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Subtec BFB-M (A.W.S. F7A2-EM12K)


Basicity Index: 3.4



Subtec BFB-M is an agglomerated submerged arc flux. It is known as a fluoride-basic flux and though it was developed as a joining flux for solid 300 series stainless steel wires and as a cladding flux for 400 series cladding wires, it can also be used with low carbon, solid steel sub-arc wires (S1 and S2) to produce welds with excellent mechanical properties. This flux is primarily used with flux-cored cladding wires. The flux is neutral which means that there is no pick-up of elements from the flux into the weld metal. 


Typical Chemical Analysis of the Weld Metal (With Subtec S2 Wire)











Typical Mechanical Properties of the Weld Metal (With Subtec S2 Wire)












Packaging and Control

Subtec BFB-M is packed in multiple layered paper sacks of 25kg which are 200 micron thick. One of the layers is plastic coated to act as a moisture repellent. The higher the basicity index of agglomerated fluxes, the more hydroscopic the flux. It is recommended that all agglomerated fluxes are stored in conditions of less than 70% relative humidity as welding with damp flux can cause porosity. Re-drying of flux which is suspected of being moist should take place for approximately 2 hours at about 300°C at a flux depth of about 25mm.

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