Torch Brazing Research Articles

トーチろう付けにおけるろう溶融域のインプロセス画像計測技術の開発

Skilled workers control the braze filler metal supply while simultaneously monitoring the formation of a metal molten area. This ensures high-reliability brazing of workpieces engaged in various states. In order to emulate the technique of skilled workers', an image processing method that monitors the formation of a metal molten area using a CCD camera is proposed. This method makes use of the fact that brazing is inevitably conducted in a reducing atmosphere. In a reducing atmosphere, the surface of a molten braze filler metal becomes a mirror having a high regular reflectance. A band pass filter and a light source so as to eliminate the burner flame light and infrared radiation light from the workpiece surfaces optically as interference lights in order to receive only the regular reflected light from the molten area were selected. The proposed method was applied to the automatic torch brazing of copper pipes in order to experimentally verify its effectiveness for high-reliability brazing.

Investigation of the properties of PMFOTsr6-4-0.03, PMFS6-0.15, and P29-76 silver-free brazing metals at cryogenic temperatures

The acute shortage of silver has made necessary the development and sue of silverfree brazing metals. As replacements for silver brazing metals in brazing joints operating at normal temperatures, brazing metals developed on the basis of copper-phosphorus and copper-manganese alloys are recommended. In this work, an investigation was made of the mechanical and production properties of PMFOTsr6-4-0.03, PMFS6-0.15 and P29-76 brazing metals for the purpose of determining the possibility of their use in the production of cryogenic equipment. As the test data indicate, with the use of copper-phosphorus brazing metals it is impossible to obtain cold-resistant brazed joints of copper and brass. The joints of steels brazed with the copper-manganese brazing metal do not possess plasticity either at 293/sup 0/K or at 77/sup 0/K. The joints of copper brazed with P29-76 brazing metal have quite high characteristics of plasticity, which do not change with a reduction in temperature to 77/sup 0/K, indicating their cold resistance at cryogenic temperatures. However, this metal wets the surface of copper poorly and flows into the gap only after repeated addition of flux and strong heating of the sample. For solution of the problem, it is desirable to develop a highly active flux for gasmore » torch brazing with copper-manganese brazing metals and to study the possibility of the use in cryogenic technology of brazing metals of the copper-manganese system alloyed with nickel.« less

リン銅ろう合金による接合部の衝撃強さに関する研究

There have been a few reports on the relation to impact strength of copper brazed butt joint with BCuP types brazing materials. However, these results of investigation do not show any definite tendency.Indifiniteness.of tendency in these experiments was considered to be due to differences in brazing temperature and in joint structure. So, it was tried to obtain a definite impact value under definite brazing temperature.The results are summarized as follows:1. With BCuP 2, BCuP 5 brazing materials and brazing temperature at 750°C, 850°C and 950°C, there is a relationship between joint thickness and charpy impact value in a range of temperatures. Charpy impact strength of a definite tendency can be gained with an increasing joint thickness. In a torch brazing where the temperature control is difficult, the relation between joint thickness and impact value differs depending on the joint structure.2. The relation detwecn brazing temperature and impact value. At brazing temperature of 950°C, impact value was high. It seems that copper base metal was dissolved in molten brazing materials and this was because of an increasing ductile copper phase in the matrix.For small brazing thickness high impact strength was obtained but when brazing temperature was high and brazing thickness was large, high impact strengh could be gained.3. Effect of cooling velocity on impact strength at brazing temperature of 850°C degree, structure became acicular dendritic after quenching and in this case, impact strength decreased by about 0.2 Kg.m/cm2 at brazing temperature, of 750°C and 950°C, there was not so much difference in the joint structure after quenching.

Torch Brazing by Reciprocal Combustion

Torch Brazing by Reciprocal Combustion