Method for measuring dendritic crystal spacing of chalcogenide free-cutting steel continuous casting billet

Abstract

The invention discloses a method for measuring dendritic crystal spacing of a chalcogenide free-cutting steel continuous casting billet, and belongs to the technical field of metal material detection.The method comprises the following specific steps and parameters: firstly, cleaning, grinding and polishing a sample, and then putting into an electron microscope for analysis; then carrying out automatic statistical analysis on the non-metallic inclusions; adjusting the current of the probe to enable the dead time of the free-cutting steel sample under the electron beam to reach 20-30%; and thelike; carrying out closed operation image processing to obtain an inclusion distribution diagram spliced by all fields of view, screening according to elements and content information of the inclusiondistribution diagram, and judging the inclusion with the S content of more than or equal to 0.1 percent and the Mn content of more than or equal to 0.1 percent as manganese sulfide inclusion; obtaining a manganese sulfide inclusion distribution diagram; and finally, averaging more than or equal to 10 positions to obtain a final measurement value of the secondary dendrite spacing. The method has the advantages that the method is simple and convenient, the measured dendrite spacing value is accurate, the analysis scanning areas can be continuously spliced, and the measurement area is more than100mm < 2 >.

Description

Technical field [0001] The invention belongs to the technical field of metal material detection, and particularly relates to a method for measuring the dendrite spacing of a sulfur-based free-cutting steel continuous casting slab. Background technique [0002] The sulfur-based free-cutting steel uses sulfur as the main free-cutting element. The sulfur content is usually controlled between 0.20% and 0.40%, and the highest is 0.60%. The sulfur content in its steel is generally several times higher than that of ordinary steel. Elements are generally removed as impurity elements. In free-cutting steel, its higher sulfur elements can combine with manganese in steel to form manganese sulfide MnS inclusions. Manganese sulfide, as a favorable inclusion, segregates during the solidification of molten steel. It precipitates in the form of dendrites, which can cut the continuity of the matrix to make turning easy to break chips, and the manganese sulfide has a lubricating effect, which can ...

AI Technical Summary

Problems solved by technology

[0005] The object of the present invention is to provide a method for measuring the distance between dendrites of continuous casting slabs of chalcogenide free-cutting steel, which solves the problem that the analysis area of ​​existing measuring methods is relatively limited, The experimental process is complicated, time-consuming and labor-intensive, etc.

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