Customized 8.8 grade T-screw T-groove bolt T-plate screw mold GB37

Heat treatment technology has a crucial impact on high-strength fasteners, especially its intrinsic quality. Therefore, in order to produce high-quality high-strength fasteners, advanced heat treatment technology and equipment must be available. 1. Status of heat treatment of high-strength fasteners High-strength fasteners have 4 performance levels, namely 8.8, 9.8, 10.9, and 12.9. These four grades of high-strength fasteners must be quenched and tempered. The purpose of heat treatment and tempering is to improve the comprehensive mechanical properties of fasteners to meet the specified tensile strength value and yield ratio of the product. Therefore, the quenching and tempering process has strict requirements on raw materials, furnace temperature control, furnace atmosphere control, quenching medium, heat treatment quality inspection and control, etc.

At present, the locking washer is widely used in the upper wheel side locking of passenger cars. During assembly, the locking washer is bent perpendicular to the thread of the axle pipe, so as to prevent the protrusion from passing through the gap between the two tooth profiles of the thread and ensure the locking The stop gasket is always in the groove of the shaft tube and cannot be rotated to achieve the purpose of locking. This method is relatively simple and is currently used more;

Commonly used standards are broadcast. For hexagonal nuts, the commonly used standards are: GB52, GB6170, GB6172 and DIN934. The main differences between them are: the thickness of GB6170 is thicker than that of GB52, GB6172 and DIN934, commonly known as thick screw cap. The other is the difference between the opposite sides, the opposite sides of DIN934, GB6170 and GB6172 in the M8 nut series are 13MM smaller than the opposite side 14MM of GB52, and the opposite sides of M10 nuts, DIN934 and GB52 are 17MM. The opposite side of GB6170 and GB6172 should be 1MM larger, M12 nut, DIN934, GB52's opposite side is 19MM larger than GB6170 and GB6172's opposite side 18MM is 1MM larger. For M14 nuts, the opposite side of DIN934 and GB52 is 22MM, which is 1MM larger than the opposite side of GB6170 and GB6172, which is 21MM. The other is the M22 nut. The opposite side of DIN934 and GB52 is 32MM, which is 2MM smaller than the opposite side of GB6170 and GB6172, which is 34MM. (Besides the thickness of GB6170 and GB6172 are the same, the width of the opposite side is exactly the same) The rest of the specifications can be used in general without considering the thickness.

Round head three-combination screws are also called pan-head three-combination screws, which are divided into large pan-head three-combination screws and small pan-head three-combination screws. The materials are divided into stainless steel and iron. The stainless steel round head three-combination screws include stainless steel small pan head three-combination screws and stainless steel large pan-head three-combination screws. The national standards are respectively expressed as GB9074.8 and GB9074.4.

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