Tension Levelling Lines

Bronx has a long and successful history of designing and building tension level lines and upgrades for both ferrous and non-ferrous metals.

Our worldwide references include:

• Europe and United Kingdom: Norway, Poland, Spain, Switzerland, UK
• Africa: South Africa
• Asia: Bangladesh, China, India, Indonesia, Korea and Taiwan
• Americas: Canada

Tension levelling corrects poor shape imparted in metal strip by cold and hot rolling processes. Table top flatness quality can usually be produced depending on the severity of the poor shape of the incoming strip. Bronx Tension Levellers are well known for producing the very best flatness in high quality surface sensitive products.

The tension levelling process also greatly improvs the physical properties of low carbon steel and other metals susceptible to the appearance of a defined yield point. Without corrections, these types of steel can form unsightly ‘luder lines’ which when severely cold worked, usually causes reject components.

Lines are built with speeds of up to 300 MPM (984.25 ft/min), thickness from 0.15mm ( .0059″) to 3mm (0,11″), widths to 1750mm  (68,89″) in both 4 and 6 high configurations.

Quick change roll cassettes are standard for both top and bottom roll clusters. Usually, two work rolls and two decurving sections are supplied and in some instances, one decurving roll section is used to reduce capital cost.

Bronx engineers have developed computer programs to ensure optimum design to level Full Hard Steel, Annealed Steel, Stainless Steel and Aluminium.

Drive Arrangements

Our engineers have standardised all electric drives for the regenerating and motoring bridles. This format produces outstanding operational results and has a number of key advantages over other types of drives.

1. Ease and flexibility of operation. changing the strip elongation on the leveller is as easy as changing the position of ones rheostat. this feature is vitally important in continuous galvanising and paint lines where physical properties of the metal varies from coil to coil and line stoppages produce large amounts of costly scrap product.
2. Maintenance of all equipment is lower, particularly when AC drives are used to power the bridles.
3. Accurate matching of bridle roll diameters is required at all times in a mechanical drive. this is not required with electrical drives.

These lines can be supplied as stand-alone lines or in conjunction with:

• Coil Build Up Lines
• Coil Inspection Lines
• Slitting Lines
• Side Trimmers
• Degreasing
• Oiling
• Embossing
• Continuous Galvanising Lines
• Continuous Paint Coating Lines

All Bronx Tension Levellers are pre-tested in-house, which saves valuable commissioning time.

Material

• Steel – Full Hard (To 0.5mm – .019685″)
• Steel – Annealed
• Aluminium
• Stainless Steel
• Material thickness – 0.15 – 3.0mm ( .0059″ to 0,11″)
• Material width – up to 1830mm (72,04″)
• Line speeds – up to 300 mpm (984.25 ft/min)

Materials processed include:

• Paint and metallic coated steel and aluminium
• Decorative and construction aluminium alloys
• Automotive steel for both internal applications and exposed skin panels
• Architectural and decorative stainless steel
• Pre and post pickled Hot rolled steel

Technology

Bronx are at the forefront of technology for tension levelling and our machines include features such as:

• 6 Hi or 4 Hi work roll cassettes
• Multi station curvature correction for line bow and crossbow
• Quick cassette changeover
• Auto pre-set system
• On-line flatness measurement

We use tried and tested work roll cassette components of the highest quality together with proven preventative management programmes to ensure each of our users can maintain the highest quality and performance from our machines.

Bridle Drive and Elongation Control Systems

An important part of the tension levelling system is the bridle drive and elongation control system which utilises entry and exit bridles to generate the tension required to achieve the necessary strip elongation through the tension leveller.

Bridle drive system:

• Independent electric drive

Our team of specialist design engineers will select the optimum drive system for each application.

Research and Development

Bronx continue to research and develop new analytical techniques in tension levelling to improve our knowledge of the tension levelling process.

Recent developments include:

• Numerical analysis of strip-roll conformity in tension levellers
• Improved predictive model
• Pre-set system for operators
• Flexible 2 axis work roll settings
• Allowance for speed effect
• Allowance for possible change in mechanical properties
• Minimum energy settings