What is the tolerance range of precision screws?
What is the tolerance range of precision screws?
(+): Cross slot (-): Slotted slot (T): Chrysanthemum slot (H): Hexagon socket (PZ): Bevel slot (+-): +- slot (Y): Y-shaped slot (H) : H-groove (L): Back-stop tooth (WIS): Single-moving spring washer (WIF): Single-moving flat washer (WIT): Single-moving external tooth washer (W2SF): Double-moving flat washer (W=6mm ): Washer outer diameter equal to 6mm (SUS): Stainless steel (Cu): Brass (Br): Red copper (8.8): Grade 8.8 screw (10.9): Grade 10.9 screw (12.9): Grade 12.9 screw (R): Other Notes
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.
The electroplating of cross recessed screws generally refers to the electroplating of iron cross recessed screws. Stainless steel cross recessed screws are rarely electroplated. The electroplating colors of cross recessed screws are divided into environmental protection and non-environmental protection. Environmental protection blue zinc, environmental protection color zinc, environmental protection black zinc, environmental protection white nickel, etc., non-environmental protection includes white nickel, white zinc, color zinc, black zinc, black nickel, black cladding, blue zinc.
In chemical production equipment, the cylinder body and the head cover need to be connected and sealed. The traditional sealing structure is to connect the two with a screw, add a non-metallic gasket in the middle and fix it with a nut. However, such a sealing structure only controls the tightening torque, and has the technical defect that the sealing ring will be twisted or even broken during repeated loading and unloading of the cylinder head cover, resulting in poor sealing performance.
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