The carbon content of High-performance cast iron rolls is approximately 2.5% to 3.5%. According to the main material, they can be classified into four major categories: common cast iron rolls, high nickel-chromium infinitely cold-hardened composite cast iron rolls, high chromium composite cast iron rolls, and alloy ductile iron rolls. The common structures in cast iron rolls can be classified into three major categories: matrix, cementite, and graphite. The matrix structures mainly include bainite, ferrite, pearlite, and martensite. The forms of graphite in cast iron generally include flaky and spherical.
To help steel mills choose the right roll material, understanding these types and structures is essential.
Ordinary cast iron rolls
Engineers classify ordinary cast iron rolls into three types: cold-hardened cast iron rolls, medium and low alloy infinite cold-hardened cast iron rolls, and medium and low alloy ductile iron rolls. They produce cold-hardened cast iron by using the molten iron’s subcooling degree. They rapidly cool it through the mold surface.
The surface of the roll body is rapidly cooled to form a white cast layer, which has high hardness and good wear resistance. Cold-hardened cast iron rolls can be classified into three major categories based on manufacturing processes and core materials: non-ductile iron, ductile iron composite, and ductile core. Infinite cold-hardened cast iron rolls are a type of material between cold-hardened cast iron and gray cast iron. Graphite exists in the matrix structure of the working layer of the roll body, and there is no obvious boundary between the working layer of the roll body and the core. Ordinary cast iron rolls are mainly used for rolls in thin plate rolling mills, three-roll Lauter medium plate rolling mills, wire rod rolling mills, bar rolling mills and section steel rolling mills
These rolls offer excellent cost performance, making them ideal for small and medium-sized rolling mills focused on efficiency.
High-nickel-chromium infinitely cold-cast composite iron rolls
Infinite chilled cast iron lies between chilled and gray cast iron. Its working layer contains uniformly distributed graphite, which increases with depth, causing hardness to decrease gradually—eliminating a clear boundary between the layer and core. Hence, it’s also called unbounded chilled cast iron. When alloyed with high chromium, nickel, and molybdenum, it becomes high-nickel-chromium chilled cast iron. Produced via full flushing or centrifugal casting, its carbide-rich surface offers wear resistance, while graphite ensures thermal resistance. These rolls are mainly used as finishing rolls in wide, medium, and thick plate and strip mills.
Their stable durability ensures consistent quality in precision rolling applications, enhancing production profitability.
High-chromium composite cast iron rolls
High-chromium composite cast iron rolls use high-chromium white cast iron with 12-22% chromium as the outer layer material of the roll body, and generally use ductile iron as the core and neck material of the roll. Manufacturers produce them through a centrifugal composite casting process. Due to the presence of plate-like Cr7C3 type eutectic carbides, chrysanthemum-like Mo2C type eutectic carbides, and granular Cr23C6 type secondary carbides in the matrix, high-chromium cast iron rolls have excellent wear resistance. Steel manufacturers widely use it as the front work roll for both rough and finish rolling in hot-rolled strip continuous rolling mills, as well as for the rough and finish rolling work rolls in wide, medium, and heavy plate rolling mills, and for the finish rolling in small-section steel and plate rolling mills.
Alloy ductile iron rolls
Alloy ductile iron rolls exhibit high tensile strength and withstand heavy loads. The uniform spherical distribution of graphite from the roll body to the core provides excellent wear resistance.The matrix structure is carbides and pearlite or needle-like bodies. Manufacturers generally divide alloy ductile iron rolls into two types based on the matrix structure of the roll body: pearlitic ductile iron rolls and nodular (needle-shaped) ductile iron rolls. They typically cast alloy ductile iron rolls as a whole. However, when producing needle-shaped ductile iron rolls, which contain high alloy content and generate large casting stress, manufacturers often adopt centrifugal composite casting to achieve optimal overall performance. These rolls offer excellent thermal shock resistance and wear resistance, making them widely used in large primary rolling mills, section steel rolling mills, bar continuous rolling mills, and large seamless pipe rolling mills.
These rolls provide long service life and strong wear resistance, supporting customers aiming for high-strength and high-precision production.
Products cover a wide range of scenarios
Ordinary cast iron rolls offer excellent cost performance. They suit rolling thin plates, bars, and wires. They help small and medium-sized rolling mill customers operate efficiently.
High nickel-chromium infinitely cold-hardened composite cast iron rolls offer stable durability. They suit precision rolling of medium and heavy plates and strip steel. Choosing them improves production line quality and profit.
High-chromium composite cast iron rolls: Wear-resistant and long service life, providing excellent support for customers pursuing high-strength and high-precision production;
Alloy ductile iron rolls have high strength.These rolls resist thermal shock. Large-scale primary rolling and seamless pipelines widely use them. Heavy-duty working conditions suit them well.
No matter your production needs, we have the right roll to boost your mill’s performance.
Boost productivity and help enterprises grow
High-quality cast iron rolls extend service life and reduce downtime. They enhance rolling efficiency and product yield. This lowers production costs and increases unit output value. As a result, enterprise profits grow. Your business gains a leading edge in the industry.
Partner with us for reliable, high-performance rolls tailored to your mill’s demands.
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