1. Classification and naming
Classification: Hexagonal bolts can be divided into iron bolts and stainless steel bolts according to the material; According to the shape of the head, it can be divided into hexagonal head, round head, square head, countersunk head, etc., among which hexagonal head is the most commonly used; According to the force mode of connection, it can be divided into ordinary bolts and bolts for hinged holes, and the bolts used for hinged holes should be matched with the size of the holes and used when subjected to transverse force.
Nomenclature: Hexagon bolts are also known as hexagonal head bolts (rough), wool hexagonal head bolts, black iron screws. Its national standard codes include GB5780, 5781, 5782, 5783, 5784, 5785, 5786-86, etc.
2. Specifications and dimensions
Hexagon bolts: The standard specifies hexagon head bolts with thread specifications of M3~M64, A and B grades. Among them, Class A is used for bolts with D≤24 and L≤10D or L≤150mm (whichever is less); Class B is used for bolts D>24 or L>10D or L>150 (whichever is less). The material is generally stainless steel or carbon steel, with a diameter range of 5mm~20mm (1/4"~3/4") and a length range of 8mm~200mm (5/16"~8").
Hexagon bolts: The head of the hexagon bolt has a hexagonal type inner hole, which can only be tightened or loosened after being inserted into the inner hole with a hex key (hex key, Allen wrench or Allen key). The head diameter is about 1.5 times the main thread diameter (1960 series), and other head types include Bottom head cap screw and Countersunk head cap screw for tapered screw holes
3. Performance and grade
Performance grade: The performance grade of bolts for steel structure connection is divided into more than 10 grades, such as 3.6, 4.6, 4.8, 5.6, 6.8, 8.8, 9.8, 10.9, 12.9, etc. Among them, the bolts of grade 8.8 and above are made of low-carbon alloy steel or medium-carbon steel and are heat-treated (quenched and tempered), commonly known as high-strength bolts; The rest are commonly known as ordinary bolts.
Strength and stress: For example, a bolt with a performance level of 4.6 means that the nominal tensile strength of the bolt material is 400MPa, the yield ratio of the bolt material is 0.6, and the nominal yield strength of the bolt material is 240MPa. The performance level of 10.9 high-strength bolts, after heat treatment, can achieve the nominal tensile strength of the bolt material up to 1000MPa, the yield ratio of the bolt material is 0.9, and the nominal yield strength of the bolt material is 900MPa.
Fourth, application scenarios
Hexagon bolts: Because of their simple and convenient operation, they are suitable for equipment that needs to be disassembled and replaced frequently. For example, various steel structure building connection nodes in construction projects, road guardrails and billboard installation of public domain facilities, automobile chassis and wheel connections in the automobile industry, etc.
Allen socket bolts: They are commonly used in electronics, instrumentation, aviation and aerospace, as well as in home improvement and furniture because they are beautiful, precise, and suitable for space-constrained assembly environments
Qingdao Xinquanxi Metal Products Co..Ltd. was established in 2001 (formerly known as Qingdao Quanxi Hardware Cable Co., LTD.), located in Jimo District, Qingdao city, the company was mainly engaged in the production and sales of Japanese open-body turnbuckle, die forging shackles, products are mainly sold to the United States, Russia, Japan and other countries.
In September 2019, with the continuous development of the company's business, it merged with Qingdao Ruihongjie Industry and Trade Co., LTD., and changed the company name to Qingdao Xinquanxi Metal Products Co., LTD. At the same time, the business range is gradually expanding, the main production and operation of hardware rigging, wire rope connecting parts, hardware machinery, Marine and automobile connecting parts, all kinds of forging, sheet metal, stamping, casting parts and other products. After more than 20 years of development, we have established a complete system, with strong technical capacity, mature production methods, advanced production equipment and testing methods.
We always adhere to the principle of quality first, safe production, timely delivery, customer satisfaction after sale service, and constantly research and learn product expertise, with the best quality products to serve customers.
1.Are you a factory or a trading company?
We have our own foundry and forging factory. The forging plant has 4 production lines and a history of more than 20 years;Foundry has a history of more than 30 years.
2.How do you control your quality?
1: Control during r&d at the beginning of production
2:Production process control
3:Dimensional control
4:Tensile tests
5:Quality inspection before delivery
3.Can we have our product markings on it?
Yes, we can add product markings according to your requirements.
4.How about packing?
Woven bag, carton, plywood pallet or by customer requirements.