Method for machining high-strength U-shaped bolt

Abstract

The invention discloses a method for machining a high-strength U-shaped bolt. The method comprises the following steps of: a, casting a U-shaped rod blank, and controlling the weight percentage of each chemical component of the rod blank to meet the following requirements: 0.28 to 0.35 percent of C, 0.25 to 0.35 percent of Mn, 0.05 to 0.09 percent of V, 0.15 to 0.35 percent of Si, 0.01 to 0.04 percent of W, less than or equal to 0.025 percent of P, less than or equal to 0.035 percent of S, 0.55 to 1.20 percent of Ni, 0.35 to 0.45 percent of Co, 0.20 to 0.30 percent of Sn, less than or equal to 0.20 percent of Al and the balance of iron; and b, forging a cast U-shaped rod at the temperature of between 650 and 700 DEG C for not more than 25 times, wherein a thin layer of graphite powder is coated on the inner wall of an impression of a forging die, and the granularity of the graphite powder is controlled to be 200 to 300 meshes; and turning an external thread of the bolt by using a precision lathe after forging. According to the method for machining the high-strength U-shaped bolt, the bolt is machined by adopting a cold extrusion process, so that the strength of the bolt is improved, the hardness value and the strength value required by the 12.9 high-strength bolt are achieved, the problems of delayed fracture and fatigue fracture of the bolt under high strength are solved, the bolt is reliable in connection during use and difficult to break, the service life of the bolt is prolonged, and the using requirement of each industry in the society for the high-strength bolt is met.

Description

technical field [0001] The invention relates to a bolt processing method, in particular to a high-strength U-shaped bolt processing method. Background technique [0002] High-strength U-shaped bolts are commonly used fasteners in the machinery industry. The current processing method is generally turning forming, and the strength is often difficult to guarantee. Sometimes unsafe phenomena such as U-turns and rod breaks occur during use, which is very harmful to industrial production. big. Therefore, it plays an important role in the development of technology and economy to study and improve the production method of high-strength bolts to ensure the quality stability of high-strength bolts. In addition, when the bolts are in a relatively humid environment, they are prone to rust and corrosion, eventually leading to breakage or cracks, forming a potential source of accidents. [0003] In view of this, it is necessary to provide a processing method for high-strength U-shaped b...

AI Technical Summary

Problems solved by technology

In addition, when the bolts are in a relatively humid environment, they are prone to rust and corrosion, eventually leading to breakage or cracks, forming a potential source of accidents