Automatic Arc Welding of Pressure Vessels by Fus-arc Welding Machine

"Fus-arc Welding Machine" has been used for welding of boilers and other pressure vessels. In this report the process and results of investigations and experiments on its routine working are given.It can be summarized as follows :1. Sulphur cracking is perfectly prevented by use of multi-pass welding method.2. Mechanical properties of multi-pass welded deposit metal which is stress-relieved are as follows :Yield point, 35-40 kg/mm2Ultimate strength, 45-50 kg/mm2Elongation, 28-30%Reduction of area, 60-70%Impact value (Izod), 6-12kg-mFrom this it will be seen that this welded metal is suitable for pressure vessel welding.3. Fatigue strength of joint specimens is equal to that of mother metal and fatigue strength of columnar structure is about 94% of that of mother metal.So the general opinion that columnar structure is weak for fatigue may be corrected.4. When welding the end of longitudinal joint of cylindrical vessel, magnetic blow occurs but it does not disturb the working.5. In the operation mentioned above, we have proper opposite strain, so we can keep the difference between the maximum and minimum diameter of any sections below 1% of designed diameter.