【国外标准】 Standard Specification for Electrodeposited Engineering Chromium Coatings on Ferrous Substrates

This specification covers the requirements for electrodeposited chromium coatings (sometimes referred to as functional or hard chromium) applied to ferrous alloy substrates for engineering applications, particularly for increasing wear, abrasion, fretting, and corrosion resistance; for reducing galling or seizing, and static and kinetic friction; and for building up undersize or worn parts. Coatings shall be classified according to their thickness. Coatings shall be sampled, tested, and shall conform accordingly to specified requirements as to appearance, stress relief and hydrogen embrittlement treatment, thickness (to measured either by microscopical, magnetic, coulometric, or X-ray spectrometry method), adhesion (to be assessed either by bend, file, heat and quench, or push test), porosity (to be examined either by ferroxyl, neutral salt spray, or copper sulfate test), workmanship, and packaging.1.1 This specification covers the requirements for electrodeposited chromium coatings applied to ferrous alloys for engineering applications.1.2 Electrodeposited engineering chromium, which is sometimes called “functional” or “hard” chromium, is usually applied directly to the basis metal and is much thicker than decorative chromium. Engineering chromium is used for the following:1.2.1 To increase wear and abrasion resistance,1.2.2 To increase fretting resistance,1.2.3 To reduce static and kinetic friction,1.2.4 To reduce galling or seizing, or both, for various metal combinations,1.2.5 To increase corrosion resistance, and1.2.6 To build up undersize or worn parts.1.3 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, health, and environmental practices and determine the applicability of regulatory limitations prior to use.1.4 This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.