Clean Parts Remove oil, grease, drawing compounds Remove oxide w/Scotch Brite, wire brush, grinder, etc. If grit blasting avoid embedding silicon, alumina, sand, etc. in base metal - hinders wetting Chemical cleaning, acid, alkaline, chemical degreasing
Brazing Flux Dissolves surface oxides and protects against oxide formation during heating Formulated to be active at braze alloy melting range Is not designed to be the base metal cleaner Is visually clear at about 1100º F – a good base metal temperature indicator
General Strength Guidelines Tensile Strength of a Brazed Joint –Joint strength depends on several factors: Clearance between parts Base metal composition Service temperature Joint quality (voids vs. good penetration) Joint design The bulk tensile strength of silver braze alloys is 40, ,000 psi. When brazing copper-based alloys, failure will often occur in the base metal. When brazing steel or other ferrous metals, joint strength over 70,000 psi can be achieved under the right conditions. Keep in mind that braze joints are primarily lap type joints and strength is a combination of tensile and shear. Joint strength is directly influenced by the above mentioned factors. The only way to accurately determine tensile or other strength values is to test the brazed assembly.