What is the tolerance range of precision screws?
What is the tolerance range of precision screws?
People often think that magnets attract stainless steel to verify its pros and cons and its authenticity. If it does not attract non-magnetism, it is considered to be good, and it is genuine; if it is magnetic, it is considered to be counterfeit. In fact, this is an extremely one-sided, unrealistic and wrong identification method. There are many kinds of stainless steel screws, which can be divided into several categories according to the organizational structure at room temperature: 1. Austenite type: such as 304, 321, 316, 310, etc.; 2. Martensite or ferrite type: such as 430, 420, 410, etc.; Austenite type is non-magnetic or weakly magnetic, and martensite or ferrite is magnetic. Most of the stainless steel usually used for decorative tube sheets is austenitic 304 material, which is generally non-magnetic or weakly magnetic, but may also appear magnetic due to fluctuations in chemical composition or different processing conditions caused by smelting, but this cannot be considered as a Counterfeit or substandard, what is the reason for this? As mentioned above, austenite is non-magnetic or weakly magnetic, while martensite or ferrite is magnetic. Due to component segregation or improper heat treatment during smelting, a small amount of martensite or ferrite in austenitic 304 stainless steel will be caused. body tissue. In this way, 304 stainless steel will have weak magnetism. In addition, after cold working of 304 stainless steel, the structure will also be transformed into martensite. The greater the cold working deformation, the more martensite transformation, and the greater the magnetic properties of the steel. Like a batch of steel strips, Φ76 tubes are produced without obvious magnetic induction, and Φ9.5 tubes are produced. The magnetic induction is more obvious due to the large deformation of the bending and bending. The deformation of the square rectangular tube is larger than that of the round tube, especially the corner part, the deformation is more intense and the magnetic force is more obvious. In order to completely eliminate the magnetic properties of 304 steel caused by the above reasons, the stable austenite structure can be restored by high-temperature solution treatment, thereby eliminating the magnetic properties. In particular, the magnetic properties of 304 stainless steel caused by the above reasons are completely different from those of other materials such as 430 and carbon steel, which means that the magnetic properties of 304 steel always show weak magnetic properties. This tells us that if the stainless steel strip is weakly magnetic or completely non-magnetic, it should be judged as 304 or 316 material; if it is the same as carbon steel, it shows strong magnetism, because it is judged as not 304 material.
The global economy continues to slump and overseas export trade is sluggish. Many fastener companies at home and abroad are facing severe tests. Accelerating economic transformation and structural upgrading is imminent, and developing overseas markets is undoubtedly an important way out for the development of the current fastener industry. From the fourth quarter of 2011 to the first half of 2012, affected by the objective environment, the development speed of the fastener industry may slow down, but from the third quarter of 2012, with the policy in place, the convening of the 18th National Congress of The upcoming series of development policies, etc., can promote the further development of the industry. And we must insist on innovation and adjustment and transformation, we must continue to rely closely on key industries such as automobiles, new energy, aerospace, shipbuilding, urban transportation, IT, electronic appliances, construction, etc., accelerate the optimization and upgrading of fastener products, and promote fasteners. The whole industry develops healthily and steadily. The global fastener market size exceeds 50 billion US dollars, and China's total fastener production in 2012 is also expected to reach about 6.8 million tons. However, compared with the manufacturing powerhouses such as the United States and Japan, there is still a big gap in my country's fastener industry.
Here Yueluo eliminates the drawbacks. The purpose of Yueluo is to provide a locking screw by which the gap existing between the locking screw and a transverse hole in a locking screw can be eliminated. Yueluo uses a locking screw to achieve the proposed object, which has the features of claim 3 . The line connecting the centers of gravity of the respective axially continuous orthogonal cross-sectional areas of the locking screw is regarded as a line. The advantage achieved by Yueluo can basically be seen that, due to the locking screw of Yueluo, the gap between the horizontal hole of the screw and the locking screw can be eliminated. Other advantages are as follows - the insertion accuracy and surgeon time spent remain within the range to date; - the strength of the locking screw is maintained; and - the extraction of an expired broken screw is assured. The further composition of Yueluo and Yueluo is explained in more detail below by means of schematic diagrams of parts of various embodiments.
The contact surface between the existing chassis and the main board is generally not a horizontal plane due to processing reasons, especially the main board is prone to warping deformation. It will increase, resulting in deformation of the motherboard and poor memory contact, affecting normal use.
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