Aluminum Ingots...? - Page 2

Originally Posted by billygoat

I have a few questions to ask, if you don't mind.

What is the name of your company and where are you located/headquartered?

Where is the overseas scrap yard located?

Just attempted to send you a private message, not sure if it went through.

Originally Posted by aurum

In most cases no one will buy ore, the ore needs to be enriched to a concentrate, to bring up the grades to a point where it is economical to ship and refine into a metal. Most ore is processed at the mine site into a concentrate and then shipped to various smelters and refiners. This is big business, very few small players in this business.

For lead and zinc, there is the Teck-Cominco smelter in Trail, BC, Canada. For copper, there is the Glencore smelter in Quebec, Canada. These are all I know of in North America. They won't be interested unless you have at least several hundred tonnes of concentrate. Minimum grades need to be 20-30%, and they are very specific with what kind of impurites are allowed and at what maximum concentrations. For example there are maximum allowable levels of things like arsenic in the concentrate, if your concentrate exceeds these levels, there will be a penalty deducted from the final payout. You need to get a good representative sample, and have it assayed, probably before you even talk to them.

Teck-Cominco smelter in Trail, BC, Canada also processes leaded glass from CRT's

Glencore smelter in Quebec, Canada also process electronic circuit boards. You would need multiple 40 ton loads.

Originally Posted by alloy2

Difficult question to answer when your not giving us any information of the type of alloy or the configuration or weight of the ingots being produced.

Q: I have been informed that pure aluminum is not usually used for structural applications and that in order to produce aluminum that is of adequate strength for the manufacture of structural components, it is necessary to add other elements to the aluminum. What elements are added to these aluminum alloys? What affect do they have on the material’s performance? And in what applications are these alloys used?

A: Your acquired information is essentially correct. It would be very unusual to find pure aluminum (1xxx series of alloys) chosen for structural fabrication because of their strength characteristics. Although the 1xxx series are almost pure aluminum, they will respond to strain hardening and especially so if they contain appreciable amounts of impurities such as iron and silicon. However, even in the strain-hardened condition, the 1xxx series alloys have very low strength when compared to the other series of aluminum alloys. When the 1xxx series alloys are chosen for a structural application, they are most often chosen for their superior corrosion resistance and/or their high electrical conductivity. The most common applications for the 1xxx series alloys are aluminum foil, electrical buss bars, metallizing wire and chemical tanks and piping systems.

The addition of alloying elements to aluminum is the principal method used to produce a selection of different materials that can be used in a wide assortment of structural applications.
If we consider the seven designated aluminum alloy series used for wrought alloys, we can immediately identify the main alloying elements used for producing each of the alloy series. We can then go further and examine each of these elements’ effects on aluminum. I have also added some other commonly used elements and their effects on aluminum.

Series Primary Alloying Element

1xxx Aluminum - 99.00% or Greater
2xxx Copper
3xxx Manganese
4xxx Silicon
5xxx Magnesium
6xxx Magnesium and Silicon
7xxx Zinc

The principal effects of alloying elements in aluminum are as follows:

Copper (Cu) 2xxx – The aluminum-copper alloys typically contain between 2 to 10% copper, with smaller additions of other elements. The copper provides substantial increases in strength and facilitates precipitation hardening. The introduction of copper to aluminum can also reduce ductility and corrosion resistance. The susceptibility to solidification cracking of aluminum-copper alloys is increased; consequently, some of these alloys can be the most challenging aluminum alloys to weld. These alloys include some of the highest strength heat treatable aluminum alloys. The most common applications for the 2xxx series alloys are aerospace, military vehicles and rocket fins.

Manganese (Mn) 3xxx – The addition of manganese to aluminum increases strength somewhat through solution strengthening and improves strain hardening while not appreciably reducing ductility or corrosion resistance. These are moderate strength nonheat-treatable materials that retain strength at elevated temperatures and are seldom used for major structural applications. The most common applications for the 3xxx series alloys are cooking utensils, radiators, air conditioning condensers, evaporators, heat exchangers and associated piping systems.


