Chinese standard GB/T382-92 zinc alloy die castings
The Chinese standard GB/T382-92 is a national standard specifically formulated for zinc alloy die-castings. It comprehensively regulates the quality requirements, inspection methods and acceptance rules for zinc alloy die-castings, providing an important technical basis for the production, circulation and use of zinc alloy die-castings. It is of great significance for ensuring product quality and improving market competitiveness.
GB/T382-92 sets strict regulations regarding dimensional accuracy and tolerances. The standard classifies zinc alloy die-castings into different dimensional tolerance grades based on their varying structural characteristics and usage requirements, and specifies the permissible dimensional deviation range for each grade. This is because zinc alloy die-castings must precisely mate with other components during assembly. Inadequate dimensional accuracy can hinder assembly and even affect the performance of the entire device. For example, when zinc alloy die-castings are used as connectors in electronic equipment, the dimensional accuracy of the plug-in and plug-out areas must be extremely high. Excessive dimensional deviation can lead to poor contact and affect the proper functioning of the device. The standard also specifies die-casting geometric tolerances, such as straightness, flatness, and perpendicularity, to ensure that the die-casting’s geometry meets design requirements. Manufacturers must ensure that die-castings meet the required dimensional accuracy and geometric tolerances through precise mold design, strict process control, and accurate measurement methods.
Surface quality requirements are one of the key focuses of GB/T382-92. The standard clearly defines the surface roughness and surface defects (such as pores, shrinkage, cracks, cold shuts, scratches, etc.) of zinc alloy die-castings. Good surface quality not only improves the appearance quality of die-castings, but also enhances their corrosion resistance and wear resistance. Excessive surface roughness can easily lead to dirt accumulation on the surface of die-castings, affecting their performance and aesthetics; while defects such as pores and cracks on the surface will seriously reduce the mechanical properties and sealing of die-castings, and may cause safety accidents in harsh environments such as high pressure and high temperature. In order to ensure the surface quality of die-castings, the standard stipulates corresponding inspection methods, such as visual inspection, roughness measurement instrument testing, and penetrant testing. Manufacturers need to strictly inspect the surface quality of die-castings to ensure that they meet the standard requirements before leaving the factory.
Internal quality requirements are the key content in GB/T382-92 to ensure the long-term and stable operation of zinc alloy die-castings. The standard requires that there must be no defects that affect the performance of zinc alloy die-castings, such as severe shrinkage cavities, porosity, inclusions, cracks, etc. Although these internal defects are difficult to detect during appearance inspection, they will significantly reduce the strength, toughness and sealing of the die-castings. During use, they may cause problems such as breakage or leakage due to uneven force. In order to inspect the internal quality of die-castings, the standard recommends the use of non-destructive testing methods such as radiographic testing and ultrasonic testing. These methods can effectively detect tiny defects inside die-castings and ensure product quality. At the same time, the standard also makes clear provisions on the allowable degree of internal defects based on the importance and use conditions of the die-castings, and divides them into different acceptance levels to meet the needs of different application scenarios.
Test methods and inspection rules are crucial for ensuring product quality in GB/T382-92. Regarding test methods, the standard specifies detailed operational procedures and technical requirements for dimensional measurement, surface quality inspection, and internal quality testing. For example, dimensional measurements should be performed using measuring instruments that meet precision requirements, such as vernier calipers and micrometers, under specified environmental conditions. Visual inspection for surface defects should be conducted under appropriate lighting conditions to ensure that even subtle surface defects can be clearly observed. Regarding inspection rules, the standard specifies the items, frequency, and judgment criteria for factory inspection and type inspection of zinc alloy die-castings. Factory inspection is a routine test conducted on each batch of products, primarily including random checks of dimensional accuracy and surface quality. Type inspection is a comprehensive inspection conducted in response to product design changes, production process adjustments, or raw material replacements, covering all technical indicators specified in the standard. Strict implementation of these test methods and inspection rules effectively ensures the quality of zinc alloy die-castings and promotes the healthy development of the industry.
GB/T382-92’s regulations on packaging, labeling, transportation, and storage are the final line of defense for ensuring the quality of zinc alloy die-castings. The standard requires that zinc alloy die-castings be packaged securely and reliably to prevent damage, corrosion, and contamination during transportation and storage. Packaging materials must meet environmental standards and avoid adverse effects on the die-castings. Regarding labeling, each packaging unit must clearly indicate the product name, model, specifications, quantity, manufacturer name, production date or batch number, etc., to facilitate product identification and traceability. During transportation, die-castings must be protected from severe impact, rain, and direct sunlight to ensure their quality is not compromised. During storage, die-castings must be stored in a dry, well-ventilated warehouse free of corrosive gases to avoid contact with hazardous substances. Appropriate moisture-proof and rust-proof measures must also be implemented to prevent rust during storage. While seemingly minor, these regulations are crucial for ensuring consistent quality of zinc alloy die-castings from production to use.
