High-strength fasteners industry is a competitive industry, relatively large , high- strength fasteners for industry want technology and markets have a thorough, objective analysis , we need to start from the following aspects:      
1 domestic industries and enterprises of high -strength fasteners competition ;       
2 high-strength fasteners industry policy ;       
3 high-strength fasteners technical standards and specifications ;       
4 of high-strength fasteners technology competition ;       
5 Chinese high- strength fasteners market level of profitability ;       
6 high-strength fasteners core technology research and development dynamics.       
According to the survey visit the 13 domestic automotive fasteners firm , surveyed companies have been certified by TS16949 system. An average of about 1,500 cars fasteners , bolts total time vehicle assembly about 2.5 ~ 3.2h. Visible variety and quality of fasteners have a significant impact on the host level and quality of vehicle . In this paper, the production of high-strength threaded fasteners staffing process , high-strength threaded fasteners for localization and supply quality management analysis.       
A high-strength threaded fasteners Process       
The production of high-strength threaded fasteners restructuring process raw materials → → cold upsetting thread processing ( rolling or Roll ) → heat treatment → surface treatment → sorting packaging, above 10.9 generally use rolling after heat treatment process .       
2 car fastener material       High strength bolts commonly used steel grades as follows: " 8.8 " bolt with 35 steel, 45 steel , ML35 steel       " 10.9 " bolt 35CrMo; 40Cr       " 12.9 " bolt 35CrMo, 42CrMo, SCM435       Baosteel automobile standard parts mainly based materials produced using domestic materials , the higher its domestic passenger car tires , commercial vehicle engines and other special high-strength steel fasteners market share. Currently , the company has become the designated manufacturer Baosteel FAW , Dongfeng, SAIC and other company specific standard steel . 10.9 and 12.9 of the engine fasteners imported materials mainly from Kobe, Japan , Nippon Steel , South Korea's POSCO and other companies. Good hardenability imported materials , high purity, assembly and stability. Cost about 15% -20 % higher than domestic material. # # hc360 breaks       At present , the domestic production of the best quality high strength bolts Shanghai exceptionally strong company from raw materials ( imported ) , cold heading process, heat treatment , surface treatment, all in accordance with the process of production joint venture partner in Japan , and its quality is stable , but the cost is higher. The largest automobile standard parts company ? Dongfeng standard for passenger cars is also dominated by imported material fastener material selection , selection of Baosteel commercial company materials. The basic raw material for the domestic fastener is hot rolled state, while other countries like Japan, the production of steel fasteners cold heading basically directly state , users do not need pre-treatment , can reduce the cost from the link. Common failure modes have assembled elongated fastener failure , fatigue fracture and delayed fracture .       3 Cold upsetting and threading ( or thread rolling rolling , tapping )       
In addition to the quality of the material threaded fasteners , thread forming equipment and processing equipment and mold ( the production process and equipment ) are the key factors to ensure its quality. Especially large quantities of many varieties available state, high precision machining of automotive fasteners , how to ensure consistency and prevent defective products is one of the problems facing the fastener production . Companies surveyed cold heading equipment and thread processing equipment, which accounts for about 40 percent of domestic equipment , equipment accounted for 50% of Taiwan's imports ( Europe, Japan ) equipment accounts for about 10% ; common defects size and geometric tolerances tolerance, head folded portion , the flow line heading off thread teeth wrinkles and cracks . For efficiency, the introduction of a dedicated high-precision machine tools , domestic companies are research, exploration, such as Shanghai Yi public company in 2004 to spend 14 million yuan to introduce a five-station Switzerland Herdbar cold heading machine ; Dongfeng Motor standard Italian company to introduce SACMA 's cold forming equipment ; SAIC marked the company introduced the American GI 's online eddy current sorter and so on.       At present , the domestic fastener factory limited funds or other reasons, more use of domestic equipment and Taiwanese equipment to produce automotive fasteners, fastener to ensure that large-scale production of high-end products, dimensional tolerances and geometric tolerances , should increase online monitoring tool and mold production levels. Eliminate the production of defective products , thus ensuring the quality of assembly OEMs , OEMs .       4 heat treatment       Heat treatment quenching is to improve the mechanical properties of fasteners to meet the product requirements of tensile strength and yield ratio . Transfer of heat treatment process for raw materials , temperature control , furnace atmosphere control , quenching medium , there are stringent requirements. The main control heart defects in materials Ministry carbon segregation , materials and surface decarburization annealing process , cold heading cracking , quenching the quench cracking and deformation.       Heat treatment : heating the material → washing → ​​washing → ​​→ → quenching and tempering → ​​Coloring → ​​downline .       Fastener enterprises surveyed about 80 % of heat treatment equipment and heat treatment line mostly used in Taiwan ; process line equipment for the continuous mesh belt furnace with protective atmosphere by the computer-controlled atmosphere , temperature and process parameters. Problems are the lack of quenching medium cooling performance measurement , carbon potential control unstable , temperature -tested heat treatment cycle is too long and so prone to defects link.