05 Welding processes 7 misc processes

Welding processes7 misc processe

           ! "#"$ % &' ( ") *   +,-.,/ 012-.'3'4.3-& 2.-0.2.-)'4(56. 56.24.'' 1.''27,24-2 3 &'89  -'  4-' "-' ,--047:')2'7 04'27-'-'7 0&40-..2'22700:4 :340&-.'0.&004 '.04''')'4   +,-.,/  4-' & 4 -' 0  2 . ;:4   '   :4 :' & ,    -4 .4-'70'.'3.',)-'-7<7 .24''0'4,704;-':34<.'7 '3  '0 .          .2   7  ;    ;'  -042  +/ 78.'.70''404'.-0 7= *5.'2847'>8 ;0?.2'82.:  +/  --2..)4+''.'2.'@/  '.07;'..'  &'4;4@2A:.  &'3;.'0'0?-440.  >,B7"&,CD"EFC">DC$ >,B7 "&7 ,CD   2  .'4 .     8  . '  2 04 '3   '4287<' .'0.77G2402'&'.2 2'..22 '4082.'H.  +0?/  +0?/ >,B ">DC$ +/         0? 8    04  H 2  04  2 . 0'7'2.&0.8:. ''22.4H2 8'-'27'.@&.84 .7''70772'' B,C>CI J&E,CFC1,CD J,&FF&K">LB"">EC$$",E J&E&B,&,E"MFC"DFEFC&CFEF"C$>C" JE",CD1,EDE,C$F"E,&FCFEFC&CF&,C$E"""D>C" JEF>>FE>C" J,EE,&>,CDC$$",E J&1",CDEFD"L">"K" J1,CD;,1>,D" JDE>>"N&"CFCC$&FD"E"C&,&"E,>   DEFINITION "& ">DC$ a resistance welding process that   -  2  . .4 .7  -4   0? 87 04   0.'H..' PRINCIPLES OF OPERATION &B&BEF"724&'8'4@243 .4.,.80.4.2''4@2 .7'2'7''..'2&8.)@'   "EFC">DC$+"/ ,.4..'04.4 -4''4. Capacitor Discharge Percussion Welding &B&B",,&FE'7.0403&204-'. bank +-/'-2'40''-004' '2' Magne"c Force Percussion Welding FE,$C"&FE"704.'&204-@'82.' .'&-@'- &-.804'4@2.' .4.!5B@:472'022.2.'2.2 [...].. .MISC Processes 6 Electroslag and Electrogas Welding ELECTROSLAG WELDING AND ELECTROGAS WELDING are two related procedures that are presently used to weld thick-section materials in the vertical or near- vertical position between retaining shoes MISC Processes 6 Electroslag and Electrogas Welding Primarily applied for joining steels of thicknesses over 50 mm (2 in.), electroslag welding (ESW)... structures Electrogas welding is a method of gas-metal arc welding (if a solid wire is used) or flux-cored arc welding (if a tubular wire is used), wherein an external gas is supplied to shield the arc and molding shoes are used to confine the molten weld metal for vertical position welding MISC Processes 6 Electroslag and Electrogas Welding Electroslag welding is a vertical welding process in which... oxide The molten iron is the actual welding material; the aluminium oxide is much less dense than the liquid iron and so floats to the top of the reaction, so the set-up for welding must take into account that the actual welding material is on the bottom and covered by floating slag MISC Processes 7 Thermite Welding The aluminothermic reaction that occurs in thermite welding follows the general formula:... metal +heat whereas the typical reaction that occurs in the thermite welding of rails is: FE2O3 + 2AL 2FE + AL2O3 (HEAT ®850 KJ) and the typical reaction that occurs in the welding of copper conductors to steel rails is: 3CU2O + 2AL 6CU + AL2O3 (HEAT ®1060 KJ) MISC Processes 8 Explosion Welding MISC Processes 8 Explosion Welding Pressure is applied by detonating a layer of explosive that... which is cast or pressed onto the flyer plate Process is particularly suitable for cladding a plate or slab with a dis-similar metal Note: Significant safety issues MISC Processes 9 Stud Welding MISC Processes 9 Stud Welding Similar to Flash Welding The stud (a small part; a threaded rod, hangar, handle) serves as one of the electrodes while being joined to another component The other component is usually... or continuously to maintain an adequate slag covering over the pool of molten metal Two or more retaining shoes hold the molten metal in place until it has solidified MISC Processes 7 Thermite Welding Thermite welding is an exothermic welding process that uses thermite to melt metal, which is poured between two workpieces to form a welded joint It was developed by Hans Goldschmidt around 1895 Commonly... (ESW) involves high energy input relative to other welding processes, resulting in generally inferior mechanical properties, specifically lower toughness of the heat-affected zone (HAZ) However, the high deposition rate and relatively low cost of the process make it attractive for heavy structural fabrication The as-welded properties of electrogas welding (EGW), usually applied to steels under 50 mm... plate The contact pressures are extremely high; the kinetic energy of the plate striking the mating component causes a wavy interface The impact mechanically interlocks the two surfaces, so that pressure welding by plastic deformation also takes place (b) The flyer plate is placed at an angle Any oxide films present at the interface are broken up and propelled out of the interface The resultant bond strength... process, and once a molten bath is achieved, the arc is extinguished Confined by cooling shoes, the molten weld pool is shielded by the molten slag, which moves along the full cross section of the joint as welding progresses The conductive slag is maintained in a molten condition by its resistance to electric current passing between the electrode and the work ESW can be considered a progressive melting and