CN103808743B - A kind of method adopting austenite content in X-ray diffraction commercial measurement steel - Google Patents

Abstract

The invention discloses a kind of method adopting austenite content in X-ray diffraction commercial measurement steel, first X-ray diffractometer is utilized to scan steel sample, obtain the XRD collection of illustrative plates of steel sample, recycling XRD collection of illustrative plates is revised martensite and austenite and tries to achieve the diffracted intensity of each crystal face, finally records the austenitic content of steel sample; In employing X-ray diffraction commercial measurement steel designed by the present invention, the method for austenite content is when there is texture in sample, improves austenite content measurement accuracy in steel.

Description

A kind of method adopting austenite content in X-ray diffraction commercial measurement steel

Technical field

The invention belongs to X-ray diffraction (X-RayDiffraction, XRD) and test field, more specifically, the present invention relates to a kind of method utilizing austenite content in X-ray diffraction commercial measurement steel.

Background technology

At present, in steel, the mensuration of austenite content often adopts directly comparing method.Specify according to standard GB/T8362-1987 and YB/T5338-2006 " in steel residual austenite quantitative analysis X-ray diffractometer method ": martensite is selected (200), the diffracted ray of (211) two crystal faces, austenite is selected (200), (220), (311) three crystal face diffracted rays, measured five diffracted rays carried out combining and calculates diffracted intensity ratio respectively, substituting into and specify computing formula to obtain austenite content.But the precondition applying this computing formula is: martensitic phase, austenite mutually in integrated intensity ratio between each diffracted ray, following table must be met and require:

The martensitic phase specified in table 1 GB, austenite mutually in integrated intensity ratio between each diffracted ray

But when sample exists texture (i.e. preferred orientation), the integrated intensity ratio of sample tends to exceed this fluctuation range.But, do not mention in standard when intensity rate exceeds allowed band, researchist this how treatment and analysis is carried out to diffraction data.Therefore, in order to overcome the impact of preferred orientation on measurement result, this patent adopts orientation probability density method to measure austenite content in steel, and its ultimate principle is:

Mathematical method is adopted the diffracted intensity with preferred orientation to be converted into the diffracted intensity of disordered orientation.Probability density revised law is also calculate austenite content according to directly comparing method principle in essence, is just revised diffracted intensity by the method for mathematics manipulation, eliminates or reduces preferred orientation to the impact of test findings.

Summary of the invention

Technical matters to be solved by this invention is, overcomes the shortcoming of prior art, provides a kind of when sample exists texture, improves the method for austenite content in the employing X-ray diffraction commercial measurement steel of austenite content measurement accuracy in steel.

In order to solve above technical matters, the invention provides a kind of method adopting austenite content in X-ray diffraction commercial measurement steel, comprising following concrete steps:

Step (1): utilize X-ray diffractometer to scan steel sample, obtain the XRD collection of illustrative plates of steel sample;

Step (2): utilize the middle XRD spectra of step (1) and following formulae discovery martensite and each crystal face of austenite without relative diffracted intensity during preferred orientation:

I=M·L _P·F ²·e ^-2M·A ^*(θ)

Wherein, L _pbe defined as lorentz polarization factor, M is defined as temperature factor, and F is defined as structure factor, A ^*(θ) inverse of absorption factor A (θ) is defined as, e ^-2Mbe defined as temperature factor, and $L_P=\frac{1+{\cos }^{2}2\mathrm{\θ}}{{4\sin }^2\mathrm{\θ}\cos \mathrm{\θ}};$

Step (3): the martensite in step (2) and each crystal face of austenite are normalized without relative diffracted intensity during preferred orientation, and the actual diffracted intensity being obtained martensite and each crystal face of austenite by XRD software;

Step (4): the orientation probability density utilizing following formulae discovery martensite and each crystal face of austenite:

${\mathrm{\ρ}}^{*}=\left(H_i{K}_i{L}_i\right)=\frac{[\underset{i=1}{\overset{n}{\mathrm{\Σ}}}P\left(H_i{K}_i{L}_i\right)\·\frac{I_t\left(H_i{K}_i{L}_i\right)}{I_u\left(H_i{K}_i{L}_i\right)}]}{\underset{j=1}{\overset{n}{\mathrm{\Σ}}}[P\left(H_j{K}_j{L}_j\right)\·\frac{I_t\left(H_j{K}_j{L}_j\right)}{I_u\left(H_j{K}_j{L}_j\right)}]}$

