Hexagonal bolts refer to fasteners composed of head and screw. Bolts are divided into iron bolts and stainless steel bolts according to their materials, namely, hexagonal head bolts (partially threaded)-Class C and hexagonal head bolts (full threaded)-Class C
Hexagonal bolts are hexagonal head bolts (partially threaded)-Grade C and hexagonal head bolts (full threaded)-Grade C. Also known as hexagon head bolts (rough) wool hexagon head bolts and black iron screws.Commonly used standards can be found in: SH3404, HG20613, HG20634, etc. Hexagonal bolt: a type of fastener composed of two parts, the head and the screw (cylinder with external thread), which need to be matched with the nut to fasten and connect two parts with through holes. This type of connection is called bolt connection. If the nut is unscrewed from the bolt, the two parts can be separated, so the bolt connection is a detachable connection.
Hexagonal bolt: a type of fastener composed of two parts, the head and the screw (cylinder with external thread), which need to be matched with the nut to fasten and connect two parts with through holes.
This type of connection is called bolt connection. If the nut is unscrewed from the bolt, the two parts can be separated, so the bolt connection is a detachable connection.
1. According to the force mode of the connection, there are ordinary and reamed holes. The bolts used for reaming holes should be matched with the size of the hole and used when subjected to lateral forces.
2. According to the shape of the head, there are hexagonal heads, round heads, square heads, countersunk heads, etc.Generally, countersunk heads are used in places where the surface is required to be smooth and no protrusions after the connection, because the countersunk head can be screwed into the part. The head can also be screwed into the part. The tightening force of the square head can be larger, but the size is large. The hexagonal head is the most commonly used.
In addition, in order to meet the need of locking after installation, there are holes on the head and holes on the rod. These holes can prevent the bolt from loosening when subjected to vibration.Some bolts have no threaded polished rods to be thin, called thin waist bolts. This kind of bolt is conducive to the connection of variable forces.
There are special high-strength bolts on the steel structure. The head will be larger. The size will also change.In addition, there are special uses: T-slot bolts, the most used on machine tool fixtures, special shapes, and both sides of the head should be cut off. Anchor bolts are used to connect and fix the machine and the ground. There are many shapes, U-shaped bolts , As mentioned above and so on.
There are also special studs for welding. One end has a thread and the other is not. It can be welded to the part, and the nut is directly screwed on the other side.
Tin is a silver-white metal, non-toxic, with good weldability and ductility. It is widely used in electronics, food, automobile and other industries. The tin plating process of hexagonal bolts is classified according to the pH value of the plating solution, which is divided into two categories: acid plating solution process and alkaline tin plating process.
The advantage of acid tin plating is its fast plating speed. The plating layer is bright and detailed, and the deep plating ability is good. The plating solution has strong tolerance to impurities, and room temperature operation saves energy. The disadvantage is that the dispersibility of the plating solution is poor, the porosity of the plating layer is relatively high, brazing is not as good as alkaline tin plating, and divalent tin is hydrolyzed. The acid tin plating of hexagonal bolts is divided into sulfate tin plating, fluoroborate tin plating, chloride tin plating and other processes due to different conductive media.
The cost of sulfuric acid tin plating is low, the plating solution is easy to control, the plating layer is bright and fine, but the dispersion ability is poor. The market is most widely used. The advantages of fluoroborate tin plating are that the plating speed is fast, larger currents can be used, and the bath stability is good. It is widely used for continuous electroplating of flange nuts, wires and strips. The disadvantage is that the plating solution is expensive, toxic, and difficult to treat wastewater.
Chloride tin plating is mainly used for crystal grain tin plating, which has the advantages of lower cost, stable plating solution and white coating. The disadvantage is that the current is not large. The advantages of alkaline tin plating of hexagonal bolts are: simple composition, good plating solution dispersion ability, fine coating, few pores, and good brazing performance. Disadvantages are: high operating temperature, high energy consumption, narrow current use range, low current efficiency, inability to obtain bright coatings, small hard coatings, and large influence on anode behavior
The performance grades of bolts for steel structure connection are 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, among which the bolts of grade 8.8 and above are made of low-carbon alloy steel or medium-carbon steel and are heat-treated (Quenching, tempering), commonly known as high-strength bolts, and the rest are commonly known as ordinary bolts. The bolt performance grade label consists of two parts, which respectively indicate the nominal tensile strength value and the yield ratio of the bolt material.
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