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About vickyyihui

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  1. The shape and connection structure of roof bolts are basically the same as those of ordinary bolts. The Cap Screw Factory will introduce the main difference between the two. Ordinary bolt connection relies on bearing pressure and shear resistance of the shaft to transmit shear force, and the pretension generated by bolts when tightening nuts is very small, so its influence will not be considered. The working principle of roof bolt connection is to intentionally apply a large pre-tension force to the bolt so as to generate extrusion force between the contact surfaces of the connected pieces, thus there is a large friction force perpendicular to the direction of the screw, and the connection shear force is transmitted by this friction force. The pretension of roof bolts is realized by tightening nuts. Common roof bolts generally adopt torque method and corner method. Torsional shear roof bolts use twist bolt tail to control pretension. Bolts connected by Roofing Bolts are made of 10.9S or 8.8S grade high-quality alloy structural steel and heat treated. Holes for high-strength bolts shall be drilled. The nominal diameter D of the aperture ratio bolt of the high-strength bolt connected by friction type is 1.5-2.0 mm larger; The nominal diameter D of the aperture ratio bolt of the high-strength bolt connected under pressure is 1.0-1.5 mm larger.
  2. vickyyihui

    Professional Cap Screw Factory

    1. Do not hammer the joint bearing when installing high-strength Roofing Bolts. 2. Flange plate connection high-strength roof bolts can only be inserted from the flange end to be connected. The nuts are tightened by the flange side of the universal shaft. If the space of the connecting parts is limited, double-headed roof bolts can be selected (except for special requirements). 3. For flange connection, 10.9-grade high-strength roof bolts and 10-grade high-strength nuts shall be used. Before screwing the nuts, a little grease shall be applied to the threaded part of the roof bolts. 4. High-strength roof bolts and nuts shall have reliable anti-loosening measures. If you want to know more about this field, then don't miss the professional Cap Screw Factory Haiyan yihui hardware technology co., ltd is the choice you can't miss.
  3. vickyyihui

    DIN 603 Fault Reason Analysis

    Cause of Failure of High Strength DIN 603 Bolt; ① During assembly, the torque is too large and the force is uneven. Since there is no strictly matched torque [1] wrench in the assembly, and the specific tightening torque is not well understood, the tighter the better. The connecting rod DIN 603 bolt is fastened with a longer force application rod, and the tightening torque is too large, which exceeds the yield limit of DIN 603 bolt material, causing the connecting rod DIN 603 bolt to yield and deform, causing it to fracture due to excessive elongation under impact load. It should be emphasized that the connecting rod DIN 603 bolt must be tightened according to the standard. The tighter and stronger the bolt, the better. (2) The connecting rods of diesel engines are divided into various grades, and attention should be paid to not replacing connecting rods of different grades during maintenance. If the connecting rod cap is messed up and incorrectly installed due to carelessness in maintenance, the large end joint surface of the connecting rod will not fit tightly, which will cause the connecting rod cap to loosen and lead to the fracture of DIN 603 bolt during engine operation. WD615 series diesel engine connecting rod big head is of oblique cut type, with an oblique cut angle of 45, and the connecting rod cap and connecting rod big head joint surface adopts a 60 zigzag positioning structure, which has the characteristics of tight fit, accurate positioning, reliability and compact structure. If the connecting rod cap is messed up and incorrectly installed during maintenance, it will inevitably lead to poor positioning of serrations on the joint surface, which will easily lead to loosening of the connecting rod cap during engine operation and fracture of the connecting rod DIN 603 bolt. (3) The connecting rod DIN 603 bolt is broken when the diesel engine runs with a runaway fault or the piston burns to death in the cylinder. If the engine has run-by-speed faults during use, the engine should be thoroughly inspected and the connecting rod DIN 603 bolt should be replaced. If serious cylinder pulling occurs in individual cylinders during operation, the connecting rod DIN 603 bolt should also be replaced when replacing the cylinder piston assembly. (4) Material problems, processing defects and heat treatment process problems will also cause the connecting rod DIN 603 bolt to fracture during engine operation. Preventive measures (1) every time running 12000km for secondary maintenance, shall remove the engine oil pan, high strength Square Bolt to check the use of the engine bearing shell, if discover individual bearing shell clearance is too large, should be replaced, replace the connecting rod square bolt should also be replaced at the same time. In normal operation, if the engine is found to be running unsteadily and has abnormal noise, it should also stop and check in time. (2) During each repair, the newly replaced connecting rod square bolt shall be inspected. Attention shall be paid to whether there are cracks or dents in the head, guiding part and thread parts of the square bolt, whether the tooth shape and pitch of the thread are abnormal, and if there are abnormal situations, it shall be resolutely avoided. (3) When assembling the connecting rod cap, use a torque wrench to tighten it according to the specified standard to prevent the torque from being too large or too small. ④ Select the connecting rod square bolt produced by the matching factory.
  4. The corrosion resistance of stainless steel Round Head Bolt in some environments is related to their passivation performance. When the steel is in a passivated state, a dense oxide film is formed on the surface of the steel, which blocks the corrosion process and temporarily stops the corrosion. Chromium is the most basic element in stainless steel, and it is also a necessary element to improve the stability of passivation film of steel. When the chromium content reaches 12%, the alloy can reach the capability of complete self-passivation. The self-passivating ability of the alloy determines the corrosion resistance of stainless steel to a certain extent. Therefore, the chromium content in austenitic stainless steel cannot be less than 12%, and the chromium content in SUS304 is less than 12% in the current market. Nickel is an element to improve the corrosion resistance of steel, especially in non-oxidizing sulfuric acid. Adding nickel to chromium stainless steel can improve its corrosion resistance in sulfuric acid, acetic acid, oxalic acid and neutral salts (especially sulfate). Manganese can also improve the corrosion resistance of chromium stainless steel in organic acids such as acetic acid, formic acid and glycolic acid, and is more effective than nickel. Molybdenum can improve the passivation capability of stainless steel DIN 603 and expand the range of passivation medium, such as the use in hot sulfuric acid, dilute hydrochloric acid, phosphoric acid and organic acid. Molybdenum-containing passivation film can be formed in stainless steel containing molybdenum, which has high stability in many strongly corrosive media and can also prevent chloride ions from damaging the film. Silicon can improve the corrosion resistance of steel in hydrochloric acid, sulfuric acid and high concentration nitric acid. Generally, 2%-4% silicon is added to stainless steel to improve its corrosion resistance in the above medium.
  5. vickyyihui

    Welding To DIN 603

    1. DIN 603 shall conform to the specifications and design requirements. If there is rust, it must be derusted before it can be used (especially DIN 603 head and large head must be free of rust and dirt), and DIN 603 with serious rust cannot be used. 2. DIN 603 welds shall be free of moisture. 3. During construction in windy days, welders should stand in the limelight to prevent spark damage. 4, pay attention to the welder's safety protection, especially when welding peripheral beam, more careful. 5, Square Bolt welder to master the performance of the welder, welding torch, do a good job in the maintenance of equipment. When flash, ablation or slag splashing occurs on the welding torch fixture, timely clean or replace the fittings to ensure smooth construction and welding quality.