How many standards are there for standard parts?

Standards are norms, and every country and department has its own standards. At present, the most commonly used standards in our daily business are: g b- ANSI-American national standard (American standard) DIN—- German national standard (German standard) ASME—- American Society of Mechanical Engineers standard JIS—- Japanese national standard (Japanese standard) BSW—- British national standard g b- National standard is one of many standards in China, and there are also industry standards, professional standards and National standards are divided into: GB (mandatory standards) and GB/T (recommended standards) and GBn (national internal standards). What we usually see, such as GB30 and GB5783, are mandatory standards. In addition to some basic dimensions, such as the opposite side of the head and the thickness of the head, the most important difference between the above standards is the thread part. Thread of GB, DIN, JIS and other standards. They are all in millimeters and are collectively referred to as metric threads. Another thread similar to ANSI and ASME is called American standard thread in inches. In addition to metric thread and American thread, there is also a BSW-British standard, whose thread is also inches, commonly known as Wyeth thread. Metric thread is in MM (millimeter) and its sharp angle is 60 degrees. Both American and English threads are in inches. The sharp angle of American thread is also 60 degrees, and that of British thread is 55 degrees. Due to the different units of measurement, the representation methods of various threads are also different. For example, M 16-2X60 represents metric threads. He specifically means that the nominal diameter of the screws is 16MM, the pitch is 2MM, and the length is 60 mm. Another example is that 1/4-20x3/4 is an English thread. He specifically means that the nominal diameter of the screws is 1/4 inch (one inch =25.4MM), and there are 20 screws in one inch. In addition, if American screws are to be represented, UNC and UNF are usually added after English screws to distinguish American coarse teeth from American fine teeth. In the usual domestic sales business, the most common standards we encounter are GB (National Standard) and DIN (German Standard). For non-aromatic products, we will mainly come into contact with the following standards: GB30；; GB5783GB5782GB52GB 6 170； GB 8 18； GB 8 19； GB845GB846GB70din 9 12； DIN933DIN93 1 etc. At present, GB30 (the old national standard) has been replaced by GB5783 (the new national standard). GB52 (old national standard) in the standard book has been replaced by GB6 170 (new national standard). 1986 China has formulated a new standard for standard parts, commonly known as the new standard in business. The most commonly used are GB5780, GB578 1, GB5782, GB5783 and GB5784. GB5780 is a half-tooth screw with hexagonal head and thick handle, and its accuracy grade is C, so it can be replaced by GB5782 (GB5782 is a full-tooth screw with hexagonal head and thick handle, and its accuracy grade is A and B). ) GB578 1 is a hexagon-head full-tooth screw, and its accuracy grade is C .. It can be replaced by GB5783 (GB5783 is a hexagon-head full-tooth screw, with accuracy grade A and B). GB5784 is a thin rod half tooth hexagon screw. The difference between the new standard and the old standard lies in the different relative widths of M8, M 10, M 12, M 14 and M22 series products. Except the M22 series of new products, the head edges of the new standard products M8, M 10, M 12 and M 14 are smaller 1MM than those of the old standard products. They are 13, 16, 18, 2 1MM respectively, but the new standard of M22 series is 2MM larger than the reverse of the old standard, so special attention should be paid. For the thickness of the head, the new standard is slightly different from the old standard, which can be used in cases where the requirements are not very strict. The difference between the new standard and the German standard is that the product specifications of M 10, M 12, M 14 and M22 are different in the opposite width. The heads of M 10, M 12 and M 14 are smaller than the german standard1mm. M22' s new product, the width of the head edge is 2MM wider than the target edge, and everything else is ok. For hexagon nuts, the commonly used standards are: GB52, GB6 170, GB6 172 and DIN934. The main difference between them is that the thickness of GB6 170 is thicker than that of GB52, GB6 172 and DIN934, which is also known as thick nut. The other is the opposite difference. In M8 nut series, the opposite sides of DIN934, GB6 170 and GB6 172 are all 13MM, which is smaller than that of GB52, and the opposite sides of DIN934 and GB52 are M 10. Compared with the opposite sides of GB6 170 and GB6 172, the opposite sides of DIN934 and GB52 for the nut of M 12 are 19MM larger than those of GB6 170 and GB6 172. For the nut of M 14, the opposite side of DIN934 and GB52 is 22MM, which is 2 1MM larger than that of GB6 170 and GB6 172. In addition, the opposite side of M22 nut, DIN934 and GB52, is 32MM, which is 2MM smaller than that of GB6 170 and GB6 172. (GB6 170 and GB6 172 have the same width on the reverse side except the thickness. ) Other specifications can be used universally, regardless of thickness. As for the hexagon socket, there are two versions in the national standard, one is GB70-76,76, and the other is GB70-8585. Our company implements the standard of DIN9 12, so we should pay attention to the difference in actual business operation: GB70-85 and DIN9 12 are completely coincident, so there is no new standard. Mainly there are some differences between GB70-76 and DIN9 12: the round head diameter of GB70-76 is 12.5MM, which is smaller than DIN9 12 13.27MM, and that of M 10 series is GB70-76. Less than 16.27 in DIN9 12. For the hexagon socket of M 12 series, the round head diameter of GB70-76 is 18MM, which is smaller than the opposite side of DIN9 12 and also looks like M 16. DIN9 12 are 24.33MM and 30.33MM respectively. In addition, due to different standards, the width of the inner edge between the old standard and the German hexagon is also different, and the inner edge of GB70-76 is smaller, so we should also pay attention to it in business operation. In addition, there are some differences in the carriage screws that may be used at ordinary times. There is also an explanation here. In the national standards, there are two standards for carriage screws, namely GB 12 (small semi-round head square neck screw) and GB 14 (large semi-round head square neck screw), and the German standard DIN603 is commonly used in the market. Now distinguish these three: for round head and neck, when comparing the same specifications, it is GB 12.