Cylindrical head socket screws, also referred to as socket head bolts, cup head screws, and socket head screws. Although they have different names, but have the same meaning. There are also 4.8, 8.8, 10.9, and 12.9 commonly used hexagon socket head screws. It is also called a hexagon socket screw and hexagon socket bolt. Its head is hexagonal and cylindrical.
1. Classification of hexagon socket head cap screws
According to the materials, they are classified as carbon steel, stainless steel, and iron.
Stainless steel has stainless steel SUS202 hexagon socket head cap screws, which are common materials of stainless steel. There are stainless steel SUS304 hexagon socket head cap screws and stainless steel SUS316 hexagon socket head cap screws.
The iron material is classified according to the strength grade of the hexagon socket head screw. There are 4.8-grade hexagon socket head screws, 8.8-grade hexagon socket head screws, 10.9-grade hexagon socket head screws, and 12.9-grade hexagon socket head screws. Grade 8.8-12.9 hexagon socket head cap screws are called high-strength and high-grade socket head bolts.
According to the head shape
The hexagon socket screws can be divided according to the shape of the head of the hexagon socket screws. The most commonly used is the cylindrical head hexagon socket screws.
According to the shape of the head of the hexagon socket screw, the hexagon socket screw can also be divided into half round head hexagon socket bolts, which are also called pan head hexagon socket bolts, and countersunk head hexagon socket bolts.
The head of the countersunk hexagon socket bolt is flat, and the inside of the bolt is also hexagonal. Headless hexagon socket bolts are also widely used, which are commonly referred to as stop screws, machine screws, and set screws. There is also a type of flower-shaped hexagon socket screw, which is generally difficult to buy or see in the market.
2. The production standard of hexagon socket head screws
The production standard of hexagon socket head screws depends on whether it is the national standard, German standard, British standard, American standard, etc. each standard is different.
Take the national standards, for example, the standards of hexagon socket head screws include grade 8.8 hexagon socket head screws for half teeth GB 5782, grade 8.8 hexagon socket head screws for full teeth GB 2783, and grade 8.8 hexagon socket head screws GB 70-85 DIN912.
All product sizes in production must comply with relevant standards, and the product quality of each screw must comply with the certification of the quality standard system ISO 9001-2000. Therefore, the manufacturer must produce stable and reliable products. Moreover, the standard GB 70-85 DIN912 for grade 8.8 hexagon socket head screws requires that the tensile strength of the hexagon socket head screws produced by the manufacturer must be higher than 640MPa, and the standard GB 2076 for grade 4.8 hexagon socket head screws requires that the tensile strength of the hexagon socket head screws produced by the manufacturer must be 320MPa, the diameter of the thread gauge M4 must be equal to or less than 7mm, and the minimum diameter must be greater than 6.7mm.
3. Common standards for Grade 12.9 hexagon socket head cap screws
Grade 12.9 hexagon socket screws are the most commonly used series of high-strength bolts: grade 12.9 hexagon socket screws are generally used on occasions with high mechanical performance requirements. Such as injection molding machinery, hydraulic equipment, mold assembly, and other places. The surface hardness of grade 12.9 hexagon socket screws after heat treatment can reach 39-44 degrees. The production standards of grade 12.9 hexagon socket screws are all produced with reference to the German standard DIN912, the national standard GB / t70.1, the American Standard, and the British standard. The supply range of American grade 12.9 socket head screws is from # 4 — 1-1 / 2, and the supply range of British grade 12.9 socket head screws is from 1 / 4 — 1-1 / 2.
Grade 12.9 hexagon socket bolts have knurled and non-knurled heads. Generally, grade 12.9 hexagon socket bolts have knurled heads, and low-strength hexagon socket bolts do not have knurled heads. For example, grade 4.8 hexagon socket bolts do not have knurled heads.
The surface of grade 12.9 hexagon socket bolts is treated with cyaniding and blackening. The product itself also has a certain anti-rust function. However, these 12.9-Grade high-strength bolt series products are mostly used in some exported equipment, and the surface of the 12.9-Grade hexagon socket head screws will be corroded by customers in some harsh environments during transportation (such as shipping). However, some equipment itself requires that the supporting hexagon socket screws be treated with nickel plating and zinc plating to enhance the corrosion resistance and appearance of grade 12.9 high-strength bolts (such as bread machinery and baking equipment).
Grade 12.9 hexagon socket bolts are generally of natural color, black and oily.
4. Advantages of KENENG hexagon socket head cap screws
- Shape regularity and finish of the hexagonal inner wall.
- Symmetry of hexagon.
- Flatness of hexagon socket inner bottom.
- Especially if the customer needs to make through holes for the hexagon socket head screws, the above requirements will be more strict and accurate.
KENENG has more than ten years of experience in fastener production and has specialized product designers and production lines. We can provide you with standard products in large quantities or customized according to your requirements, if you need them, please feel free to contact us.