A New Method of Welding

1920 Scientific American  
System of Holding the Welding Rod to the Rear of the Torch T HE usual method employed in autogenous weldlng con sists in 'hohling the torch inclined in the dil'ection o.f the plaoee to be welded and imparting to. it a slight vibratory movement. A new method has 'bee n recently described in the French magazine Revue da la Soudure Autogene (July-Augnst) called SOlldure en arriere (Welill ng to. the Rear). In this pro /less the welding rod or filler rod (I.e., the stick which tht> oper ator holds
more » ... t> oper ator holds in front of the blow pipe and which gradually melts and fills up the space between the edges of the two. pieces of FloG. L WELD,ING DF THICK SHEEl'I'S OF MEl'A L metal that al'e being joined), follows the torch instead of preceding it. Thi'S process, which was devised for welding soft steel by M. Roulleau dur'ing the war, and which has bee n employed in a number of iactmies, both in Italy and in France, presents considerable advantages: the metal is sounder, the rapidity of advance is greater, and, finally, there is a sa ving of at least 25 per cent in la:bor, in gas, and in filler metal. The fusion of the fi ller metal is affected no longer directly by the point of the flame but by the heat proceeding from the entire flame, the torch being inclined towards the rear, i.e., towards the welding rod. The stick of filler metal is pretty smartly inclined with re spect to the line of the welding in the forward direcfh'n, i.e., in the dil"ection contrary to that of the indination of the flame. The angle which appears to be the most favorable between the line of welding and the filler ·red is 45 deg. for fuieknesses starting at 6 to 7 mm. and a little bit less below these down to 30 deg. for weldings upon sheets of metal 3 mm. in thickness. This inclination, furthermore, is a function of the move ment which is imparted to the end of the filler :ro::l in the line of the -welding. In thicknesses of about 6 mm. this move ment oonsists in causing the extremity of the filler rod to FIG. 3. POSITION OF THE TORCH, TIP OF FLAME IN ANGIJE FORMED BY THE CHAMFERS melt, by moving alternately from one side to the other of the line of welding (Fig. 1). In thicknesses below 6 mm. the movement,becomes at first ellipsoidal in character and with shee' ts of metal having a thickness of from ,3 to 4 mm. (and still more so for these having a thickness of 2 mm.) it finally exhibits a back and forth longitudinal movement unac<Xlmpa nied by a transverse movement (Fig. 2) . In both cases the extremity of the filler rod remains cons1:antly immersed in the fused metal. In order that the welding line may present a homogeneous aspect it is advisable to operate at the same rate of speed from start to finish. otherwise if one moves the torch too rapidly at one end the free fusion and the regular advance will not be obtained until after the lapse of a certain length of time from the begin' ning of the welding. It is well, how eyer, previously to heat the sheets of metal with the blow pipe along the line of the weld for a breadth of a few centi meters. The blow pipe and the filler stick are held, as indi cated, the tip of the flame penetrating tho:roughly into the angle of the opposite chamfers or beveled edges of the sheets of metal, and the first melting is obtained by imparting a slight gyratory movement; then the filler rod 1fl immoohtely introduced into the molten metal, while at the same time the blow pipe begins to advance at a regular rate of speed. The filler rod, on the other hand, which immediately follows the flame, is given a reciprocating movement, either perpendic· ular to the edges of the line of welding, or else more or less elliptical or longitudinal, according to the thickness of the metal, but always retaining the same angle of in-clination. By following this method the welding is accomplished in a normal and very continuous fashiO'l1. The operator must be careful to employ an amount of filler sufficient to entil"ely close the line of welding with neither an excess nor a defi ciency. Upon arriving at the end of the line of weldin' g the FIG. 2. WELDING OF THIN SHEETS OF , METAL position of the blow pipe is changed as required, in order to secure a neat 'finish, the blow ,pipe and the welding stick being skilfully manipulated as in the ordinary process. Since the molten metal is directed towards the rear, it is always the faces of the chamfers which are attacked; the welding i< s of the character ]mown as bien traverse (well filled), and smears are almost impossil ble. However, the operator should never proceed with too much speed, but must go slow, enough to give the faces of the chamfers time fully to melt, while, at the same time, avoiding the creation, by going too slow, of "candles" of melted metal on the opposite side of the welding by reason of too great an applioeation of heat at the point of the V (Fig. 3) . ELECl'ROPERGUSSIVE WELDING. E. VIALL descrIbes a method of jointing wires by connecting the two pieces to the tenuinals of a charged condenser, and bringing them suddenly together with some force. Sufficient electrical energy is liberated by the diseharge to melt the wires, while the force of the blow welds them together. 522
doi:10.1038/scientificamerican06011920-522asupp fatcat:wmsstp3zmzhbtk45t7yco3u7gq