CN102279136A - Method for drawing temper brittleness curve - Google Patents
Method for drawing temper brittleness curve Download PDFInfo
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- CN102279136A CN102279136A CN 201110212620 CN201110212620A CN102279136A CN 102279136 A CN102279136 A CN 102279136A CN 201110212620 CN201110212620 CN 201110212620 CN 201110212620 A CN201110212620 A CN 201110212620A CN 102279136 A CN102279136 A CN 102279136A
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Abstract
The invention relates to the field of temper brittleness curves, in particular to a method for drawing the temper brittleness curve. The method comprises the following steps of: (1) testing to acquire step-cooling test data, namely temper brittleness transformation temperature test data; (2) processing the step-cooling test data; (3) fitting the temper brittleness curve; and (4) drawing the temper brittleness curve. The temper brittleness curve drawn by using the method is high in precision and extremely applicable to index evaluation.
Description
Technical field
The present invention relates to temper brittleness curve field, especially a kind of method for drafting of temper brittleness curve.
Background technology
The material such as the iron of temper embrittlement take place, because toughness reduces, can come its temper embrittlement degree of quantitative evaluation with the ascending amount of transition temperature under certain ballistic work or fracture transition temperature, this just needs to draw the temper brittleness curve.At present, the temper brittleness curve generally adopts the method for manual drawing, and this method exists that curve plotting is random big, degree of accuracy is poor, be difficult to the defective used as evaluation index.
Summary of the invention
The objective of the invention is to propose a kind of method for drafting of temper brittleness curve,, be highly suitable for evaluation index and use by the temper brittleness curve precision height that this method is drawn.
The present invention adopts following technical scheme to realize: a kind of method for drafting of temper brittleness curve, and wherein this method may further comprise the steps:
(1) obtaining step cold test data by test is temper brittleness transition temperature test figure:
Choose two test plate (panel)s, respectively test figure is tested and obtained to two test plate (panel)s,, at first, carry out the minimum thermal Processing Test, then, test plate (panel) is carried out Charpy-type test for first test plate (panel); For second test plate (panel), at first, carry out the minimum thermal Processing Test; In second step, test plate (panel) is carried out the ladder cooling test; In the 3rd step, test plate (panel) to room temperature, carries out Charpy-type test through ladder cooling test and air cooling; When test plate (panel) is carried out Charpy-type test, under eight different temperature conditions, carry out three Charpy-type tests respectively, must comprise-30 ℃ in described eight different temperatures, remaining test temperature should make the temperature transition curve of its generation can clearly express transition region and upper mounting plate and lower platform, and last lower platform will respectively have two test temperature points at least, the centre will have four test temperature points at least, test figure to the Charpy-type test under eight different temperatures is carried out record, thereby obtain 16 groups of step cold test data, comprise three test figures in every group of test figure;
(2) step cold test data are handled:
Respectively 16 groups of test figures are handled respectively,, outlier is analyzed, and handled respectively according to the number of outlier at three test figures of every group;
(3) the temper brittleness curve is carried out match:
Adopt least square method to carry out match, the fitting function of employing is
According to least square method, obtain θ
1, θ
2, θ
3, θ
4Value, in the substitution fitting function, resulting equation is fit equation;
(4) draw the temper brittleness curve:
As ordinate, temperature is a horizontal ordinate with ballistic work, and fit equation is plotted in this coordinate system, and resulting curvilinear figure is the temper brittleness curve.
Among the present invention, described Charpy-type test comprising respectively-90～-80 ℃ ,-70～-60 ℃ ,-50～-40 ℃ ,-30 ℃ ,-20～-10 ℃, 0～10 ℃, 20～30 ℃ with 40～50 ℃ of eight different temperature conditions under carry out.
Described disposal route to outlier is as described below: when not having outlier, illustrate that these group data do not need to handle; When having an outlier, at first choose wherein data discrete degree data subset preferably, on the basis of this data subset, improve the weights of outlier then or directly delete outlier; When having two outlier,, and in curve fitting, adopt the method for weighted fitting to improve the degree of accuracy of match according to the definite weights separately of dispersion degree of each point in these group data.
Described θ
1Be the lower platform value of curve, θ
2Be the upper mounting plate value of curve, when adopting least square method to carry out the function curve match,, choose the θ of different numerical value every group of treated test figure difference substitution fitting function
1, θ
2, θ
3, θ
4, the substitution fitting function is obtained the y value, obtains the quadratic sum of every group of test figure and the deviation of corresponding y value according to least square method, contrasts all quadratic sums at last, chooses quadratic sum hour pairing θ
1, θ
2, θ
3, θ
4, in the substitution fitting function, resulting equation is exactly that sum of square of deviations is minimum fit equation.
