1. FILLER METAL OF ALUMINUM BASED ALLOYS

Table 1.1 - Chemical Composition Requirements for Aluminum Filler Metals

1.1 Filler Metal selection

1.1.1 Cracking

1.1.2 Corrosion Resitance

1.1.3 Elevated Temperature Service

1.1.4 Selection of Filler Metal

Table 1.2 - Suggested fillers for commonly welded aluminum alloys

1.1.5 Storage and Use of Aluminum Filler Metal

1.2 Typical procedures for welding Aluminum

Table 1.3 - Guide to the choice of filler metal for general purpose welding

1.2.1 GMAW

Table 1.4 - Approximate groove welding procedures for the gas metal-arc welding of aluminum

1.2.2 GTAW

Table 1.5 - Typical procedure for manual welding of groove joints in aluminum and its alloys by using the gas tungsten-arc welding process (electrode negative)

1.3 Properties and Performance of Weldments

Table 1.6 - Tensile strength and elongation of gas-shielded arc welded groove joints in some nonheat-threated aluminum alloys

Table 1.7 - Typical strength and elongation of gas-shielded arc welded groove joints in some heat treatable aluminum alloys

Table 1.8 - Effect of welding conditions on strength of groove joints in alloy 6061 with filler metal 4190

Table 1.9 - Minimum Tensile strengths at various temperatures across arc-welded butt joints in alluminum alloys

Table 1.1 - Chemical Composition Requirements for Aluminum Filler Metals ñ Top

Notes:
ΠThe filler metal shall be analyzed for the specific elements for which values are shown in this table. If the presence of other elements is indicated in the course of this work, the amount of these elements shall be determined to ensure that they do not exceed the limits specified for "Other Elements." Single values are maximum, except where otherwise specified.
� Silicon plus Iron shall not exceed 0.95 percent.
Ž Beryllium shall not exceed 0.0008 percent.
� The Aluminum content for unalloyed Aluminum is the difference between 100.00 percent and the sum of other metallic elements present in amounts of 0.010 percent or more each, expressed to the second decimal before determining the sum.
� Vanadium content shall be 0.05-0.15 percent. Zirconium content shall be 0.10-0.25 percent.

1.1 Filler Metal Selection. ñ Top

The proper choice of aluminum filler metal mainly depends on the base metal properties needed to be achieved and welding technique. Post weld cracking, corrosion resistance and behavior under elevated temperatures also need to be taken into consideration.

1.1.1 Cracking ñ Top

Cracking usually can be minimized by choosing a filler alloy of higher alloy content than the base metal. For example, alloy 6061 is extremely crack sensitive when welded with 6061 filler; but is readily welded with 4043 filler metal (LAC Stock # 4190), which contains approximately 5% Silicon. Alloy 4043 has the advantage of both melting and solidifying at a temperature lower than the usual base metal on which it is used. For this reason, it remains plastic after the base metal has cooled somewhat, and the contraction stresses which might cause cracking are relieved by the plasticity of the filler metal. Under other conditions a higher magnesium alloy filler- such as 5356 (Stk. # A106) and 5183 (Stk # A105) - increases weld strength and decreases crack sensitivity. Filler alloy 4043 should not be used on higher magnesium alloys 5083, 5086 or 5456, since excessive magnesium-silicide eutectics can develop in the weld structure to decrease ductility and increase crack sensitivity.

To control hot cracking of aluminum weldments, it is desirable to avoid weld metal compositions (the result of the filler metal plus dilution) that are known to be crack sensitive. Severe cracking is known to occur in weld metal when the geometry of the joints, coupled with weld metal chemistry and welding techniques, causes the dilution of the elements to fall within a critical composition range. Cracking problems decrease when the weld metal composition range is below or above this critical range. For silicon this critical range is from approximately 0.5% to approximately 2%. for example, a 4043 filler diluted 80% with alloy 1100 base material (as in a square butt weld) would result in a silicon content in the crack sensitive range.

1.1.2 Corrosion Resistance. ñ Top

Assemblies, vessels and drums for use in certain corrosive environments or with certain chemicals may require special filler alloys. These alloys may be of higher purity or may have closer composition limits on some of the alloying constituents. Aluminum-magnesium filler alloys are highly resistant to corrosion, but tend to be anodic to many other nonheat-treatable alloys, particularly in joints with low dilution. For this reason, they should be used with base alloys possessing a similar solution potential whenever the weld and base metal are to be continuously or cyclically exposed to an electrolyte. A good example is the use of 1100 (stk. # 4180) with 1100 parent metal in some salt water or corrosive applications.

1.1.3 Elevated Temperature Serviceñ Top

The choice of both base metal and filler metal is important when selecting aluminum alloys for elevated temperature service. Aluminum alloys of over 3.5% magnesium are not ordinarily recommended for continuous service at temperatures of 150°F and above.

1.1.4 Selection of Filler Metalñ Top

Metallurgically, the selection of the correct filler alloy greatly influences the service life of an aluminum weldment. Recommended filler alloys for general purpose welding of various aluminum alloy combination, including casting, are given in Tables 1.2 and 1.3. In the repair of castings, the filler alloy is usually chosen to match the composition of the casting.

