As the arc force is considered to be an important factor in the problems of the penetration in arc welding and of the characteristic of welding rod, we made some measurements of it in the argon-tungsten arc, using a kind of electromagnetic balance (Figs. 1 and 2). The experimental results are summarized as follows: (1) The impinging force of shielding gas is found to be additive to the arc force. (Figs. 5 and 6) (2) The arc force varies little with the arc length or the thickness of electrode in the usual range. (Fig. 6) (3) The arc force depends principally upon the arc current and is proportional to the square of it. (Fig. 7) (4) The arc force in DCRP is almost 15% less than that in DCSP, and these are given by the following experimental formulae. farc. S.P.=0.455×10-4I2 farc. R.P.=0.385×10-4I2 (5) The addition of hydrogen into shielding gas is found to increase the arc force. (6) The main part of the arc force in argon-tungsten arc is considered due to the impinging force of high temperature gas of arc.
To investigate the workability of type 316L austenitic stainless steel, authors have studied strength, ductility, hardenability, corrosion resistance and effects of post heat tratment on the abovementioned properties after cold or hot tensile straining is applied. During fairly severe hot bending cracks were found in some locations of the bending plastic deformation region. In order to study the cause of these cracks, hot ductility during hot tensile straining was investigated by applying the reproducing apparatus of weld thermal and stress cycles. Test results are summarised as follows : 1. In the bending formation of type 316L austenitic stainless steel, cold working is preferable from the viewpoint of workability and performance after the working-up. 2. Hot bending should be performed above the temperature of 800°C. Especially in the case of heavy working-up, care must be taken against cracks due to decreased ductility by inter-granular precipitations at the temperatures range from 650°C to 750°C. 3. After working-up, solution heat tratment (1050°C, 1/2 hr, air cooled) is desirable. Ductility and corrosion resistance reduced by working-up are enhanced sufficiently by solution heat treatment.
On the basis of the experimental results described in the first report and an assumption that a molten metal welded reaches an equilibrium state with produced slag and the compositions of molten metal and slag when reached the equilibrium are retained by them after solidification, the oxidizing reactions of carbon, silicon and manganese were discussed. And the equilibrium constants of those reactions between weld metal (weight %) and slag (mole %) were obtained as follows:…… Lo=(∑FeO)/[O]=341 [C]⋅[O]=0.00446 Ksi=(∑SiO2)/(∑FeO)2⋅[Si]=0.49 KMn=(∑MnO)/(∑FeO)2⋅[Mn]=3.68 The limit contents of carbon, silicon and manganese of weld steel free from porosity were deduced with those values.
The effect of five alloying elements on notch toughness of basic weldmetals were investigated. By manual are welding the all weld metals were obtained which composions were varied by systematic addition of alloy elements. Manganese and nickel decreases tramsition temperature at a rate of 20°C and 15°C per 1 percent, but vanadiam raises transition temperature 20°C per 0.1 percent. Molybdenum does not change transition temmperature up to 0.15 percent, but by farther addition it raises transition temperature at a rate of 6°C per 0.1 percent. Chromium raises transition temperature several degrees up to 0.4 percent, but decreases it by further addition of chromium.
By the high speed camera, the welding phenomena were photographed together with images of arc voltage and current on the same films in use of the cathode ray oscilloscope. By the high speed motion pictures, the following points were studied. (1) Variation of arc voltage and current at instant of separation of molten metal droplet from wire end. (2) Effects of polarity on shapes of droplet and on its transference.
This paper deals with the effect of steel temperature from the standpoint of cutting efficiency. The technique employed in this study was essentially the same as that described in the previous report excepting that each test specimen was heated with gas burners and cutting was done when its temperature slowly dropped to the testing temperature. The results showed that steel temperature has a substantial influence on both the oxygen consumption requird for cutting and the speed of cutting. Concerning the relations among steel temperature, cutting efficiency and cutting variables, experimental formulas were obtained. Moreover, from these formulas it was found that the maximum cutting efficiency obtainable was increased in comparison with the room temperature. For instance, the efficiency was increased by 33, 67 and 160 per cent at the respctive steel temperatures of 400, 700 and 1, 000°C. Furthermore, the temperature distribution in the steel ahead of the cutting reaction zone and the direction of cutting was measured. Some considerations were made on the results obtained.