The invention has the beneficial effects as follows: at first, can draw the temper brittleness curve exactly, make the temper brittleness curve be applicable to the use of evaluation index by this method; In addition, when utilizing this method to draw the temper brittleness curve, computing machine can be used for the drafting of temper brittleness curve, therefore can improve the render speed of temper brittleness curve greatly.
Figure of description
Fig. 1 is the temperature variation synoptic diagram of ladder cooling test among the embodiment 1.
Embodiment
Embodiment 1
The present invention relates to a kind of method for drafting of temper brittleness curve, this method may further comprise the steps:
At first, obtaining step cold test data by test is temper brittleness transition temperature test figure.
In order to obtain the step cold test data that are similar to material in the routine work environment, must the residing routine work environment of simulation test material and some extreme working environments, therefore the present invention chooses two test plate (panel)s, and test figure is tested and write down to two test plate (panel)s respectively.For first test plate (panel), at first, carry out minimum thermal and handle, then, test plate (panel) is carried out Charpy-type test and writes down test figure; For second test plate (panel), at first, carry out minimum thermal and handle, second step, test plate (panel) is carried out the ladder cooling test, in the 3rd step, test plate (panel), carries out Charpy-type test and writes down test figure to room temperature through ladder cooling test air cooling.Wherein, after described minimum thermal was handled and is meant that the sample simulation material is through normalizing and initial tempering, the whole thermal treatments in manufacture process comprised that all surpass intermediate heat-treatment and the finally a kind of specific thermal treatment of post weld heat treatment more than 482 ℃.Described ladder cooling test is carried out ladder heating and ladder cooling according to mode as shown in Figure 1, at first, test plate (panel) is heated to 316 ℃ by room temperature, be heated to 593 ℃ with the speed that is not more than 56 ℃/h then, and be incubated 1 hour, next begin cooling for the first time, speed with 6 ℃/h is cooled to 538 ℃, be incubated 15 hours then, cooling for the second time is cooled to 524 ℃ with the speed of 6 ℃/h, is incubated 24 hours then, and the speed of cooling off for the third time with 6 ℃/h is cooled to 496 ℃, be incubated 60 hours then, the 4th cooling is cooled to 468 ℃ with the speed of 6 ℃/h, is incubated 100 hours then, and the 5th cooling is cooled to 316 ℃ with the speed of 28 ℃/h, make the test plate (panel) air cooling at last, make test plate (panel) be cooled to room temperature state.Described Charpy-type test is in order to measure the test of the anti-notch sensitivity of metal material, preparation U-shaped breach or V-notch on test plate (panel), on charpy impact test machine, be in the free beam state, make one-shot with the pendulum that testing machine lifts, sample is thrust along breach, pendulum rises the absorption merit that difference in height is calculated sample again when fractureing, Charpy-type test is generally carried out with reference to GB/T 229-2007 " the metal summer is than test with notched test piece method ", promptly under eight different temperature conditions, carry out three Charpy-type tests respectively, described eight different temperatures are respectively-80 ℃,-60 ℃,-40 ℃,-30 ℃,-10 ℃, 0 ℃, 20 ℃, 40 ℃, ballistic work to each time Charpy-type test under eight different temperatures carries out record, thereby obtains step cold test data.
In second step, the step cold test data that obtain by test are handled.
Will there be following several problem in the step cold test data owner of test gained: the impact toughness value of the ballistic work that obtains during (1) low temperature during greater than high temperature, that is to say that flex point can appear in the temper brittleness curve that obtains, there is the bigger point of error in this situation explanation test figure, directly influenced the accuracy of test figure; (2) test figure under the same temperature, most of data discrete degree is less, and there have utmost point individual data to depart from overall arithmetic mean value to be bigger, becomes outlier, and these points often produce bigger influence to the match of temper brittleness curve, can cause certain error; (3) the whole dispersion of the test figure under the same temperature is bigger, and data are disperseed, and do not have the less data subset of dispersion.At the problems referred to above, if only that these errors are bigger point is rejected away before curve plotting, can influence the precision of gained curve greatly, therefore must handle step cold test data.The purpose of handling is, makes step cold test data fit physical significance on the one hand, and there is not flex point in the temper brittleness curve that match obtains; On the other hand, reduce to go on foot the dispersion of cold test data as far as possible, improve the fitting precision of temper brittleness curve.
