Stop-off agents for stainless steel vacuum brazing

Abstract

The invention relates to the technical field of welding, and aims to provide a stop-off agent for stainless steel vacuum brazing. The stop-off agent comprises, by weight percentage, 5-10% of zirconiapowder, 5-10% of titanium oxide powder, 35-55% of aluminum oxide powder, 0.5-5% of neodymium oxide powder, 0.15-0.5% of carbomer 940, 4.0-9.0% of VAE emulsion, 1.5-5% of methylcellulose, 2-4% of propylene glycol and 18-30.35% of deionized water. By means of the stop-off agent for stainless steel vacuum brazing, the problem that in the processing procedure of stainless steel vacuum brazing, oxide components in stop-off agents are sintered and cause hard aggregation or caking is solved. The stop-off agent can be removed through non-destructive modes like water washing and blowing after brazing,and the surface of a workpiece is not damaged.

Description

technical field [0001] The invention relates to the field of welding technology, in particular to a flow blocking agent for stainless steel vacuum 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 combination of viscosity and rheological properties can effectively prevent the molten solder from flowing freely on the surface of the metal to be brazed at the brazing temperature, and its requirement is that it can be removed in a certain way after brazing without pollution and corrosion metal workpiece. [0003] The brazing temperature of nickel-based brazing filler metals used in stainless steel vacuum brazing is relatively high, generally around 1000°C, and the commonly used flow-stopping oxide fillers include alumina, chromium oxide, titanium oxide, and magnesi...

AI Technical Summary

Problems solved by technology

[0003] The brazing temperature of nickel-based brazing filler metals used in stainless steel vacuum brazing is relatively high, generally around 1000°C, and the commonly used flow-stopping oxide fillers include alumina, chromium oxide, titanium oxide, and magnesium oxide. Under normal circumstances, the oxides used in conventional flow blocking agents, including alumina, chromium oxide, titanium oxide, magnesium oxide, etc., will sinter to varying degrees, resulting in hard agglomeration or agglomeration, which makes it impossible to pass non- Destruction methods (such as water washing, air blowing, solvent washing, etc.) to remove the residual flow blocking agent

However, although destructive methods such as grinding and polishing can effectively remove the flow blocking agent residue, it also causes permanent damage to the surface of the workpiece.