【国外标准】 Standard Practice for Investment Castings, Surface Acceptance Standards, Visual Examination

This practice covers the acceptance criteria for surface inspection of investment castings through visual examination. The material shall conform to Levels II, III, and IV acceptance criteria for features of surface pits, positive metal, parting line and ejector pin marks, gate height, and surface roughness. The material shall be free of any linear discontinuity.1.1 This practice covers the acceptance criteria for surface inspection of investment castings by visual examination.1.2 This practice is expressed in both inch-pound units and in SI units; however, unless the purchase order or contract specifies the applicable M-specification designation (SI units), the inch-pound units shall apply.1.3 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 nonconformance with the standard.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, health, and environmental practices and determine the applicability of regulatory limitations prior to use.1.5 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.