Silicon (Si) 4xxx – The addition of silicon to aluminum reduces melting temperature and improves fluidity. Silicon alone in aluminum produces a nonheat-treatable alloy; however, in combination with magnesium it produces a precipitation hardening heat-treatable alloy. Consequently, there are both heat-treatable and nonheat-treatable alloys within the 4xxx series. Silicon additions to aluminum are commonly used for the manufacturing of castings. The most common applications for the 4xxx series alloys are filler wires for fusion welding and brazing of aluminum.


Magnesium (Mg) 5xxx - The addition of magnesium to aluminum increases strength through solid solution strengthening and improves their strain hardening ability. These alloys are the highest strength nonheat-treatable aluminum alloys and are, therefore, used extensively for structural applications. The 5xxx series alloys are produced mainly as sheet and plate and only occasionally as extrusions. The reason for this is that these alloys strain harden quickly and, are, therefore difficult and expensive to extrude. Some common applications for the 5xxx series alloys are truck and train bodies, buildings, armored vehicles, ship and boat building, chemical tankers, pressure vessels and cryogenic tanks.


Magnesium and Silicon (Mg2Si) 6xxx – The addition of magnesium and silicon to aluminum produces the compound magnesium-silicide (Mg2Si). The formation of this compound provides the 6xxx series their heat-treatability. The 6xxx series alloys are easily and economically extruded and for this reason are most often found in an extensive selection of extruded shapes. These alloys form an important complementary system with the 5xxx series alloy. The 5xxx series alloy used in the form of plate and the 6xxx are often joined to the plate in some extruded form. Some of the common applications for the 6xxx series alloys are handrails, drive shafts, automotive frame sections, bicycle frames, tubular lawn furniture, scaffolding, stiffeners and braces used on trucks, boats and many other structural fabrications.


Zinc (Zn) 7xxx – The addition of zinc to aluminum (in conjunction with some other elements, primarily magnesium and/or copper) produces heat-treatable aluminum alloys of the highest strength. The zinc substantially increases strength and permits precipitation hardening. Some of these alloys can be susceptible to stress corrosion cracking and for this reason are not usually fusion welded. Other alloys within this series are often fusion welded with excellent results. Some of the common applications of the 7xxx series alloys are aerospace, armored vehicles, baseball bats and bicycle frames.


Iron (Fe) – Iron is the most common impurity found in aluminum and is intentionally added to some pure (1xxx series) alloys to provide a slight increase in strength.


Chromium (Cr) – Chromium is added to aluminum to control grain structure, to prevent grain growth in aluminum-magnesium alloys, and to prevent recrystallization in aluminum-magnesium-silicon or aluminum-magnesium-zinc alloys during heat treatment. Chromium will also reduce stress corrosion susceptibility and improves toughness.


Nickel (Ni) – Nickel is added to aluminum-copper and to aluminum-silicon alloys to improve hardness and strength at elevated temperatures and to reduce the coefficient of expansion.


Titanium (Ti) – Titanium is added to aluminum primarily as a grain refiner. The grain refining effect of titanium is enhanced if boron is present in the melt or if it is added as a master alloy containing boron largely combined as TiB2. Titanium is a common addition to aluminum weld filler wire as it refines the weld structure and helps to prevent weld cracking.


Zirconium (Zr) – Zirconium is added to aluminum to form a fine precipitate of intermatallic particles that inhibit recrystallization.


Lithium (Li) - The addition of lithium to aluminum can substantially increase strength and, Young’s modulus, provide precipitation hardening and decreases density.


Lead (Pb) and Bismuth (Bi) – Lead and bismuth are added to aluminum to assist in chip formation and improve machinability. These free machining alloys are often not weldable because the lead and bismuth produce low melting constituents and can produce poor mechanical properties and/or high crack sensitivity on solidification.


Summary:

There are many aluminium alloys used in industry today - over 400 wrought alloys and over 200 casting allloys are currently registered with the Aluminum Association. Certainly one of the most important considerations encountered during the welding of aluminium is the identification of the aluminium base alloy type to be welded. If the base material type of the component to be welded is not available through a reliable source, it can be difficult to select a suitable welding procedure. There are some general guidelines as to the most probable type of aluminium used in different applications, such as those mentioned above. However, it is very important to be aware that incorrect assumptions as to the chemistry of an aluminium alloy can result in very serious effects on the weld performance. It is strongly recommended that positive identification of the type of aluminium be made and that welding procedures be developed and tested in order to verify weld performance.

