Forging method of thin-wall drill bit and through diameter reducing die

Abstract

The invention provides a forging method of a thin-wall drill bit, which comprises the steps of blanking, preparing a blank, reversely extruding, reaming, reducing the diameter and upsetting. In the step of reversely extruding, a bar stock obtained after the step of preparing the blank is carried out is placed into a die cavity of a reverse extruding die to be subjected to reverse extrusion so as to form a cylinder blank of which one end is provided with a barrel-shaped inner hole; in the reaming step, the cylinder blank with the barrel-shaped inner hole is reamed into a cylinder blank with a tapered hole; in the step of reducing the diameter, the cylinder blank with the tapered hole is placed into a diameter reducing die to be subjected to diameter reduction, so that the diameter of the excircle of the cylinder blank with the tapered hole is reduced, the diameter of the tapered hole is unchanged and a cylinder forging stock with the tapered hole is obtained; and in the upsetting step, a solid cylinder part of the forging stock is subjected to upsetting to form an inverted cone head part of the thin-wall drill bit, so that a thin-wall drill bit forged piece is obtained. Compared with the prior art, according to the invention, a cold extrusion process is adopted to replace a cutting machining process, not only the production efficiency can be improved, but also the product accuracy can be ensured and consumables are reduced.

Description

【Technical field】 [0001] The invention relates to the field of metal precision forging, in particular to a forging method of a thin-walled drill bit and a through-diameter reducing die. 【Background technique】 [0002] The drill bit is a tool installed on the front end of the drill rod to impact the rotary rock drilling hole, and it is used in a large amount in the coal mining industry. Please refer to figure 1 As shown, it is a thin-walled drill bit. The thin-walled drill bit is integrally formed, which includes an inverted truncated cone head 110 and a cylindrical rod 120 connected to the small end of the inverted truncated cone 110 with a tapered inner hole 122, and the tapered inner hole 122 The orifice is located at the lower end of the cylindrical shaft 120 . The specified dimension of the orifice wall thickness Δd of the thin-walled drill bit is Δd≤2.5mm (generally 1.5mm≤Δd≤2.5mm). Since the tapered inner hole 122 is used for subsequent assembly of welding alloy to...

AI Technical Summary

Problems solved by technology

At present, thin-walled drill bits are mostly produced by the integrated process of cutting and milling. However, due to the thin wall thickness of the orifice of the thin-walled drill bit, the product after cutting will be slightly bumped, and cracks and fractures will occur at the orifice. The production efficiency is low, the cutting precision of the inner hole is not high, it is difficult to guarantee mass production

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