Papers by Keyword: Furnace Brazing

Abstract: Wetting and spreading ability of Ag-Cu-Zn filler and Ag-Cu-P filler on copper surface under heat treatment furnace was studied. The microstructures of brazed joints of Ag-Cu-Zn and Ag-Cu-P filler under the same parameter were also observed. The microstructure shows that the wetting ability of Ag-Cu-Zn filler on the copper surface is better than Ag-Cu-P and its structure is uniformed and regulated. It is founded that there were obvious dissolution and diffusion between base metal and filler for the copper/Ag-Cu-Zn/copper joint, there were white and black eutectic structure formed in the joint interface.

Abstract: Al-Cu joints have been widely used in electronic and heat exchanger industries due to their excellent electrical and thermal conductivity. Meanwhile, the use of Al in the Al-Cu joints can result in lower weight and cost of the final structure. The purpose of the current study is to join Al to Cu by furnace brazing using ultrafine Al-Si powder. To study the microstructure of the join area, the brazing tests were conducted in the range of 590 to 610°C for 5 to 15 minutes under inert atmosphere. The microstructure of Al/Cu joints was studied by scanning electron microscopy (SEM). The elemental analysis was conducted using an energy dispersive spectrometry (EDS) system. Experimental results show that two kinds of intermetallic compounds (IMCs) mainly Cu₃Al₂ and CuAl₂ phases are formed near the interface of copper and in the braze layer region. The bulky prismatic structure which is formed on the side of Al substrate was found to be α-Al+CuAl₂ eutectic.

Abstract: As wearing parts, shearer picks, in which the huge consumption and inefficient are caused by the poor quality of brazing, are widely used in the mining process. In this paper, the cemented carbide YG15, 42CrMo steel and HL105 copper brazing film were used as the head, body and solder, respectively, and the furnace brazing was used for shearer picks where the home-made water-soluble copper brazing agent was fabricated instead of the traditional dehydrated borax. The results show that the strength of the welded joint improves greatly and is up to a superior level. When the copper brazing agent and water in a four-to-six ratio, the solder is completely wetted, the best bending resistance of the head is obtained, the brazing seam of picks which are superior to the factory production is brimming, and thus the service life is significantly improved.

Abstract: Continuous process brazing in shielding-gas furnaces is tailor-made for manufacturing mass production components by means of brazing technology. Which brazing tasks can actually be carried out by a shielding-gas furnace, depend on many ancillary conditions. In particular these are, besides the component size and joint geometry, the base materials and brazing filler metals as well as the material specific process parameters which are to be maintained in a continuous furnace in order that a process assured brazing can be guaranteed. In this context, the activation of the component's surfaces play a central role for wetting with the braze melt. Within the scope of this contribution, the variables and ancillary conditions concerning this matter are presented and discussed using the brazing process on stainless steels as an example.

Abstract: Microstructural and mechanical characterization of Nitinol gas tungsten arc weld (GTAW) and furnace brazing (FB) welds for grade 1 titanium plates are carried out in order to study the microstructure developed after welding and its effect on the mechanical properties of welds. The GTAW process yields the highest hardness weld. The constituents for this weld consist of a dendritic structure of NiTi and NiTi2 intermetallic phases. The FB process promotes a change of the welds chemical composition due to atomic diffusion of Ti. The weld microconstituents consist of a mixture of a Ti-rich and NiTi2 eutectic and a proeutectic Ti-rich phase.