July 2020

HF-Form sets benchmarks

HANSA-FLEX presents its own tube forming system

HF-Form works with the union nuts which are tried and tested in fluid technology (24° sealing cone connection in accordance with DIN EN ISO 8434-1) and therefore, in contrast to other solutions, does not require expensive special components. With numerous innovationsHF-Form, which was developed completely in-house, sets new benchmarks in terms of tightness, cleanliness, flow characteristics, reliability and ease of installation.


The development of the HF-Form system is a crucial key piece for us as a system provider in fluid technology. Ranging from formed and bent tubes via mating parts to assembly materials, it enables us to offer our customers the full range of components from a single source”, explains Florian Burchards, Head of R&D at HANSA-FLEX. For customers the fluid specialist is accordingly positioning itself as a reliable onestop partner. In future companies will no longer have to mix components from different manufacturers when it comes to formed tubes, and will be able to obtain everything from the HANSA-FLEX range. Thanks to in-house production, incompatibilities or unclear responsibilities in warranty cases are a thing of the past. To prevent the latter from happening in the first place, HF-Form offers a range of safety features and has undergone numerous tests from the development stage right through to series production.

High purity level

Regardless of manufacturer and system, the following principle applies: the forming process creates a kind of contour fold (compression area) in the interior of the tube. In developing HF-Form, HANSA-FLEX attached great importance to ensuring that the formed connecting contour at the end of the tube not only complies with all the applicable standards, but also minimises the compression area contour that forms

inside the tube. Describing a central advantage of the HF-Form system, Burchards says: “Comprehensive analyses in the HANSA-FLEX laboratory for testing technical cleanliness in accordance with VDA Volume 19 regulations have shown that – compared to other suppliers – the much smaller compression area created by HF-Form makes cleaning much easier, as fewer foreign bodies can accumulate in the tube”. This applies not only to the standard cleaning of the tube after production at HANSA-FLEX, but also to operations at a customer installation, for example when flushing programmes are carried out in a plant to prevent deposits.

Optimised flow behavior and simplified assembly

A further advantage is that the flow behaviour in the tube is improved by reducing the compression area to a minimum. Turbulence that causes pressure losses and therefore a drop in performance is consistently avoided, to which the extremely small gap dimensions also contribute. HF-Form is a full alternative to conventional cutting rings and requires no planning modifications in designs. Existing drawings can easily be updated to use HF-Form. Companies which decide to use the HFForm system also benefit from numerous advantages in assembly: firstly they save time, as the step of cutting ring assembly is no longer necessary. They simultaneously increase their process reliability, as the risk of incorrect assembly caused by faulty attachment of the cutting ring is completely eliminated by tube forming. In short, with this forming system HANSA-FLEX will in future offer an effective and safe hydraulic connection system. The over-tightening protection integrated into the HF-Form design also contributes to this. A further benefit is that HANSA-FLEX uses standard parts, in that connecting the formed tube only requires a standardised union nut. Fitters don’t need any special parts or tools, and can connect the tube lines in the usual way.

No special parts

One of the central requirements during development was to design HF-Form for use with standard parts. Explaining the decision to dispense with special parts Burchards states: “Comparable solutions onthe market often require specific functional parts such as special nuts or seals. These not only involve higher costs, but also make procurement more complicated”. HF-Form, on the other hand, uses the proven and standardised union nut in accordance with DIN EN ISO 8434-1 from the HANSA-FLEX range, which is also used for the assembly of cutting rings and tube fittings. In the case of elastomer seals HANSA-FLEX also uses standard parts. Standardised O rings, which can optionally be made of Viton or NBR, are used instead of sometimes expensive special seals for different media and temperature ranges. This means that customers benefit from simplified warehousing, lower costs and uncomplicated procurement. The latter aspect in particular plays an important role if, in the event of an unplanned repair of an installation or machine, it is possible to fall back on standard parts that are available immediately and worldwide.

Certified safety

With HF-Form, three sealing zones provide longterm protection against leakage. In addition to an elastomer seal in the form of an O-ring, two metallic sealing surfaces provide additional safety, because the sealing zones are designed redundantly: “If, for example, the O-ring is inadvertently left out during installation, the other sealing zones still ensure problem-free operation – while complying with all standards,” clarifies Burchards. In numerous tests HF-Form has successfully demonstrated its functional capacity and reliability. All tests were carried out in the accredited test laboratory of the “Internationale Hydraulik Akademie” (IHA) and at HANSA-FLEX, with the requirements specified in the standards being significantly exceeded.


Wide range

The HF-Form system will in future be available without restrictions in terms of heavy and light dimensions. In addition to DIN EN 10305-4 steel tubes in the qualities E235+N and E355+N (ST37.4 and ST52.4), galvanised or black, forming of stainless steel tubes is also possible. There are also practically no limits to further processing: compared to other forming solutions, the HANSA-FLEX forming system offers a very short clamping length. This means that the tube can be bent to customer specifications shortly after forming. Selected nominal diameters will be available at the turn of the year, and the forming portfolio will also be continuously expanded.