Wherein, I _t(H _ik _il _i) and I _t(H _jk _jl _j) be respectively (H when there is preferred orientation _ik _il _i) and (H _jk _jl _j) diffracted intensity in face; ρ ^*(H _ik _il _i) be (H _ik _il _i) the orientation probability density in face, i.e. Polar orderatim; P (H _ik _il _i) and P (H _jk _jl _j) be (H _ik _il _i) and (H _jk _jl _j) repetition factor in face; I _u(H _ik _il _i) and I _u(H _jk _jl _j) be respectively without (H during preferred orientation _ik _il _i) face and (H _jk _jl _j) the relative diffracted intensity in face, n is the diffraction surfaces number selected;

Step (5): utilize the orientation probability density in step (4) and following formula to try to achieve the diffracted intensity of the rear martensite of correction and each crystal face of austenite:

$I\left(H_i{K}_i{L}_i\right)=\frac{I_t\left(H_i{K}_i{L}_i\right)}{{\mathrm{\ρ}}^{*}\left(H_i{K}_i{L}_i\right)}$

Wherein: I (H _ik _il _i) be (H after preferred orientation corrects _ik _il _i) diffracted intensity in face; I _t(H _ik _il _i) for there is preferred orientation time (H _ik _il _i) diffracted intensity in face; ρ ^*(H _ik _il _i) be (H _ik _il _i) the orientation probability density in face;

Step (6): utilize the diffracted intensity of martensite and each crystal face of austenite after revising in step (5) and following formula finally to record the austenitic content of steel sample:

$V_A=\frac{1-V_c}{1+G\frac{I_{M\left(\mathrm{hkl}\right)i}}{I_{A\left(\mathrm{hkl}\right)i}}}$

Wherein, V _aorientate the volume fraction of austenite phase as; V _cbe defined as the volume fraction of Carbide Phases total amount in steel; I _{m (hkl) i}be defined as martensite in steel (hkl) _ithe integrated intensity of crystal face diffracted ray; I _{a (hkl) i}be defined as austenite in steel (hkl) _jthe integrated intensity of crystal face diffracted ray; G is defined as austenite (hkl) _jcrystal face and martensite (hkl) _ithe ratio of the intensity factor corresponding to crystal face.

Technique effect: adopt probability density method to revise after adopting above-mentioned technical scheme in the sample that there is texture, more accurate test findings can be obtained, compensate for the weak point existed in standard, and orientation probability density method is a kind of mathematical processing methods in essence, eliminate the impact of manual operation on experimental result.

The technical scheme that the present invention limits further is:

Further, the method for austenite content in aforesaid employing X-ray diffraction commercial measurement steel, in step (1), the sweep velocity of X-ray diffractometer is less than or equal to 1 °/min.

The present invention compared with prior art tool has the following advantages:

1. the present invention eliminates the impact of texture on measurement result to a certain extent, adopts probability density method to revise, can obtain more accurate test findings, compensate for the weak point existed in standard in the sample that there is texture;

2. the orientation probability density method in the present invention is a kind of mathematical processing methods in essence, eliminates the impact of manual operation on experimental result.

Accompanying drawing explanation

Fig. 1 is the XRD spectra of 1# sample in embodiments of the invention;

Fig. 2 is the XRD spectra of 2# sample in embodiments of the invention.

