High-strength toughness carburized and air-cooled steel for tunneling tool and production method thereof

A high-strength and toughness, air-cooled technology, applied in the field of materials, can solve problems such as reducing strength and toughness, and achieve the effects of improving hardenability, strength and toughness, and increasing tempering temperature.

Active Publication Date: 2016-07-06
贵州惠沣众一机械制造有限公司
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

However, Si-Mn-Mo-rare earth air-cooled bainitic steel is prone to pro-eutectoid ferrite, island bainite or even island structure under the air-cooling condition of the center of large-scale components, which greatly reduces the air-cooling condition. toughness

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0013] A method for producing steel for high-strength and toughness carburized air-cooled excavation tools, comprising the following steps:

[0014] C: 0.28%, Si: 1.05%, Mn: 2.2%, Mo: 0.28%, V: 0.10%, Cr: 1.8%, rare earth elements Ce, La: 0.012%, and the balance is iron.

[0015] (1) The above proportioned materials are smelted into ingots, forged and rolled at 1100°C, then heated at 900°C and then air-cooled: bainite structure is obtained at a cooling rate of 50°C / min, and have excellent strength after tempering at 250°C. toughness;

[0016] (2) The steel is conventionally air-cooled at a cooling rate of 100°C / min after carburizing at 900°C. After testing: the surface hardness is HRC62.4, there is no internal oxidation defect, the core part is HRC54.1, and the absolute value of the surface compressive stress (negative value) reaches more than 400MPa.

Embodiment 2

[0018] A method for producing steel for high-strength and toughness carburized air-cooled excavation tools, comprising the following steps:

[0019] C: 0.1%, Si: 0.7%, Mn: 1.7%, Mo: 0.3%, V: 0.2%, Cr: 0.70%, rare earth elements Ce, La: 0.02%, and the balance is iron.

[0020] (1) The materials with the above proportions are smelted into ingots, forged and rolled at 1100°C, then heated at 900°C and then air-cooled: 100°C / min cooling rate to obtain bainite + martensite structure, tempered at 100°C. Has excellent strength and toughness;

[0021] (2) The steel is conventionally air-cooled at a cooling rate of 200°C / min after carburizing at 920°C. After testing: the surface hardness is HRC63, there is no internal oxidation defect, the core part is HRC55, and the absolute value of the surface compressive stress (negative value) reaches more than 400MPa.

Embodiment 3

[0023] A method for producing steel for high-strength and toughness carburized air-cooled excavation tools, comprising the following steps:

[0024] C: 0.40%, Si: 1.3%, Mn: 2.4%, Mo: 0.3%, V: 0.04%, Cr: 2.0%, rare earth elements Ce, La: 0.001%, and the balance is iron.

[0025] (1) The materials with the above ratio are smelted into ingots, forged and rolled at 1100°C, then heated at 900°C and then air-cooled: bainite + martensite structure is obtained at a cooling rate of 200°C / min, and tempered at 300°C. Has excellent strength and toughness;

[0026] (2) The steel is conventionally air-cooled at a cooling rate of 10°C / min after carburizing at 900°C. After testing: the surface hardness is HRC57, without internal oxidation defects, the core is HRC38, and the absolute value of the surface compressive stress (negative value) reaches more than 400MPa.

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Abstract

The invention discloses high-strength toughness carburized and air-cooled steel for a tunneling tool and a production method thereof. The steel comprises the following ingredients in percentage by weight: 0.1-0.40% of C, 0.7-1.3% of Si, 1.7-2.4% of Mn, 0.1-0.3% of Mo, 0.04-0.2% of V, 0.70-2.0% of Cr, 0.01-0.02% of rare earth elements Ce and La and the balance of iron. The production method comprises the following steps of: smelting the materials into an ingot blank in the ratio, forging and rolling into a finished material at the temperature of 1100 DEG C, heating at the temperature of 900 DEG C, and then carrying out air cooling, namely obtaining a bainite structure at a cooling rate of 1-100 DEG C/min, obtaining a bainite+martensite structure at a cooling rate of 100-200 DEG C/min, and annealing at the temperature of 100-300 DEG C; and carburizing the steel at the temperature of 900-920 DEG C, and then carrying out conventional air cooling at a cooling rate of 10-200 DEG C/min. The production method disclosed by the invention has the beneficial effects that toughness and ductility can be enhanced, optimal strength and toughness combination is formed between the material and components such as the tunnelling tool, and the service life and fatigue life of the tunnelling tool are obviously prolonged.

Description

technical field [0001] The invention relates to the technical field of materials, in particular to a high-strength toughness carburized air-cooled excavation tool steel, and also to a production method of the high-strength toughness carburized air-cooled excavation tool steel. Background technique [0002] Rock drilling tools are slender rods, and direct liquid quenching will easily lead to severe deformation and make them unusable. Therefore, heavy-duty drill rods are made of low-carbon alloy steel, and then carburized, air-cooled, quenched, and tempered at low temperature to reduce quenching deformation. Martensite is obtained in the surface carburized layer, and martensite plus bainite is obtained in the center as the final use structure. However, most of these steels currently use low-carbon Ni-Cr steels, which have the advantages of stable performance, excellent strength and toughness, low notch sensitivity, and gentle surface carbon concentration gradient after car...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C22C38/02C22C38/04C22C38/18C22C38/12C21D1/18C23C8/22
CPCC21D1/18C22C38/005C22C38/02C22C38/04C22C38/12C22C38/18C23C8/22
Inventor 梁益龙雷旻刘勇
Owner 贵州惠沣众一机械制造有限公司
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