Introduction
Hydroforming and universal rolling mills, also known as levelers, are essential pieces of equipment for level rolling of plate material in the metals industry, such as steel plate, aluminum plate, and stainless steel plate. The levelers are used for equalizing the thickness of the sheets, leveling the micro-inclusions in the material, minimizing the irregularities in the surface profile, and improving the plate surface quality. Levelers typically comprise a roller supporting transfer arm, two flats for rollers, two rollers for edge work, and two rollers for longitudinal work. The rollers of each type are usually made of different materials with different hardness and properties to suit the different purposes of each task. Leverlers that are used for steel plate rolling often have edge rollers and longitudinal rollers made of different materials.
Roller Types
The purpose of edge roller is to produce evenly rolled edges. Edge rollers are typically made of a composite material composed of a hard central portion and softer external portions, where the material is evaluated on the basis of its ability to resist wear and impact. Common materials used for edge rollers include 75Cr iron, 40Cr carbon steel, and cast iron.
The purpose of longitudinal roller is to level the strip material and control strip crown. Longitudinal rollers are typically machined with serpentine profile on the roller surface, which is then ground and lightly polished for optimum performance. Common materials used for longitudinal rollers include 55NiCrMoV, 20Cr2Ni4, 60CrMoV, and hardened steel.
Rollers for steel rollers are typically up to 45 inches in diameter and their surface profile is usually enhanced by manganese phosphate coating, which acts as a lubricant and reduces wear. The hardness of the rollers is important and is typically designed around a hardness range of 45-55 HRC for the two roller types.
Conclusion
In conclusion, the rollers used on a universal rolling mill for steel plate rolling are critical and vary by the application. Edge rollers are typically made of composite materials and provide a uniform edge on the sheet material. Longitudinal rollers are machined with a serpentine profile and are usually made of hardened steel or high-strength alloy steel. The roller surface is typically coated with manganese phosphate to reduce wear and improve lubrication. The hardness of the rollers is typically designed to be within the range of 45-55 HRC or higher. The materials used on the rollers of a leveler are important to ensure the workpiece is flattened, leveled, and has the desired surface finish.
