Stainless steel plate refers to a steel plate with a thickness of 4~25.0mm. The thickness of 25.0~100.0mm is called thick plate, and the thickness of more than 100.0mm is called extra-thick plate. Widely used in the manufacture of various vessels, furnace shells, furnace plates, bridges and car static steel plates, low alloy steel plates, bridge steel plates, general steel plates, boiler steel plates, pressure vessel steel plates, patterned steel plates, car beam steel plates, tractor steel plates, etc. parts and welded components.
Disadvantages of steel plate
During the use of stainless steel medium and heavy plates, attention should be paid to the occurrence of defects. Small longitudinal cracks, peak cracks, edge cracks, doping, and scarring on the surface of the steel plate will affect the appearance quality, resulting in a change of judgment and a decline in product quality.
The shape of the shortcomings of the steel plate reflects
1. Small longitudinal crack, the shape of the small longitudinal crack on the surface of the steel plate is less than 200mm in length, less than 3mm in width, and less than 0.3mm in depth.
2. Peak-shaped cracks. All the cracks occur at 5-60mm from the edge of the bottom surface of the steel plate. The microscopic direction is straight with the rolling direction, and it is in the shape of a "mountain peak".
3. Edge cracks. The cracks mainly occur at 20-80mm from the edge of the steel plate. The shape is a number of parallel longitudinal cracks of different sizes. The rule is that the thicker and wider the steel plate is, the more serious such defects will be.
4. Doping, scarring, doping and scarring are regularly distributed, and the phenomenon after finishing operations such as edge flame peeling crack inspection or casting billet scratch flame finishing is obvious.
The reason for the defect
Small longitudinal cracks are formed by mixing fine impurities into the mold; the reason for peak-shaped cracks is mainly caused by transverse cracks in the sub-corner of the outer arc of the billet; edge cracks are caused by the rollover of the edges and corners of the billet to the surface during the rolling process. The doping and scarring are caused by the surface oxide slag not being cleaned up during finishing.
Ways to prevent defects
1. Regularly check the crystallizer, especially the water sample, to check whether there are small impurities mixed in, causing the water quality to change.
2. Strictly control the over-age service of the equipment to ensure the timely maintenance of the sector segment, and prevent the deep scratches of the casting billet due to the non-rotation of the rollers in the segment segment.
3. Implement the water distribution zone control of the tortuous section, dynamically control the corner temperature of the end face slabs with different widths, and prevent the corner temperature of the slab from entering the brittle zone during the tortuous process.
4. Use wide-end cast slabs as much as possible to produce large-width steel plates, reduce the amount of broadening during rolling of the steel plate, and then reduce the degree of uneven deformation of the edge during rolling of the wide steel plate, and weaken the width of the edge crack of the steel plate.
5. Improve the uniformity of the temperature of the casting billet in the heating furnace, optimize the slab heating process, reduce the temperature difference between the top and bottom of the billet, reduce the deformation resistance difference between the top and bottom of the rolling piece, and then reduce the uneven deformation of the edge of the rolling piece.
6. Improve the finishing ability of the billet, and prevent the occurrence of secondary defects such as incomplete slag finishing and partial deep burn marks after the billet finishing.
