Manufacturing process of high low screws

Abstract

The invention discloses a manufacturing process of high low screws. The manufacturing process comprises the following steps of firstly, cutting a required blank at a room temperature, putting the cut blank into a mould cavity and forming a head part and a rod part required for screws through utilizing the blank by virtue of forging power; then processing threads in a screw rod by utilizing a thread rolling machine, wherein the thread rolling machine is provided with a high low thread rolling plate and can be used for rolling a high thread and a low thread at a step, the height of the high thread is 7.6-8.1mm, and the height of the low thread is 6.0-6.5mm; performing carburizing treatment on the screws formed after thread rolling, wherein the carburizing layer is 0.25-0.35mm; and finally performing thermal rust-preventing treatment on the surface. According to the manufacturing process, on one hand, a cold heading technology is adopted for processing the high low screws, so that the strength of the high low screws is improved, the delayed breakage and fatigue breakage problems of a bolt under a high bolt are solved, and the form and location tolerance and the thread accuracy of finished products of the high low screws can be effectively ensured; and on the other hand, by adopting the cold heading technology for processing, no waste materials can be generated, raw materials are saved, and the production cost is lowered.

Description

technical field [0001] The invention relates to a screw manufacturing process, in particular to a high-low pitch screw manufacturing process. Background technique [0002] High and low tooth screw, on the screw rod, there are high thread and low thread double-thread thread, one low and one high are arranged in sequence. This structure improves the tapping speed, increases the contact area, strengthens the bonding strength, and is fixed firmly and is not easy to fall off. At present, The processing method is generally turning and forming, and the strength is often difficult to guarantee. Sometimes unsafe phenomena such as U-turn and rod breakage occur during use, which is very harmful to industrial production. Therefore, it is necessary to study and improve the production method of the high-low screw with this structure to ensure the stable quality of the high-low screw, so it is necessary to provide a high-strength, high-quality guaranteed high-low screw manufacturing proces...

AI Technical Summary

Problems solved by technology

[0002] High and low tooth screw, on the screw rod, there are high thread and low thread double-thread thread, one low and one high are arranged in sequence. This structure improves the tapping speed, increases the contact area, strengthens the bonding strength, and is fixed firmly and is not easy to fall off. At present, The processing method is generally turning and forming, and the strength is often difficult to guarantee. Sometimes unsafe phenomena such as U-turn and rod breakage occur during use, which is very harmful to industrial production.

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