Part 15 (2/2)

Steel is welded with dry borax powder, this flux being applied at the same time as the iron flux justand a s may also be used for either class of work Mixtures of sal ammoniac with borax have been successfully used, the proportions being about four parts of borax to one of sal a powders are on thesatisfactory results

After the h to reach a red heat, it is reh in size, the ends are dipped into a box of flux If the pieces are large, they e of the fire and the flux then sprinkled on the portions to be joined

A greater quantity of flux is required in forge welding than in electric or oxy-acetylene processes because of the losses in the fire After the powder has been applied to the surfaces, the work is returned to the fire and heated to the welding te scarfed, the two pieces to be welded are placed in the fire and brought to the correct tenized by experiment and experience The in to be thrown out of the fire and naturally this is a hard point to distinguish At the welding heat the metal is alainst the background of the fire and coal the color appears to be a creaht yellow and the work feels soft as it is handled

It is absolutely necessary that both parts be heated unifor temperature at the saether in the fire as possible and side by side When reether, time is saved if they are picked up in such a way that when laid together naturally the beveled surfaces coether This makes it necessary that the workman remember whether the scarfed side is up or down, and to assist in this it is a good thing to mark the scarfed side with chalk or in some other noticeable manner, so that nothe work on the anvil

The co allows the temperature to rise until the s above this point will surely result in burning that will ruin the iron or steel being handled The best welding heat can be discerned by the appearance of the ained with this particular material Test welds can be ained through different degrees of heat can be known before atte_--When the work has reached the welding te been replaced in the fire with the flux applied, the two parts are quickly tapped to remove the loose scale from their surfaces They are then i placed in a diagonal position if both pieces are straight The lower piece is rested on the anvil first with the scarf turned up and ready to receive the top piece in the position desired The second piece must be laid in exactly the position it is to finally occupy because the two parts will stick together as soon as they touch and they cannot well beonce been allowed to come in contact with each other This part of the work must be done without any unnecessary loss of time because the comparatively low heat at which the parts weld allows the tereatest difficulty will be experienced in withdrawing theit joined before it cools below this critical point The beveled edges of the scarf are, of course, the first parts to cool and the weld must be made before they reach a point at which they will not join, or else the ill be defective in appearance and in fact

If the parts being handled are of such a shape that there is danger of bending a portion back of the weld, this partthe work on the anvil to be joined

The work the joint, and his helper, if one is ee With the two parts of the work in place on the anvil, the work at a point directly over the center of the weld, so that the joint will start froes After the pieces have united the helper strikes alternate bloith his sledge, always striking in exactly the same place as the last stroke of the workes of the weld and are resses

The ai the first part of the operation should be to make a perfect joint, with every part of the surfaces united, and too much attention should not be paid to appearance, at least not enough to take any chance with the strength of the work

It will be found, after coth equal to one-half the thickness of thewelded This loss is occasioned by the burned metal and the scale which has been for the Weld_--If it is possible to do so, the material should be hammered into the shape that it should re It will usually be found, however, that the metal has cooled below the point at which it can be worked to advantage It should then be replaced in the fire and brought back to a forging heat

[Illustration: Figure 52--Upsetting and Scarfing the End of a Rod]

While shaping the work at this forging heat every part that has been at a red heat should be haht and even blows as it cools This restores the grain and strength of the iron or steel to a great extent and makes the unavoidable weakness as small as possible

_Forms of Welds_--The simplest of all welds is that called a ”lap weld” This is made between the ends of two pieces of equal size and si one on top of the other while they are haure 52) is made between the ends of two pieces of shaft or other bar shapes by upsetting the ends so that they have a considerable flare and shaping the face of the end so that it is slightly higher in the center than around the edges, this being done to ether first The pieces are heated and pushed into contact, after which the ha is done as with any other weld

[Illustration: Figure 53--Scarfing for a T Weld]

A for the end of a bar to a flat surface and is called a jump weld The bar is shaped in the same way as for a butt weld The flat plate may be left as it is, but if possible a depression should be made at the point where the shaft is to be placed With the two parts heated as usual, the bar is dropped into position and hammered from above As soon as the center of the weld has been made perfect, the joint may be finished with a fuller driven all the way around the edge of the joint

When it is required to join a bar to another bar or to the edge of any piece at right angles the work is called a ”T” weld froure 53) The end of the bar is scarfed as described and the point of the other bar or piece where the weld is to be e like one-half of a circular depression The pieces are then laid together and hammered as for a lap weld

The ends of heavy bar shapes are often joined with a ”V,” or cleft, weld

One bar end is shaped so that it is tapering on both sides and coe like the end of a chisel The other bar is heated to a forging tethwise direction so that the V-shaped opening which is fore of the first piece With the work at welding heat, the two parts are driven together by ha then continues as with a lap weld, except that the work is turned over to coure 54-Splitting Ends to Be Welded in Thin Work]

The forether in the proper position after reht loss of tiht stock, this fall of temperature would be so rapid that the ould be unsuccessful, and in this case the ”lock” weld is resorted to The ends of the two pieces to be joined are split for some distance back, and one-half of each end is bent up and the other half down (Figure 54) The two are then pushed together and placed in the fire in this position When the welding heat is reached, it is only necessary to take the work out of the fire and haether, inasmuch as they are already in the correct position

Other forms of welds in which the parts are too s the them so that they can be temporarily fastened in any convenient hen first placed in the fire