Heat treatment technology for heavy drill rod with diameter being larger than or equal to phi 175 mm

Abstract

The invention discloses a heat treatment technology for a heavy drill rod with the diameter being larger than or equal to phi 175 mm. The heat treatment technology comprises the following steps that (1) the drill rod is heated and austenitized; (2) the drill rod processed through the step (1) is immersed into hot water at the temperature of 75-100 DEG C for quenching, and the drill rod is taken out after being integrally and directly quenched to form a quenched sorbite structure; and (3) the drill rod obtained in the step (2) is cooled to obtain a final finished product. The heat treatment technology is ingenious, the heavy drill rod is quenched into the quenched finished product through a hot water quenching mode, the production efficiency is very high, the cost is only 50% of that of common quenching and tempering heat treatment, and the whole technology is more environmentally friendly; the service life of the obtained heavy drill rod is prolonged by 75% or above compared with thatof an existing heavy drill rod subjected to quenching and tempering heat treatment, the use cost of the drill rod is reduced, in addition, steel resources are saved, and especially, under the condition that heavy drill rods are nearly increased exponentially every year, economic benefits and environmental benefits are great.

Description

technical field [0001] The invention belongs to the field of heat treatment, and in particular relates to a heat treatment process for a heavy-duty drill rod with a diameter ≥ φ175mm by quenching a heavy-duty drill rod with hot water at 75-100°C into a quenched sorbite structure. Background technique [0002] With the increasing volume of rock drilling projects such as mining, tunnel excavation, water conservancy projects and urban infrastructure, the demand for heavy-duty drill rods has grown exponentially (more than tenfold from 2017 to 2019). Heavy-duty drill rods mainly refer to drill rods with a diameter ≥ φ195mm. The steel type is 42CrMo. The production process is first forged, turned and formed, and then quenched and tempered. [0003] The purpose of adjusting the heat treatment is that according to the environmental conditions of the heavy-duty drill rod, the drill rod is required: 1). The overall ability to absorb impact energy is strong, and the core of the drill r...

AI Technical Summary

Problems solved by technology

[0006] However, even so, the hardenability of steel is still limited, even if the hardening radius of brine quenching is ≤55mm, there is no problem in hardening small drill rods

However, there are difficulties in hardening heavy-duty drill rods. For this problem, the current practice of major manufacturers is to either use the purchased expensive quenching liquid (but it can only be improved, the hardening radius is still ≤75mm, and it is still not hardenable. Heavy-duty drill rods with a diameter ≥ φ195mm), the process cost is very high, which makes it difficult for manufacturers to bear; or the traditional process used in the production of small drill rods is still used. The wear resistance of the internal structure is very poor. In fact, it is the original pearlite structure formed during hot rolling. Therefore, when using this kind of drill rod, the wear rate of the drill rod is high, which is 5-6 times faster than that of all hardened drill rods. times, the long-term use cost is also higher

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