Highly-active soldering flux suitable for stepped brazing of magnesium-aluminum alloy and preparation method of highly-active soldering flux

Abstract

The invention provides a highly-active soldering flux suitable for stepped brazing of a magnesium-aluminum alloy, which comprises the following components by weight percent: 46.5-50.5 percent of aluminum fluoride, 40-42.5 percent of potassium fluoride, 1.5-2.5 percent of cesium fluoride, 2-4 percent of zinc fluoride, 1-1.5 percent of lithium fluoride, 2-4 percent of potassium fluosilicate and 0.5-1.5 percent of lead fluoride. The invention also provides a preparation method of the soldering flux. The invention has the advantage that the brazing temperature can reach above 590 DEG C. The soldering flux can be ground and prepared in atmosphere, has low preparation process cost, accurate finished product composition and high activity, is noncorrosive, is nonhygroscopic in air and can also be saved for a long time.

Description

technical field [0001] The invention belongs to the technical field of brazing, and in particular relates to a highly active flux suitable for step brazing of magnesium-containing aluminum alloys and a preparation method thereof. Background technique [0002] Magnesium-containing aluminum alloys mainly include 5××× series and 6××× series aluminum alloys. Due to their small specific gravity, good thermal conductivity and other advantages, they have been widely used in aerospace, electronics, metallurgy, machinery manufacturing and light industry. application. In recent years, the connection technology of magnesium-containing aluminum alloys has developed rapidly, and brazing is one of the important connection methods for magnesium-containing aluminum alloys. [0003] Compared with other metals, aluminum and aluminum alloys are more difficult to braze. The reason is that aluminum has a great affinity for oxygen, and it is easy to form a dense and chemically stable layer of A...

AI Technical Summary

Problems solved by technology

Chinese invention patents CN1175957C, CN101439449A and CN101407003A have reported fluxes and methods suitable for brazing of magnesium-containing aluminum alloys, but these fluxes are all medium-temperature fluxes, and are suitable for brazing temperatures at about 460°C-560°C. The welding structure needs to be brazed multiple times with a temperature gradient, that is, step brazing. It is required that the brazing flux can maintain high activity for a long time when it is brazed at a higher temperature and higher temperature (above 590 ° C), and the medium temperature brazing flux is Long time heating and high temperature brazing often lose most of the activity, resulting in the quality of brazing can not be guaranteed

Images