Chemical Active Coated Rods Used for Brazing

Abstract

Brazing copper or copper-steel structures imposes measurements regarding deposits and base materials, and regarding the gas content, hydrogen and oxygen, that comes from the deoxidizing coat. The deoxidizing coat is made out of complex salts, hydroxides and acids with high hygroscopicity. Research effected in order to improve the deoxidizer capacity of the coat and to reduce its hygroscopicity, taking into account the ratio at coating of the rods, has highlighted the possibility of equipping the material with powders that have chemical active proprieties for deoxidizing processes at brazing. To this end we developed the pre-alloy type 48%Cu–47%Sn–4%P–1%Si, powder, grain size 0,05mm. The product was used, with a participation of 8% of the total coating mass, at manufacturing by extrusion of the new rods for brazing copper semi-products. We executed and characterized deep joints type copper-copper and copper-stainless steel.Brazing process results, have appreciated, detected by melted metal deposition tests, moistening angle and respectively of the mechanical characteristics of the achieved joints.Results have confirmed the above mentioned hypothesis; it highlighted superior values to those obtained with classic rods, at technical and technological proprieties.