Embodiment

Below in conjunction with accompanying drawing, the present invention is described in further detail:

Embodiment 1

The present embodiment provides a kind of method adopting austenite content in X-ray diffraction commercial measurement steel, comprises following concrete steps:

Step (1): utilize X-ray diffractometer to scan steel sample, obtain the XRD collection of illustrative plates of steel sample, sweep velocity is less than or equal to 1 °/min, to improve signal to noise ratio (S/N ratio), obtains high-quality XRD collection of illustrative plates;

Step (2): utilize the middle XRD spectra of step (1) and following formulae discovery martensite and each crystal face of austenite without relative diffracted intensity during preferred orientation:

$I=M\·L_P\·F^2\·e^{-2M}\·A^{*}\left(\mathrm{\θ}\right)---\left(1\right)$

Wherein, L _pbe defined as lorentz polarization factor, M is defined as temperature factor, and F is defined as structure factor, A ^*(θ) inverse of absorption factor A (θ) is defined as, e ^-2Mbe defined as temperature factor, and $L_P=\frac{1+{\cos }^{2}2\mathrm{\θ}}{{4\sin }^2\mathrm{\θ}\cos \mathrm{\θ}};$

Step (3): the martensite in step (2) and each crystal face of austenite are normalized without relative diffracted intensity during preferred orientation, and the actual diffracted intensity being obtained martensite and each crystal face of austenite by XRD software;

Step (4): the orientation probability density utilizing following formulae discovery martensite and each crystal face of austenite:

${\mathrm{\ρ}}^{*}=\left(H_i{K}_i{L}_i\right)=\frac{[\underset{i=1}{\overset{n}{\mathrm{\Σ}}}P\left(H_i{K}_i{L}_i\right)\·\frac{I_t\left(H_i{K}_i{L}_i\right)}{I_u\left(H_i{K}_i{L}_i\right)}]}{\underset{j=1}{\overset{n}{\mathrm{\Σ}}}[P\left(H_j{K}_j{L}_j\right)\·\frac{I_t\left(H_j{K}_j{L}_j\right)}{I_u\left(H_j{K}_j{L}_j\right)}]}---\left(2\right)$

Wherein, I _t(H _ik _il _i) and I _t(H _jk _jl _j) be respectively (H when there is preferred orientation _ik _il _i) and (H _jk _jl _j) diffracted intensity in face; ρ ^*(H _ik _il _i) be (H _ik _il _i) the orientation probability density in face, i.e. Polar orderatim; P (H _ik _il _i) and P (H _jk _jl _j) be (H _ik _il _i) and (H _jk _jl _j) repetition factor in face; I _u(H _ik _il _i) and I _u(H _jk _jl _j) be respectively without (H during preferred orientation _ik _il _i) face and (H _jk _jl _j) the relative diffracted intensity in face, n is the diffraction surfaces number selected;

Step (5): utilize the orientation probability density in step (4) and following formula to try to achieve the diffracted intensity of the rear martensite of correction and each crystal face of austenite:

$I\left(H_i{K}_i{L}_i\right)=\frac{I_t\left(H_i{K}_i{L}_i\right)}{{\mathrm{\ρ}}^{*}\left(H_i{K}_i{L}_i\right)}---\left(3\right)$

Wherein: I (H _ik _il _i) be (H after preferred orientation corrects _ik _il _i) diffracted intensity in face; I _t(H _ik _il _i) for there is preferred orientation time (H _ik _il _i) diffracted intensity in face; ρ ^*(H _ik _il _i) be (H _ik _il _i) the orientation probability density in face;

Step (6): utilize the diffracted intensity of martensite and each crystal face of austenite after revising in step (5) and following formula finally to record the austenitic content of steel sample:

$V_A=\frac{1-V_c}{1+G\frac{I_{M\left(\mathrm{hkl}\right)i}}{I_{A\left(\mathrm{hkl}\right)i}}}---\left(4\right)$

Wherein, V _aorientate the volume fraction of austenite phase as; V _cbe defined as the volume fraction of Carbide Phases total amount in steel; I _{m (hkl) i}be defined as martensite in steel (hkl) _ithe integrated intensity of crystal face diffracted ray; I _{a (hkl) i}be defined as austenite in steel (hkl) _jthe integrated intensity of crystal face diffracted ray; G is defined as austenite (hkl) _jcrystal face and martensite (hkl) _ithe ratio of the intensity factor corresponding to crystal face.

After have employed above-mentioned technical scheme, in the sample that there is texture, adopt probability density method to revise, more accurate test findings can be obtained, compensate for the weak point existed in standard, and orientation probability density method is a kind of mathematical processing methods in essence, eliminate the impact of manual operation on experimental result.

