Hexagon Head Thick Shank Half Thread Bolt DIN931

According to the force mode of the connection, the hexagonal head bolts are ordinary and have reamed holes. The bolts used for reaming holes should be matched with the size of the hole and used when subjected to lateral force. According to the shape of the head, there are hexagonal heads, Round head, square head, countersunk head, etc.Generally, countersunk heads are used where the surface after connection is required to be smooth without protrusions, because the countersunk head can be screwed into the part. The round head can also be screwed into the part. The tightening force can be larger, but the size is large. Hexagon 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 it is vibrated.

High-strength hexagon bolts are the most widely used type of bolts. Grade A and Grade B high-strength hexagon bolts are used for important assembly precision requirements, and places subject to greater impact, vibration or load. Class C high-strength hexagon bolts are used in places where the appearance is rough and the assembly accuracy is not high.

The threads of high-strength hexagonal bolts are generally coarse-threaded ordinary threads, and fine-threaded ordinary threaded bolts have better self-locking properties. They are mainly used for thin-walled parts or places subject to impact, vibration or alternating loads. Generally, partial threads are made on bolts, and full-thread bolts are mainly used in places that require longer threads. Bolts with holes are used where bolts are required to be locked.

The high-strength hexagonal bolts with reamed holes can accurately fix the mutual position of the connected parts, and can accept the shear and extrusion caused by the transverse force.

Hexagon head bolt material

At present, the hexagon socket screws on the market mainly include carbon steel, stainless steel, and copper.

1. Carbon steel. We distinguish low-carbon steel, medium-carbon steel, high-carbon steel and alloy steel based on the carbon content of carbon steel materials.

1) Low carbon steel C%≤0.25% is usually called A3 steel in China. It is basically called 1008, 1015, 1018, 1022, etc. abroad. Mainly used for grade 4.8 bolts, grade 4 nuts, small screws and other products that have no hardness requirements (Note: 1022 materials are mainly used for drill tail screws).

2) Medium carbon steel 0.25% 0.45%. At present, it is basically not used in the market.

3) Alloy steel: Add alloy elements to ordinary carbon steel to increase some special properties of the steel: such as 35, 40 chromium molybdenum, SCM435, 10B38. Fangsheng screws mainly use SCM435 chromium-molybdenum alloy steel, the main components are C, Si, Mn, P, S, Cr, Mo.

2. Stainless steel. Performance grade: 45, 50, 60, 70, 80 mainly divided into austenite (18%Cr, 8%Ni), good heat resistance, good corrosion resistance, and good weldability. A1, A2, A4 martensite and 13%Cr have poor corrosion resistance, high strength and good wear resistance. C1, C2, C4 ferritic stainless steel. 18%Cr has better upsetting and corrosion resistance than martensite. Currently imported materials on the market are mainly Japanese products. According to the level, it is mainly divided into SUS302, SUS304, and SUS316.

3. Copper. Commonly used materials are brass-zinc-copper alloys. The market mainly uses H62, H65, H68 copper as standard parts. Disc element used in carbon steel products: serial number Type of optional material 1 4.8 grade hex screw 1008K 1010 1015K 2 6.8 grade hex screw.

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