High-temperature Vacuum Brazing Furnace Design
Source：http://www.jmzkkj.comRelease Time：2018-06-01
In the high-temperature vacuum brazing furnace, the metal honeycomb carrier of the three-way catalytic converter for automotive vacuum brazing was used. In a short period of time, the molybdenum screen of the furnace galling showed deformation and cracking failure. The appearance and chemical composition analysis of the molybdenum screen in the cracked high-temperature vacuum brazing furnace were carried out before and after use. The results show that the molybdenum screen accelerates deformation and cracking due to the deposition of nickel-based solder on the surface of the molybdenum screen. The deposits change the microstructure of the molybdenum screen and change the physical properties of the molybdenum screen. According to this, the design points of the high-temperature vacuum brazing furnace furnace gallium molybdenum screen are proposed.
High-temperature vacuum brazing furnaces are widely used to solve brazing of structural parts that are difficult to connect with general methods, and are particularly suitable for vacuum brazing of metal materials such as titanium alloys and stainless steels. In the process of welding various structural parts using a high-temperature vacuum brazing furnace, the deposition of brazing filler metal can cause the failure modes such as deformation and cracking of the furnace molybdenum screen. Under normal use conditions, the molybdenum screen of the high-temperature vacuum brazing furnace will be deformed and cracked due to alternating cold and hot impact deformation and the metallographic structure of the molybdenum screen. The time is about 5 years.
In the process of brazing the three-way catalytic converter metal honeycomb carrier used in the automotive industry by high temperature vacuum brazing furnace, a large amount of nickel base brazing material is volatilized in large quantities, and a part of the nickel base brazing material is volatilized by a vacuum brazing furnace. A considerable part of it is deposited on the thermal insulation layer of the furnace, mainly because the first layer of molybdenum screen is obviously deposited in the face of high temperature. A large number of nickel-based solder deposits cause deformation and cracking of the high-temperature vacuum brazing furnace gallium molybdenum screen, and the time is short. Generally, the molybdenum screen of the furnace needs to be replaced in about 1 year.
For the vacuum brazing process of the metal honeycomb support of the three-way catalytic converter, the phenomenon of deformation and cracking of the molybdenum screen occurs within a short time after the equipment is used. The molybdenum screen of the cracking high-temperature vacuum brazing furnace is shaped before and after use. Visual contrast and analysis of chemical composition. The results show that the molybdenum screen accelerates deformation and cracking due to the deposition of nickel-based solder on the surface of the molybdenum screen. The deposits change the microstructure of the molybdenum screen and change the physical properties of the molybdenum screen.
According to this, the design points of the high-temperature vacuum brazing furnace furnace gallium molybdenum screen are proposed. In the high-temperature vacuum brazing furnace, once the molybdenum screen used for thermal insulation is deformed or cracked, it will cause heat leakage and insulation failure of the high-temperature vacuum brazing furnace, and the final result may be high-temperature vacuum brazing. Furnace temperature index could not reach; more serious situation is: warped molybdenum screen will be shorted with the heating belt, resulting in heating short circuit, damage the vacuum furnace.
简体中文 
English