Method for improving dimensional stability of GT35 steel-bonded hard alloy

A technology of steel-bonded cemented carbide and dimensional stability, applied in the field of improving the dimensional stability of GT35 steel-bonded cemented carbide, can solve the problems of reducing the precision and service life of the device, increasing the internal stress of the material, and deteriorating the structure stability, etc. Achieve the effects of superior dimensional stability, low surface residual stress and stable microstructure

Active Publication Date: 2019-06-25
CENT SOUTH UNIV
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

Due to the action of alternating temperature, thermal stress, processing stress, etc., the material will undergo obvious changes in the structure and stress state, especially when the changing range of the alternating temperature field is large, the material will even undergo phase transition, which will further aggravate the internal stress of the material. Changes in stress; all of the above lead to poor structural stability of existing cemented carbide materials, and even deformation. Errors caused by such small deformations will significantly reduce the accuracy and service life of the device

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0027] Carry out high-temperature austenitization treatment on GT35 steel-bonded cemented carbide, heat it from room temperature to 500°C, the heating rate is 5°C / min, after holding for 20 minutes, heat it to 850°C, the heating rate is 5°C / min, after holding for 10 minutes , water quenching, and then continue heating to 850°C for 50 minutes, then quenching with liquid nitrogen. The quenched cemented carbide is subjected to stress tempering treatment, rapidly heated from room temperature to 200°C for 1h tempering treatment, and a tensile stress of 50MPa is applied at the same time. Compared with the conventional treatment method, the cemented carbide obtained by the treatment in this example can effectively reduce the residual stress on the surface of the alloy by 50MPa, increase the hardness of the cemented carbide by 40Hv, and the dimensional change after half a year at room temperature is less than 0.007%.

Embodiment 2

[0029] Carry out high-temperature austenitization treatment on GT35 steel-bonded cemented carbide, heat from room temperature to 500°C, the heating rate is 7°C / min, after holding for 10 minutes, heat to 950°C, the heating rate is 6°C / min, after holding for 100 minutes , oil quenching, and then continue heating to 950°C for 100 minutes, then water quenching. The quenched cemented carbide is subjected to stress tempering treatment, rapidly heated from room temperature to 250°C for 12h tempering treatment, and a tensile stress of 125MPa is applied at the same time. Compared with the conventional treatment method, the cemented carbide obtained by the treatment in this example can effectively reduce the residual stress on the surface of the alloy by 100MPa, increase the hardness of the cemented carbide by 70Hv, and the dimensional change after half a year at room temperature is less than 0.001%.

Embodiment 3

[0031] Carry out high-temperature austenitization treatment on GT35 steel-bonded cemented carbide, heat from room temperature to 500°C, the heating rate is 10°C / min, after holding for 30 minutes, heat to 1050°C, the heating rate is 8°C / min, after holding for 50 minutes , liquid nitrogen quenching, and then continue to heat to 1050 ° C for 10 minutes, oil quenching. The quenched cemented carbide is subjected to stress tempering treatment, rapidly heated from room temperature to 300°C for 20h tempering treatment, and a tensile stress of 200MPa is applied at the same time. Compared with the conventional treatment method, the cemented carbide obtained in this example can effectively reduce the residual stress on the surface of the alloy by 72MPa, increase the hardness of the cemented carbide by 53Hv, and the dimensional change after half a year at room temperature is less than 0.004%.

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Abstract

The invention provides a method for high dimensional stability obtaining of a GT35 steel-bonded hard alloy, and belongs to the field of metal-based composite material processing. The hard alloy is theGT35 steel-bonded hard alloy after forging, the hard alloy is heat-treated in the subsequent processing process, and the hard alloy with small and stable structure and small residual stress. According to the GT35 steel-bonded hard alloy obtained through an optimization technology, compared with conventional treatment methods, the surface residual stress of the hard alloy can be effectively lowered by 50-100 MPa, the hardness of the hard alloy is improved by 40-70 Hv, and as for storage for half a year or above at the room temperature, the dimensional change is less than 0.007%.

Description

technical field [0001] The invention relates to a method for improving the dimensional stability of GT35 steel-bonded hard alloy, which belongs to the field of metal matrix composite material processing. Background technique [0002] GT35 has the characteristics of high hardness, good wear resistance, and excellent machining performance. It can be applied to high-precision equipment such as molds and aerospace vehicles. These parts have extremely high requirements for dimensional stability, but in actual application, especially in high temperature environments, any deformation may affect the reliability and life of the material, and at the same time affect the stability of the overall device. Therefore, the thermal expansion coefficient and material stability of GT35 materials are critical to the accuracy, lifetime and reliability of the device. Due to the particularity of the application environment in the fields of molds and aerospace vehicles, long-term work in the alter...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C21D1/18
Inventor 肖来荣宋宇峰赵小军余宸旭涂小萱
Owner CENT SOUTH UNIV
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