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highly reflective over a large range of light wavelengths. is metal characteristic makes welding silver difficult for a laser,
but poses no problems for a Pulse Arc welder. Second, silver is a very mobile metal when in a liquid state and has low
surface tension when compared to other metals. Because of these properties, how the weld energy is applied to silver is
important.
When welding silver it is important to understand the concentration of your weld energy relative to the size of the silver
being welded. For very small welds, a sharp electrode poses no problem. is means that in the Orion’s arc mode, silver
will typically behave well even with a concentrated, focused beam of energy (i.e. a very sharp electrode tip point). However,
as the desired spot size gets larger (bigger arc mode welds and almost all pulse arc mode welds) the liquid silver is easily
pushed around by the welding pulse. is will lead to large blobs of material being displaced from the weld site resulting
in a noticeable hole. To avoid this problem, simply un-focus the weld energy by creating a truncated electrode tip flat. e
size of the flat depends on the size of the weld. For relatively small welds a small flat is all that is required. For very high
energy welds the electrode may be completely flat (1mm diameter).
Resistance welding silver in tack mode is very difficult because of silver’s high electrical conductivity. Sterling silver has a
high electrical conductivity very similar to that of copper. However, Argentium silver is approximately 30% less conductive.
is means that more heat can be generated during the spot welding process due to the additional material resistance.
Use Argentium silver if your application requires spot welding as opposed to pulse arc welding. Even while pulse arc
welding it may be desirable to use Argentium silver because of its superior tarnish resistance. in Argentium silver parts
can be welded directly using copper electrodes. icker silver parts may require a weld projection or “bump” to focus the
weld current. is welding strategy is discussed in detail in Chapter 4 - Tack Welding.
ALUMINUM AL
Aluminum behaves very much like silver during the pulse arc welding process. Aluminum has a very low melting
temperature (660 deg C) and is very mobile when in a liquid phase. is means that the same principles that apply to
welding silver also apply to Aluminum. Aluminum also has one additional complication that may make it difficult to work
with in some situations. is metal is very susceptible to hot cracking. On occasion the weld parameters or geometry may
be such that a crack may appear in the weld. Always perform test welds for strength verification. In general, pulse arc
welding in aluminum will produce a weaker weld than with other metals.
STAINLESS STEEL
Stainless steels are relatively simple to weld. e weld puddle looks smooth and joins easily and the resulting weld joint
is strong. Because of the low thermal conductivity of stainless steel, it is easy to hold the workpiece in hand while welding
without weld heat immediately making the workpiece too hot to hold. Use only stainless steel fill wire when welding. If
regular low carbon steel is used, the weld joint will eventually rust over time.
Austenitic stainless steels, (304 for example) weld easily. However, hot cracking is a possibility with this material. To
help avoid any cracking it is helpful to weld using an alloy that will produce a small amount of ferritic crystal structure in
the weld joint. e addition of the ferritic crystal structure will help suppress cracking. For example, when welding 304
stainless, a 308 stainless fill wire can be used. Not all situations will require crack suppression techniques. Smaller parts,
like those typically welded using the Orion, do not require these procedures. (201, 202, 205, 216, 301, 302, 303, 304, 305,
308, 309, 310, 312, 314, 316, 317, 321, 329, 330, 332, 347, 348, 384, 385 stainless steels).
Martensitic stainless steels (410 for example) have a high carbon content. is high carbon content increases the risk of
cracking. To decrease the risk of cracking it may be helpful to increase the workpiece temperature to between 200 – 300
deg C. Often material thinner than 3mm can be welded successfully without heat treatment provided that pure argon is
used during the welding process. (403, 410, 414, 416, 418, 420, 422, 431, 440, 501, 502, 503, 504 stainless steels).
LOW CARBON STEELS MILD STEEL
Low carbon steels typically weld easily with no major cautions. Please be advised that low carbon steel will rust and will
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