Bump

Understanding the Aluminum Alloy Designation System


With the growth of aluminum within the welding fabrication industry, and its acceptance as an excellent alternative to steel for many applications, there are increasing requirements for those involved with developing aluminum projects to become more familiar with this group of materials. To fully understand aluminum, it is advisable to start by becoming acquainted with the aluminum identification / designation system, the many aluminum alloys available and their characteristics.
The Aluminum Alloy Temper and Designation System
In North America, The Aluminum Association Inc. is responsible for the allocation and registration of aluminum alloys. Currently there are over 400 wrought aluminum and wrought aluminum alloys and over 200 aluminum alloys in the form of castings and ingots registered with the Aluminum Association. The alloy chemical composition limits for all of these registered alloys are contained in the Aluminum Association’s Teal Book entitled “International Alloy Designations and Chemical Composition Limits for Wrought Aluminum and Wrought Aluminum Alloys” and in their Pink Book entitled “Designations and Chemical Composition Limits for Aluminum Alloys in the Form of Castings and Ingot. These publications can be extremely useful to the welding engineer when developing welding procedures, and when the consideration of chemistry and its association with crack sensitivity is of importance.
Aluminum alloys can be categorized into a number of groups based on the particular material’s characteristics such as its ability to respond to thermal and mechanical treatment and the primary alloying element added to the aluminum alloy. When we consider the numbering / identification system used for aluminum alloys, the above characteristics are identified. The wrought and cast aluminums have different systems of identification; the wrought having a 4-digit system, and the castings having a 3-digit and 1-decimal place system.
Wrought Alloy Designation System
We shall first consider the 4-digit wrought aluminum alloy identification system.
The first digit (Xxxx) indicates the principal alloying element, which has been added to the aluminum alloy and is often used to describe the aluminum alloy series, i.e., 1000 series, 2000 series, 3000 series, up to 8000 series (see table 1).

WROUGHT ALUMINUM ALLOY DESIGNATION SYSTEM

Alloy Series	Principal Alloying Element
1xx	99.000% Minimum Aluminum
2xx	Copper
3xx	Manganese
4xx	Silicon
5xx	Magnesium
6xx	Magnesium and Silicon
7xx	Zinc
8xx	Other Elements

Table 1
The second single digit (xXxx), if different from 0, indicates a modification of the specific alloy, and the third and fourth digits (xxXX) are arbitrary numbers given to identify a specific alloy in the series. Example: In alloy 5183, the number 5 indicates that it is of the magnesium alloy series, the 1 indicates that it is the 1st modification to the original alloy 5083, and the 83 identifies it in the 5xxx series.
The only exception to this alloy numbering system is with the 1xxx series aluminum alloys (pure aluminums) in which case, the last 2 digits provide the minimum aluminum percentage above 99%, i.e., Alloy 1350 (99.50% minimum aluminum).
Cast Alloy Designation
The cast alloy designation system is based on a 3 digit-plus decimal designation xxx.x (i.e. 356.0). The first digit (Xxx.x) indicates the principal alloying element, which has been added to the aluminum alloy (see table 2).

CAST ALUMINUM ALLOY DESIGNATION SYSTEM

Alloy Series	Principal Alloying Element
1xx.x	99.000% minimum Aluminum
2xx.x	Copper
3xx.x	Silicon Plus Copper and/or Magnesium
4xx.x	Silicon
5xx.x	Magnesium
6xx.x	Unused Series
7xx.x	Zinc
8xx.x	Tin
9xx.x	Other Elements

