Skip to content

Understanding Roller Straightening: Enhancing Metal Precision

Straightening Machine Manufacturers

Roll straightening, also known as roller leveling, is a crucial process in the metalworking industry. This technique employs a set of staggered rollers to repeatedly bend metal sheets or coils, correcting any curvatures and deformations. Roll straightening(roller leveling) is particularly utilized to rectify issues like longitudinal bending, cross-sectional inconsistencies, and the removal of stresses induced by welding in steel pipes.

Straightening Machine Manufacturers
Straightening Machine Manufacturers

Process of Roll Straightening

Roll straightening(roller leveling) involves correcting the shape defects caused by the repeated bending of materials between two rows of rollers. It can be performed using a roll straightening(roller leveling) machine or a slant roller straightening machine, each tailored to specific materials and requirements. The process is extensively employed for various applications: plate, strip, and profile straightening machines are used for sheets and profiles, while slant roller machines are designed for pipes and rods. It’s an indispensable procedure in sheet metal fabrication, where factors such as straightening force and variations in the straightening length impact the overall result.

Roll Straightening Structure

Roll straightening machines(leveling machine) are categorized based on purpose and structure: plate roll straighteners, profile roll straighteners, and slant roller straighteners for pipes and rods. The primary components of a roll straightener include motors, gearboxes, gear seats, connecting shafts, and the straightening roller assembly.

Plate Roll Straighteners: Depending on roller arrangement and adjustment methods, plate roll straighteners come in various types: parallel roller straighteners, adjustable crown correction roller straighteners, and slant roller straighteners.

Parallel Roller Straighteners: These machines feature two rows of parallel rollers, with the lower rollers fixed and the upper rollers adjustable individually.

Slant Roller Straighteners: In slant roller machines, the lower rollers are fixed, while the upper rollers are mounted on adjustable devices in the upper frame. This allows for a controlled slant angle between the upper and lower rollers.

Pipe and Rod Straighteners: These machines, often called slant roller straighteners, are used to rectify pipes and rods. They involve inclined rollers where, besides linear movement, the material also undergoes rotational motion. Slant roller straighteners come in variations such as three-roll, five-roll, six-roll, and seven-roll configurations.

Working Principle of Roll Straightening

The initial curvature of metal varies in magnitude and direction. Roll straightening(roller leveling) subjects the metal to repeated bending, gradually eliminating uneven curvature and achieving a flatter surface.

In roll straightening(roller leveling), two correction approaches are proposed based on the amount of metal deformation (compression) induced by each roller: small deformation correction and large deformation correction.

Small Deformation Correction: This approach assumes that each roller in the straightening machine can be individually adjusted. The principle behind adjusting the downward pressure of each roller is to eliminate the maximum original curvature that the metal carries when entering the rollers. This part of the material can be flattened.

Large Deformation Correction: Due to the evolving and often difficult-to-determine original curvature of the metal being corrected, the large deformation correction approach is commonly adopted in production.

Roller Straightening Machine Manufacturers

There are many leading metal processing machinery manufacturers in China, with a series of equipment such as slitting lines, fixed-length cross-cutting lines, stainless steel polishing lines, longitudinal welded pipe production lines, cold bending machines, and embossing lines.

Roller levelers are the core equipment for strip and plate processing and they have always been committed to producing high quality precision levelers for these applications. Most of them produce levelers with some small equipment, which can process various ferrous and non-ferrous metal materials, with a thickness ranging from 0.1mm to 25mm and a width of up to 2500mm.

Depending on material type and scope of processing, these small leveler producers offer custom solutions with optimum roll diameter, roll spacing and speed to eliminate coil packs, bowing, edge waviness, center bow, indentation, curvature and edge warping Defects such as curvature. This ensures the highest level of material flatness accuracy.


Roll leveling is a fundamental technology in the metalworking industry, playing a key role in correcting material deformation and achieving precise, flat surfaces. By adopting innovative machinery from China Leveling Machine Manufacturers, manufacturers can improve their production processes and provide high-quality products to various industries. The application of roll straightening underscores the importance of precision and efficiency in modern metal fabrication.