Strip flotation lines are employed for the continuous horizontal heat treatment of aluminum strips, catering to the stringent requirements of the aerospace and automotive industries.

Both the furnace and the air cooling sections operate on the strip flotation principle: The running strip is supported on an air cushion as it undergoes heating, cooling and drying. The well-proven OTTO JUNKER nozzle system ensures high heat input and non-contact transport of the strip prioritizing gentle treatment of the product. The system’s efficient heat transfer contributes to high throughput rates, even with minimal line length. The centering properties of the patented centering nozzles ensure stable strip movement, even at low strip tension.

By means of the patented HiPreQ® quench, precise cooling rates can be set depending on strip thickness and alloy, with the mist quench function covering the cooling rates between water and air cooling, ensuring a low-deformation cooling of thin strips.

Benefits at a glance:

  • Non-contact annealing with almost zero strip tension

  • Excellent temperature uniformity across the entire strip width

  • Reproducible production results

  • Continuous operation

  • High heat input

  • High throughput

  • Minimal line length

  • Minimal deformation due to precisely adjustable cooling rates

The OTTO JUNKER strip flotation furnace for aluminum is normally integrated into a strip treatment line. OTTO JUNKER has considerable experience in connection with the integration with the relevant terminal equipment suppliers.

Arrangement and concept of the strip flotation furnace are tailored to the requirements with regard to space, layout, take-over and hand-over points and integration of the control system.

The lateral arrangement of the recirculating fans in the OTTO JUNKER flotation concept allows the perfect integration in multi-storage plants. No space is required above or below the furnace, so that, say, a horizontal strip storage system can be arranged directly below the furnace platform. 

Heating can be by either gas or electricity with electrical heating giving the opportunity of CO2-free operation. With gas heating, the optimal combination of self-recuperating high velocity burners with maximum efficiency and cold air burners being used.

The strong recirculation by means of high convection provides a high heating rate and homogeneous temperature distribution, free from streaks and without local overheating, while at the same time generating the supporting air cushion in the line.

A patent-pending flow system avoids the undesired pre-cooling before entry into the quench which might otherwise occur with aerospace alloys with long soaking times.

Cooling of the coil takes place downstream of the furnace in the HiPreQ® quench. Precisely adjustable cooling rates ensure the metallurgical properties of the different alloys and can be adjusted to the strip thickness to minimize deformations.

In the concept of the overall strip treatment line, OTTO JUNKER can also supply the integrated pre-aging furnace shortly upstream of the recoiler assembly, which is also designed as a strip flotation furnace.

Automation and visualization

Reliability and ease of operation are essential for high product quality at maximum throughputs. Schematic images in visualization provide information about the production process and the function of system components at any time. Process data are continuously recorded for quality monitoring. An integration into higher-level IT systems (Level 3) is possible.

Due to the integration of this system into a complete strip treatment line with further treatment processes (CALP lines, CASH lines etc.), an integration of the control systems at all control levels is of major importance. OTTO JUNKER has extensive experience in the cooperation with a huge number of suppliers in this regard.

Mathematical model / Digital Twin

Mathematical model for optimization of your furnace plant.

  • Optimum adjustment 
  • Continuous reduction of costs and resources due to efficient use of energy

The integrated process model calculates the temperature in the strip. Due to the known temperature distribution, the model helps to make full use of the temperature overshoot, thus reducing the heating-up time.

The model allows an improved power control increasing process repeatability.

The integrated process model ideally complements the heating process. By calculating the temperature curve in real time, heat input can be applied in the best possible way.

OTTO JUNKER can also offer you to retrofit a process model individually tailored for your production. We supply the required hardware and software and integrate the model into your existing control software.

Installation on site

Detailed planning and execution of the complete equipment installation by our specialists on site ensure a workmanlike and timely installation.

Zu unseren Leistungen gehören:

  • Supervision of installation
  • Commissioning of the equipment
  • Delegation of installation personnel with tools, hoisting gear, etc.


  • Everything from a single source
  • Timely and workmanlike installation
  • Professional site management
  • Start of production with Junker personnel on stand-by
  • Long service life

Technology Centre

Basic investigations can be carried out on test facilities for heating and cooling in the OTTO JUNKER Technology Centre. Apart from process observations, flow and thermal investigations can be performed.

If necessary, the facilities can be adjusted to your individual questions.

Strip width

max. 2,350 mm

Strip thickness

0.6 - 7 mm


aluminium strip in 2xxx, 5xxx, 6xxx, 7xxx alloys


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