Table 2
The second and third digits (xXX.x) are arbitrary numbers given to identify a specific alloy in the series. The number following the decimal point indicates whether the alloy is a casting (.0) or an ingot (.1 or .2). A capital letter prefix indicates a modification to a specific alloy.
Example: Alloy - A356.0 the capital A (Axxx.x) indicates a modification of alloy 356.0. The number 3 (A3xx.x) indicates that it is of the silicon plus copper and/or magnesium series. The 56 (Ax56.0) identifies the alloy within the 3xx.x series, and the .0 (Axxx.0) indicates that it is a final shape casting and not an ingot.
The Aluminum Temper Designation System
If we consider the different series of aluminum alloys, we will see that there are considerable differences in their characteristics and consequent application. The first point to recognize, after understanding the identification system, is that there are two distinctly different types of aluminum within the series mentioned above. These are the Heat Treatable Aluminum alloys (those which can gain strength through the addition of heat) and the Non-Heat Treatable Aluminum alloys. This distinction is particularly important when considering the affects of arc welding on these two types of materials.
The 1xxx, 3xxx, and 5xxx series wrought aluminum alloys are non-heat treatable and are strain hardenable only. The 2xxx, 6xxx, and 7xxx series wrought aluminum alloys are heat treatable and the 4xxx series consist of both heat treatable and non-heat treatable alloys. The 2xx.x, 3xx.x, 4xx.x and 7xx.x series cast alloys are heat treatable. Strain hardening is not generally applied to castings.
The heat treatable alloys acquire their optimum mechanical properties through a process of thermal treatment, the most common thermal treatments being Solution Heat Treatment and Artificial Aging. Solution Heat Treatment is the process of heating the alloy to an elevated temperature (around 990 Deg. F) in order to put the alloying elements or compounds into solution. This is followed by quenching, usually in water, to produce a supersaturated solution at room temperature. Solution heat treatment is usually followed by aging. Aging is the precipitation of a portion of the elements or compounds from a supersaturated solution in order to yield desirable properties. The aging process is divided into two types: aging at room temperature, which is termed natural aging, and aging at elevated temperatures termed artificial aging. Artificial aging temperatures are typically about 320 Deg. F. Many heat treatable aluminum alloys are used for welding fabrication in their solution heat treated and artificially aged condition.
The non-heat treatable alloys acquire their optimum mechanical properties through Strain Hardening. Strain hardening is the method of increasing strength through the application of cold working. The Temper Designation System addresses the material conditions called tempers. The Temper Designation System is an extension of the alloy numbering system and consists of a series of letters and numbers which follow the alloy designation number and are connected by a hyphen. Examples: 6061-T6, 6063-T4, 5052-H32, 5083-H112.

THE BASIC TEMPER DESIGNATIONS

Letter	Meaning
F	As fabricated – Applies to products of a forming process in which no special control over thermal or strain hardening conditions is employed
O	Annealed – Applies to product which has been heated to produce the lowest strength condition to improve ductility and dimensional stability
H	Strain Hardened – Applies to products which are strengthened through cold-working. The strain hardening may be followed by supplementary thermal treatment, which produces some reduction in strength. The “H” is always followed by two or more digits (see table 4)
W	Solution Heat-Treated – An unstable temper applicable only to alloys which age spontaneously at room temperature after solution heat-treatment
T	Thermally Treated - To produce stable tempers other than F, O, or H. Applies to product which has been heat-treated, sometimes with supplementary strain-hardening, to produce a stable temper. The “T” is always followed by one or more digits (see table 5)

Table 3
Further to the basic temper designation, there are two subdivision categories, one addressing the “H” Temper – Strain Hardening, and the other addressing the “T” Temper – Thermally Treated designation.
Table 4 - Subdivisions of H Temper – Strain Hardened
The first digit after the H indicates a basic operation:
H1 – Strain Hardened Only.
H2 – Strain Hardened and Partially Annealed.
H3 – Strain Hardened and Stabilized.
H4 – Strain Hardened and Lacquered or Painted.
The second digit after the H indicates the degree of strain hardening:
HX2 – Quarter Hard HX4 – Half Hard HX6 – Three-Quarters Hard
HX8 – Full Hard HX9 – Extra Hard

