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Brazing Alloys Information

Solpro Brazing Alloys come in variety of options:

Silver Brazing Alloys

Silver Brazing Alloys

These alloys are the optimum choice for a large range of industrial metal joining applications.  The free-flowing properties of these alloys, coupled with good joint strengths means that they find use when joining dissimilar parent metals (e.g. stainless steel, mild steels, brasses, bronzes and copper) in a wide range of environments, from industrial cooling to food and pharmaceutical manufacture.

The use of a suitable flux for the parent metal/brazing alloy combination is a requirement for these alloys.  See our flux information page for more guidance.

Table 1 below details the alloys that are silicon free and generally preferred by UK manufacturers.

Table 1

 Product

ISO 17672:2016

Nominal Composition (%)  Melting Range °C 
M25T Ag 155

Silver: 55 Copper: 21 Zinc: 22 Tin: 2.0

630 - 660
M15T Ag 145 Silver: 45 Copper: 27 Zinc:25.5 Tin: 2.5 640 - 680
M10T Ag 140 Silver: 40 Copper: 30 Zinc: 28 Tin: 2.0 650 - 710
M8T Ag 138 Silver: 38 Copper: 32 Zinc: 28 Tin: 2.0 650 - 720

Flux-Coated Silver Brazing Alloy Rods

Fluxcoated Silver Brazing Alloy

The most popular of the silver brazing alloys can be supplied with an especially formulated flux coating which is designed to be particularly fluid and active as the flux is applied relatively late in the brazing cycle.  These rods offer the advantages of consistency, safety and convenience when compared to using a bare rod and separate flux paste.

These rods are typically supplied with a white flexible flux coating, however other colours may be available and it is also possible to apply printing to the rods.

We can also offer different ratios of flux to rod dependent on your requirements - please contact us for further details on the products available.

Phosphorus Brazing Alloys - Self Fluxing

Phosphorus Brazing Alloys

Brazing with Silver-Copper-Phosphorus and Copper Phosphorus alloys is widely used for joining of Copper to Copper where the absence of a flux is a major benefit.  The self-fluxing action of the Phosphorus ensures that flux entrapment problems are largely avoided and that high standards of joint soundness can be maintained.

High Phosphorus levels give excellent capillary penetration since the fluidity of the molten brazing alloy is controlled by the Phosphorus content Alloys with high Phosphorus content are less ductile than those with lower Phosphorus and higher Silver contents.

For applications where optimum mechanical strength, or resistance to vibration, is required the lower Phosphorus alloys are necessary (i.e. Phos 5, Phos 2 and Phos 0).  The tin-containing alloy, Phos OT, offers controlled fluidity, a low melting point and joints of good appearance.  Phosphorus containing alloys should not be used on Ferrous or Nickel based parent alloys as they will result in brittle joints.  This family of alloys can also be used for brazing high copper content alloys, providing that a suitable flux is used.

Table 2

 Product

ISO 17672:2016

Nominal Composition (%)  Melting Range °C 
Phos 5 CuP281

Silver: 5  Copper: 89 Phos: 6 

645 - 815
Phos 2 CuP279 Silver: 2 Copper: 91.7 Phos: 6.3 645 - 825
Phos 0 CuP182 Silver: 0 Copper: 92.2 Phos: 7.8  710 - 770

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