What is the tolerance range of precision screws?
What is the tolerance range of precision screws?
Stud bolts are manufactured in accordance with GB897-GB901 standards, the materials used are: Q235, 45#, 40Cr, 35CrMoA, Q345D, the specifications are: M3mm-M100mm, and the length can be customized according to user needs. High strength stud bolts, materials are 35#, 45#, 35CrMoA, 25Cr2MoV, 304, 316, 304L, 316L, 2H, 2HM, B7, B7M, B16, B8, 8, B8M, 8M, widely used in electric power, chemical industry , oil refining, valves, railways, bridges, steel structures, automobile and motorcycle accessories and other fields: generally used in mining machinery, bridges, automobiles, motorcycles, boiler steel structures, pendant towers, long-span steel structures and large buildings, etc. . Representation method of stud bolts: General stud bolts are expressed as: M12×100 GB 901-88 (standard) 35#/35# (material) 8.8 grade/8 grade (modulation grade) means: diameter = 12mm length = 100mm GB 901-88 adopts the national standard (of course, the industry standard can also be used as needed) stud bolt standard: GB 900-1988 Introduction to stud bolts Stud bolts save time and cost All stud bolt structures do not require drilling, Steps such as punching, threading, riveting, threading and finishing continue to expand the application potential of structural design, high current and small penetration. Therefore, welding to very thin sheets is possible. The workpiece for stud welding must be welded from one side. Can be soldered in all positions, with the help of extenders on vertical bulkheads that can be restricted. Since it is welded for a short time and there is little deformation after welding, no trimming is required. Because the welded structure does not require drilling, there is no leakage. The joint can achieve high strength, that is, the joint strength of stud welding is greater than the strength of the stud itself. How to install studs Good economy The advantage of other welding methods is the welding power. For mass-produced workpieces, standard studs are low cost. There are various types of equipment and welding torches, and the acquisition cost of equipment is relatively low. According to the product, it can be made into a multi-station automatic welding machine, or a high-precision gantry-type CNC automatic welding machine. Stud welding has high quality reproducibility and low rejection rate. However, in the application of stud welding, it should be noted that, like other fusion welding, there are certain restrictions on the carbon content in the steel. For structural steel studs, welding should be performed according to the recommended combination of stud material and base metal. There will be infusibility with the base metal. Combinations of stud material and base metal outside the recommended range shall be tested to determine the weldability and the product design requirements of the anchor bolt for the possibility of relevant inspection and evaluation.
It can be seen from the extrusion process that the screw works under high temperature, certain corrosion, strong wear and high torque. Therefore, the screw must: 1) High temperature resistance, no deformation under high temperature; 2) Wear resistance, long life; 3 ) Corrosion resistance, the material is corrosive; 4) High strength, can withstand large torque, high speed; 5) Good cutting performance; 6) After heat treatment, the residual stress is small, and the thermal deformation is small. [1]
T-bolt, the European standard is called hammer bolt, the material is carbon steel, the surface is galvanized or nickel-plated, the T-bolt can be directly put into the groove of the aluminum profile, and it can be automatically positioned and locked during the installation process. Used in conjunction with the blue nut, it is a standard matching connector when installing corner fittings. It can be selected and used according to the profile groove width and different series of profiles. When the T-bolts on the market are installed with the installation channel, the bolts need to be placed into the channel from the port of the channel, and then tightened when moving to the designated position. The bolts are easy to rotate during installation, and the connection is not tight. Therefore, it is necessary to propose a mounting structure that uses T-bolts and grooves.
Generally known bolts refer to screws with a larger diameter. According to this statement, the diameter of screws is much smaller than that of bolts. Stud bolts do not have a head, and some are called studs. Both ends of the stud are threaded, with no thread in the middle and a smooth rod in the middle. Studs are used on large equipment such as gear racks. In actual use, the external load will have vibration and the influence of temperature will reduce the frictional force, and the threaded connection will loosen and fail over time. Therefore, it is necessary to do a good job in the maintenance of the stud bolts at ordinary times. Stud bolts or anchor bolts will have problems under the action of mechanical friction for a long time. When problems occur, the engine oil pan should be removed, and the use of the engine bearing bushes should be carefully checked, and the clearance between the bearing bushes should be checked. Whether it is too large, if the gap is too large, it should be replaced in time. When replacing the stud bolts, also replace the connecting rod bolts. When some large equipment such as nail making machines are in normal operation, if they find that the engine is not running very stable or there is abnormal noise, they should stop and check in time to avoid bigger problems.
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