Table 1.2 - Suggested fillers for commonly welded aluminum alloysñ Top

1.1.5 Storage and Use of Aluminum Filler Metal. ñ Top

A major step towards producing good aluminum welds is the use of high quality filler metal. It should be free of gas and non metalic impurities, with a clean, smooth surface free of moisture, lubricant or other contaminants. Certain care must be taken during storage and use to prevent contamination that could result in poor welds.

To avoid contamination, filler metal supplies should be kept covered, and stored in a dry place at a relatively uniform temperature. Spooled wire temporarily left un-used on the welding machine, in between work shifts, should be covered with a clean cloth or plastic bag if the feed unit does not have its own cover. If a spool of wire will not be used for a considerable length of time, it should be returned to its carton and tightly sealed. Original electrode or wire containers should not be opened until the contents are to be used.

Finally, it is very important in the Gas Metal-Arc process since a relatively small diameter filler wire feeds through the welding gun at a high rate of speed, that the electrode wire be uniform in diameter, of a suitable temper, free from slivers, continuous scratches, inclusions, kinks, waves or sharp bends, and spooled so that it is free to unwind without restrictions.

Lancaster Alloys Company is a reliable source for aluminum filler metal of the highest quality. Our customers can be absolutely sure of uniformity, absence of any surface defects and containment free products which do not require additional work that is readily available for welding in the condition received. Lancaster Alloys Company can offer a wide variety of re-sealable packing bags covered by requirements of AMS, AWS, and other commercial practices to keep the filler metal containment free as long as it stays in the original packaging.

1.2 Typical procedures for welding Aluminum ñ Top

There are several welding techniques and procedures used in joining Aluminum alloys. In this catalog we have outlined the two most widely use practices of groove welding for Gas Metal-Arc (GMAW) and Gas Tungsten-Arc (GTAW) welding.

Table 1.3 - Guide to the choice of filler metal for general purpose welding ñ Top

Notes:
1. Service conditions such as immersion in fresh or salt water, exposure to specific chemicals, or a sustained high temperature (over 150°F [66°F]) may limit the choice of filler metals. Filler metals A105 and A106 are not recommended for sustained elevated temperature service.
2. Recommendations in this table apply to gas shielded arc welding processes. For oxyfuel gas welding, only 4180, 4184, 4185, and 4190 filler metals are ordinarily used.
3. Where no filler metal is listed, the base metal combination is not recommend for welding.
Π4184 may be used for some applications.
� 4185 may be used for some applications
Ž 4190 may be used for some applications.
� A105 and A106 may be used. In some cases, they provide: (1) improved color match after anodizing treatment, (2) highest welding ductility, and (3) higher weld strength.
� 4191 may be used for some applications. It can supply high strength when the weldment is post-weld solution heat threaded and aged.

1.2.1 GMAWñ Top

For the GMAW process spooled filler metal is used in smaller wire diameters ranging from .030" to .1/16" (very seldom in 3/32").

Table 1.4 shows the typical groove weld procedure on GMAW.

Lancaster Alloys Company can suppply aluminum weld wire on layer wound spools in 2", 8", and 12" OD in accordance with requirements of AMS and AWS specifications. The inner end of each spool is easily accesible for alloy verification. Filler metal on each spool is one continuous length of wire free of splices.

Table 1.4 - Approximate groove welding procedures for the gas metal-arc welding of aluminumñ Top

Metal Thickness in.	Weld Position Œ	Root Opening, in.	Weld Passes	Electrode Diameter, in.	DC, Amps	Arc Voltage	Argon Gas Flow, cfh	Arc travel speed, ipm	Approximate Electrode Consumption, Lb/100 ft
1/16	F	None 3/32	1 1	.030 .030	70-110 70-110	15-20 15-20	25	25-45 25-45	1.3 2
3/32	F F,V,H,O	NONE 1/8	1 1	.030-3/64 .030	90-150 110-130	18-22 18-23	30 30	25-45 23-30	1.6 2
1/8	F,V,H F,V,H,O	0-3/32 3/16	1 1	.030-3/64 .030-3/64	120-150 110-135	20-24 19-23	30 30	24-30 18-28	2 3
3/16	F,V,H F,V,H O F,V O,H	0-1/6 0-1/16 0-1/16 3/32-3/16 3/16	1F,1R 1 2F 2 3	.030-3/64 3/34 3/64 3/64-1/16 3/64	130-175 140-180 140-175 140-185 130-175	22-26 23-27 23-27 23-27 23-27	35 35 60 35 60	24-30 24-30 24-30 24-30 25-35	4 5 5 8 10
1/4	F F V,H O F,V O,H	0-3/32 0-3/32 0-3/32 0-3/32 1/8-1/4 1/4	1F,1R 2 3F,1R 3F,1R 2-3 4-6	3/64-1/16 3/64-1/16 3/64 3/64-1/16 3/64-1/16 3/64-1/16	175-200 185-225 165-190 180-200 175-225 170-200	24-28 24-29 25-29 25-29 25-29 25-29	40 40 45 60 40 60	24-30 24-30 25-35 25-35 24-30 25-40	6 8 10 10 12 12
3/8	F F V,H O F,V O,H	0-3/32 0-3/32 0-3/32 0-3/32 1/4-3/8 3/8	1F,1R 2F,1R 3F,1R 5F,1R 4 8-10	1/16 1/16 1/16 1/16 1/16 1/16	225-290 210-275 190-220 200-250 210-290 190-260	26-29 26-29 26-29 26-29 26-29 26-29	50 50 55 80 50 80	20-30 24-35 24-30 25-40 24-30 25-40	16 18 20 20 35 50
3/4	F F V,H,O F V,H,O	0-3/32 0-1/8 0-1/16 0-1/16 0-1/16	3F,1R 4F,1R 8F,1R 3F,3R 6F,6R	1/16-3/32 3/32 1/16 1/16 1/16	340-400 325-375 240-300 270-330 230-280	26-31 26-31 26-30 26-30 26-30	60 60 80 60 80	14-20 16-20 24-30 16-24 16-24	50 70 75 70 75

