Method for measuring particle size of inclusion in metal by emission spectrum intensity of element constituting inclusion in metal, and method for forming particle size distribution of inclusion in metal, and apparatus for executing that method

Abstract

An electron probe microanalyzer determines the particle size of intermetallic inclusions in a master while scanning an area of φ5 mm located at an arbitrary location on the surface of the master. A calibration curve representative of the relationship between the particle size of intermetallic inclusions and the emission spectrum intensity of an constituent element constituting intermetallic inclusions is generated based on the determined particle size of the intermetallic inclusions. Intermetallic inclusions existing on emission spots on the surface of a test sample are specified based on data of emission spectrum intensity of an element existing on the emission spots, and a particle size of the specified intermetallic inclusions is determined based on the data of emission spectrum intensity and the generated calibration curve.

1 . A particle size-determining method for determining a particle size of intermetallic inclusions based on an emission spectrum intensity of a constituent element of the intermetallic inclusions, 
 the particle size-determining method comprising the steps of: 
 determining a particle size of the intermetallic inclusions, which is known, in a predetermined area of a reference sample;  
 determining an intensity of emission spectra emitted from the constituent element of the intermetallic inclusions, from a relationship thereof to an intensity of emission spectra from spark discharge spots within the predetermined area, through emission spectral analysis of the reference sample; and  
 forming an inclusion particle size-intensity calibration curve representative of relationship between the particle size of the intermetallic inclusions and the emission spectrum intensity of the constituent element of the intermetallic inclusions.  
   
     
     
         2 . A particle size-determining method according to  claim 1 , wherein the particle size of the intermetallic inclusions, which is known, in the predetermined area of the reference sample is determined through surface analysis by an electron probe microanalyzer.  
     
     
         3 . A particle size-determining method for determining a particle size of intermetallic inclusions based on an emission spectrum intensity of a constituent element of the intermetallic inclusions, 
 the particle size-determining method comprising the steps of: 
 determining an intensity of emission spectra emitted from a principle component having an already known concentration and contained in a reference sample having an already known concentration in spark discharge spots within a predetermined area of the reference sample, through emission spectral analysis of the reference sample;  
 forming a principle component known concentration-intensity calibration curve representative of relationship between the emission spectrum intensity of the principle component having an already known concentration and the known concentration of the principle component;  
 determining an intensity of emission spectra emitted from a principle component contained in a real steel material-reference sample in spark discharge spots within a predetermined area of the real steel material-reference sample, and an intensity of emission spectra emitted from a constituent element of intermetallic inclusions contained in the real steel material-reference sample, through emission spectral analysis of the real steel material-reference sample;  
 calculating a concentration of the principle component contained in the real steel material-reference sample from the emission spectrum intensity of the principle component of the real steel material-reference sample, based on the principle component known concentration-intensity calibration curve;  
 calculating a concentration of the constituent element of the intermetallic inclusions contained in the real steel material-reference sample, based on the calculated concentration of the principle component of the real steel material-reference sample;  
 forming a real steel material-contained intermetallic inclusion constituent element concentration-intensity calibration curve representative of relationship between the concentration of the constituent element of the intermetallic inclusions and the emission spectrum intensity of the constituent element of the intermetallic inclusions;  
 determining an intensity of emission spectra emitted from a base element of a real steel material-pure base sample in spark discharge spots within a predetermined area of the real steel material-pure base sample, and a base element evaporation amount indicative of mass of the base element having been evaporated due to spark discharge thereon, through emission spectral analysis of the real steel material-pure base sample; and  
 forming a base element evaporation amount-intensity calibration curve representative of relationship between the base element evaporation amount and the intensity of emission spectra emitted from the base element.  
   
     
     
         4 . A particle size-determining method according to  claim 3 , comprising the steps of: 
 calculating a base element evaporation volume indicative of a volume of the evaporated base element, from the base element evaporation amount based on a density of the base element, and calculating, from the base element evaporation volume, a particle size of the intermetallic inclusions as a diameter thereof corresponding to the base element evaporation volume, based on a formula of calculating a spherical volume;    determining a known concentration of the principle component from the emission spectrum intensity of the base element, based on the principle component known concentration-intensity calibration curve;    calculating a concentration of the constituent element of the intermetallic inclusions based on the determined known concentration of the principle component;    determining an intensity of emission spectra of the constituent element of the intermetallic inclusions from the calculated concentration of the constituent element of the intermetallic inclusion, based on the real steel material-contained intermetallic inclusion constituent element concentration-intensity calibration curve; and    forming an intermetallic inclusion particle size-intensity calibration curve representative of relationship between the calculated particle size of the intermetallic inclusions and the determined emission spectrum intensity of the constituent element of the intermetallic inclusions.    
     
