Aluminium clad strip for Engineering Machinery

Aluminium brazing material production

Complex assemblies can be turned into single unit by just one pass through a brazing furnace. Aluminium brazing facilitates the joining of parts with a near-eutectic Ai-Si filler alloy, the liquid temperature which is about 50 º C lower than that of the core. In serial heat exchanger production the filler alloy is supplied via a thin clad on a core alloy.

Compound Material

Aluminium brazing material is a sophisticated multi-layer compound consisting of a core alloy which provides the stength and life cycle requirements of the heat exchanger and a clad brazing filler. A one-sided protection layer can also be clad, in order to prevent water-side radiator corrosion.

During brazing, only the clad brazing alloy melts, while the core alloys remain solid. The design and the applied materials of the heat exchanger are adjusted to optimize the brazing result regarding the required post braze mechanical properties as well as the corrosion resistance.

Roll cladding

Today, two basic cladding techniques, roll bonding and cast cladding, have become established industrially. Roll cladding is a solid-state welding process, which is used to join similar and dissimilar aluminium alloys, and represents the primary method of manufacturing fuselage skin sheet for aircraft, bright products and brazing sheet for automotive applications. The cladding layers are attached to the core slab by welding and metallurgical bonding using hot rolling. The cast cladding technique is based on a conventional direct chill mould modified in order to allow multiple metal streams to be casted into one single ingot.

Cladding thickness

Signi's well established, roll bonding process guarantees tight cladding thickness tolerances, which are essential for ensuring stable brazing results. Rather thin clad layers of 5% can be manufactured, as well as brazing materials also with a cladding thickness of 20%.

1> Tolerance according to EN and ASTM.
2> Higher thickness on request.
3> Special dimensions, tolerances, and alloys on request.

The state-of-art slitting line also allows Signi Aluminium to meet the demand for ever-closer width tolerances for tube stock materials. Depending on the material thickness width tolerances from max. 0.05mm up to max 0.20mm can be ensured.
Clad Alloys