International Fastener Standard System

International Fastener Standard System

There are two independent standard systems for international fasteners: meter standard and imperial standard. Metric standard system is a metric unit of measurement, mainly based on international ISO standard, European Community EN standard, German DIN standard and Chinese GB standard;Imperial standards can be divided into two categories, namely the United States UNC/UNF imperial standard and the United Kingdom BSW/BSF imperial standard.The different standard systems of fasteners are essentially caused by two different measurement systems, that is, the second type of fastener standard system.

The current international fasteners between the two major standard system can not be interchangeable, especially the type of fastener size and technical conditions can not be completely unified, while the British standard in the United States and the British standard between the two systems, the size of the type and technical specification requirements are not the same, can not be interchangeable.

And because the American fastener product type size, thread and quality assurance standards are issued in the name of ANSI American National Standard and ASME American Engineers Association, and the basic technical standards related to fastener materials, mechanical properties, surface treatment, surface defects and so on are all issued in the name of ASTM American Society for Testing and Materials, SAE American Society of Mobile Engineers and IFI American Industrial Fastener Association respectively, this is unique in the international fastener standard system.

ISO International Organization for Standardization and EN European Union standards as far as possible through the standard to unify and coordinate the consistency of metric fastener standards. At present, the products and basic standard systems of metric fasteners are mostly equivalent or equivalent in national standards. The product standards have covered bolts, screws, studs, nuts, rivets, pins, pads, self-tapping screws, wood screws, gear rings, welding nails, steel structure high-strength fasteners and other varieties, with complete and series of basic technical standards.

Countries generally refer to ISO standards directly, or directly translate them into national standards without change or slight modification. The main representative countries are DIN, NF, JIS, UNI, BSM, SIS, GB and other fastener products and basic technical standards and ISO standards are basically the same.

Germany is the representative of metric fastener standards. ISO international fastener standards are mainly formulated and issued on the basis of German standards. Germany is relatively active in implementing and implementing ISO standards. DIN newly issued product standards are synchronized with ISO and EN standards. DIN fastener basic standards have basically implemented ISO standards. However, it is also worth noting that the old DIN product standards that have been canceled in Germany (such as DIN 931, 933, 934, 985, etc. are not unified with ISO standards), and the old DIN product standards are still popular in international trade.

The adoption of ISO standards for fasteners in China is the most active and one of the most effective representative countries. China adopts the two basic principles of ISO standard degree. The basic standard for ISO fasteners is IDT (or idt)-equivalent adoption (including the "equivalent adoption" standard issued in the early 1980 s); However, the adopted ISO fastener product standard shall belong to MOD-modified adoption (or the original eqv-equivalent adoption) according to regulations.

From1978StartStart the work of "adopting international standards" to revise the standards of fasteners in China. It took 5 years to complete the work of adopting the ISO fastener product standard in an all-round way, so that the fastener standard in China reached the international advanced standard level in the 1980 s. China's fourth comprehensive revision of national standards for fasteners involves a wide range of standards and a large number of standards, which is the largest in history. It has completed the revision of more than 160 national standards in total. At present, China's tight standards committee keeps pace with the changes in international standards. Once a new ISO standard standard is issued, it will revise China's standards as timely as possible; fasteners of the international standard conversion rate of more than 98% (of which nearly 50% for 1999 and after the release of the latest international standards), for China's fastener standards and international standards to keep pace with the development of laid a good foundation, and reached the early 21st century international advanced standard level, for the export of fastener products to create favorable conditions for foreign exchange.