Application effect analysis of high chromium cast iron in large autogenous mill liner

Select a mine φ 12.2 m × The middle ring liner of 11.0 m autogenous mill is taken as the research object, and the field liner installation is shown in Fig. 1 and 2. In Figure 1, the dark area is the liner of high chromium cast iron, and the wear-resistant alloy steel liner is still used in other areas. The height of lifting strip of liner is 450 mm and that of bottom plate is 86 mm. During the service life of liner, the accumulated ore handling capacity reaches 4 553 662 t.

In order to further verify the wear resistance and application effect of high chromium cast iron liner, laser three-dimensional scanning technology was used to detect its wear. Firstly, the wear data are measured and collected by 3D scanner, and then the test results are processed by Geomagic software to obtain the wear data of mill liner in different periods of service. The data collected by laser three-dimensional scanning is a collection of a large number of three-dimensional point coordinates. Due to the huge number of points, the data is called cloud point data.

Because there are many noises in the cloud point data, firstly, the redundant points in the cloud point data are filtered by using the functions of noise reduction, sampling, deleting outliers and so on of Geomagic; After the scanner scans the surface contour of the inner liner of the mill, an ideal model of the back contour of the liner is established, which is aligned with the cloud point space in Geomagic software. The deviation between the ideal model and the scanning cloud point is calculated by 3D comparison function, and the overall thickness cloud images of all the scanning liners are obtained; Then, according to the installation position of the liner, the cloud point data is divided into several sub files. By adjusting the chromatographic display of the 3D cloud image, the high-risk wear area of the whole liner can be quickly and accurately located; Then, the dangerous area is cut in 2D, and the residual thickness of the dangerous area, the distribution law of the cutting plane direction and the wear trend are directly obtained by using the 2D annotation function. The optimization method of liner based on Geomagic software is especially suitable for large semi autogenous mill and autogenous mill liner with bad working environment and rapid wear. Figure 3 reflects the current thickness of the lifting strip and bottom plate of the feed end liner as a whole. According to the color on the cloud image, it can be judged whether the liner is worn too fast.

The thickness changes of wear-resistant alloy steel liner, high chromium cast iron liner lifting strip and bottom plate of feed end middle ring are shown in Fig. 4 and 5 respectively. In Figure 4 and figure 5, the height of each point on the middle surface from the bottom of the lining plate reflects the thickness change of different parts of the middle ring lining plate. The comparison of the average residual thickness of two kinds of lining plates in the middle ring of the feeding end after use is shown in Table 1. It can be seen from table 1 that the center residual thickness of lifting bar of high chromium cast iron liner is about 16.45% thicker than that of wear-resistant alloy steel liner, and there is little difference between the two. It can be seen that different materials have a greater impact on the central wear of the liner lifting strip, but have a smaller impact on the central wear of the bottom plate.

The 3D laser scanning technology can accurately collect the contour cloud data of the lining plate, and realize the quantitative expression of the wear law of the lining plate through the powerful post-processing analysis technology. The service conditions of two kinds of lining plates in the middle ring of the feeding end are listed in Table 2. Through the analysis of wear data, it is found that compared with the wear-resistant alloy steel lining, the high chromium cast iron lining has better performance in residual thickness, average wear rate and predicted ore amount. The residual thickness of the thinnest part is 98 mm thicker than the wear-resistant alloy steel lining, and the average wear rate is reduced by 28.3%. When the liner thickness reaches the failure standard of 90 mm, the total ore handling capacity is predicted to reach 6608710 T, and the ore handling capacity can be increased by 39.5%. The application results show that the high chromium cast iron liner has obvious advantages.

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