CN103969277A - Characterization method for distinguishing multi-phase sinter in hot-rolled silicon steel - Google Patents

Abstract

The invention relates to a characterization method for distinguishing multi-phase sinter in hot-rolled silicon steel, and belongs to the technical field of status analysis of steel and iron materials. The method adopts an electron probe and an EBSD (electron backscatter diffraction) device arranged on a scanning electronic microscope for micro-structural characterization on four phases of Fe2O3, Fe3O4, FeO and Fe2SiO4 on the surface of the polished hot-rolled silicon steel. The method comprises the following steps: according to the diversities of L Beta/L Alpha peak intensity ratios of the Fe elements in different valence states, through the adoption of the status analysis of the electron probe to resolve three typical oxides of Fe, and the use of the middle-phase resolution function of the EBSD technology to distinguish Fe2SiO4, the in-depth research on the microstructures of the sinter containing different phases is carried out in order to eventually realize the comprehensive characterization of the multi-phase sinter.

Description

A kind of characterizing method of distinguishing heterogeneous oxidation iron sheet in hot rolled silicon steel

Technical field

The invention belongs to ferrous materials state analysis technical field, particularly a kind of technology differentiation hot rolled silicon steel surface Fe that adopts electron probe and EBSD (Electron Backscatter Diffraction) to combine ₂o ₃, Fe ₃o ₄, FeO and Fe ₂siO ₄the analytical approach of iron scale four phases.

Background technology

In course of hot rolling, the microstructure of iron scale is to weigh the important indicator of hot rolled silicon steel plates surface quality.The composition of hot rolling iron scale mainly contains Fe ₂o ₃(haematite), Fe ₃o ₄three kinds of (magnetic iron ore) and FeO (wustite), the thickness of three layers of phase is more approaching under the condition of high temperature.But the growth of iron scale and structure are subject to the impact of alloying element obvious, as higher in silicone content in silicon steel, so easily form fayalite (FeO2SiO at steel and iron scale interface ₂).Research work shows, FeO2SiO ₂layer viscosity is high, strong with basal body binding force, can worsen iron scale stripping performance, has a strong impact on product surface quality.And the microstructure of hot rolling iron scale directly affects the speed of pickling, be also simultaneously that in cold-rolled process, iron scale such as is pressed at the immediate cause that defect produces.Therefore, the microstructure of iron scale is characterized and seems most important.

For studying the classic method of hot rolled silicon steel iron scale and the problem of existence: 1. electron probe surface Analysis, the method is the distribution of each element in the surface analysis gain-of-function iron scale utilizing in electron probe, but the valence distribution of element can not accurately be described; 2. electron probe state analysis method, the method is according to different valence state Fe element L _β/ L _αthe difference of the strong ratio in peak is told the oxide of Fe, but for silicon steel, is rich in Si element in iron scale, and it is to Fe element L _β/ L _αpeak is strong than having a certain impact, and cannot carry out the accurate analysis of oxidase complex iron sheet thing phase; 3. EBSD phase analysis, the method principle is that electron beam and inclination sample surfaces interact, the diffraction electronics producing carries the Kikuchi band of a large amount of structural informations, by can obtain the distribution of the iron scale of different structure to the analysis of Kikuchi band, but this method efficiency is lower, the thing of distinguishing different structure often needs to take a long time mutually, and is difficult to the complete above-mentioned siliceous oxidase complex iron sheet that calibrates.

This technology, by electron probe state analysis and the effective combination of EBSD facies analysis technology, has overcome the defect of above-mentioned the whole bag of tricks, the structure of iron scale is furtherd investigate, to determine the micromechanism of oxidase complex iron sheet.

The present invention and existing main literature, patent comparison, have following improvement:

(1) document " state of electron probing analysis steel scale on surface " cannot be distinguished more complicated iron scale thing phase.The present invention can not only distinguish three kinds of conventional typical oxides, and can distinguish Fe ₂siO ₄phase, can also find out not micromechanism and the distribution of jljl phase intuitively.

(2) the iron scale region of demarcating in document " microscopic analysis of hot rolled plate scale structure " is rule relatively, and what the present invention relates to is hot rolled silicon steel high-temperature oxydation iron sheet, its more complicated and contained thing that distributes exceedes three kinds mutually, and this method may extend to the analysis of all oxidase complex iron sheet thing phases.

Summary of the invention

The object of the present invention is to provide a kind of method that adopts electron probe and the effective binding analysis iron scale of EBSD technology, mainly utilize EBSD device in electron probe and the scanning electron microscope Fe to hot rolled silicon steel surface ₂o ₃, Fe ₃o ₄, FeO and Fe ₂siO ₄four carry out Multiphasic analysis mutually.

Concrete technology step of the present invention is as follows:

1. a characterizing method of distinguishing hot rolled silicon steel heterogeneous oxidation iron sheet, is characterized in that, specifically carries out according to the following steps:

1) cold edge, grinding and polishing are carried out in the longitudinal section of sample; Utilize full-automatic polished machine to carry out sample preparation, first with 220# mill corase grind, then use respectively 9 μ m, the diamond polishing agent polishing of 3 μ m and 1 μ m, finally throw eventually with the aluminium oxide brilliant polish of 0.02 μ m, should guarantee not destroy in sample making course the form of oxide skin;

2) described sample is carried out to electron probe state analysis; Setting accelerating potential is 10-25kV, and electron beam line is 50-150nA, and beam spot diameter, is 1 μ m, and analytical wavelength range is arrive test duration is 5-15min.First measure the L of Fe element in standard model _β/ L _αpeak is compared to by force standard value, then measures the L of Fe element in testing sample _β/ L _αpeak by force than, compare with standard value, thus distinguish Fe ₂o ₃, Fe ₃o ₄and the oxide of tri-kinds of iron of FeO;

3) described sample is carried out to EBSD analysis; 0.1 μ m is selected in experiment stepping, and selected thing comprises the oxide phase of Fe and the phase of Fe-Si-O combination mutually, treats that EBSD data acquisition completes laggard row data processing, utilizes the resolution function mutually in EBSD technology to tell Fe ₂siO ₄.

