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Method for characterizing ductile-brittle transition critical point of material

A technology of ductile-brittle transition and critical point, which is applied in the field of characterizing the critical point of ductile-brittle transition of materials, to achieve the effect of increasing convenience and diversity without increasing cost, increasing convenience and accuracy

Inactive Publication Date: 2019-01-04
XI'AN PETROLEUM UNIVERSITY
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0004] However, the transformation of the average work must be done through experiments, and standard samples must be processed. There are more problems in the transformation of the fracture surface, especially when the material is not necessarily a complete fiber fracture when it is on the upper platform.

Method used

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  • Method for characterizing ductile-brittle transition critical point of material

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0023] First, test the impact performance of the sample at different temperatures to obtain the impact energy value.

[0024] The material is steel for oil drilling pipes, and the main components are shown in the table below:

[0025] element

C%

Si%

Mn%

P%

S%

Cr%

Mo%

Ni%

Fe%

quality score

0.281

0.4

0.452

＜0.005

0.0024

1.347

0.689

0.657

>95

[0026] Limited by material size, all samples are 3 / 4 samples, namely 7.5X10X55. The test was carried out under different temperature environments, including 80°C, 60°C, 40°C, 20°C, 0°C, -20°C, -40°C, -60°C. Conduct impact performance tests on the above 6 groups of samples to obtain the impact energy value;

[0027] temperature / ℃

80

60

40

20

0

-20

-40

-60

Impact energy value / J

110.1

110.3

107.5

96.75

68.00

56.60

44.20

37.70

[0028] Second, measure the shrinkage of the non-shear zone W min...

Embodiment 2

[0040] First, test the impact performance of the sample at different temperatures to obtain the impact energy value;

[0041] The material is steel for oil drilling pipes, and the main components are shown in the table below:

[0042] element

C%

Si%

Mn%

P%

S%

Cr%

Mo%

Fe%

quality score

0.234

0.293

0.831

0.0052

0.0021

1.111

1.665

>95

[0043] Limited by the size of the material, all samples are 3 / 4 samples, that is, 7.5X10X55, and the test is carried out in different temperature environments, including 40°C, 20°C, -20°C, -60°C, and the above samples are impacted Performance testing to obtain the impact energy value;

[0044] temperature / ℃

40

20

-20

-60

Impact energy value / J

96.8

100.2

68.1

37.9

[0045] Second, measure the shrinkage of the non-shear zone W min ;

[0046] temperature / ℃

40

20

-20

-60

Diameter shrinkage in non-shear ...

Embodiment 3

[0057] First, test the impact performance of the sample at different temperatures to obtain the impact energy value;

[0058] The material is steel, and the main components are shown in the table below:

[0059] element

C%

Si%

Mn%

P%

S%

Cr%

Mo%

Fe%

quality score

0.24

0.08

0.72

0.005

0.002

2.09

0.82

>95

[0060] The samples are all full samples, that is, 10X10X55, with a V-shaped incision. The test is carried out in different temperature environments, including 80°C, 40°C, 10°C, 0°C, -20°C, -40°C, -60°C, and the impact performance test is carried out on the above 7 groups of samples to obtain the impact energy value;

[0061] temperature / ℃

80

40

10

0

-20

-40

-60

Impact energy value / J

69.90

34.63

18.39

8.30

6.82

6.50

6.22

[0062] Second, measure the shrinkage of the non-shear zone W min ;

[0063] 80 temperature / ℃

80

40

10...

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Abstract

The invention relates to a method for characterizing the ductile-brittle transition critical point of a material. The method comprises the following steps: 1, testing the impact property of a sample at different temperatures to acquire an impact energy value; 2, measuring the minimal size of radial shrinkage of a non-shearing area; 3, calculating the radial shrinkage ratio beta of the non-shearingarea; 4, drawing a relational graph for the relation between beta and the temperature by using origin or excel software, calculating the critical temperature point according to a Boltzmann formula; and 5, comparing the critical temperature point determined through an average power transformation method. The method has the characteristics that the cost is not increased, the method is simple, and the scope of application is wide.

Description

technical field [0001] The invention belongs to the technical field of material fracture performance characterization, and in particular relates to a method for characterizing the critical point of ductile-brittle transition of a material. Background technique [0002] When studying the impact properties of casing drilling steel and drill pipe steel, it is found that the critical point of ductile-brittle transition is an important characteristic parameter of the material. If it exceeds this point, the material can be used safely. If it is lower than this point, the impact performance of the material will be extremely reduced. Significantly increases the chance of breaking. [0003] At present, there are many methods to characterize the critical point of impact toughness of materials, such as plastic fracture transition, fracture morphology transition, average work transition, ductility transition and so on. In contrast, the average work transition and the fracture morpholog...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): G01N25/12
CPCG01N25/12
Inventor 许天旱王党会姚婷珍
Owner XI'AN PETROLEUM UNIVERSITY