Vacuum brazing furnace operation requirements
(1) the vacuum brazing furnace needs sufficient heating rate and large pumping speed, the ultimate vacuum is required to be less than 4 * 10-4 Pa, the working vacuum is less than 3.0 * 10-3 Pa, and the temperature fluctuation in the brazing immersion zone is less than 3 c;
(2) the vacuum brazing furnace shall have an advanced, reliable and safe electrical control and protection system;
(3) the size of vacuum brazing furnace heating chamber can accommodate brazing parts;
(4) the vacuum brazing furnace shall have forced cooling function. Firstly, it can meet the requirements of material vacuum brazing technology. Secondly, it can shorten the time of vacuum brazing. Vacuum brazing is performed before and after vacuum brazing to prevent brazing defects such as impermeability, melting and filler metal loss.
In this process, the following points should be noted:
(1) the vacuum brazing temperature and holding time should be strictly controlled to ensure that the vacuum degree and temperature uniformity of the vacuum brazing furnace system meet the standard requirements.
(2) before vacuum brazing, grease and oxide film on the surface of the cleaning parts should be thoroughly cleaned to make the liquid solder completely wet the core layer.
(3) the assembly of the workpiece shall be reasonable to ensure the normal filling of the liquid-filled metal. The fixture of vacuum brazing assembly should be designed reasonably so as to minimize the heat capacity of the fixture and prevent the brazing deformation of the product.