     
         5 . A particle size distribution-generating method for generating a particle size distribution of intermetallic inclusions, comprising the steps of: 
 executing a data sorting process for counting a number of data items of emission spectra of a constituent element of the intermetallic inclusions in a test sample; and    generating a particle size distribution based on the counted number of the data items and the particle size of the intermetallic inclusions in the test sample, which have been determined by the particle size-determining method according to any of  claims 1  to  4 .    
     
     
         6 . A particle size distribution-generating method according to  claim 5 , wherein in the data sorting process, the data items of emission spectra of the constituent element of the intermetallic inclusions in the test sample are rearranged in order of intensity, and then the number of the rearranged data items is counted.  
     
     
         7 . A particle size distribution-generating method according to  claim 5  or  6 , wherein in the data sorting process, it is determined whether or not an emission spectrum intensity of the constituent element of the intermetallic inclusions in the test sample is larger than a threshold value, and then data items of intensity of emission spectra of the constituent element of the intermetallic inclusions in the test sample to be rearranged in order of intensity are extracted based on a result of the determination.  
     
     
         8 . A particle size distribution-generating method according to  claim 5  or  6 , further comprising the step of determining an intensity of emission spectra emitted from a principle component contained in the test sample; and 
 wherein in the data sorting process, the data items of intensity of emission spectra of the constituent element of the intermetallic inclusions in the test sample to be rearranged in order of intensity are extracted based on a result of comparison between the intensity of emission spectra emitted from the principle component contained in the test sample and the intensity of emission spectra of the constituent element of the intermetallic inclusions in the test sample.  
 
     
     
         9 . A particle size distribution-generating method according to any of  claims 5  to  8 , further comprising the steps of: 
 forming an intensity correction curve representative of relationship between a number of times of generation of spark discharge for emission spectral analysis and an amount of attenuation of an intensity of emission spectra of the constituent element of the intermetallic inclusions in the test sample after carrying out the spark discharge; and  
 correcting the intensity of emission spectra of the constituent element of the intermetallic inclusions in the test sample according to the number of times of generation of spark discharge for emission spectral analysis, based on the generated intensity correction curve.  
 
     
     
         10 . A particle size distribution-generating method according to any of  claims 5  to  9 , wherein a kind of the constituent element of the intermetallic inclusions contained in the test sample is identified based on a result of comparison between the intensity of emission spectra emitted from the principle component contained in the test sample and the intensity of emission spectra of the constituent element of the intermetallic inclusions in the test sample.  
     
     
         11 . A particle size-determining apparatus for determining a particle size of intermetallic inclusions based on an emission spectrum intensity of a constituent element of the intermetallic inclusions, 
 the particle size-determining apparatus comprising: 
 acquiring means for acquiring a particle size of the intermetallic inclusions, which is known, in a predetermined area of a reference sample;  
 acquiring means for acquiring an intensity of emission spectra emitted from the constituent element of the intermetallic inclusions, from a relationship thereof to an intensity of emission spectra from spark discharge spots within the predetermined area, through emission spectral analysis of the reference sample; and  
 forming means for forming an inclusion particle size-intensity calibration curve representative of relationship between the particle size of the intermetallic inclusions and the emission spectrum intensity of the constituent element of the intermetallic inclusions.  
   
     
     
         12 . A particle size-determining apparatus according to  claim 11 , comprising acquiring means for acquiring the particle size of the intermetallic inclusions, which is known, in the predetermined area of the reference sample through surface analysis by an electron probe microanalyzer.  
     
     
         13 . A particle size-determining apparatus for determining a particle size of intermetallic inclusions based on an emission spectrum intensity of a constituent element of the intermetallic inclusions, 
 the particle size-determining apparatus comprising: 
 acquiring means for acquiring an intensity of emission spectra emitted from a principle component having an already known concentration and contained in a reference sample having an already known concentration in spark discharge spots within a predetermined area of the reference sample, through emission spectral analysis of the reference sample;  
 forming means for forming a principle component known concentration-intensity calibration curve representative of relationship between the emission spectrum intensity of the principle component having an already known concentration and the known concentration of the principle component;  
 acquiring means for acquiring an intensity of emission spectra emitted from a principle component contained in a real steel material-reference sample in spark discharge spots within a predetermined area of the real steel material-reference sample, and an intensity of emission spectra emitted from a constituent element of intermetallic inclusions contained in the real steel material-reference sample, through emission spectral analysis of the real steel material-reference sample;  
 calculating means for calculating a concentration of the principle component contained in the real steel material-reference sample from the emission spectrum intensity of the principle component of the real steel material-reference sample, based on the principle component known concentration-intensity calibration curve;  
 calculating means for calculating a concentration of the constituent element of the intermetallic inclusions contained in the real steel material-reference sample, based on the calculated concentration of the principle component of the real steel material-reference sample;  
 forming means for forming a real steel material-contained intermetallic inclusion constituent element concentration-intensity calibration curve representative of relationship between the concentration of the constituent element of the intermetallic inclusions and the emission spectrum intensity of the constituent element of the intermetallic inclusions;  
 acquiring means for acquiring an intensity of emission spectra emitted from a base element of a real steel material-pure base sample in spark discharge spots within a predetermined area of the real steel material-pure base sample, and a base element evaporation amount indicative of mass of the base element having been evaporated due to spark discharge thereon, through emission spectral analysis of the real steel material-pure base sample; and  
 forming means for forming a base element evaporation amount-intensity calibration curve representative of relationship between the base element evaporation amount and the intensity of emission spectra emitted from the base element.  
   
