From the Empire State Building in New York to the Eiffel Tower in Paris and the Burj Khalifa in Dubai, the steel is used in the world's most famous landmarks and in all aspects of our surroundings, buildings, bridges, highways or other civil engineering projects. HV and HR bolt sets are used extensively in European steel construction applications. This system consists of bolts, pre-lubricated nuts and washers. The radius under the bolt head is a specific characteristic of the bolt sleeve, which is larger than the normal standard bolt radius to achieve the effect of reducing the punching effect. So far, there is no satisfactory method of protection for the protection of HV/HR bolt sleeves used in steel structures. If the bolt is loose due to vibration and dynamic loads, there is no other solution than the time-consuming and costly tightening procedure. Based on the world's leading Nord-Lock wedge lock technology, Nord-Lock steel construction washers (SC) are specifically designed for steel construction applications and are suitable for HV and HR kits (in accordance with European standards EN 14399-4 and EN 14399-3) Bolts and nuts). Designed to replace the EN 14399-6 chamfered flat washers to improve the safety of pre-assembled components of steel structural high-strength structures under dynamic load and vibration conditions. Nord-Lock wedge lock technology uses tension instead of friction to protect the bolts, preventing the bolts from loosening during rotation. The Nord-Lock SC-washer for the HV bolt sleeve has the CE mark. The safe use of its high-strength bolts has been confirmed by the national technical certification number Z-14.4-62 and the DIBT issued (on request) European technical certification ETA-13/0246. Tungsten , also known as wolfram which is a chemical element with the symbol of W. Tungsten Metal is a hard, rare metal, As a high performance materials, pure tungsten has high melting temperature, high density, low vapor pressure, low thermal expansion combined with good thermal conductivity, sufficient electrical resistance, high modulus of elasticity. We can supply many kinds of tungten products, like Tungsten Sheet, Tungsten Tube, Tungsten Bar, tungsten foil, tungten crucibe, tungsten boat, tungsten heating elements and other Tungsten Deep Processing Parts. The tungsten products are widely used for Furnace parts, Semiconductor Base Plates, Components for Electron Tubes, Emission Cathodes for Electron Beam Evaporation, Cathodes and Anodes for Ion Implantation, Tubes / Boats for Sintering of Capacitors, Targets for X-ray Diagnostics, Crucibles, Heating Elements, X-ray Radiation Shielding, Sputtering Targets, Electrodes and so on. Tungsten Tungsten Wire,Tungsten Bar,Tungsten Plate,Tungsten Alloy Baoji Shengyuan Metal Material Co., Ltd. , https://www.baojisymetal.com