of a commonly used engineering metals such as aluminum, nickel alloys, cast iron, steels, copper, copper alloys, and titanium. Substrate requirements including smoothness, fatigue, high-strength steel stress relief, and oxidation are specified. The procedure and requirements for the following are detailed: (1) racking, including rack and anode designs, (2) cleaning, (3) deoxidizing and etching such as anodic etching in chromic acid solution, in plating solution, and in sulfuric acid solution, and slight etching by acid immersion, (4) chromium electroplating process, (5) treatment of chromium coatings such as baking to avoid hydrogen embrittlement, and mechanical finishing by grinding, grinding and honing, or lapping, (6) repair of chromium electrodeposits on steel substrates, and (7) test methods such as thickness determination, hardness test, and adhesion test.

This abstract is a brief summary of the referenced standard. It is informational only and not an official part of the standard; the full text of the standard itself must be referred to for its use and application. ASTM does not give any warranty express or implied or make any representation that the contents of this abstract are accurate, complete or up to date.

1. Scope

1.1 This guide provides information about the deposition of chromium on steel for engineering uses. This is sometimes called “functional” or “hard” chromium and is usually applied directly to the basis metal and is usually thicker than decorative deposits.

1.2 The values stated in either SI units or inch-pound units are to be regarded separately as standard. The values stated in each system may not be exact equivalents; therefore, each system shall be used independently of the other. Combining values from the two systems may result in non-conformance with the standard.

1.3 This guide is not intended as a standardized procedure, but as a guide for obtaining smooth, adherent coatings of chromium of a desired thickness while retaining the required physical and mechanical properties of the base metals. Specified chromium electrodeposits on ferrous surfaces are defined in Specification B650.

1.4 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use.

2. Referenced Documents (purchase separately) The documents listed below are referenced within the subject standard but are not provided as part of the standard.

ASTM Standards

B183 Practice for Preparation of Low-Carbon Steel for Electroplating

B242 Guide for Preparation of High-Carbon Steel for Electroplating

B244 Test Method for Measurement of Thickness of Anodic Coatings on Aluminum and of Other Nonconductive Coatings on Nonmagnetic Basis Metals with Eddy-Current Instruments

B253 Guide for Preparation of Aluminum Alloys for Electroplating

B254 Practice for Preparation of and Electroplating on Stainless Steel

B281 Practice for Preparation of Copper and Copper-Base Alloys for Electroplating and Conversion Coatings

B320 Practice for Preparation of Iron Castings for Electroplating

B322 Guide for Cleaning Metals Prior to Electroplating

B481 Practice for Preparation of Titanium and Titanium Alloys for Electroplating

B487 Test Method for Measurement of Metal and Oxide Coating Thickness by Microscopical Examination of Cross Section

B499 Test Method for Measurement of Coating Thicknesses by the Magnetic Method: Nonmagnetic Coatings on Magnetic Basis Metals

B504 Test Method for Measurement of Thickness of Metallic Coatings by the Coulometric Method

B507 Practice for Design of Articles to Be Electroplated on Racks

B558 Practice for Preparation of Nickel Alloys for Electroplating

B568 Test Method for Measurement of Coating Thickness by X-Ray Spectrometry

B571 Practice for Qualitative Adhesion Testing of Metallic Coatings

B578 Test Method for Microhardness of Electroplated Coatings

B602 Test Method for Attribute Sampling of Metallic and Inorganic Coatings

B630 Practice for Preparation of Chromium for Electroplating with Chromium

B650 Specification for Electrodeposited Engineering Chromium Coatings on Ferrous Substrates

B697 Guide for Selection of Sampling Plans for Inspection of Electrodeposited Metallic and Inorganic Coatings

B762 Test Method of Variables Sampling of Metallic and Inorganic Coatings

B849 Specification for Pre-Treatments of Iron or Steel for Reducing Risk of Hydrogen Embrittlement

B850 Guide for Post-Coating Treatments of Steel for Reducing the Risk of Hydrogen Embrittlement

B851 Specification for Automated Controlled Shot Peening of Metallic Articles Prior to Nickel, Autocatalytic Nickel, or Chromium Plating, or as Final Finish

F519 Test Method for Mechanical Hydrogen Embrittlement Evaluation of Plating/Coating Processes and Service Environments

Military Standard

Keywords

chromium electroplating; Chromium electroplating; Engineered electrodeposited coatings; Specimen preparation (general)--electroplating; Steel; Steel--electroplating;

ICS Code

ICS Number Code 25.220.99 (Other treatments and coatings)

Citing ASTM Standards

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