What are the advantages of cast iron rolls?



With the improvement of modern energy saving and environmental protection requirements, how to reduce the cost of raw materials has become a concern of cast iron roll enterprises. The steel material has the advantage of reusability.

Roller is one of the components consumed in steel production, which plays an important role in metallurgical equipment manufacturing and steel production. Due to its low cost and good adaptability, high chromium cast iron is still one of the commonly used roll materials for hot rolling mills. With the improvement of modern energy saving and environmental protection requirements, how to reduce the cost of raw materials has becomecast iron rollBusiness concerns. The steel material has the advantage of reusability. The use of scrap steel can not only realize waste utilization, but also greatly reduce the cost of raw materials.


The production of high chromium cast iron rolls is generally made by electric furnace smelting and centrifugal casting. Electric furnace smelting is a smelting method that can make full use of scrap steel, and a large number of waste rolls and scrap steel have become a common practice in steel rolling enterprises. However, due to different waste raw materials, due to the same smelting and casting, the casting organization may be different, which affects the process performance and organization and performance of the roll. To reduce high chromiumcast iron rollProduction costs, with high chromium cast iron wear plate (25% Cr) instead of Cr-Fe alloy as the main raw material to produce high chromium cast iron rolls. However, in the subsequent heat treatment, the composition of this batch of rollers is not much different from that of the rollers produced with ferroalloys, but there are some differences in the heat treatment process, and the tendency of secondary fire cracking increases, but the reason is not clear. Therefore, how to make rational use of waste high chromium cast iron, it is necessary to analyze the solidification structure of the two rolls and the organizational transformation of the roll heat treatment process and its influence on the organization and performance.

In this paper, the solidification tissue of two rollers of the same size produced by the same process is analyzed by comparing the raw materials of high carbon sponge iron, a small amount of scrap steel and ferroalloy: one is made of high chromium cast iron wear plate as the main raw material. At the same time, the difference of the organization and performance of the two rolls after the same heat treatment process is studied, through the study of the difference of the organization and process performance, the rational use of waste, adjust the heat treatment of the casting roll, and provide experimental data to ensure the performance of the roll.

Experimental materials were from two specifications of the same high chromiumcast iron rollUpper cut open loop. Both rolls are produced using the same smelting and casting process, with sponge iron, ferroalloy and a small amount of scrap as raw materials, called roll A (Rollera). A 58% waste high chromium cast iron wear-resistant plate is called roll B. The chemical composition of the two rolls is not much different. The difference is that the carbon content of roll B is about 0.1 lower than that of roll A.

In order to study the differences in heat treatment process of two kinds of roll materials, the effects of heating temperature and cooling rate on the phase transformation of cooling process were measured by LINSEISL78 expander. The sample size is 3mm 10mm cylinder; The austenitizing temperature is 1020mm and the insulation is 0.5h. The cooling rates were 10, 3 and 1/min, respectively. In order to simulate the effect of the heat treatment process of the actual roll on the microstructure and properties, the sample size of 10mm10mm8mm was used to quench and temper the sample in the muffler. After the sample is austenized for 1020 and heat preservation for 1h, the cooling speed is adjusted, which is similar to the actual roll quenching cooling, cooled at room temperature, and then ignited twice by 400, 450, 500, 550 and heat preservation for 10h respectively. After the sample was corroded by 5% nitrate alcohol, the microstructure was observed by Axiovert200MAT optical microscope. The morphology of carbide was observed by S-3400 thermal field emission scanning electron microscope (SEM). The residual austenite content was measured using D/MAX2500PC type X-ray diffraction (XRD). The hardness of each sample was measured using a HR-150C type Rockwell hardness tester, each sample was tested at least 5 times, and averaged.