Customized GB845 cross pan head PB color galvanized cut tail self-tapping round head screw

The national standard name of the cross recessed small pan head three-combination screw is the cross recessed small pan head screw, the spring washer and the flat washer assembly. The national label is GB/T9074.8-1988. This 1988 refers to the year, that is, this standard is the standard issued by the country in 1988. The specifications of the cross recessed small pan head three-combination screw, our company's minimum is M2.5, the shortest is 5mm, the largest is M10, and the longest is 90mm. Of course, as customers have higher and higher requirements for small pan head combination screws, or require smaller and longer combination screws. If the quantity is large, or with the development of our company. Buy some advanced combination screw machines. Come and go to meet the higher requirements of our customers.

Beneficial effects The commonly used nuts and bolts in the prior art are in the shape of a hexagon, the fastening surface is a regular hexagonal plane, and there are six elastic surfaces, and the adjacent elastic surfaces intersect with a straight line, and the opposite elastic surfaces are parallel to each other, In this way, the tightening operation can be easily performed with conventional tools, which is convenient and practical. However, there are some special occasions where the nuts and bolts of this structure are not suitable. Guangdong Yueluo Hardware Industry Co., Ltd. changed the fastening surface into a pentagon shape, and the adjacent elastic surfaces are connected by an arc angle. sex.

Standards are norms, and each country and sector has its own standards. The most commonly used standards in our daily business are as follows: GB—China National Standard (National Standard) 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 GB - National Standard is one of many standards in my country, as well as industry standards, professional standards and department standards. National standards are divided into: GB (mandatory standards) and GB/T (recommended standards) and GBn (national internal standards) and so on. We usually see GB30, GB5783, etc. are mandatory standards. In addition to some basic dimensions such as head-to-side, head thickness, etc., the above standards are mainly different in the threaded part. The threads of GB, DIN, JIS, etc. are all in MM (millimeters), which are collectively referred to as metric threads. Another thread like ANSI, ASME, etc. is called American standard thread in inches. In addition to metric threads and American threads, there is also a BSW-imperial standard, whose threads are also in inches, commonly known as Wyeth threads.

Although there are many types of self-tapping screws, they all have the following common points: (1) They are generally made of carburized steel (accounting for 99% of the total output). Also available in stainless steel or non-ferrous metals. (2) The product must be heat treated. Carbon steel self-tapping screws must be carburized, and stainless steel self-tapping screws must be solution hardened. In order to make the self-tapping screw meet the mechanical properties and performance required by the standard. (3) The product has high surface hardness and good core toughness. That is, inner softness and outer rigidity. This is a major feature of the performance requirements of self-tapping screws. If the surface hardness is low, it cannot be screwed into the matrix; if the toughness of the core is poor, it will break as soon as it is screwed, and it cannot be used. Therefore, inner soft outer steel is a very important requirement for self-tapping screws to meet the performance requirements. (4) The surface of the product needs surface protection treatment, generally electroplating treatment. The surface of some products must be treated with phosphate (phosphating), such as wallboard self-tapping screws are mostly phosphated. (5) Produced by cold heading process. It is recommended to use high-speed cold heading machine and high-speed thread rolling machine or high-speed planetary thread rolling machine for production. The emphasis here is on high speed to ensure product quality. Only self-tapping screws produced by high-speed machines have well-formed heads and high-quality threads.

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