Our solutions in extruded aluminium - HE Tubing B.V. (2024)

Micro Port Extrusion Round Tubing Strips / Cable

Micro Port Extrusion for R744 / CO2

Width: 4 – 88 mm
Height: 1 – 20 mm
Wall thickness: ≥ 0.1 mm

A Zinc layer applied during the extrusion step creates an extra corrosion protection. The electro-chemical behaviour of Zinc towards aluminium will protect the aluminium from corrosion. The sacrificial behaviour of the Zinc in the possible corrosion process will elongate the life time of the aluminium even more.

Zinc layers of 5-18 gr/m2 can be applied on the tube surface with the use of a twin wire electric arc spray process. The common tolerances of the zinc layer are ± 2 gr/m2.

Different coatings that contain fluxing materials, zinc components and/or braze components like silicon particles or aluminium/silicon particles belong also to the capabilities (product portfolio) at HE Tubing. The Flux coatings are applied on the MPE tube surface in a separate production process after extrusion and before sizing and cutting the MPE to the Customers end specifications. Flux coatings can eliminate the need for fluxing and flux stations at the heat exchanger manufacturer production lines.

Since 2011 has HE Tubing a flux coating line in operation. A multi strand “state of the art” coating line containing a very precise roll coater machine that has the ability to apply a consistent thin coating layer on the aluminium substrate. Depending on the type of coating, a layer thicknesses between 8 and 35 gram / m2 can easily be applied.

HE Tubing produces coated materials according customer specifications which means that for each individual semi finished product the paint mixture has been developed, which makes it possible to achieve the best coating quality combined with the highest productivity. HE Tubing is using the finest components available in the market place in order to make this possible.

HE Tubings laboratory is well equipped to carry out all kind of supporting analysis and investigations on new developed coatings as well on existing coating recipes. In our laboratory we have a “lab-coater” that makes it possible to apply all typical flux braze coatings on laboratory scale. With the use of our braze oven a copy of the customers braze cycle can be simulated. Adjacent to this, SWAAT tests and metallographic analysis can be carried out in our laboratory as well. More deep analysis e.g. mapping of the coating components can be done with our SEM-microscope equipment.

HE Tubing has developed several types of coatings and together with the existing and widely used recipes HE Tubing can offer coating solutions to cover most, if not all of the applications.

The benefits of the use of a flux or braze coating is related to costs and environmental issues.The use of an applied braze coating reduces the number of production steps compared to the traditional process.

The difference between the traditional system and the “braze coating” system.

The advantages in costs are due to elimination of process equipment, possibly better utilization of the braze furniture (stacking of heat exchangers during brazing), precisely applied coating amount (no spill due to overspray), hardly any uncontrolled contamination of fluxing components with the environment and the possibility to apply zinc enriched components in order to create a galvanic corrosion protection during the same process.

An important challenge during design and brazing is to optimise the combination of the different materials of fin, Micro Port Extrusion (MPE) and header used in the heat exchanger.

Over the years, a strong down-gauging trend has been observed for the various automotive heat exchanger materials, answering the continuing pressure for weight and cost reduction. Downgauging, on the other hand, requires an improvement of the corrosion resistance of both the micro port extrusion and fin stock alloys. Air-side corrosion resistance has been ensured by the application of suitable pre-treatment and corrosion protection systems.

NEXCOR™ Long Life Alloys (LLA’s): superior extruded aluminium MPE’s and Round Tubing for Automotive and HVAC/R heat exchanger applications.

• Most highly corrosion resistant bare aluminium alloys – requiring no zinc arc spray or chromate coating to withstand intense environmentally corrosive conditions
• Extends high efficiency life cycle of heat exchangers – no tube-to-fin separation to degrade performance
• Durable and promotes a higher post-braze strength for a more stable microstructure
• Substantial cost saving over copper (HVAC/R applications) with a weight reduction of 40-50%

NEXCOR™ includes three highly engineered alloys: AA3026 (C47B), AA3110 (C19E) and C47D. Chemistries
of each are shown below, including a comparison with the industry standards AA1100 and AA3102.

With the introduction of highly corrosion resistant LLA’s for the MPE with optimized compositions like the EN AW-3110 NEXCOR™ alloy, it has been possible to eliminate these costly and sometimes environmentally hazardous surface treatments. Additional protection of the external surface of the MPE can be achieved by using fin material alloys that preferentially corrode in contact with the MPE alloy (i.e. the fins act as sacrificial anodes). For this reason, the fin alloy must be more electronegative than the MPE alloy. The low melting point Al-Si alloys which are used to clad the MPE are – in the brazed condition – already slightly electronegative to most of the Al-Mn based MPE alloys, i.e. the addition of Zn to the clad alloy is often not necessary.

Alloys available at HE Tubing:

On customer specific request, we do have following Alloys available:

• EN AW-3102 modified
• EN AW 3003 modified

• Heat transfer applications for the automotive marketing (battery cooling and air conditioning)
• Heat transfer applications for the HVAC&R (heating, ventilation, air conditioning and refrigeration) market
• Solar thermal market
• Other industrial applications

Willem Flier

Sales and Marketing Manager

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