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Method for improving low temperature impact toughness of 40CrNiMoA material

A low-temperature impact toughness and low-temperature technology, applied in the field of cryogenic treatment and heat treatment, can solve the problems of lack of data, adverse effects of 40CrNiMoA material design and application, etc.

Inactive Publication Date: 2015-02-25
TECHNICAL INST OF PHYSICS & CHEMISTRY - CHINESE ACAD OF SCI +1
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

The low-temperature mechanical behavior of metal materials has an important impact on the service and safety of equipment, but the data on the low-temperature impact toughness of 40CrNiMoA materials is relatively lacking, especially the impact toughness at temperatures below -60 ° C has not been reported, which gives the actual strength of 40CrNiMoA materials. Detrimental effects of design and application

Method used

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  • Method for improving low temperature impact toughness of 40CrNiMoA material

Examples

Experimental program
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Effect test

Embodiment 1

[0015] Cool the 40CrNiMoA material after vacuum oil quenching and vacuum high-temperature tempering to -80°C at a rate of 2°C / min, and keep it warm for 0.5h;

[0016] Then continue to cool down to -180°C at a rate of 2°C / min, and hold for 3 hours; then heat the 40CrNiMoA material to 160°C at a heating rate of 2°C / min, and hold for 2 hours; cool with the furnace after the low-temperature tempering process.

[0017] The treated 40CrNiMoA material was tested for low-temperature impact performance at different temperatures. The test method used was the national standard GB / T 229-2007 "Metallic Materials Charpy Pendulum Impact Test Method". The test results are shown in Table 1.

Embodiment 2

[0019] Cool the 40CrNiMoA material (the material is the same as in Example 1) after vacuum oil quenching and vacuum high-temperature tempering to -85°C at a rate of 3°C / min, and keep it for 1h; then continue to cool down to -180°C at a rate of 3°C / min ℃, holding for 2h; then heating the 40CrNiMoA material to 170°C at a heating rate of 3°C / min, holding for 2h; cooling with the furnace after the low-temperature tempering process.

[0020] The treated 40CrNiMoA was tested for low-temperature impact performance at different temperatures. The test methods used were all based on the national standard GB / T 229-2007 "Metallic Materials Charpy Pendulum Impact Test Method". The test results are shown in Table 1.

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Abstract

The invention discloses a method for improving the low temperature impact toughness of a 40CrNiMoA material. The method comprises: first cooling the 40CrNiMoA material to a temperature ranging from -80DEG C to -85DEG C at a rate of 2-3DEG C / min, conducting heat preservation for 0.5h-1h; then performing further cooling to a temperature ranging from -180DEG C to -185DEG C, and conducting heat preservation for 2h-3h; and then, raising the temperature to 160DEG C-170DEG C still at a rate of 2-3DEG C / min, conducting heat preservation for 1h-2h, and finally performing cooling along with a furnace. The low temperature impact toughness of the 40CrNiMoA material treated by the method provided in the invention is higher than that of materials that do not undergo deep cooling and low temperature tempering treatments. Thus, the method provided in the invention has great industrial application prospects.

Description

technical field [0001] The invention relates to the technical field of cryogenic treatment and heat treatment, in particular to a method for improving the low-temperature impact toughness of 40CrNiMoA material. Background technique [0002] 40CrNiMoA steel has high strength and toughness, and good hardenability. It is widely used in petrochemical, oil drilling equipment, offshore oil drilling platforms and important parts with large cross-section and load. In order to give full play to its comprehensive mechanical properties, it is used in the quenched and tempered state. Due to the harsh service conditions of oil drilling and production equipment, many of which work in severe cold environments, there are certain requirements for the low-temperature impact performance of materials. On the other hand, the low-temperature impact performance of materials is also an important basis for structural design. The low-temperature mechanical behavior of metal materials has an importa...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): C21D1/18
Inventor 张红李勤峰王俊杰薛小代周远夏浩
Owner TECHNICAL INST OF PHYSICS & CHEMISTRY - CHINESE ACAD OF SCI