As a method to investigate the weldability the bead-bend tests both non-notched and notched are adopted widely. The representative of the notched bend tests is Lehigh bend test and the non-notched is Austrian test. Judging from the results of performed experiments it is known that the weldabillity can be judged precisely in some cases and not clearly in others. When the fluctuation of the testing results are predominant the weldability can not be desided precisely. To judge this property we must notice to the deformation characteaistics in the range of plastic deformation, The maximum load seems to be anavail able to judge the weldability. If we observe the characteristic deformation (plastic deformation) of the test plate the bend test may be able to use as a method of quality controls for the manufacturing and testing of the arc-welding electrodes.
Following on the Report 1, we measured the removed metal per cm2 of cut surfaces and analysed the slag composition, the results thus obtdaicned are as follows, 1) The weight of removed metal ane the width of the kerf increased at increased cutting pressures and showed little difference with increased cutting speed at the same cutting pressure. 2) The slag contained some metallic iron, and the percentage of metallic iron increased with cutting pressure. 3) Irregularity (wauiness and roughness) of the cutting surfaces increased with cutting pressure 4) For plates of thickness 40mm under, we deduced an emprical formula about width of kerf b≤2.0d (b: width of kerf d : nozzle diameter)
This paper reports the effect of electrode pressure in spot welding. In this experiments, electrode pressure has been investigated as a factor affecting temperature rise in spot welding, and to find the effect of pressure some experiment have been performed. The results were as follows ; i) Pressure controls the deformation of metals, so in spot welding electrode pressure affects the conditions of the contact surface. And its effect results temperature rise. ii) Not only the initial electrode pressure but also the pressure during welding affects the extent of melt. iii) It is neccessary in order to determine the proper electrode pressure that the mechanical properties of the metal are known.
The relation between corrosion resistivity and various temperatures of heat treatment on welded parts for austenitic stainless steel was researched in 65 % HNO3 and 5 % H2SO4 at boiling. The results obtained are as follows: (1) The acid resistivity of specimen treated at 700°C is much inferior to that at other temperatures, and is followed with specimens treated at 800°C and 600°C. As-welded condition is comparably good and above all that treated at 1, 100°C is most excellent. (2) Corrosion amount can be easily confirmed by macroscopic appearances and decreasing amount of corrosion, but not apparently by the method of Charpy-impact specimen except of 700°C treatment. (3) Comparing mother plate with deposited metal, the latter is much superior to the former in corrosion resistivity. From micro-structural researches there are much mote carbide precipitations causing intergranular corrosion in the grain boundaries of mother plate, while intergranular precipitations of carbide are less found in deposited metals by developement of dendritic structure. Moreover, by the heat treatment at high, temperatures the diffusion and the dissolution of carbon in the matrix are caused, and then intergranular attack seems to be eliminated. (4) Impact value on heat-affected zone is the highest, and gradually decreases on weld metal and next junction parts. Generally Cb bearing electrode is superior and there is no difference among other electrodes. (5) The organization of corrosion in HNO3 and H2SO4 is not same. In the former grain boundaries containing precipitated carbide are selectively attacked, and in the latter over-all matrix is corroded. Therefore in HNO3 the differential effects of heat treatment seem to greatly indicate, while not so different in H2SO4. Range of corrosion amount in the former widely covers from 0.16 gr/m2-hr to 62.5 gr/m2-hr, in the latter slightly from 2.7 gr/m2-hr to 7.5 gr/m2-hr
In order to specify the notch toughness of steels the authors recently proposed the adoption of the criterion : φ=(maximum load)/(maximum load-point deflection) at room temperature on the notched slow bending test. In this report the behaviors of φ under three kinds of deflection rates were investigated, using the V-type standard charpy specimens, in connection with the notch toughness of materials. As the results of this experiment, the behaviors of φ were found as follows: (a)φ value remains constant within certain temperature range into which room temperature is included. (b) The larger deflection rate causes the transition temperature and φ value of material to be higher. And thus the larger φ value is connected with the higher transition temperature. Consequently the presumption of the notch toughness of materials by φ value in the notched slow bending test could be substantiated in the case of various deflection rates.
In the previous report, authors confirmed the upper limit of the tip temperaure. In this report, the effect of tip temperature for gas ratio of oxy-acetylene flame was determined. The gas ratio O2/C2H2 was calculated from gas pressures and consumptions on Type III (see Table 1 in Report 1). The test results showed that; (a) Gas ratio was increased accoding to temperature rise. (d) Gas ratio in the so called "Neutral Flame" had to be shown that's O2/C2H2 to the conditions which have been used. (c) The more oxygen and acetylene pressure rose, the more there were few effects of tip temperature for gas ratio, when suitable volume of acetylene was supplied to tip.