A flow blocking agent for flame brazing or molten salt immersion brazing

Abstract

The invention relates to the technical field of welding, and aims to provide a stopping-off agent for flame brazing or fused salt impregnation brazing. The stopping-off agent is prepared from the following components in percentage by weight: 2 percent to 7 percent of cerium oxide powder, 35 percent to 60 percent of aluminum oxide powder, 3 percent to 6 percent of calcium fluoride powder, 15 percent to 25 percent of chromic oxide powder, 1 percent to 5 percent of potassium fluoborate, 0.15 percent to 0.5 percent of methylcellulose, 2 percent to 4 percent of ethanediol, and 6.5 percent to 27.85percent of hexylene glycol. The stopping-off agent provided by the invention can resist corrosion of a molten brazing flux or fused salt during a brazing process, and has better reactionlessness underthe action of the molten brazing flux or the fused salt; and the stopping-off agent provided by the invention has a better binding force with a workpiece surface during the brazing process, so that an original covered surface cannot be easily washed away by the molten brazing flux or the fused salt.

Description

technical field [0001] The invention relates to the field of welding technology, in particular to a flow blocking agent for flame brazing or molten salt immersion brazing. Background technique [0002] The anti-flow agent is a material used to protect the surface of the metal to be welded during the brazing process. It is a stable suspension system made by mixing oxides and binders. It can be formulated to have a suitable The composition of viscosity and rheological properties, its function is to effectively prevent the molten solder from flowing freely to the surface that does not need to be welded at the brazing temperature, and can be removed in a certain way after brazing without pollution and corrosion brazing metal. [0003] The flow blocking agent used in flame brazing or molten salt immersion brazing often needs to resist the erosion of molten flux and molten salt during brazing to ensure its own stability during use and not dissolve in molten flux In the molten sa...

AI Technical Summary

Problems solved by technology

[0004] Existing flow blocking agents (such as NICROBRAZ Yellow Stop Off) need to increase the dosage to achieve a better flow blocking effect when dealing with brazing conditions that require the application of a large amount of flux or molten salt, but in molten salt environments, a large amount of The use of flow blocking agent will cause the flow blocking agent to peel off or fall off under the scouring of molten salt, resulting in a decrease in the flow blocking effect, and at the same time causing pollution to molten salt components