【国外标准】 Standard Practice for Descaling and Cleaning Zirconium and Zirconium Alloy Surfaces

This practice covers a cleaning and de-scaling procedure useful to producers, users, and fabricators of zirconium and zirconium alloys for the removal of ordinary shop soils, oxides, and scales resulting from heat treatment operations and foreign substances present as surface contaminants. Grease, oil, and lubricants employed in machining, forming, and fabricating operations on zirconium and zirconium alloys should be removed by employing one of the methods or a combination of methods: alkaline or emulsion soak-type cleaners, ultrasonic cleaning, acetone, citrus based cleaners, or safety solvent immersion washing or vapor degreasing, or electrolytic alkaline cleaning system. Mechanical de-scaling methods such as sandblasting, shot blasting, and vapor blasting may be used to remove hot work scales and lubricants from zirconium surfaces if followed by thorough conditioning and cleaning. Aluminum oxide, silicon carbide, silica sand, zircon sand, and steel grit are acceptable media for mechanical de-scaling. Recommended post treatment of shot or abrasive blasted zirconium surfaces may include acid pickling to ensure complete removal of metallic iron, oxide, scale, and other surface contaminants. Visual inspection of material cleaned in accordance with this practice should show no evidence of paint, oil, grease, glass, graphite, lubricant, scale, abrasive, iron, or other forms of contamination.1.1 This practice covers a cleaning and descaling procedure useful to producers, users, and fabricators of zirconium and zirconium alloys for the removal of ordinary shop soils, oxides, and scales resulting from heat treatment operations and foreign substances present as surface contaminants.1.2 It is not intended that these procedures become mandatory for removal of any of the indicated soils but rather serve as a guide when zirconium and zirconium alloys are being processed in the wrought, cast, or fabricated form.1.3 It is the intent that these soils be removed prior to chemical milling, joining, plating, welding, fabrication, and in any situation where foreign substances interfere with the corrosion resistance, stability, and quality of the finished product.1.4 Unless a single unit is used, for example, solution concentrations in g/l, the values stated in either inch-pound or SI units are to be regarded separately as standard. The values stated in each system are not exact equivalents; therefore, each system must be used independently of the other. SI values cannot be mixed with inch-pound values.1.5 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. For specific hazard statements, see Sections 3 and 7.1.6 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.