No abstract available

[en] A method is described which allows the evaluation of the mechanical strength of a brazed joint by measuring the surface voltage when a current runs through the joint. The results are discussed and compared with those obtained from traditionnal destructive tests

[en] The process described is for the hot assembly of similar or dissimilar metallic, non-metallic or partially metallic components, without direct contact with a cleaning flux by means of a weld metal or alloy having a melting point lower than that of the most easily melted component. The components to be assembled as well as the weld metal or alloy are brought to a temperature equal at least to that causing the weld metal or alloy to melt, in an enclosure substantially empty of air and containing one or several free or combined halogens of which at least a proportion is in a gaseous state, or passes into it, during at least part of the heating time

No abstract available

[en] A typical braze joint consists of a metallic region which wets the surface of the two metals being joined, thereby achieving a bond of good mechanical integrity. An ultrasonic signal reflected from this bond can normally distinguish between bonded and unbonded regions but gives little information about the strength of such a region. For some brazes (and other bonding operations), there is a good correlation between thickness and bond strength in that a bond falling within a specified thickness range can be shown to perform adequately while both thinner and thicker bonds exhibit degraded performance. For a 50 μm thick braze, ultrasonic reflections are ''separated'' by roughly 16 nsec. For any real transducer, this means that there is significant overlap of the front and back surface reflections. We have studied a model system consisting of thin (12 to 90 μm) aluminum bonded to the back surface beryllium. By computer fitting the time dependence of the elastic disturbance reflected from the beryllium-aluminum region to a two-plane wave reflector model and allowing for multiple reflection, we correctly predict the interface separations. Details of the data acquisition and analysis, including the fitting procedure and an error analysis, are given. Accuracy depends upon the separation; a 50 μm thick (2 mil) bond can be determined with an accuracy of about 20%. The thickness of highly graded joins, consisting of two different braze materials, can be determined with an accuracy of about 30%

[en] The results of investigations of weld metal formation when brazing specimens of 20 and 35 steel in vacuum with a wide soldering gap (∼ 2 mm) filled with powder of an iron-nickel alloy with spherical partcles of 100-400 μm in diameter are considered. It is shown that it is possible to increase mechanical properties of joints only at certain combination of the filler composition and a solder, method and condition of brazing if the letter is carried out with a wide soldering gap

[en] The mechanism of joining of silicon carbide (SiC) to silicon carbide, and silicon carbide to stainless steel (SUS) using Ag-Cu Ti alloy is discussed. The behavior of Titanium(Ti) at the brazed joint of (SiC) and (SUS) at low and high temperatures, as well as the reaction products that appear and their probable effect on bonding, were examined. It was observed that brazing of SiC/SUS cannot be possible under the same heating condition as for brazing SiC/SiC, because lower temperatures favour SUS/SiC, bond, while high temperatures favour SiC/Alloy bond. Thus brazing SiC/SUS under either of the above-mentioned conditions will put both materials at a disadvantage in one way or the others. (author)

[en] The paper presents examples showing the potentials of non-destructive testing applying a microfocus X-ray tube and microscopy, as well as the limits set to applicability of this method for reasons of physics and the of standardization.₍orig./MM)

[en] An analysis of papers relative to welded joint inspection is given, following the 8th world conference on nondestructive testing. The acoustic emission and trace-element methods used in the course of welding are presented. Leak testing, liquid penetrant inspection, electric measurements, radiography, ultrasonic testing are described for welding inspection. Ultrasonic testing is mainly developed in three directions: implementation of focused beams, automation, adjustment of ultrasonic testing to austenitic steel welds with development of specific sensors

[en] The technological process of exothermic brazing of pipes made of steel 20 of economizers and superheaters of steam boilers by solder on the iron-manganese P87 base is developed. Optimal dimensions of thermal grains are determined, advisability of application of joints brazing by level butt groove edges during repair is istablished