Direction-changing forging process for large cake forgings

Abstract

The invention relates to a turning forging process for large cake forgings. The turning forging process comprises the steps that firstly, steel ingots are chamfered and drawn out, and risers are chopped; step 2, upsetting the forge piece; thirdly, transverse flattening is conducted; turning forging is conducted on the steel ingot, and transverse flattening is conducted; step 4, squaring and chamfering; transversely flattening, transversely forging to form a square shape, and then chamfering; step 5, rolling and forming; and after transverse forging rounding, rotary upsetting is conducted, and then leveling is conducted to the forge piece forming size. According to the invention, the steel ingot is flattened in a variable direction, and the axis direction of the steel ingot is changed, so that defects in the center of the steel ingot are scattered, inclusion defects are not gathered any more but scattered all around, the number of defects in unit area is greatly reduced, the product quality is improved, and the yield is higher.

Description

Technical field [0001] The present invention relates to the field of forging techniques of cakes, in particular, to a changeable forging process of large cake forgings. Background technique [0002] Large biscuits are large, generally more than 2000mm, thin thickness, generally around 200-300mm, see figure 1 , Commonly used in pressure vessel equipment, a cover plate in a petrochemical industry valve device. [0003] The raw material steel ingot passes the production of ingots, and the steel ingot has physical and chemical changes due to the process of steel from liquid to solid state, and the internal organization of the steel ingots is very complicated. figure 2 For the steel ingot profile, the internal tissue displayed from the center is displayed: the water port is deposited as a cone region, which is usually a negative polarizing zone, and the internal impurities are generally smaller; the risewoman is the upper floating impurity region formed by chemical reaction. The impur...

AI Technical Summary

Problems solved by technology

[0004] In the area of ​​the ingot body, because the outermost surface is in contact with the inner wall of the ingot mold, the molten steel is the first to solidify, and the cooling rate is faster, so the grains are the thinnest; inwardly, the dendrites grow from the fine grain area on the surface to the inner grain boundary, showing a Columnar crystal; because the inside is the most center, the molten steel cools the slowest and is also the place where it solidifies last. When the liquid state changes to a solid state, the volume shrinks. The surface of the steel ingot solidifies first, and the center solidifies last, so the crystal grains in the center are the thickest. Loose shape, there is internal stress, and some inclusions in the molten steel are solidified at the upper riser end first, and the molten steel in the center is solidified last, and the inclusions in it cannot float up and can only remain in the center of the ingot. Although such defects can be The quality of molten steel can be improved by improving the steelmaking process, but it can only be reduced but not completely removed

[0005] Therefore, the pie forging is to forge the ingot body to improve the internal looseness of the forging and make it meet the standard requirements of product design. However, other inherent material defects in the raw material smelting process are concentrated in the center of the ingot body. It cannot be removed and directly affects the quality level of the product, see image 3 , is a schematic diagram of defects of cake forgings produced in the prior art. The conventional forging method is to upset the steel ingot body vertically, and then shape it along the axis of the ingot body. The axis of the steel ingot does not change during the entire forging process, that is, the ingot The materials in the central area are all compressed to the center of the product and concentrated in the center of the product, which leads to the fact that the inclusion defects of the material are all concentrated in the center of the forging. The area is small and the defects are concentrated, which leads to the forging. During flaw detection, due to dense defects or excessive concentration of a single defect, it exceeds the standard, and cannot pass the acceptance inspection and is scrapped

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