Large hexagonal bolts are one of the commodities used in many fields. Don't underestimate it. Its test is very strict, because it has a particularly critical function. It can be said that without it, many jobs cannot be carried out normally. Quality testing standards for new large hexagonal bolts: 1. Specifications for construction and construction acceptance of steel structure engineering (GB50205-2001). 2. Manufacturing standards for steel bridges on railway lines (TB10212-2012). 3. Process standards for high toughness large hexagon head bolts, large hexagon nuts and steel frame structure sealing rings (GB/T1231-2006). (1) The construction sequence and original and torsional torque of the large hexagonal bolt connection should comply with the formulation and requirements of JGJ82, which is the current national standard for large and medium-sized hexagonal bolt connection design schemes, engineering construction and engineering acceptance. (2) After finally tightening a pair of large hexagonal bolts, the bolt threads should be exposed by 2-3 buckles, and 10% of the bolt threads should be exposed by 1 buckle or 4 buckles. Inspection frequency: 5% of the total number of connection points, not less than 10. (3) The friction surface connected by large hexagonal bolts should be kept dry and clean. There should be no shiny, burr, welding spatter, welding scars, compound scale, stains, etc. It should not be painted except to design scheme standards. (4) Large hexagonal bolts should be able to pass through the bolt holes freely. Hex head bolt holes should not be drilled by oxygen cutting. The number of reaming holes shall be permitted by the design plan. The hole diameter after boring should not exceed 1.2D (d is the bolt diameter). (5) After the general installation of the large hexagon bolt ball joint, the large hexagon head bolt and the ball joint should be connected through gaps. The thread length of the large hexagon head bolt screwed into the bolt ball should not be less than 1.0d (d is the diameter of the bolt), and there should be no gap or looseness at the joint. The above is the inspection of large hexagonal bolts. Our products have passed rigorous testing to ensure that they meet relevant national industry standards. Our products have been updated and improved for better results.