     
     
         14 . A particle size-determining apparatus according to  claim 13 , comprising: 
 calculating means for calculating a base element evaporation volume indicative of a volume of the evaporated base element, from the base element evaporation amount based on a density of the base element, and calculating, from the base element evaporation volume, a particle size of the intermetallic inclusions as a diameter thereof corresponding to the base element evaporation volume, based on a formula of calculating a spherical volume;    acquiring means for acquiring a known concentration of the principle component from the emission spectrum intensity of the base element, based on the principle component known concentration-intensity calibration curve;    calculating means for calculating a concentration of the constituent element of the intermetallic inclusions based on the determined known concentration of the principle component;    acquiring means for acquiring an intensity of emission spectra of the constituent element of the intermetallic inclusions from the calculated concentration of the constituent element of the intermetallic inclusion, based on the real steel material-contained intermetallic inclusion constituent element concentration-intensity calibration curve; and    forming means for forming an intermetallic inclusion particle size-intensity calibration curve representative of relationship between the calculated particle size of the intermetallic inclusions and the determined emission spectrum intensity of the constituent element of the intermetallic inclusions.    
     
     
         15 . A particle size distribution-generating apparatus for generating a particle size distribution of intermetallic inclusions, comprising: 
 data sorting means for executing a data sorting process for counting a number of data items of emission spectra of a constituent element of the intermetallic inclusions in a test sample; and    generating means for generating a particle size distribution based on the counted number of the data items and the particle size of the intermetallic inclusions in the test sample, which have been determined by the particle size-determining apparatus for determining a particle size of intermetallic inclusions based on an emission spectrum intensity of a constituent element of the intermetallic inclusions, according to any of  claims 11  to  14 .    
     
     
         16 . A particle size distribution-generating apparatus according to  claim 15 , wherein said data sorting means rearranges the data items of emission spectra of the constituent element of the intermetallic inclusions in the test sample counts the number of the rearranged data items.  
     
     
         17 . A particle size distribution-generating apparatus according to  claim 15  or  16 , wherein said data sorting means determines whether or not an emission spectrum intensity of the constituent element of the intermetallic inclusions in the test sample is larger than a threshold value, and then extracts data items of intensity of emission spectra of the constituent element of the intermetallic inclusions in the test sample to be rearranged in order of intensity, based on a result of the determination.  
     
     
         18 . A particle size distribution-generating apparatus according to  claim 15  or  16 , further comprising acquiring means for acquiring an intensity of emission spectra emitted from a principle component contained in the test sample; and 
 wherein said data sorting means extracts the data items of intensity of emission spectra of the constituent element of the intermetallic inclusions in the test sample to be rearranged in order of intensity, based on a result of comparison between the intensity of emission spectra emitted from the principle component contained in the test sample and the intensity of emission spectra of the constituent element of the intermetallic inclusions in the test sample.  
 
     
     
         19 . A particle size distribution-generating apparatus according to any of  claims 15  to  18 , further comprising: 
 forming means for forming an intensity correction curve representative of relationship between a number of times of generation of spark discharge for emission spectral analysis and an amount of attenuation of an intensity of emission spectra of the constituent element of the intermetallic inclusions in the test sample after carrying out the spark discharge; and  
 correcting means for correcting the intensity of emission spectra of the constituent element of the intermetallic inclusions in the test sample according to the number of times of generation of spark discharge for emission spectral analysis, based on the generated intensity correction curve.  
 
     
     
         20 . A particle size distribution-generating apparatus according to any of  claims 15  to  19 , comprising identifying means for identifying a kind of the constituent element of the intermetallic inclusions contained in the test sample, based on a result of comparison between the intensity of emission spectra emitted from the principle component contained in the test sample and the intensity of emission spectra of the constituent element of the intermetallic inclusions in the test sample.