By test, under each temperature, obtain three test figures respectively, be one group with per three test figures, obtain 16 groups of test figures altogether.At per three test figures, outlier is analyzed, and according to following several situations outlier is handled respectively: (1) does not have outlier: in this case, illustrate that the dispersion of these group data is comparatively desirable, do not need to handle, can directly use; (2) outlier is arranged: in this case, should at first choose wherein data discrete degree data subset preferably, judge according to actual conditions on this basis then, improve the weights of outlier or directly delete outlier; (3) two outlier are arranged: at this moment,, and in curve fitting, adopt the method for weighted fitting to improve the degree of accuracy of match according to the definite weights separately of dispersion degree of each point in these group data.By said method, respectively 16 groups of test figures are handled.
In the 3rd step, the temper brittleness curve is carried out match.
The present invention adopts least square method to carry out match, and the principle of match is: for given data point { (X
i, Y
i) (i=0,1,2,3 ... the quadratic sum E of distance m)
2Minimum, E
2=∑ [p (X
i)-Y
i]
2From geometric meaning, seek exactly and set point { (X
i, Y
i) (i=0,1,2,3 ... square distance m) and be minimum curve y=p (x), wherein function p (x) is called fitting function or least square solution, asks the method for fitting function p (x) to be called the least square method of curve fitting.Fitting function of the present invention is the Boltzmann function, and the general type of this function is
In this function formula, θ
1Be the lower platform value of curve, θ
2Upper mounting plate value for curve.When adopting least square method to carry out the match of Boltzmann function curve, according to the least square method theorem, the optimum condition of match is that the sum of square of deviations of each trial value and match value is minimum.Every group of treated test figure distinguished substitution Boltzmann function, and choose the θ of different numerical value
1, θ
2, θ
3, θ
4, substitution Boltzmann function is obtained the y value, obtains the quadratic sum of every group of test figure and the deviation of corresponding y value according to least square method, contrasts all quadratic sums at last, chooses quadratic sum hour pairing θ
1, θ
2, θ
3, θ
4Numerical value, in the formula of substitution Boltzmann function, to be exactly sum of square of deviations be minimum fit equation to resulting equation.
In the 4th step, draw the temper brittleness curve.
As ordinate, temperature is a horizontal ordinate with ballistic work, and fit equation is plotted in this coordinate system, and resulting curvilinear figure is the temper brittleness curve.
Embodiment 2
In the present embodiment, when material is carried out Charpy-type test, make test plate (panel) under eight different temperature conditions, carry out three Charpy-type tests respectively, described eight different temperatures are respectively-90 ℃ ,-70 ℃ ,-50 ℃ ,-30 ℃ ,-10 ℃, 10 ℃, 30 ℃, 50 ℃, test figure to the Charpy-type test under eight different temperatures is carried out record respectively, thereby obtains step cold test data.
Eight temperature values of Charpy-type test also can still must comprise-30 ℃ for other are worth, and remaining test temperature should be selected rightly.When selecting test temperature, should make the temperature transition curve of its generation can clearly express transition region and upper mounting plate and lower platform, and upward lower platform will respectively have two test temperature points at least, the centre will have four test temperature points at least.
Other is with embodiment 1.
Embodiment 3
In the present embodiment, when material is carried out Charpy-type test, make test plate (panel) under eight different temperature conditions, carry out three Charpy-type tests respectively, described eight different temperatures are respectively-85 ℃ ,-75 ℃ ,-55 ℃ ,-30 ℃ ,-15 ℃, 5 ℃, 25 ℃, 45 ℃, test figure to the Charpy-type test under eight different temperatures is carried out record respectively, thereby obtains step cold test data.
Other is with embodiment 1.
