Heat treatment process for pick body of cutting pick

A tooth body and pick technology, which is applied in the field of heat treatment of the pick body, can solve problems such as reducing mechanical properties, and achieve the effects of eliminating quenching residual stress, promoting rapidity and increasing cooling rate.

Pending Publication Date: 2021-12-07
广西斯达奔材料科技有限公司
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

Due to the annealing of the matrix, the hardness within 30mm from the tip of the tooth decreases, and it is less than 20HRC, and there are coarse widmanstatten structures and even burnt structures, which greatly reduces its comprehensive mechanical properties
However, there is still a gap with foreign countries in terms of picks required for the high-end market, especially for hard rock bottoms.

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0039] A heat treatment process for a pick tooth body, comprising the following steps:

[0040] S1. Smelting: After melting 42CrMo stainless steel as a raw material into carbon molten steel through an electric furnace, add 1-3 parts of Cr and 0.5-2 parts of Mo to alloy it; the present invention increases the content of Cr and Mo elements in the tooth body, The Fe and Cr elements can be combined with carbon to form more hard Fe3C and chromium carbide hard precipitates, while the Mo element can adjust the thermodynamics and kinetics of the precipitates through the change of solid solubility, and at the same time can improve high temperature stability and reduce Softening phenomenon during high temperature service;

[0041] S2. Casting: Casting the molten carbon steel obtained in step S1 into stainless steel rods at a casting temperature of 1000-1500°C;

[0042] S3. Forming: After the stainless steel bar is forged and pressed, it is formed into a rectangular pick tooth body by m...

Embodiment 2

[0048] A heat treatment process for a pick tooth body, comprising the following steps:

[0049] S1. Smelting: After melting 42CrMo stainless steel as a raw material into carbon molten steel through an electric furnace, add 1 part of Cr and 2 parts of Mo to alloy it;

[0050] S2. Casting: Casting the molten carbon steel obtained in step S1 into stainless steel rods at a casting temperature of 1000°C;

[0051] S3. Forming: After the stainless steel bar is forged and pressed, it is formed into a rectangular pick tooth body by machining;

[0052] S4. Quenching: heating the tooth body of the pick obtained in step S3 to 750° C. at a heating rate of 5° C. / min and then keeping it warm for 60 minutes, and then cooling the tooth body of the pick in an emulsion to room temperature;

[0053] S5. Tempering: Heat the quenched pick tooth body obtained in step S4 to 250° C. at a heating rate of 5° C. / min, then keep it warm for 30 minutes, and then place it in air to cool to room temperature....

Embodiment 3

[0056] A heat treatment process for a pick tooth body, comprising the following steps:

[0057] S1. Melting: After melting 42CrMo stainless steel as raw material into carbon steel molten steel through an electric furnace, add 2 parts of Cr and 1 part of Mo to alloy it;

[0058] S2. Casting: Casting the molten carbon steel obtained in step S1 into stainless steel rods at a casting temperature of 1500°C;

[0059] S3. Forming: After the stainless steel bar is forged and pressed, it is formed into a rectangular pick tooth body by machining;

[0060] S4. Quenching: heating the tooth body of the pick obtained in step S3 to 950° C. at a heating rate of 5° C. / min and then keeping it warm for 90 minutes, and then cooling the tooth body of the pick in liquid nitrogen to room temperature;

[0061] S5. Tempering: heat the quenched pick tooth body obtained in step S4 to 450° C. at a heating rate of 5° C. / min, then keep it warm for 90 minutes, and then place it in air to cool to room tempe...

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PUM

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Abstract

The invention relates to a heat treatment process for a pick body of a cutting pick. The heat treatment process comprises the following steps that S1, after 42CrMo stainless steel is molten into molten carbon steel, 1 part-3 parts of Cr and 0.5 part-2 parts of Mo are added; S2, the molten carbon steel is cast into a stainless steel bar; S3, after the stainless steel bar is forged and pressed, the stainless steel bar is machined and formed into the cutting pick body; S4, quenching is conducted, the cutting pick body is heated to 730 DEG C-950 DEG C at the heating rate of 5 DEG C / min, then heat preservation is conducted for 30 min-90 min, and then the cutting pick body is placed in emulsified liquid or liquid nitrogen to be cooled to the room temperature; and S5, the quenched cutting pick body is heated to 250 DEG C-450 DEG C at the heating rate of 5 DEG C / min and then subjected to heat preservation for 30 min-90 min, and then the quenched cutting pick body is placed in air to be cooled to the room temperature. According to the heat treatment process, 42CrMo is taken as a basis, the hardness of the alloy is adjusted by adjusting the relative contents of C, Cr and Mo elements and quenching and tempering processes through the carbon content, the morphology and distribution of a hard phase are controlled, and the high-temperature strength of the pick body is improved.

Description

technical field [0001] The invention relates to the field of metal material design and heat treatment, and relates to a heat treatment process for a tooth body of a pick. Background technique [0002] Geological rock formations can be divided into low hardness rock formations, hard rock formations and high hardness formations according to their hardness indicators. When carrying out construction operations such as tunnels, bridges, and subways on high-hardness rock formations, it is usually necessary to use large-scale rotary drilling rigs and shield machines to penetrate the rock formations. These machines disrupt rock formations with rotating working heads. The core part of the working head is the pick, which is made of hard alloy welded on the alloy steel tooth body. The engineering conditions under these conditions are extremely harsh, the working temperature of the working head can reach 600-800°C, and the firmness coefficient of the rock can reach above 12-15. At pr...

Claims

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Application Information

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IPC IPC(8): C21D9/32C21D6/00C21D6/04
CPCC21D9/32C21D6/002C21D6/04
Inventor 何哲宇陈明军刘敏锋朱彦兴黄刚祥
Owner 广西斯达奔材料科技有限公司
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