In concrete experiment, 9Ni steel plate selected by our sample, and adopt the heat treating regime that two kinds different, specimen coding is 1# and 2#, and each sample is polished to surfacing light after all polishing step by step with abrasive paper for metallograph again.1# and 2# sample through NEC JSM6490 type scanning electron microscope electron back scattering diffraction (EBSD) annex test, austenite content be respectively 6.52% and 8.40%(volume fraction);

The XRD-7000 type X-ray diffraction analysis instrument that X-ray diffraction analysis adopts Japanese Shimadzu Corporation to produce, Cu-K _αradiation, graphite curved-crystal monochromator, tube voltage 40kV, tube current 30mA, continuous sweep, sweep velocity is 1 °/min, and step-length is 0.02 °, and XRD collection of illustrative plates is shown in shown in Fig. 1 and Fig. 2.

Utilize XRD-7000 peak analysis software (BasicProcess module), respectively following data process is carried out to the XRD collection of illustrative plates in Fig. 1, comprising: smoothing processing, background subtraction, the separation of k α 1-k α 2 two-wire, diffraction peak peak-seeking, Systematic Error Correction and accurate correction etc., the integrated intensity of each diffraction peak can be obtained after above-mentioned process, as shown in table 2.

The cumulative actual intensity of each diffraction peak of table 2

The diffracted ray of (200), (211) two crystal faces selected in martensite (α phase), austenite (γ phase) is selected (200), (220), the diffracted ray of (311) three crystal faces, according to the regulation of standard GB/T/T8362-1987 " in steel residual austenite quantitative analysis X-ray diffractometer method ", calculate corresponding integrated intensity ratio between five diffracted rays respectively, and compare with GB/T8362-1987 direct comparison method, result is as shown in table 3, as can be seen from Table 3, between each diffracted ray in integrated intensity ratio, I (the 220)/I (311) of γ phase and I (311)/I (200) exceeds GB/T8362-1987 regulation allowable fluctuation range, and numerical value deviation compared with national standard is very large, carefully analyze experimental result can find, the main cause of these deviations is caused to be that austenite (311) diffraction peak intensity is too low.This illustrates that austenite exists preferred orientation mutually.

Cumulative actual strength ratio between table 3 diffracted ray

The integrated intensity of diffraction peak each in table 2 is substituted into formula (4) and calculates austenite content in steel, result is as shown in table 4.Can see by table 4, to be combined by five diffracted rays and the austenite content difference calculated respectively is very large, the data discrete obtained like this is very large, get its mean value and there is no practical significance, can not by the measured value of its mean value as austenite content in steel, therefore, when the integrated intensity ratio of sample exceeds GB allowed band, error calculated is very large, and GB is no longer applicable.

The austenite content that table 4 calculates according to national regulations

Introduce orientation probability density method to revise original diffraction intensity, result is as shown in table 5.

The revised diffracted ray intensity of table 5 orientation probability density method

Can see from table 5, after revising, integrated intensity value on γ phase (311) crystal face is significantly increased (contrasting with table 2), by the regulation of revised diffracted intensity according to GB/T8362-1987 " in steel residual austenite quantitative analysis X-ray diffractometer method ", calculate integrated intensity ratio between revised diffracted ray, as shown in table 6, can see from table 6, between revised diffracted ray, integrated intensity ratio all specifies within allowable fluctuation range at GB/T8362-1987.

Integrated intensity ratio between rear diffracted ray revised by table 6

Revised diffracted intensity (see table 5) is substituted into formula (4) and calculates austenite content, as shown in table 7; From table 7, we can see, diffraction peak integrated intensity data are after the correction of orientation probability density method, the austenite content numerical fluctuations calculated is less, and it is close with EBSD analysis result, error≤5%, therefore, this modification method eliminates the impact of preferred orientation on austenite content in steel to a certain extent.

The austenite content obtained after the correction of table 7 orientation probability density method

Above embodiment is only and technological thought of the present invention is described, can not limit protection scope of the present invention with this, and every technological thought proposed according to the present invention, any change that technical scheme basis is done, all falls within scope.

