Tunnel Spear Bolt is classified under the special type of bolts that are known as structural bolts which can be produced in various grades, sizes and load capacities depending on their specific use. These spear tunnel Bolt are utilized to make transportation through undersea and underground tunnels possible by binding together a number of metal beams and posts which make up the tunnel`s frame.
Application of Tunnel Spear Bolt
For comnecting concrete rings by casting plastic dowel in
Photos of Application of Tunnel Spear Bolt
Technical Requirement of Tunnel Spear Bolt
1.Material :grade 4.6,5.8,6.8,8.8,10.9,12.9
2. finish
Plain,Dacroment,Hot Dip Galvanized
Supply city of Tunnel Spear Bolt
Denmark,Spain,India,Italy,USA
Tunnel Spear Bolt,Rail Steel Tie,Spear Bolt With Washer,Hdg Spear Bolt TAICANG ZHONGBO RAILWAY FASTENING CO., LTD. , https://www.railfastener.com
Cryogenic valve is an indispensable low-temperature fluid pipeline control device. The function of the ultra-low temperature valve is basically the same as that of the ordinary valve. It is also used to connect or disconnect the pipeline medium and regulate the medium pressure and flow rate. At present, ultra-low temperature valve gate valve, globe valve, check valve, ball valve, butterfly valve and throttle type, mainly for gas liquefaction, separation, transportation and storage equipment, the use of temperature up to - 270 ℃ below. Cryogenic valves are valves that operate at cryogenic temperatures. The demarcation of its working temperature, there is no uniform regulation. For example, Russia (the former Soviet Union) called the valve operating at a temperature in the range of - 272 ° C to 153 ° C as a cryogenic valve. Japan's LPG management rules refer to valves operating below -1500C as cryogenic valves. China has not yet provided for the ultra-low temperature valve temperature limits. In the valve industry, the tendency to - 100 ℃ as the ultra-low temperature valve operating temperature limit, that is, the operating temperature below -100 ℃ valve as ultra-low temperature valve. This is a method of demarcating valve materials. That is, when working temperature ultra-low temperature valve working medium not only low temperature, and most or toxic, or flammable and explosive, and permeability, and therefore decided on the valve timber of many special requirements. (1) good low temperature resistance Cryogenic valve not only requires the normal operation at the set temperature, but also to ensure that the performance at room temperature. Therefore, the selected material should not only meet the mechanical properties at room temperature, but also meet the requirements of the mechanical properties under the use of temperature. In particular, the material is required to have sufficient toughness at cryogenic temperatures to prevent brittle fracture under low stress. At the same time, it requires the material organization to be stable and ensure that the size change will not be caused by the phase change during the process of use, which eventually leads to the failure of the valve seal. (2) Compatibility with medium The cryogenic valve material shall be compatible with the working medium, that is, it has enough chemical resistance to the medium to ensure that the chemical and physical properties of the material in contact with the medium will not be significant within the service life of the valve Variety. At the same time, the valve material should also be consistent with low temperature medium explosion-proof compatible conditions. (3) low thermal conductivity As the cryogenic valve temperature is very low, in order to reduce heat transfer, heat leak control, in addition to the valve with a special structure (set insulation), but also the choice of materials with relatively low thermal conductivity to Reduce heat loss. (4) Good Weldability Forged valve body material or butt welded valve body material should consider the welding performance of the material and the reliability of the weld under the working temperature. When welding the sealing surface of special alloy (such as Co - Cr - W cemented carbide), the feasibility of surfacing (spray welding) of the material itself should also be considered. After analysis, with face-centered cubic lattice of copper, aluminum and austenitic stainless steel and other materials, because there is no low-temperature brittleness, it can be used as ultra-low temperature valve timber. Although copper, aluminum have their own advantages, but because of low strength, generally only used for low pressure and small-caliber valves. Although 9% nickel steel can be used in - 196 ℃ condition, but due to complex technology, generally seldom used. Only austenitic stainless steel suitable as a variety of specifications, different pressure levels of ultra-low temperature valve timber.