ΠF=Flat; V=Vertical; H=Horizontal; O=Overhead

1.2.2 GTAWñ Top

For the manual GTAW process, straight length (rods) are used and may be cut to lengths specified by the customer, usually in diameters ranging from 3/64" to 1/4".

Table 1.5 shows the typical procedure for manual GTAW of groove joints in aluminum alloys.

Table 1.5 - Typical procedure for manual welding of groove joints in aluminum and its alloys by using the gas tungsten-arc welding process (electrode negative) ñ Top

Notes
1. 1. Helium is recommended for gas tungsten-arc welding of aluminum and its alloys with straight polarity direct current.
2. 2. Helium arc voltage is 40% greater then argon arc voltage per unit of arc length, resulting in a hotter arc, deeper penetration, greater travel speeds, and in some instances, minimum of heat effects on work.
3. 3.For a given change in arc length the helium arc voltage changes more then the argon arc voltage. This makes possible more sensitive control of automatic welding with helium shielding gas.
4. 4. Aluminum, because of its high thermal conductivity, requires the high rate of heat which helium gas produces.

Lancaster Alloys Company can supply aluminum welding rods in 18", 27", 36", and other lengths may be available upon request. All rods can be flag tagged one end or two ends in accordance with AMS 2816 requirements. Rods can be packaged in 1, 5 or 10 lb bags.

1.3 Properties and Performance of Weldmentsñ Top

Development of GTAW and GMAW has made practical the use of high-strength filler metals, and permitted the welding of alloys not joinable by other fusion processes that resulted in achieving welds with increased strength and ductility.

The properties and performance of weldments may be influenced by many factors, including the composition, form and temper of the base metals, the filler metal used, the welding process, travel speed, rate of cooling, joint design and service environment. The effect of these and other variables should be considered. In many instances, weldments are designed so that the welds are in non-critical areas and in case of overload, the assembly will be stressed to failure at some other location. Most of the information given here applies to situations where the weld and adjacent metal are critical from the standpoint of strength and performance.

Tables 1.6 through 1.7 gives examples of some properties of welded joints in non-heat treated and heat treatable aluminum alloys.

Table 1.6 - Tensile strength and elongation of gas-shielded arc welded groove joints in some nonheat-threated aluminum alloys Ζ Top

ΠReduced section tensile

Table 1.7 - Typical strength and elongation of gas-shielded arc welded groove joints in some heat treatable aluminum alloys ñ Top

ΠReduced section tensile
� 0.2% offset in 2 inch gage.
Ž Postweld aged only.

Table 1.8 - Effect of welding conditions on strength of groove joints in alloy 6061 with filler metal 4190ñ Top

Table 1.9 - Minimum Tensile strengths at various temperatures across arc-welded butt joints in alluminum alloys ñ Top

Base Alloy Aluminum Association designation	Filler Alloy Metal	Ultimate Tensile Strength (Psi) Œ
		-300°F	-200°F	-100°F	100°F	300°F	500°F
2219-T37 �	4191	48 ,500	40 ,000	36 ,000	35 ,000	31 ,000	19 ,000
2219-T62 Ž	4191	64 ,500	59 ,500	55 ,000	50 ,000	38 ,000	22 ,000
3003	4180	27 ,500	21 ,500	17 ,500	14 ,000	9 ,500	5 ,000
5052	A106	38 ,000	31 ,000	26 ,500	25 ,000	21 ,000	10 ,500
5083	A105	54 ,500	46 ,000	40 ,500	40 ,000	-	-
5086	A106	48 ,000	40 ,500	35 ,500	35 ,000	-	-
6061-T6	4190	34 ,500	30 ,000	26 ,500	24 ,000	20 ,000	6 ,000
6061-T6	4190	55 ,000	49 ,500	46 ,000	42 ,000	31 ,500	7 ,000

Œ Alloys not listed at 300°F and 500°F are not recommended for use at sustained operating temperatures of over 150°F
� As welded
Ž Heat treated and aged after welding