Measuring method for quantification of central looseness of casting blank

Abstract

The invention relates to a measuring method for quantification of central looseness of a casting blank. The method utilizes a principle that the density of a loose part is different from the density of a compact part, so that the central looseness can be described quantitatively. Moreover, the method utilizes the Archimedes principle to autonomously design a casting blank density measuring device. The density measuring device is utilized to measure the densities of a compact part specimen and a loose part specimen of the casting blank, respectively measure the mass of the specimens in water and air, and compute the densities of the specimens so as to quantitatively describe the central looseness of the specimens. Compared with the traditional method that after hot acid corrosion, naked eyes observe to quantitatively grade the central looseness of the casting blank, the measuring method has the advantages of no corrosion, accurate evaluation, small human error, superior measurement environment, visual and clear result and the like, therefore the measuring result of the quantification of central looseness of the measuring method has a more realistic and workable important guiding significance on field production, such as continuous casting, rolling and the like.

Description

technical field [0001] The invention relates to a quantitative measurement method for central porosity of slab produced by continuous casting or die casting in the field of metallurgy, and is an accurate, relatively simple and practical quantitative evaluation technology for slab central porosity. Background technique [0002] Porosity refers to the tiny or large pores formed after solidification at the end of the solidification of the slab due to the inability to be fully replenished by the liquid phase due to solidification shrinkage. These pores are generally scattered in the center of the continuous casting slab or die casting slab, which is generally called central porosity. Center porosity has an important influence on the performance of the product. Some larger loose spots in the slab cannot be completely welded after rolling, especially when the compression ratio is small, the possibility of these loose spots being rolled is further reduced, which in turn causes fla...

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Problems solved by technology

However, this method currently has the following important disadvantages: (1) This method can only rate the central porosity on a slab section, and due to cutting, it is likely that some sections containing central porosity are not otherwise cut Therefore, the central porosity cannot be observed, resulting in the error of the central porosity rating; (2) The traditional method needs to corrode the section of the slab, and the central porosity of the slab section after corrosion is likely to be corroded and enlarged, resulting in the rating of the central porosity (3) For some steel types that are difficult to corrode, such as acid-resistant pipeline steel, due to the strong acid resistance of the steel type, it is difficult to corrode, so it is difficult to make a correct rating for the center porosity; (4) For The small central porosity in the slab is difficult to identify with the naked eye, especially in the harsh environmental conditions of the steel plant. With the improvement of the quality of steel products, these small central porosities It is likely to cause subsequent problems such as inconsistency in performance; (5) The method of rating with a loose center has a lot of human factors, and different people perform ratings, and the results are not the same, sometimes very different, so the rating results are not objective enough

Therefore, the traditional rating method of center looseness is not accurate enough and has large errors, and has very limited guiding significance for the production practice of the subsequent rolling process.

[0004] In addition, the current in-situ analysis method, electron microscope observation, ultrasonic flaw detection, etc. are also one of the evaluation methods for center porosity. However, these methods also have the same cumbersome operation, can only evaluate a section of the billet, large evaluation errors, and expensive equipment. and other shortcomings

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