Introduction to the Brazing Performance of Organic Boron Gas Flux

Issuing time:2021-04-22 13:03

Introduction

Organic boron gas soldering flux is a brazing flux with organic boron as the main component and exists in a liquid form. Its addition method is to spray it onto the workpiece to be brazed through a flame. The flux is deposited on the workpiece in the form of gas to form a layer of flux film. When the heating temperature reaches the activation temperature of the flux, the filler metal flows and spreads to form a brazed joint.

The gas soldering flux is classified as A5.31 (FB3K) according to AWS/ANSI. Its operating temperature is above 850℃. Therefore, the gas soldering flux is mainly used for brazing steel and ferrous metals with brass-based filler metals, replacing the traditional borax (boric acid flux). It can also be used for brazing copper and copper alloys with copper (phosphorus-based filler metals). It can prevent the oxidation of the brazed joint and obtain a smooth brazed joint without discoloration.

In addition, according to research, when brazing pure copper with silver filler metal (Ag - Cu - Zn series) without adding other fluxes, the gas soldering flux can be used to braze flat lap specimens with a lap length of more than 10mm, and a smooth, dense and full fillet can be formed on the reverse side. However, the brazing temperature should be slightly higher than that when using QJ102 flux. In short, with the in - depth understanding of gas soldering flux, this type of flux will be more and more widely used.

1. Characteristics of gas soldering flux

｜The liquid does not contain borax, has a very low boiling point, is easy to volatilize and burn, and the flux is deposited evenly.

｜It is directly sprayed from the flame without the need for traditional dipping and coating of the flux, which improves the productivity.

｜It has good brazing performance. Wherever the flame reaches, the flux can participate in the reaction, and it is especially suitable for joints with complex structures.

｜It has a protective effect on the workpiece to be brazed. After welding, the surface of the workpiece is smooth and clean.

｜The reactant (slag) generated after brazing is a soluble borate rather than an insoluble complex metaborate, which simplifies the post - brazing cleaning process or eliminates the need for cleaning.

｜It can replace the brass filler metal with externally coated flux, reducing costs.

｜It is easy to be applied in automated brazing.

｜The process parameters (gas pressure, gas flow rate, brazing time) during brazing basically maintain the original flame brazing parameters.

Advantages

In actual brazing, the use of gas soldering flux also shows the following advantages: fast brazing speed, full and smooth brazed seams, no pores, no welding slag at the brazed place, eliminating the pickling and slag removal process, high brazing strength, high quality of painting and electroplating, and less environmental pollution caused by pickling.

2. Use of gas soldering flux

The use of organic boron gas soldering flux is relatively simple. Only a flux generator needs to be added, and the flux generator is connected in series on the gas pipeline. As shown in the following figure:

The gas soldering flux is a flammable liquid. The production enterprise needs a “Work Safety License” issued by the state. Xinrui Company is a gas soldering flux production enterprise with this certificate. It has a brand - new standardized workshop and advanced production technology. Thank you for choosing “Xinrui” and choosing products with reliable quality, formality and legality.