A heat treatment process of drill steel xgq25 with hardness gradient distribution

A kind of hardness gradient, drill tool steel technology, applied in metal material coating process, solid diffusion coating, coating and other directions, can solve the problem of short tool life, difficult to obtain the external strength and internal toughness of the drill tool, and inability to achieve the surface of the drill tool. and other problems, to achieve good matching, improve service life, and avoid the effect of phase change

Inactive Publication Date: 2018-09-14
UNIV OF SCI & TECH BEIJING
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

At present, for the XGQ25 material used for drilling tools, at present, most of the domestic drilling tool companies use oil quenching, air cooling, and isothermal salt bath quenching after quenching and heat preservation in the process of using this steel type. These heat treatment methods cannot be realized. The gentle transition of the hardness from the surface of the drill tool to the core makes it difficult to obtain a good match between the outer strength and inner toughness of the drill tool after carburizing, resulting in the current domestic drill tool life generally being short

Method used

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  • A heat treatment process of drill steel xgq25 with hardness gradient distribution
  • A heat treatment process of drill steel xgq25 with hardness gradient distribution

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0019] Hot-rolled XGQ25 steel bar (chemical composition is C: 0.24-0.26%, Si: 1.62-1.72%, Mn: 1.45-1.55%, Cr: 0.32-0.38%, Ni: 1.46-1.55%, Mo: 0.63-0.68 %, V:0.10-0.12%, P:≤0.015%, S:≤0.008%) for rough machining, after the rough machining is completed, perform the following operations:

[0020] Step 1: Carburizing process: The drilling tools are made of hot-rolled XGQ25 steel rods, placed in a multifunctional carburizing furnace at 930°C for carburizing, the carburizing agent is kerosene, and the carburizing process is carried out in two stages: the carbon potential is controlled to 1.2 % when carburizing for 3 hours; then adjust the carbon potential to 1.0% and hold for 3 hours; after carburizing, cool to 850°C with the furnace, hold for 30 minutes, and oil quench to room temperature;

[0021] Step 2: Temper the drill tool after carburizing in the above steps at a high temperature of 650°C, keep it warm for 60 minutes, air-cool, and then finish machining according to the size ...

Embodiment 2

[0024] Hot-rolled XGQ25 steel bar (chemical composition is C: 0.24-0.26%, Si: 1.62-1.72%, Mn: 1.45-1.55%, Cr: 0.32-0.38%, Ni: 1.46-1.55%, Mo: 0.63-0.68 %, V:0.10-0.12%, P:≤0.015%, S:≤0.008%) for rough machining, after the rough machining is completed, perform the following operations:

[0025] Step 1: Carburizing process: The drilling tools are made of hot-rolled XGQ25 steel rods, placed in a multifunctional carburizing furnace at 940°C for carburizing, the carburizing agent is kerosene, and the carburizing process is carried out in two stages: the carbon potential is controlled to 1.2 % when carburizing for 3 hours; then adjust the carbon potential to 1.0% and hold for 3 hours; after carburizing, cool to 850°C with the furnace, hold for 30 minutes, and oil quench to room temperature;

[0026] Step 2: Temper the drill tool after carburizing in the above steps at a high temperature of 650°C, keep it warm for 60 minutes, air-cool, and then finish machining according to the size ...

Embodiment 3

[0029] Hot-rolled XGQ25 steel bar (chemical composition is C: 0.24-0.26%, Si: 1.62-1.72%, Mn: 1.45-1.55%, Cr: 0.32-0.38%, Ni: 1.46-1.55%, Mo: 0.63-0.68 %, V:0.10-0.12%, P:≤0.015%, S:≤0.008%) for rough machining, after the rough machining is completed, perform the following operations:

[0030] Step 1: Carburizing process: The drilling tools are made of hot-rolled XGQ25 steel rods, placed in a multifunctional carburizing furnace at 930°C for carburizing, the carburizing agent is kerosene, and the carburizing process is carried out in two stages: the carbon potential is controlled to 1.2 % when carburizing for 3 hours; then adjust the carbon potential to 1.0% and hold for 3 hours; after carburizing, cool to 850°C with the furnace, hold for 30 minutes, and oil quench to room temperature;

[0031] Step 2: Temper the drill tool after carburizing in the above steps at a high temperature of 650°C, keep it warm for 60 minutes, air-cool, and then finish machining according to the size ...

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PUM

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Abstract

The invention relates to a heat treatment process of brazing tool steel XGQ25 with gradient hardness distribution; and the process can realize reasonable gradient hardness distribution of a carburized brazing tool from the surface to the basal body. The process comprises the following steps: the carburized brazing tool is quenched and insulated by 60 minutes at 800+-10 DEG C, and is cooled by three stages after the insulation is finished; firstly, the oil cooling is performed to reach 400+-10 DEG C; then, the furnace cooling is performed to reach 200 DEG C, and the cooling speed is 0.05-0.1 DEG C / s; and then, the air cooling is performed below 200 DEG C to reach the room temperature. The tempering insulation is performed by 120 minutes at 200 DEG C; and the air cooling is performed to reach the room temperature after the insulation is finished. Through actuation of the process, the carburized brazing tool forms a high-carbon martensite structure (HV640-660) with high surface hardness, a lower bainite structure (no-gap impact power of 115-120 J) with high center toughness and a lower bainite and low-carbon martensite complex-phase structure with a wider transition layer (width of 0.5-1.0 mm), so that excellent toughness matchability is obtained, and the service life of the brazing tool is effectively prolonged.

Description

technical field [0001] The invention belongs to the field of metal materials, and is XGQ25 steel used for drilling tools, and in particular relates to a heat treatment process for drilling tool steel XGQ25 with hardness gradient distribution. Background technique [0002] With the mining and utilization of mineral resources in our country and the construction and development of the energy field, the basic engineering facilities are becoming more and more complete, and the road traffic is constantly improving, which makes the demand for drilling tools for rock drilling show an upward trend. During the service process, brazing and drilling tools must continuously withstand compressive, torsion, and bending cyclic stresses, as well as high-frequency impacts of about 2,000 to 9,000 times / min, and each impact energy is 25 to 500J. The main failure forms of the drilling tool are rod body wear, deformation, fracture failure and shedding of the drill bit carbide, plastic deformation...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): C23C8/46C21D1/18C21D1/74
CPCC21D1/18C21D1/74C21D2211/002C21D2211/008C21D2221/10C23C8/46
Inventor 刘雅政蒋波周乐育张朝磊黄斌陈列王磊英王国存赵海东
Owner UNIV OF SCI & TECH BEIJING
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