ASTM Standards: B Practice for Operating Salt Spray (Fog) Apparatus2. B Guide for Engineering Chromium Electroplating3. B Practice for. Endorsed by AmericanDesignation: B – 01 (Reapproved )e1. ASTM B/BM() Standard Guide for Engineering Chromium Electroplating Scope
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Aluminum, titanium, and certain nickel alloys sstm need to have cleaning and etching operations done before racking due to entrapment of cleaning and etching solutions in the plating rack which can result in adhesion failures due to seepage during chromium electroplating.
This is a very dangerous exothermic reaction. If the document is revised or amended, you will be notified by email. In all cases, the duration of the bake shall commence from the time at which the whole of each part attains the specied temperature. Originally published as B — Ast, guide provides information on the deposition of engineering chromium by electroplating.
N177 Coatings on Magnetic Basis Metals. All baths of this type include barium salts or other precipitants for sulfate. These baths produce microcracked deposits which may be an advantage in some deposits. Face shield, chemical goggles, rubber gloves, and other safety equipment should be used when handling sulfuric acid and when making this addition. A number in parentheses indicates the year of last reapproval. Current edition approved Nov.
ASTM B177/B177M – 11(2017)
Specified chromium electrodeposits on ferrous surfaces are defined awtm Specification B This standard is not included in any packages. Please first verify your email before subscribing to alerts. For deposits up to 50 m 2 milsTest Method B may be used and does not destroy the part, but does remove the chromium electrodeposit on the area tested, which may necessitate replating.
This abstract is a brief summary of the referenced standard. Chemical lead is also satisfactory where hardness and rigidity are not important.
Add to Alert PDF. Most nonferrous metals enter the chromium plating solution under live current and are not placed in the chromium-plating solution for warming prior to electroplating.
Standard Guide for Engineering Chromium Electroplating
Need more ashm one copy? Most proprietary chromium plating baths are co-catalyzed plating solutions in which an additional catalyst is used in conjunction with the traditional sulfate anion catalyst. Polarized surfaces in high-nickel stainless steels can cause skip plating if not properly activated.
Some stainless steels benet from a Woods nickel strike prior to chromium electroplating.
The efficiency is very high and the chromium evidentially deposits in a different crystal structure than is obtained in other baths. Combining values from the two systems may result in non-conformance with the standard. To reduce the increase in roughness resulting from etching, the etching times should be kept as short as is consistent with good adhesion, particularly in the case of highly nished surfaces.
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.
The required surface smoothness may be obtained by suitable chemical, mechanical, or electrochemical procedures. There are many modications reported in the literature and some manufacturers offer proprietary baths.
For parts loaded in compression or not subject to cyclical applications of stress during operation, or both, this may not be a consideration.
ASTM B / BM – 11() Standard Guide for Engineering Chromium Electroplating
Shorter times at higher temperatures may be used, if the resulting loss in surface hardness is acceptable. You can download and open this file to your own computer but DRM prevents opening this file on another computer, including a networked server. The most recent baths do not use uoride co-catalysts and do not etch unprotected low current density areas. As the deposit is nonconductive, the maximum thickness that can be expected is 3 to 5 m which requires 4 to astj min.
B17 to Checkout Continue Shopping. Lead and aluminum tapes will provide a sharp line of demarcation between coated and uncoated areas with a minimum of buildup.
ASTM B/BM() – Standard Guide for Engineering Chromium Electroplating
Proprietary baths should be evaluated for the tendency towards macrocracking if fatigue life is an important design consideration. Substrate requirements including smoothness, fatigue, high-strength steel stress relief, and oxidation are specified.
This is sometimes called “functional” or “hard” chromium and is usually applied directly to the basis metal and is usually thicker than decorative deposits. Literature references suggest preparing this bath by adding sodium hydroxide to a 4 Mol chromic acid solution.