MIG Filler Wire

Low carbon or mild steel filler wire specifications are found in the CSA standard W48.8 and in the AWS standard A5.18.

CSA

ER 480S-6

E = Electrode

R = The wire can be used as filler rod for TIG welding

480 = 480 MPa tensile strength

S = Solid wire

6 = Deoxidizers and other additions in the wire

AWS

ER 70S-6

E = Electrode

R = The wire can be used as filler rod for TIG welding

70 = 70,000 psi tensile strength

S = Solid wire

6 = Deoxidizers and other additions in the wire

MIG Gases

MIG Gases (Short Circuit Transfer)
Metal	Gas	Advantages
Carbon Steel	75% argon + 25% carbon dioxide	Less than 1/8” thick -High welding speed -No burn-through -Minimum distortion and spatter
	75% argon + 25% carbon dioxide	More than 1/8” thick -Minimum spatter -Clean weld appearance -Good puddle control in vertical and overhead positions -Both GMAW and FCAW
	carbon dioxide	-Deeper penetration -Faster welding speeds -Both GMAW and FCAW
Stainless Steel	90% helium + 7.5% argon + 2.5% carbon dioxide	-No effect on corrosion resistance -Small heat-affected zone -No undercut -Minimum distortion
Low Alloy Steel	60-70% helium + 25-35% argon + 4-5% carbon dioxide	-Minimum reactivity -Excellent toughness -Excellent arc stability, wetting characteristics and bead contour -Little spatter.
	75% argon + 25% carbon dioxide	-Fair toughness -Excellent arc stability, wetting characteristics and bead contour -Little spatter
Aluminum, Copper, Magnesium, Nickel and their alloys	Argon & argon + helium	-Satisfactory on sheet metal -Argon-helium preferred on material over 1/8”

MIG Gases (Spray Transfer)
Metal	Gas	Advantages
Carbon Steel	Argon + 1-5% oxygen	-Improved arc stability -More fluid and controllable weld puddle -Good bead contour -Minimum undercut -Higher speeds than pure argon
	Argon + 3-10% carbon dioxide	-Good bead shape -Minimum spatter -Reduced chance of cold lap -Flat/horizontal position only
Low Alloy Steel	Argon + 2% oxygen	-Minimum undercut -Good toughness
Aluminum	Argon	Up to 1" thick -Best metal transfer and arc stability -Least spatter
	35% argon + 65% helium	Up to 1" thick -Higher heat input than pure argon -Improved fusion characteristics with 5XXX series Al-Mg alloys
	25% argon + 75% helium	Over 3” thick -Highest heat input -Minimum porosity
Magnesium	Argon	-Excellent cleaning action
Stainless Steel	Argon + 1% oxygen	-Improved arc stability -More fluid and controllable weld puddle -Good bead contour -Minimum undercut on heavier stainless steels
	Argon + 2% oxygen	-Better arc stability & welding speed than 1% oxygen mixture for thinner stainless steels
Copper, nickel and their alloys	Argon	-Good wetting characteristics -Decreased fluidity of weld metal for thickness' up to 1/8”
	Argon + helium	-Higher heat inputs to 50 and 75% helium mixtures offset high heat dissipation of heavier gauge materials
Titanium	Argon	-Good arc stability -Minimum weld contamination -Inert gas backing is required to prevent air contamination on back of weld

Mig Whip Size

Whip Size
Amps	Max. Cable Length	Cable Size
200	15'	No. 1
300	15'	No. 2/0
400	15'	No. 3/0
500	15'	No. 4/0
600	15'	No. 2-2/0

MIG

MIG welding (also known as GMAW or wire welding) is one of the most popular forms of welding. It is mainly used in high production projects where speed is a factor.

• MIG = Metal Inert Gas

• GMAW = Gas Metal Arc Welding

• Always DC current. DCEP usually for steel and always for aluminum.

• Often constant potential (CP/CV) machines used.

• High deposition rate

• 92% - 98% filler metal forms weld deposit. 

• Concentrates more current at one point than SMAW arc, producing deeper penetration.

• Less heat input per linear inch of weld.

• Suited to welding low carbon structural steels, low alloy stainless steels and hardsurfacing.

• Penetration is highest when doing globular transfer.

• Spray transfer requires a minimum of 80% argon and only on DCEP. 

• Longer stickout = voltage increases/current decreases 

• Shorter stickout = voltage decreases/current increases

• Inductance controls the rate of current rise. 

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Metal Melting Temperatures

Metal Melting Point (Celcius) (Farenheit) Admiralty Brass 900 - 940 1650 - 1720 Aluminum 660 1220 Aluminum Bronze 600 - 655 1190 - 1215 Antimony 630 1170 Beryllium 1285 2345 Beryllium Copper 865 - 955 1587 - 1750 Bismuth 271.4 520.5 Brass 930 1710 Cadmium 321 610 Cast Iron, gray 1175 - 1290 2150 - 2360 Chromium 1860 3380 Cobalt 1495 2723 Copper 1084 1983 Cupronickel 1170 - 1240 2140 - 2260 Gold 1063 1945 Hastelloy C 1320 - 1350 2410 - 2460 Inconel 1390 - 1425 2540 - 2600 Incoloy 1390 - 1425 2540 - 2600 Iridium 2450 4440 Iron 1536 2797 Lead 327.5 621 Magnesium 650 1200 Manganese 1244 2271 Manganese bronze 865 - 890 1590 - 1630 Mercury -38.86 -37.95 Molybdenum 2620 4750 Monel 1300 - 1350 2370 - 2460 Nickel 1453 2647 Niobium (Columbium) 2470 4473 Osmium 3025 5477 Platinum 1770 3220 Plutonium 640 1180 Potassium 63.3 146 Red Brass 990 - 1025 1810 - 1880 Rhodium 1965 3569 Selenium 217 423 Silicon 1411 2572 Silver 961 1760 Sodium 97.83 208 Carbon Steel 1425 - 1540 2600 - 2800 Stainless Steel 1510 2750 Tantalum 2980 5400 Thorium 1750 3180 Tin 232 449.4 Titanium 1670 3040 Tungsten 3400 6150 Uranium 1132 2070 Vanadium 1900 3450 Yellow Brass 905 - 932 1660 - 1710 Zinc 419.5 787 Zirconium 1854 3369

MIG like TIG

Everyone wants to make their welds look like TIG welds these days. To do so you don't really have to do much. If you just step forward, then pause and let your puddle fill in you will get the general profile of a TIG weld. Just practice with your rate of travel and pause length and you will have it in no time.
This is my attempt:

TIG

TIG welding may be one of the more difficult welding processes to learn but once you get it down it just looks and feels like you should have been doing it all along.

Here's some tips to get you started:

• TIG = Tungsten Inert Gas

• GTAW = Gas Tungsten Arc Welding

• Tungsten Melting Temp.=3375ºC (6100ºF)

• Water cooled torch for amperage’s over 150 A

• TIG machines must produce a constant current (CC) 

• Mild and stainless steel = DCEN (approx. 2/3^rds of heat in workpiece, 1/3^rd of heat in electrode)

• Aluminum = AC or ACHF (Greater current during the DCEN half cycle and a reduced DCEP half cycle)

• Water Cooling Pressure = Around 35 psi (245 kPa), approx. 1L per minute.

• Pulsed Current used for thinner materials and for vertical and overhead positions.