Attention Problems in Installation of High Strength Hexagonal Bolts In the installation of high strength hexagonal bolt, we need to pay attention to the following matters to ensure the quality of high strength (including internal and external) hexagonal bolts. 1. Installation and construction of high-strength hexagonal bolt should be avoided in rainy and snowy weather [...]
Heat treated high strength fasteners are conditioned according to technical requirements. Heat treatment quenching and tempering is to improve the comprehensive mechanical properties of fasteners to meet the required tensile strength and yield strength ratio of products. Heat treatment process has a vital impact on the internal quality of high-strength fasteners, especially its internal quality. [...]
There are five main ways to distinguish high strength national standard bolts from fake bolts: 1. Look at the logo, the packing box of the general bolt has the logo. It is divided into 8.8, 10.9 and 12.9 grades. Generally, there is no grade mark on the hexagonal plane of hexagonal bolts. Generally, high strength [...]
How are the bolt heads and threads processed? The forming of bolt head adopts cold heading plastic processing. Compared with cutting processing, the metal fibers are continuous along the shape of the product without cutting in the middle, which improves the strength of the product, especially the mechanical properties. Cold upsetting process includes cutting and [...]
Fasteners Classification and Characteristics There are many kinds of fasteners. According to their names, fastener can be divided into seven basic categories: bolts, screws, nuts, rivets, pins, welding nails and washers. Bolts include external hexagonal bolts, flange bolts, double-headed bolts, anchor bolts, U-shaped bolts, live bolts, carriage bolts, etc. Nuts include hexagonal nuts, cap nuts, [...]
Heavy external hexagonal bolts: Standard: A325M. Level: 4.8/5.8/6.8/8.8/10.9/12.9; Grade 2/5/8. Specification: M6-M24; 1/4 inch-1 inch. Length: 10mm-270mm; 1/2inch-10inches. Surface treatment: natural color, blackening, galvanizing, hot galvanizing, dacromet. Packing: 25 kg in bulk and 36 cases in pallets. Or according to customer requirements. Heavy external hexagonal bolts application: It is suitable for fixing heavy loads on [...]
High strength galvanized bolt is galvanized, so what are their advantages? Hot dip galvanizing is also used to prevent corrosion on the surface of screw, bolt and nut. High strength galvanized bolt has better corrosion resistance than galvanized screw, but the cost is higher, and high strength structure is not suitable for hot dip galvanizing. [...]
High strength Dacromet bolt is treated by Dacromet, so what are the advantages? 1. Superior corrosion resistance. Unetched galvanized coatings are usually corroded by rainbow colored film with thickness of 1-3 micron for 20 hours in salt spray test. The corrosion resistance of Dacromet treated metal surface is about 10 times higher than that of [...]
Ultra-long bolts are usually constructed by the method of torque-one-axis force. They are divided into two stages: initial and final twisting. Torque coefficient refers to the coefficient between the torque and the axial force of the bolts in the process of tightening. Generally speaking, it has a great relationship with the friction coefficient of the [...]
Points for Attention in Connecting of Building Steel Structures Bolts 1 In order to make the connection reliable, the number of permanent bolts should not be less than two for each member on the joint and at the end of the splice joint. However, one end connection can be used for the patches of composite [...]
The SB of bored bolts refers to the ultimate tensile strength of bolts, indicating the maximum resistance of bored bolts to failure under tension. Tensile strength is the maximum nominal tensile stress of the specimen before breaking. It is the critical value of metal transition from uniform plastic deformation to locally concentrated plastic deformation, and [...]
High-strength wind power bolt-nut connection has no requirement for bolt fastening axial force, so the bolt fastening construction is based on operator's hand feeling and the shape control of connecting joint. Generally speaking, an operator can tighten the nut with ordinary wrench by his own strength to ensure that the connecting contact surface can be [...]