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Technology for controlling hardness distribution of material for 23CrNi3Mo drill tool

A technology of hardness distribution and drilling tools, applied in metal material coating process, coating, earthwork drilling and other directions, can solve the problems of early failure of drilling tools, low life of drilling tools, and gradual decrease of micro-hardness of drilling tools, etc. The effect of improving the service life and wide range of use

Inactive Publication Date: 2013-06-05
UNIV OF SCI & TECH BEIJING
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0004] At present, in the process of using most domestic drilling tools enterprises, oil quenching, air cooling, isothermal salt bath quenching and other methods are generally used after quenching and heat preservation are completed. These manufacturing methods cannot realize the microhardness of the drilling tools from the surface to the core. Reduced, the hardness distribution often drops rapidly at the transition position between the carburized layer and the core matrix, so that the high hardness of the surface of the drill tool after carburizing and the high toughness of the core can not be optimally matched and transitioned, often resulting in the drill tool Early failure is also the main reason for the low service life of domestic drilling tools, and the reasonable control of the microhardness gradient distribution of drilling tools is the key to improving the service life of drilling steel and drilling tools

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0015] Hot-rolled 23CrNi3Mo steel bar (chemical composition is C: 0.22-0.24%, Si: 0.20-0.30%, Mn: 0.65-0.75%, Cr 1.25-1.35%, Ni 2.89-2.98%, Mo 0.23-0.28%, P ≤0.015%, S ≤0.008%) for rough machining, after rough machining, perform the following operations:

[0016] 1. Carburize in a multifunctional carburizing furnace at 930 ℃, the penetrating agent is kerosene, and the carburizing process is carried out in two stages: when the carbon potential is controlled to 1.2%c, carburize for 7 hours; then adjust the carbon potential to 1.0% c heat preservation for 4 hours; after the carburizing is completed, it is cooled to 400 ℃ with the furnace, and it is air-cooled when it is out of the furnace;

[0017] 2. Temper the drill tool after carburizing through the above steps at a high temperature of 680 ℃, air-cool, and then finish machining according to the size requirements;

[0018] 3. Quenching treatment: place the finished brazing tool in a salt bath furnace, and then quench at 880 °C...

Embodiment 2

[0020] Hot-rolled 23CrNi3Mo steel bar (chemical composition is C: 0.22-0.24%, Si: 0.20-0.30%, Mn: 0.65-0.75%, Cr 1.25-1.35%, Ni 2.89-2.98%, Mo 0.23-0.28%, P ≤0.015%, S ≤0.008%) for rough machining, after rough machining, perform the following operations:

[0021] 1. Carburize in a multifunctional carburizing furnace at 920 ℃, the penetrating agent is kerosene, and the carburizing process is carried out in two stages: when the carbon potential is controlled to 1.2%c, carburize for 7 hours; then adjust the carbon potential to 1.0% c heat preservation for 4 hours; after the carburizing is completed, it is cooled to 400 ℃ with the furnace, and it is air-cooled when it is out of the furnace;

[0022] 2. Temper the drill tool after carburizing through the above steps at a high temperature of 690 ℃, air-cool, and then finish machining according to the size requirements;

[0023] 3. Quenching treatment: place the finished brazing tool in a salt bath furnace, and keep it at a quenchin...

Embodiment 3

[0025] Hot-rolled 23CrNi3Mo steel bar (chemical composition is C: 0.22-0.24%, Si: 0.20-0.30%, Mn: 0.65-0.75%, Cr 1.25-1.35%, Ni 2.89-2.98%, Mo 0.23-0.28%, P ≤0.015%, S ≤0.008%) for rough machining, after rough machining, perform the following operations:

[0026] 1. Carburize in a multifunctional carburizing furnace at 940 ℃, the penetrating agent is kerosene, and the carburizing process is carried out in two stages: when the carbon potential is controlled to 1.2%c, carburize for 7 hours; then adjust the carbon potential to 1.0% c heat preservation for 4 hours; after the carburizing is completed, it is cooled to 400 ℃ with the furnace, and it is air-cooled when it is out of the furnace;

[0027] 2. After the above steps of carburizing, the drill tool is tempered at a high temperature of 670 ℃, air-cooled, and then fine-machined according to the size requirements;

[0028] 3. Quenching treatment: place the finished drilling tools in a protective atmosphere of nitrogen, and the...

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Abstract

The invention relates to a technology for controlling hardness distribution of a material for a 23CrNi3Mo drill tool. After carburization, mild hardness gradient distribution of the drill tool from surface to center is realized, namely, micro hardness from the surface to the center tissue of the drill tool drops mildly, so that after carburization, the drill tool forms a complex phase tissue which has high surface hardness, high center toughness and a transition layer with certain width, the drill tool is good in toughness and is prolonged in service life. The technology comprises the following steps of quenching the carburized drill tool at 880DEG C+ / -10 DEG C; preserving heat for 45 minutes; after thermal insulation, cooling by two sections, wherein the cooling rate is more than or equal to 5 DEG C per second in temperature range of 880-450; cooling to room temperature along with a furnace below 450 DEG C; tempering at 220 DEG C and preserving heat for 120 minutes; and carrying out air cooling to reach room temperature after thermal insulation.

Description

technical field [0001] The invention relates to a specific hardness distribution control process of a 23CrNi3Mo brazing tool material. Background technique [0002] Drilling tool is an indispensable tool in rock drilling and blasting. The drill bit contacts and breaks the rock mass during the drilling process, and bears the cyclic stress of tension, compression, bending, and torsion imposed by the high-frequency, high-impact rock drill, and at the same time bears With huge impact load and severe abrasive wear. In addition, the drill bit is also subjected to corrosion and abrasion of working media such as rocks, rock powder and mineral water under the environmental conditions of high-speed rotation and collision. Therefore, the service conditions of the drill bit are very harsh, and the service life is often only a few minutes or tens of minutes. [0003] The quality and performance of iron and steel tools mainly depend on their organizational structure, and a reasonable or...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C23F17/00C23C8/22C21D1/18E21B10/36
Inventor 刘雅政闫永明周乐育徐盛朱洪武
Owner UNIV OF SCI & TECH BEIJING
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