OTHER WELDING PROCESS

OTHER WELDING PROCESS

@ Resistance Welding :-

            the resistance welding is a group of welding process in which parts to be welded are 1st heated to the fusion temperature by the resistance of the work piece to the flow of electric current and then squeeze by the mechanical pressure to an accomplish weld no filler metal id added

@ Principle of resistance welding :-

      principle envolved in resistance welding is that when an electric current is passed at a high temperature , so obtain by the resistance of the metal to passage to the current the contact surface are not in perfect contact and offer the higher resistance and are thus heated up first , the heat produced is given by the relationship where
h= total heat generated
I = Electric current
R = resistance
T= Time

@ Resistance spot and seam Welding :-

              the seam resistance welding is similar to spot welding except that the shades overlap each other making a continous weld seam. in this process the spot welding tips are placed by continously relating wheel type electrode. the electrodes power driven and grip as well as move the work while rotating . The current is automatically turn on and off at regular interval and it is so adjusted with the speed of the roller that overlapping spotof weld are produced to give a gas and liquid proof joint such a welding is called roll spot welding or stitch welding

@ Principle of operation :-

          the principle of seam welding . the work pieces to be seam welder are clean, overlap suitably and placed between the two circular electrode . which clamped the workpiece together by the electrode force, switch on the coolant and the current supply as the first current impulse is applied,the power driven circular electrode are set in rotation and the work piece moves forward if  the current is put off and on quickly a continous  fusion zone made up of overlapping is obtained . it is also known as stitch welding. if individual spot weld are obtained by constant and regularly time of the elding current the process  is known as spot welding

@ advantages of seam welding :-

          - The roller replacement problem is less
- Heat affected zone is less, because the heat input is low
- the process is fast

@ Disadvantages :-

* Cost of equipment is high as compared to spot welding set
* it is difficult to weld thickness greater than 3mm

@ Application of seam welding ;-

                 it is used for welding of stain less steel aluminium and its alloys , nickel its alloy, etc