The development history of rollers
The varieties and manufacturing processes of rolls continue to develop with the advancement of metallurgical technology and the evolution of steel rolling equipment. In the Middle Ages, low-strength gray cast iron rollers were used to roll soft non-ferrous metals. In the mid-18th century, Britain mastered the production technology of chilled cast iron rollers for rolling steel plates. The advancement of European steelmaking technology in the second half of the 19th century required the rolling of larger tonnage steel ingots, and the strength of either gray cast iron or chilled cast iron rolls could no longer meet the requirements. Ordinary cast steel rolls with a carbon content of 0.4% to 0.6% were born accordingly. The emergence of heavy-duty forging equipment has further improved the strength and toughness of forged rolls with this composition. The use of alloying elements and the introduction of heat treatment in the early 20th century significantly improved the wear resistance and toughness of hot and cold rolls of cast and forged steel. Adding molybdenum to the cast iron rolls used for hot-rolled strips improves the surface quality of the rolled material. The flushing method composite casting significantly improves the core strength of the casting roll.
The extensive use of alloy elements in rolls began after World War II. This was the development of large-scale, continuous, high-speed, and automated steel rolling equipment, as well as the improvement of rolled material strength and deformation resistance, which put higher requirements on roll performance. the result of. During this period, semi-steel rolls and ductile iron rolls appeared successively. After the 1960s, powdered tungsten carbide rollers were successfully developed. The centrifugal casting technology and differential temperature heat treatment technology of rolls that were widely promoted in Japan and Europe in the early 1970s have significantly improved the overall performance of strip rolls. Composite high chromium cast iron rolls are also successfully used on hot strip mills. During the same period, forged white iron and semi-steel rolls were used in Japan. In the 1980s, Europe introduced high-chromium steel rolls and ultra-deep hardened layer cold rolls, as well as special alloy cast iron rolls for finishing rolling of small sections and wire rods. The development of contemporary steel rolling technology has led to the development of higher performance rolls. The core produced by centrifugal casting method and new composite methods such as continuous casting composite method (CPC method), spray deposition method (Osprey method), electroslag welding method and hot isostatic pressing method is forged steel or ductile graphite with good strength and toughness. Cast iron, composite rolls with high-speed steel outer layers and cermet rolls have been used in new generation profile, wire rod and strip rolling mills in Europe and Japan respectively.
China began to produce cast rolls in batches in the 1930s, but there were very few varieties. In the late 1950s, China's first professional roll factory was established in Xingtai, Hebei Province. In 1958, Anshan Iron and Steel Company trial-produced and used 1050 large ductile iron rolls for blooming for the first time in the world. In the 1960s, cold-rolled work rolls and large-scale forged steel rolls were successfully manufactured. In the late 1970s, Taiyuan Iron and Steel Company and Beijing Iron and Steel Research Institute jointly successfully trial-produced centrifugal cast iron rolls for steckel rolling mills and hot-strip wide-band rolling mills. Xingtai Metallurgical Machinery Roll Co., Ltd. successfully trial-produced semi-steel work rolls for hot-strip steel rolling mills. and work rolls for cold-rolled wide-band steel mills. In the 1980s, China successively developed new varieties such as large-scale forged steel backup rollers, forged semi-steel and forged white cast iron rollers, powdered tungsten carbide roller rings, and high-chromium cast iron rollers. By the 1990s, China's roll production had basically met domestic needs and some were exported, but the variety needed to be increased and the quality still needed to be improved.