A method for controlling network carbon and banded structures

Abstract

A method for controlling network carbon and banded structures is disclosed. The method includes detecting whether the density of the center zone of a casting billet reaches a first set range or not, with the first set range being determined according to steel variety and casting billet uniformity; if the density reaches the first set range, putting the casting billet into a heating furnace, heating the casting billet, and setting heating time of the heating furnace according to the detected density of the center zone of the casting billet; if the density does not reach the first set range, determining whether a reduction roller exists in a position behind a position where the center solid fraction of the casting billet is 0.6; if the reduction roller exists, increasing the reduction of thereduction roller; and if no reduction roller exists, additionally arranging a reduction roller in a position behind a position where the center solid fraction of the casting billet is 0.6. The methodensures structure uniformity of a final material, ensures product performance, and can significantly reduce the production cost of current processes.

Description

technical field [0001] The invention relates to the technical field of iron and steel metallurgy, and more specifically, relates to a method for controlling net carbon and banded structure. Background technique [0002] The existence of network carbon and banded structure will affect the performance of the final product. For example, for bearings, they are subjected to various stresses during use, mainly alternating stress, which requires high uniformity in mechanical properties, and the existence of carbides The mechanical properties of the bearing are uneven, which affects the service life; for example, the grade of mesh carbon has a great influence on the drawing performance of the cord steel, which is easy to cause frequent wire breakage in the production process of the cord steel. [0003] The existence of network carbon and banded structure is related to the element segregation in the region, which is difficult to eliminate, but the level can be reduced and controlled ...

AI Technical Summary

Problems solved by technology

[0004] Existing continuous casting technologies, such as low-speed casting, electric stirring at the end, and light reduction, can all improve the central shrinkage cavity, porosity, and segregation of the slab, but they are not effective in improving the carbide network carbon and banded structure of the final material. The level effect is not obvious; the controlled rolling and controlled cooling process will have a significant impact on the net carbon, but it cannot significantly reduce the level; the long time of holding time in the heating furnace (high temperature diffusion time of rolling steel) can significantly reduce the final material net carbon and band Organization level

[0005] Under the existing process conditions, to reduce or even eliminate the network carbon and banded structure, it is necessary to greatly extend the heating and holding time in the heating furnace, so that the elements can be fully diffused. Like bearing steel, continuous casting adopts the traditional process route, and it takes about 30 hours. High temperature holding time can effectively reduce the level of network carbon and banded structure, and control the level of end material carbide network carbon at about 1.5. However, long heating and holding time will cause over-burning, grain coarsening, and too thick decarburization layer, etc. At the same time, the long heating time also brings difficulty to the atmosphere control in the heating furnace, which seriously increases the production cost

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