What is the tolerance range of precision screws?
What is the tolerance range of precision screws?
Gaskets are mechanical seals between two objects, usually used to prevent pressure, corrosion, and natural thermal expansion and contraction of pipes between two objects and leakage. Since machining the surface is not possible, irregularities can be filled with spacers. Gaskets are usually made from sheet materials such as pad paper, rubber, silicone rubber, metal, cork, felt, neoprene, rubber, fiberglass or plastic polymers such as Teflon. Gaskets for specific applications may contain asbestos. The existing gasket is easily deformed for a long time in use, and the gasket cannot play the role of making up the difference. In addition, during the use process of the gasket, the adhesion between the gasket and the nut or the mechanical surface becomes poor, resulting in a poor sealing effect.
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.
Screw, some people call it screw [Screw] (screw), screw (screw rod). In fact, the screw is a general term, and the screw and the screw rod are different from each other. Screws are generally called wood screws; they are the ones with a pointed end at the front and a larger pitch. They are generally used to fasten wooden and plastic parts. The screw rod is a machine screw (machine screw), which is the kind of flat head at the front end. The pitch is small and uniform. It is generally used to fasten metal and machine parts.
A crank press with bilateral transmission, such as a briquettes machine, requires 1. The rotation phase of the main shaft gears on both sides must be consistent; 2. The connection between the main shaft and the main shaft gear should be free of gaps. In order to meet this requirement, there are mainly two schemes for the connection between the main shaft and the main shaft gear. Option 1, one or both ends of the main shaft and the main shaft gear are connected by flat keys. This scheme requires that the matching clearance between the main shaft and the gear hub is small, so it is difficult to process, assemble and maintain; Option 2, one or both ends of the main shaft and the main shaft gear Using taper-sleeve connection, this solution has good performance, but high cost and poor rigidity
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