<\/figure><\/div>\n\n\n\nSurfacing Weld<\/h3>\n\n\n\n As the name indicates, these welds are simply depositions of weld metal on the surface of base metal. This kind of surfacing is generally done to obtain a corrosion resistant surface on a metal surface, or to obtain a hard-facing surface that is resistant to wear and tear. <\/p>\n\n\n\n
Sometimes, the surfacing is in the form of buttering \u2013 done to make one surface compatible for welding with another part. Sometimes surfacing is done to build up a surface to restore its\u2019 thickness.<\/p>\n\n\n\n <\/figure>\n\n\n\nPlug Weld <\/h2>\n\n\n\n See the above figure. As the name suggests, these welds are meant to plug<\/em> a hole. One plate is kept over another, and a hole exists in one of the plates. The weld is deposited in this hole to plug it. The walls of the hole are straight. Although, it is not necessary. The walls can be inclined too.<\/p>\n\n\n\nThe hole is generally filled fully, although this is not necessary either. The hole can be partially filled too, as desired by the designer. Plug welds are sometimes considered as a replacement for rivet joints.<\/p>\n\n\n\n
Slot Weld <\/h2>\n\n\n\n Slot weld is also shown in the figure above. It is quite similar to the plug weld, except that the hole is not circular, it is an elongated hole in the shape of an ellipse. This elongated hole is filled with weld metal, thus joining the part containing the hole to the second part that is exposed through the hole. <\/p>\n\n\n\n
Like plug weld, the hole may be partially filled or completely filled.<\/p>\n\n\n\n
Flash Weld <\/h2>\n\n\n\n In this type of weld, the two parts to be joined are kept at a predetermined distance to each other, and a electric current is passed. The small gap between the parts gets ionized due to the high voltage difference, and offers resistance to the current flow. Due to this resistance, heat gets generated, and the surface of both the parts gets melted. <\/p>\n\n\n\n
When this happens, both the parts are pressed against each other with force. This achieves the weld.<\/p>\n\n\n\n
<\/figure><\/div>\n\n\n\nSeam Weld<\/h2>\n\n\n\n This is a type of weld produced by resistance welding. Two sheets are pressed against each other between two wheels. During the welding, the work-pieces roll between the two wheels. The wheels have a current flowing between them. <\/p>\n\n\n\n
The electrical resistance posed by the work-pieces generates heat between the two parts. This heat melts the part surfaces facing each other at the inside at the point of contact of wheels, and a weld gets created. <\/p>\n\n\n\n
As the wheels roll on, a seam of weld gets thus created along the length. Hence the name seam weld.<\/p>\n\n\n\n
Spot Weld<\/h2>\n\n\n\n Spot welding is a variation of seam resistance welding. Instead of a length, the weld is in the form of a nugget localized at a spot. Hence the name spot weld. <\/p>\n\n\n\n
Upset Weld <\/h2>\n\n\n\n An upset weld is similar to flash weld. Heat for welding is obtained through resistance offered by the work-piece to the flow of current. However, the weld is obtained not simultaneously over the entire area, but progressively along a joint. Pressure is applied between the abutting parts to achieve the weld.<\/p>\n\n\n\n
What Type Of Weld Is Suitable For A Given Weld Joint Type?<\/h2>\n\n\n\n As we have seen above, a joint and weld are not the same thing. The weld and joint combine together to make a weld joint. However, not all weld types can be combined with all joint types. The following table tells what welds can be combined with what joints to produce a weld joint.<\/p>\n\n\n\n