Service Hotlinetotal of 13 domestic automotive fastener companies were interviewed and investigated in this survey, and all the companies under investigation have passed the TS16949 system certification. An average car has about 1500 fasteners, and the total bolt assembly time for each car is about 2.5~3.2h. It can be seen that the variety and quality of fasteners have an important impact on the level of the main engine and the quality of the vehicle. This article analyzes the localization of high-strength threaded fasteners and the management of supply quality from the perspective of the production process of high-strength threaded fasteners. Product flow of high-strength threaded fasteners The production process of high-strength threaded fasteners is raw material transformation → cold heading forming → thread processing (thread rolling or thread rolling) → heat treatment → surface treatment → sorting and packaging, generally used above grade 10.9 Thread rolling process after heat treatment. The steel grades commonly used for high-strength bolts of automotive fastener materials are 35 steel, 45 steel, and ML35 steel for grade 8.8 bolts; 35CrMo for grade 10.9 bolts; 40Cr; 35CrMo, 42CrMo, and SCM435 for grade 12.9 bolts. The raw materials for domestic fasteners are basically in the hot-rolled state, while the steel for fasteners produced in Japan and other countries is basically in the state of direct cold heading. Users do not need pretreatment, which can reduce costs from the link. Common failure modes of fastener failure are assembly elongation, fatigue fracture, and delayed fracture. In addition to the material, the quality of cold heading forming and thread processing (thread rolling or thread rolling, tapping) threaded fasteners, forming equipment and thread processing equipment and molds (production process and equipment) are the key factors to ensure their quality. Especially in the state of large-scale and multi-variety supply, automotive fasteners that require high machining accuracy, how to ensure product consistency and defect prevention is one of the problems faced by fastener production. For the cold heading equipment and thread processing equipment of the investigated companies, domestic equipment accounts for about 40%, Taiwan equipment accounts for 50%, and imported (Europe, America, Japan) equipment accounts for about 10%; Partial folding, thread streamline upsetting, tooth wrinkles and cracks, etc. Domestic fastener factories are limited by capital or other reasons, and most of them use domestic equipment and Taiwan equipment to produce fasteners for automobiles. To ensure the dimensional tolerance and geometric tolerance of large-scale production of high-end fastener products, online monitoring should be increased. Means and mold making level. Eliminate unqualified products in production, so as to ensure the assembly quality of OEMs and OEMs. [1] About 80% of the surveyed fastener enterprises have heat treatment equipment, and most of them use Taiwan heat treatment process lines; the process line equipment is a continuous mesh belt furnace with atmosphere protection, and the atmosphere, temperature and process parameters are controlled by a computer. The high-strength fastener industry is a relatively competitive industry. If we want to have a thorough and objective analysis of the technology and market of the high-strength fastener industry, we need to start from the following aspects: domestic high-strength fasteners Industry and Enterprise Competition Pattern High-strength Fastener Industry Industrial Policy High-strength Fastener Product Technical Standards and Regulations my country's High-strength Fastener Product Technology Competition Pattern Dynamics Regarding these six aspects, many domestic research institutions have conducted in-depth research and research, and many institutions have long been engaged in research and research in this industry.
When checking the finished blind rivet, check: the diameter of the rivet body, the length of the rivet body, the thickness of the rivet body cap, the diameter of the cap, the total length of the mandrel, the exposed size of the mandrel, the size of the nail cap, and the outer diameter after assembly can be considered. In the actual inspection, the weak links of the product can be measured, such as: tensile force, shear resistance, and core pull-out resistance. The key is to pay attention to the rivets, if the rivets are insufficient, whether they are riveted in place; or because the cap of the mandrel is too large, so that the mouth of the rivet body cannot be pulled down; and there are jump heads, that is, the mandrel is too low or broken. The size is too small etc. Length measurement of closed blind rivets
The flat screw mainly includes a rotating part and a screw locking part, wherein the rotating part and the screw locking part are respectively flat-shaped structures; At least two sides of the screw lock portion are respectively provided with tooth rows, and the two tooth rows are mutually dislocated, so that the screw lock portion can be locked in a pre-formed screw hole in the workpiece.
At present, the locking washer is widely used in the upper wheel side locking of passenger cars. During assembly, the locking washer is bent perpendicular to the thread of the axle pipe, so as to prevent the protrusion from passing through the gap between the two tooth profiles of the thread and ensure the locking The stop gasket is always in the groove of the shaft tube and cannot be rotated to achieve the purpose of locking. This method is relatively simple and is currently used more;
screw is a tool that uses the physical and mathematical principles of the circular rotation and rotation of the oblique surface of an object to gradually fasten the mechanism of the utensil. A screw is a common term for fasteners, an everyday colloquial language. Screws are indispensable industrial necessities in daily life: tiny screws used in cameras, glasses, clocks, electronics, etc.; general screws in televisions, electrical products, musical instruments, furniture, etc.; as for engineering, construction, and bridges, large screws are used. Screws and nuts; transportation equipment, airplanes, trams, automobiles, etc. are used together with large and small screws. Screws have important tasks in industry. As long as there is industry on earth, the function of screws will always be important. The screw is a common invention in people's production and life for thousands of years. According to the application field, it is a great invention of human beings. At present, the head of the screw on the market is generally punched with a cross groove or a word groove, which is used for tightening or Remove the screw, but the cross slot or the slot is easy to deform after a long time, it is difficult to disassemble it with tools, and sometimes the tool of the corresponding size cannot be found and the disassembly cannot be carried out, and the disassembly is relatively inconvenient.
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