Claims (4)
1. the method for drafting of a temper brittleness curve is characterized in that this method may further comprise the steps:
(1) obtaining step cold test data by test is temper brittleness transition temperature test figure:
Choose two test plate (panel)s, respectively test figure is tested and obtained to two test plate (panel)s,, at first, carry out the minimum thermal Processing Test, then, test plate (panel) is carried out Charpy-type test for first test plate (panel); For second test plate (panel), at first, carry out the minimum thermal Processing Test; In second step, test plate (panel) is carried out the ladder cooling test; In the 3rd step, test plate (panel) to room temperature, carries out Charpy-type test through ladder cooling test and air cooling; When test plate (panel) is carried out Charpy-type test, under eight different temperature conditions, carry out three Charpy-type tests respectively, must comprise-30 ℃ in described eight different temperatures, remaining test temperature should make the temperature transition curve of its generation can clearly express transition region and upper mounting plate and lower platform, and last lower platform will respectively have two test temperature points at least, the centre will have four test temperature points at least, test figure to the Charpy-type test under eight different temperatures is carried out record, thereby obtain 16 groups of step cold test data, comprise three test figures in every group of test figure;
(2) step cold test data are handled:
Respectively 16 groups of test figures are handled respectively,, outlier is analyzed, and handled respectively according to the number of outlier at three test figures of every group;
(3) the temper brittleness curve is carried out match:
Adopt least square method to carry out match, the fitting function of employing is
According to least square method, obtain θ
1, θ
2, θ
3, θ
4Value, in the substitution fitting function, resulting equation is fit equation;
(4) draw the temper brittleness curve:
As ordinate, temperature is a horizontal ordinate with ballistic work, and fit equation is plotted in this coordinate system, and resulting curvilinear figure is the temper brittleness curve.
2. the method for drafting of temper brittleness curve according to claim 1 is characterized in that: described Charpy-type test comprising respectively-90～-80 ℃ ,-70～-60 ℃ ,-50～-40 ℃ ,-30 ℃ ,-20～-10 ℃, 0～10 ℃, 20～30 ℃ with 40～50 ℃ of eight different temperature conditions under carry out.
3. the method for drafting of temper brittleness curve according to claim 1 is characterized in that the disposal route of outlier as described below: when not having outlier, illustrate that these group data do not need to handle; When having an outlier, at first choose wherein data discrete degree data subset preferably, on the basis of this data subset, improve the weights of outlier then or directly delete outlier; When having two outlier,, and in curve fitting, adopt the method for weighted fitting to improve the degree of accuracy of match according to the definite weights separately of dispersion degree of each point in these group data.
4. the method for drafting of temper brittleness curve according to claim 1 is characterized in that: described θ
1Be the lower platform value of curve, θ
2Be the upper mounting plate value of curve, when adopting least square method to carry out the function curve match,, choose the θ of different numerical value every group of treated test figure difference substitution fitting function
1, θ
2, θ
3, θ
4, the substitution fitting function is obtained the y value, obtains the quadratic sum of every group of test figure and the deviation of corresponding y value according to least square method, contrasts all quadratic sums at last, chooses quadratic sum hour pairing θ
1, θ
2, θ
3, θ
4, in the substitution fitting function, resulting equation is exactly that sum of square of deviations is minimum fit equation.
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Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN104004890A (en) * | 2014-06-05 | 2014-08-27 | 通裕重工股份有限公司 | Method for determining temper temperature of 20SiMn2MoV structural alloy steel |
| CN109030231A (en) * | 2017-06-12 | 2018-12-18 | 株式会社日立制作所 | The black brittleness of metal is analyzed and test method |
Citations (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US4518464A (en) * | 1983-07-06 | 1985-05-21 | Kabushiki Kaisha Toshiba | Method of detecting embrittlement of heat-resisting steel |
| CN101852701A (en) * | 2010-05-11 | 2010-10-06 | 东方锅炉（集团）股份有限公司 | Method for estimating long-term enduring performance of 9-12 Cr percent ferrite heat resistant steel |
-
2011
- 2011-07-28 CN CN 201110212620 patent/CN102279136A/en active Pending
Patent Citations (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US4518464A (en) * | 1983-07-06 | 1985-05-21 | Kabushiki Kaisha Toshiba | Method of detecting embrittlement of heat-resisting steel |
| CN101852701A (en) * | 2010-05-11 | 2010-10-06 | 东方锅炉（集团）股份有限公司 | Method for estimating long-term enduring performance of 9-12 Cr percent ferrite heat resistant steel |
Non-Patent Citations (2)
| Title |
|---|
| 《焊接》 20110625 李梦贤等 《加氢反应器焊缝步冷试验数据优化方法探讨》 第59-66页 1-4 , 第6期 * |
| 《理化检验-物理分册》 20071231 毕绪文等 《用计算机绘制回火脆性转变温度曲线》 第182-187页 1-4 第43卷, 第4期 * |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN104004890A (en) * | 2014-06-05 | 2014-08-27 | 通裕重工股份有限公司 | Method for determining temper temperature of 20SiMn2MoV structural alloy steel |
| CN109030231A (en) * | 2017-06-12 | 2018-12-18 | 株式会社日立制作所 | The black brittleness of metal is analyzed and test method |
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Application publication date: 20111214 |