DIN7991 Hex Socket Countersunk Screw Grade Carbon Steel Black Oxide Grade 8.8 10.9

DIN7991 countersunk hexagon socket screw, the head is conical, the middle is a recessed hexagon, the screw head can be embedded in the mounting surface after installation, the surface is smooth and beautiful. The head of countersunk hexagon socket screw can be embedded in the component, and can apply larger torque, and the connection strength is higher. It can replace the hexagon socket bolt. Often used in the structure of compact, smooth appearance of the joint. DIN7991 hexagon socket countersunk head screw is A reference to German standard DIN7991-1986, which specifies the thread specification from M3 -- M24 ISO metric thread, product grade A hexagon socket countersunk head screw.

DIN7991 hexagon socket countersunk head screws are available in carbon steel and stainless steel. The performance grades of carbon steel hexagon socket countersunk head screws are 8.8, 10.9, 12.9, the standard can refer to GB3098.1. Carbon steel materials generally need surface treatment, common is oxidation, electroplating, such as the need for other surface coating or surface treatment, can also be negotiated. Stainless steel hexagon socket countersunk head screws commonly used on the market are made of SUS304 and SUS316, stainless steel material corrosion resistance and heat resistance are strong. SUS304 medium work hardening rate, suitable for general cold work and stretching; The CORROSION RESISTANCE OF SUS316 IS BETTER THAN THAT OF 304. It IS ESPECIALLY suitable FOR Marine and chemical media. It has better corrosion resistance and hole corrosion resistance. 

Hexagon socket screws are divided into cylindrical head hexagon socket bolts according to the head, which is commonly used, and it also has many kinds, according to the material, there are iron, that is, carbon steel and stainless steel. Stainless steel hex bolts also have stainless steel 304 and 202 and so on material. Semi - round head hex socket bolt, this also have called pan head hex socket bolt. Countersunk head hex socket bolt, head is flat head, inside is hex socket. There is a kind of national standard is more special, called headless hexagon bolt. Which is what we often call the meter screw, the payment screw, the set screw. These are common terms for headless hex bolts, but they all mean the same thing. Of course, there are also some bolts with flowered inner hexagon head. This use is less, the market is also basically difficult to see. Hexagon socket screw although the variety of national standards are also more, but basically some more special, basically few people will go to use on the market. Used more or number of cylindrical head hex socket screws, also known as cylindrical head hex socket screws.