Stretch Leveler Production Drives Next-Generation Cut-to-Length Lines — Spotlight on SUMIKURA Co., Ltd.

Modern Demands Fuel Cut-to-Length Innovation

As global demand grows for precision-flat steel and aluminum sheets — especially in sectors like automotive, shipbuilding, construction, and appliances — manufacturers are placing increasing value on flatness, dimensional accuracy, and stress-free flat sheet output. In response, the industry is evolving: “stretch leveling” is fast becoming a standard component in modern cut-to-length (CTL) lines, enabling metal service centers and coil processors to deliver “memory-free” sheets that maintain perfect flatness even under demanding downstream processes like laser cutting, forming, and welding.

SUMIKURA’s 6-High Stretch Leveler Cut-to-Length Line: A High-Precision Solution

SUMIKURA Co., Ltd. — a Japanese specialist in coil processing lines with nearly eight decades of experience — has introduced its “6-High Stretch Leveler Cut-to-Length Line,” bringing stretch-leveling technology in-house and offering an advanced CTL platform tailored for demanding modern use cases. 

Key capabilities of the line include:

Processing of a wide variety of materials — high-strength steels (HSS), cold-rolled steel (CRS), hot-rolled steel (HRS), stainless steel, and aluminum. 

Handling coil widths up to 2,500 mm, and coil weights up to 35 tons — making it suitable for large-scale industrial production. 

Thickness range from 0.2 mm to 9.0 mm, supporting both thin-gauge and heavier plate applications. 

Adjustable processing speed up to 80 m/min, with both stop-shear and rotary-shear options for flexible cutting performance. 

Integrated 6-high stretch leveling technology to eliminate internal stresses such as crossbow, coil set, or residual stress — delivering consistently flat sheets with excellent surface quality. 

This configuration enables coil-to-sheet processing with both precision and throughput — ideal for manufacturers requiring high-flatness output for downstream forming or fabricating.

Why Stretch Leveler Production Matters — Industry Perspective

The adoption of stretch levelers — either as part of CTL lines or integrated into heavy-gauge processing plants — reflects growing market pressure for “memory-free,” laser-flat sheets. Traditional roller-leveling or simple flattening often leaves residual stress (“coil memory”) that can cause bowing, warping, or spring-back when sheets are later cut, formed, or welded. 

By contrast, stretch leveling applies controlled tension beyond the yield point, then releases the strip so internal stresses are minimized — producing stress-relieved, stable, flat sheets ideally suited for high-precision downstream applications. 

This capability is particularly critical for:

Automotive body panels, structural reinforcements, and chassis parts — where surface quality, dimensional stability, and flatness are essential. 

Laser-cutting and high-precision fabrication operations — where any warping or spring-back can cause defects or rejection. 

Heavy-duty structural material processing — where managing internal stress is key to avoiding later deformation under load.

Positioning SUMIKURA’s Solution in the Global Metals Market

SUMIKURA’s 6-High Stretch Leveler CTL line arrives at a pivotal time: as fabricators and OEMs increasingly require “ready-to-use” flat sheets with minimal post-processing. By integrating stretch leveling directly into CTL machinery, SUMIKURA enables metal service centers and manufacturers to shorten lead times, reduce scrap and rework, and meet tighter tolerances for flatness and consistency.

Moreover, by handling a broad range of materials — from thin aluminum to heavy-gauge steel — and providing flexibility in coil size, thickness, and cut length (up to 12,000 mm), SUMIKURA’s line is well-suited to diverse markets: automotive, shipbuilding, construction, appliance manufacturing, and more.

Implications for Manufacturers and Metal Processors

Reduced waste and rework: With stress-relieved, flat sheets, downstream operations such as laser cutting, stamping, or forming are less prone to warping or distortion — reducing scrap rates and improving yield.

Improved throughput: Automated coil handling, shear options, and efficient stretch-leveling enable higher output without sacrificing quality — a major advantage for high-volume operations.

Flexibility across materials: The ability to process a wide variety of metals and thicknesses makes the line suitable for both standard carbon steels and specialty materials like stainless or aluminum.

Competitive differentiation: Offering stretcher-levelled cut-to-length sheets can be a selling point for metal service centers aiming to supply OEMs or fabricators requiring tight flatness tolerances.