Preparation method of stopping-off agent for flame brazing or molten salt dip brazing

Abstract

The invention relates to the technical field of welding, and aims to provide a preparation method of a stopping-off agent for flame brazing or molten salt dip brazing. The preparation method comprisesthe steps as follows: cerium oxide powder and chromium oxide powder are subjected to ball-milling and then taken out, and a mixture I is obtained; aluminum oxide powder, calcium fluoride powder and potassium fluoborate are subjected to ball-milling, and a mixture II is obtained; after ethylene glycol and hexylene glycol are mixed and stirred uniformly, methyl cellulose is added and stirred uniformly, and a mixture III is obtained; the mixture I and the mixture II are added to the mixture III, and after stirring, a mixture IV is obtained; the mixture IV is added to a three-roll grinder for grinding and cooled to the room temperature, and the stopping-off agent for flame brazing or molten salt dip brazing is obtained. The stopping-off agent can be resistant to erosion of a molten brazing flux or molten salt in a brazing process, has quite good reactionlessness under the action of the molten brazing flux or molten salt and has better binding force with the surface of a workpiece in the brazing process, thereby having low probability of being washed away from the originally covered surface by the molten brazing flux or molten salt.

Description

Technical field [0001] The invention relates to the technical field of welding, in particular to a method for preparing a flow inhibitor for flame brazing or molten salt immersion brazing. Background technique [0002] The flow inhibitor is a material used to protect the surface of the welded metal during the brazing process. It is made into a stable suspension system by mixing oxides and binders. It can be formulated into a suitable suspension system according to the application process. The composition with high 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 it can be removed in a certain way after brazing without pollution and corrosion Brazing metal. [0003] The flow inhibitor used in flame brazing or molten salt immersion brazing often needs to resist the erosion of molten flux and molten salt during the brazing process to ensure ...

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