Claims (2)

1. adopt a method for austenite content in X-ray diffraction commercial measurement steel, it is characterized in that, comprise following concrete steps:

Step (1): utilize X-ray diffractometer to scan steel sample, obtain the XRD collection of illustrative plates of steel sample;

Step (2): utilize the middle XRD spectra of step (1) and following formulae discovery martensite and each crystal face of austenite without relative diffracted intensity during preferred orientation:

I=ML _pf ²e ^-2Ma ^*(θ) formula (1)

Wherein, L _pbe defined as lorentz polarization factor, M is defined as multiplicity factor, and F is defined as structure factor, A ^*(θ) inverse of absorption factor A (θ) is defined as, e ^-2Mbe defined as temperature factor, and

$L_P=\frac{1+{\cos }^{2}2\mathrm{\θ}}{4{\sin }^2\mathrm{\θ}cos\mathrm{\θ}};$

Step (3): the martensite in step (2) and each crystal face of austenite are normalized without relative diffracted intensity during preferred orientation, martensite and austenitic maximum diffraction intensity are set to 100, and obtain the actual diffracted intensity of martensite and each crystal face of austenite by XRD software;

Step (4): the orientation probability density utilizing following formulae discovery martensite and each crystal face of austenite:

${\mathrm{\ρ}}^{*}\left(H_i{K}_i{L}_i\right)=\frac{\[\underset{i=1}{\overset{n}{\Σ}}P\left(H_i{K}_i{L}_i\right)\·\frac{I_t\left(H_i{K}_i{L}_i\right)}{I_u\left(H_i{K}_i{L}_i\right)}\]}{\underset{j=1}{\overset{n}{\Σ}}\[P\left(H_j{K}_j{L}_j\right)\·\frac{I_t\left(H_j{K}_j{L}_j\right)}{I_u\left(H_j{K}_j{L}_j\right)}\]}$ Formula (2)

Wherein, I _t(H _ik _il _i) and I _t(H _jk _jl _j) be respectively (H when there is preferred orientation _ik _il _i) and (H _jk _jl _j) diffracted intensity in face; ρ ^*(H _ik _il _i) be (H _ik _il _i) the orientation probability density in face, i.e. Polar orderatim; P (H _ik _il _i) and P (H _jk _jl _j) be (H _ik _il _i) and (H _jk _jl _j) repetition factor in face; I _u(H _ik _il _i) and I _u(H _jk _jl _j) be respectively without (H during preferred orientation _ik _il _i) face and (H _jk _jl _j) the relative diffracted intensity in face, n is the diffraction surfaces number selected;

Step (5): utilize the orientation probability density in step (4) and following formula to try to achieve the diffracted intensity of the rear martensite of correction and each crystal face of austenite:

$I\left(H_i{K}_i{L}_i\right)=\frac{I_t\left(H_i{K}_i{L}_i\right)}{{\mathrm{\ρ}}^{*}\left(H_i{K}_i{L}_i\right)}$ Formula (3)

Wherein: I (H _ik _il _i) be (H after preferred orientation corrects _ik _il _i) diffracted intensity in face; I _t(H _ik _il _i) for there is preferred orientation time (H _ik _il _i) diffracted intensity in face; ρ ^*(H _ik _il _i) be (H _ik _il _i) the orientation probability density in face;

Step (6): utilize the diffracted intensity of martensite and each crystal face of austenite after revising in step (5) and following formula finally to record the austenitic content of steel sample:

$V_A=\frac{1-V_c}{1+G\frac{I_{M\left(hkl\right)i}}{I_{A\left(hkl\right)i}}}$ Formula (4)

Wherein, V _aorientate the volume fraction of austenite phase as; V _cbe defined as the volume fraction of Carbide Phases total amount in steel; I _{m (hkl) i}be defined as martensite in steel (hkl) _ithe integrated intensity of crystal face diffracted ray; I _{a (hkl) i}be defined as austenite in steel (hkl) _jthe integrated intensity of crystal face diffracted ray; G is defined as austenite (hkl) _jcrystal face and martensite (hkl) _ithe ratio of the intensity factor corresponding to crystal face.

2. the method for austenite content in employing X-ray diffraction commercial measurement steel according to claim 1, is characterized in that, in step (1), the sweep velocity of X-ray diffractometer is less than or equal to 1 °/min.