【国外标准】 Standard Practice for Preparation of Iron Castings for Electroplating

This practice covers preparation of iron castings for electroplating and is intended to assist electroplaters in establishing and maintaining a satisfactory pre-electroplating cycle for malleable iron, gray iron, nodular iron, and white iron castings. It is also intended to indicate certain foundry practices which will facilitate subsequent finishing. The seacoal content of the molding and facing sands should be maintained at the maximum practicable limits to minimize the occlusion of sand in the surfaces of the castings. The steps for the preparation of ferrous castings for electroplating are presented. The various solutions used for the treatment of malleable and gray iron castings should be maintained by chemical analysis so far as is practicable. When the amount of soil is excessive, particularly where no precleaning is done, it may be desirable to double the cleaning and pickling facilities. Where doubling the facilities is impossible or impracticable, similar economies may be obtained to a degree by providing cleaner and pickle tanks with overflow dams, sumps and pumps with which the solution may be recirculated. In electrified tanks removable electrodes should be employed in preference to using the tank as an electrode, to facilitate inspection and cleaning. All immersion rinse tanks should be equipped with dam-type overflows to ensure skimming of oil, grease, and light dirt from the surface of the water. The paper presents the cleaning procedure cycle generally used for racked parts which will subsequently electroplated in still tanks, semiautomatic equipment, and full-automatic equipment. The most reliable test of the effectiveness of the preplating cleaning cycle is the appearance of the electroplated part and its performance in service.1.1 This practice is intended to assist electroplaters in establishing and maintaining a satisfactory pre-electroplating cycle for malleable iron, gray iron, nodular iron, and white iron castings. It is also intended to indicate certain foundry practices which will facilitate subsequent finishing. Most of the practices that follow have been based on experience with malleable and gray iron. However, since they are related to the other forms, the same practices will probably apply. Nodular iron is also known as spheroidal or ductile iron, which is defined as cast iron with the graphite substantially in spherical shape and substantially free of flake graphite.1.2 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. Specific precautionary statements are given in 2.1.1.3 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.