Centrifugal casting process for large heat-resistant steel furnace bottom roller body

Abstract

The invention discloses a casting process for a large heat-resistant steel furnace bottom roller. The centrifugal casting process is adopted, and the interval between two supporting wheels at the rear end of a rolling wheel centrifugal machine adopted by centrifugal casting is set to be 1366 mm. The centrifugal casting process has the following advantages that (1) when the length of a casting exceeds the capability scope of the centrifugal machine, equipment can be modified and a short shaft system of the centrifugal machine is replaced by a long shaft system so as to meet the operation requirement of a casting mold under the condition that the motor power, the centrifugal rotating speed, the machine body strength and the wheel interval of the equipment can bear the long shaft system; and (2) vibration of the casting mold is reduced as much as possible, a water cooling measure is not adopted for the casting mold so as to avoid large temperature jump during solidification of the casting, a coating layer is thin and even so as to avoid and impede contraction of the casting, and therefore the cracking defect can be better prevented.

Description

technical field [0001] The invention relates to the technical field of hearth rolls, in particular to a casting process for large heat-resistant steel hearth rolls. Background technique [0002] The hearth roller is the most important and vulnerable part in the roller hearth continuous heat treatment furnace. It works at a high temperature of 900°C. This part is used in a large amount and has a short life. It is generally imported from abroad and is expensive. The most critical part of the hearth roll is the hearth roll body, which can only be produced by centrifugal casting. For the production of large furnace bottom rolls with a large length-to-diameter ratio, the requirements for centrifuge equipment are high, and the matching of centrifugal casting process parameters is also very particular. Because of many influencing factors and complex processes, castings are prone to cracks and cold insulation interlayers And pores and other defects, so centrifugal casting is very d...

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Problems solved by technology

[0012] According to the size of the casting, there are two types of situations: the first type is that the length of the casting is too long, which has exceeded the capacity of the existing equipment, and the problem of insufficient equipment capacity must be solved first; the second type is the following three types of casting defects The risk is very high: ①The length of the casting is very long and the outer diameter is small. During the process of cooling and shrinking, the casting is subjected to great resistance from the mold and coating, and the large-scale roller centrifuge has a large vibration during operation. It is easy to produce crack defects; ②Since the outer diameter of the casting is Ф388mm and the length is 2950mm, the working surface area of ​​the casting mold is very large. If the thickness is too small, it is very easy to produce cold insulation interlayer defects; ③The ratio of the length to the outside diameter of the casting is very large, reaching 7.6, the gas in the mold is difficult to discharge, and it is easy to produce pore defects

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