Type of 12.9 grade high strength screw

Type of 12.9 grade high strength screw

Grade 12.9 high-strength screws are commonly used in high-strength bolt series. Grade 12.9 hex screws are usually used in situations where high mechanical performance requirements are required. Injection machines, hydraulic equipment, mold assembly, etc. The surface hardness of grade 12.9 hex screws can reach 39-44 degrees after heat treatment. The production standards of grade 12.9 hexagon screws refer to German standards DIN912, GB/T70.1, American standard, British standard production. The supply range of U.S. grade 12.9 hexagon screws is within the supply range of #4 - 1-1/2 and imperial grade 12.9 hexagon screws, currently at 1/4- Sales under common specifications such as 1-1/2.

Type of 12.9 grade high strength screw

According to the project, it is divided into 12.9-grade external hexagonal screws, 12.9-grade hexagonal cylindrical head screws (cup heads), 10.9-grade countersunk head hexagonal screws (flat cups), 10.9-grade semicircular head hexagonal screws (round cups), 12.9-grade fastening screws (machine meters), and 12.9-grade internal thread coarse teeth.

Grade 12.9 is the harder variety of screws, with higher hardness and tensile strength, and the Rockwell hardness (HRC) reaches 1220N/mm2 between 39-44, but the shape of the screws is different, so the countersunk hexagon produced from the same material can also fully meet the special circumstances of industrial and mining enterprises and the high requirements for parts fasteners. The production of good 12.9-grade high-strength screws mainly depends on three aspects: raw materials, heat treatment and laboratory.

Standard for Grade 12.9 High Strength Screws

The basic (pin gear class is not below) of all fasteners are in the thread. No screws can not be matched (except for special fasteners such as rivet products). The thread is a regular spiral concave and convex point produced on the metal surface. The two threads and the rotation form a complete locking function. Imperial threads are often used in the country, and imperial external threads and national standard threads may be different.

In the daily use of 12.9-grade high-strength screws, the surface is not plated, and the 12.9-grade high-strength screws are prone to hydrogen embrittlement after plating. This hydrogen embrittlement phenomenon cannot be controlled many times, and this phenomenon is a sudden phenomenon. In other words, no one knows when the quality problem of the guillotine will occur.

All 12.9-grade high-strength screws enter the oxidation blackening process on the surface after the production is completed, and this hydrogenation blackening may be very serious. It is not our common life black. It is a hydrogenated black made through high temperature and strict process. This black looks bright and a little greasy, but it has no effect on use and will not rust even if it is stored in daily environments for many years. Wuxi Part of the specifications of the 12.9-grade screws stored in the warehouse of Pan-Austrian Fastener Co., Ltd. have been placed for more than 10 years, but there is no corrosion at all.