Japan's Nitto Seiko introduced the first self-tapping screws in China that use double heat treatment technology. Generally, when special self-drilling screws for heat-treated steel plates are used, the hot refining (heat quenching and tempering) method often used in bolts is not used, but carburizing and quenching is used. . This is because the thermal refining method cannot ensure the hardness of the thread, and the advantage of the carburizing and quenching method is to increase the surface hardness. However, if you want to use carburized and quenched self-drilling screws on steel plates with high axial force requirements, you will find that the toughness is weaker than those of hot-refined screws, and the risk of metal fatigue damage will be higher. So now someone will use hot-refined bolts to tap the thread.
In view of this, the screw introduced by Nitto Seiko is based on the "CORFLEX®-I" heat treatment technology, which can be applied not only to the tapped part to improve the hardness, but also to keep the joints the same as the hot refining bolts. Hardness and tensile strength. In this way, it is possible to have both the hardness of the hot refining (avoiding the fatigue damage of the metal) and the function of the self-tapping thread, and it is not a problem even if it encounters a steel plate requiring a high axial force.
Summarize the advantages of the product: (1) Self-tapping thread on steel plate (2) The ability to resist fatigue damage is the same as that of hot-refined bolts. (3) No thread pre-processing is required to reduce the total cost. The product has been launched in December 2015 with a target monthly production of 1 million pieces for the automotive, construction and agricultural machinery industries.
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