2. a kind of characterizing method of distinguishing hot rolled silicon steel heterogeneous oxidation iron sheet according to claim 1, is characterized in that: carry out cold edge, the sample of grinding and polishing is hot rolled silicon steel, and surface exists the combined oxidation iron sheet that contains alloying element.

The invention has the beneficial effects as follows: the method is passed through electron probe state analysis and the effective combination of EBSD facies analysis technology, having realized the complicated microstructure of iron scale in hot rolled silicon steel characterizes and heterogeneous differentiation, and the method analysis result is accurate, conventional efficient is high, efficiently solves complicated thing in iron scale and is difficult to mutually a difficult problem of differentiating.

Brief description of the drawings

Fig. 1 is the backward scattering figure in hot rolled silicon steel iron scale electron probe state analysis region in embodiment 1.

Fig. 2 is the iron scale recombination region figure that contains Si element that in embodiment 1, EBSD analyzes.

Fig. 3 is the color-patch map of the different oxides of Fe in hot rolled silicon steel iron scale Kikuchi band contrast figure in embodiment 1.

Embodiment

Embodiment 1

1) sample carries out that longitudinal section is cold inlays, utilize full-automatic polished machine to carry out 220# mill corase grind, then through 9 μ m, 3 μ m and 1 μ m diamond polishing, polishing time is respectively 5min, 5min and 5min, last essence is together thrown and selected granularity is the aluminium oxide brilliant polish of 0.02 μ m, and polishing time is 3min left and right, until do not observe obvious cut at 50～100 times of lower specimen surfaces of metaloscope, polishing sample is cleaned rapidly in absolute ethyl alcohol, and uses hair dryer hot blast drying;

2) by Shimadzu EPMA-1610 type electron probe, sample is carried out the displaing microstructure observing of iron scale, utilize state analysis function to carry out data acquisition to sample;

3) to gather standard specimen consistent, all as follows with parameter set when the test sample information for electron probe: accelerating potential is 15kV, and electric current is 100nA, and beam spot diameter, is 1 μ m, and analytical wavelength range is arrive select first passage RAP crystal, the test duration is 6min;

Analysis result is processed as follows: the L in region 1,2,3,4 to be measured _β/ L _αpeak is strong than being respectively 0.38,0.41,0.41,0.48, standard specimen Fe ₂o ₃, Fe ₃o ₄, the L of FeO _β/ L _αpeak is strong than being respectively: 0.37,0.41,0.47, by treat test sample with the peak of standard specimen by force than comparing, can determine the distribution of three kinds of oxides of iron, region 1 is Fe ₂o ₃, region 2,3 is Fe ₃o ₄, region 4 is FeO, as shown in Figure 1;

4) the HKL Channel5EBSD system of utilizing NEC JSM-7001F type field emission scanning electron microscope to be equipped with is carried out EBSD data acquisition to the iron scale recombination region that contains Si element (white edge region in Fig. 2);

5) set step-length 0.1 μ m while collection chooses the region of 40.5 μ m × 27.8 μ m areas and carries out EBSD experiment under 3000 times, the data that record is demarcated;

After EBSD data acquisition completes, open analysis software, collected EBSD data carried out to following analyzing and processing:

Distinguish Fe ₂siO ₄phase: not punctuate and the mistake punctuate removed in experimental result are removed noise afterwards step by step, then process data into Kikuchi band contrast (BC) figure, utilize textural difference to give different colours by the oxide of different Fe in BC figure, and dark-grey is Fe ₂siO ₄, light gray is FeO, as shown in Figure 3.

Claims (2)

1. a characterizing method of distinguishing heterogeneous oxidation iron sheet in hot rolled silicon steel, is characterized in that, specifically carries out according to the following steps:

1) cold edge, grinding and polishing are carried out in the longitudinal section of sample; Utilize full-automatic polished machine to carry out sample preparation, first with 220# mill corase grind, then use respectively 9 μ m, the diamond polishing agent polishing of 3 μ m and 1 μ m, finally throw eventually with the aluminium oxide brilliant polish of 0.02 μ m, should guarantee not destroy in sample making course the form of oxide skin;

2) described sample is carried out to electron probe state analysis; Setting accelerating potential is 10-25kV, and electron beam line is 50-150nA, and beam spot diameter, is 1 μ m, and analytical wavelength range is arrive test duration is 5-15min.First measure the L of Fe element in standard model _β/ L _αpeak is compared to by force standard value, then measures the L of Fe element in testing sample _β/ L _αpeak by force than, compare with standard value, thus distinguish Fe ₂o ₃, Fe ₃o ₄and the oxide of tri-kinds of iron of FeO;

3) described sample is carried out to EBSD analysis; 0.1 μ m is selected in experiment stepping, and selected thing comprises the oxide phase of Fe and the phase of Fe-Si-O combination mutually, treats that EBSD data acquisition completes laggard row data processing, utilizes the resolution function mutually in EBSD technology to tell Fe ₂siO ₄.

2. a kind of characterizing method of distinguishing hot rolled silicon steel heterogeneous oxidation iron sheet according to claim 1, is characterized in that: carry out cold edge, the sample of grinding and polishing is hot rolled silicon steel, and surface exists the combined oxidation iron sheet that contains alloying element.