Table 5 - Subdivisions of T Temper – Thermally Treated
T1 - Naturally aged after cooling from an elevated temperature shaping process, such as extruding.
T2 - Cold worked after cooling from an elevated temperature shaping process and then naturally aged.
T3 - Solution heat treated, cold worked and naturally aged.
T4 - Solution heat treated and naturally aged.
T5 - Artificially aged after cooling from an elevated temperature shaping process.
T6 - Solution heat treated and artificially aged.
T7 - Solution heat treated and stabilized (overaged).
T8 - Solution heat treated, cold worked and artificially aged.
T9 - Solution heat treated, artificially aged and cold worked.
T10 - Cold worked after cooling from an elevated temperature shaping process and then artificially aged.
Additional digits indicate stress relief.
Examples:
TX51 or TXX51 – Stress relieved by stretching.
TX52 or TXX52 – Stress relieved by compressing.
Aluminum Alloys And Their Characteristics
If we consider the seven series of wrought aluminum alloys, we will appreciate their differences and understand their applications and characteristics.
1xxx Series Alloys – (non-heat treatable – with ultimate tensile strength of 10 to 27 ksi) this series is often referred to as the pure aluminum series because it is required to have 99.0% minimum aluminum. They are weldable. However, because of their narrow melting range, they require certain considerations in order to produce acceptable welding procedures. When considered for fabrication, these alloys are selected primarily for their superior corrosion resistance such as in specialized chemical tanks and piping, or for their excellent electrical conductivity as in bus bar applications. These alloys have relatively poor mechanical properties and would seldom be considered for general structural applications. These base alloys are often welded with matching filler material or with 4xxx filler alloys dependent on application and performance requirements.
2xxx Series Alloys – (heat treatable– with ultimate tensile strength of 27 to 62 ksi) these are aluminum / copper alloys (copper additions ranging from 0.7 to 6.8%), and are high strength, high performance alloys that are often used for aerospace and aircraft applications. They have excellent strength over a wide range of temperature. Some of these alloys are considered non-weldable by the arc welding processes because of their susceptibility to hot cracking and stress corrosion cracking; however, others are arc welded very successfully with the correct welding procedures. These base materials are often welded with high strength 2xxx series filler alloys designed to match their performance, but can sometimes be welded with the 4xxx series fillers containing silicon or silicon and copper, dependent on the application and service requirements.
3xxx Series Alloys – (non-heat treatable – with ultimate tensile strength of 16 to 41 ksi) These are the aluminum / manganese alloys (manganese additions ranging from 0.05 to 1.8%) and are of moderate strength, have good corrosion resistance, good formability and are suited for use at elevated temperatures. One of their first uses was pots and pans, and they are the major component today for heat exchangers in vehicles and power plants. Their moderate strength, however, often precludes their consideration for structural applications. These base alloys are welded with 1xxx, 4xxx and 5xxx series filler alloys, dependent on their specific chemistry and particular application and service requirements.
4xxx Series Alloys – (heat treatable and non-heat treatable – with ultimate tensile strength of 25 to 55 ksi) These are the aluminum / silicon alloys (silicon additions ranging from 0.6 to 21.5%) and are the only series which contain both heat treatable and non-heat treatable alloys. Silicon, when added to aluminum, reduces its melting point and improves its fluidity when molten. These characteristics are desirable for filler materials used for both fusion welding and brazing. Consequently, this series of alloys is predominantly found as filler material. Silicon, independently in aluminum, is non-heat treatable; however, a number of these silicon alloys have been designed to have additions of magnesium or copper, which provides them with the ability to respond favorably to solution heat treatment. Typically, these heat treatable filler alloys are used only when a welded component is to be subjected to post weld thermal treatments.
5xxx Series Alloys – (non-heat treatable – with ultimate tensile strength of 18 to 51 ksi) These are the aluminum / magnesium alloys (magnesium additions ranging from 0.2 to 6.2%) and have the highest strength of the non-heat treatable alloys. In addition, this alloy series is readily weldable, and for these reasons they are used for a wide variety of applications such as shipbuilding, transportation, pressure vessels, bridges and buildings. The magnesium base alloys are often welded with filler alloys, which are selected after consideration of the magnesium content of the base material, and the application and service conditions of the welded component. Alloys in this series with more than 3.0% magnesium are not recommended for elevated temperature service above 150 deg F because of their potential for sensitization and subsequent susceptibility to stress corrosion cracking. Base alloys with less than approximately 2.5% magnesium are often welded successfully with the 5xxx or 4xxx series filler alloys. The base alloy 5052 is generally recognized as the maximum magnesium content base alloy that can be welded with a 4xxx series filler alloy. Because of problems associated with eutectic melting and associated poor as-welded mechanical properties, it is not recommended to weld material in this alloy series, which contain higher amounts of magnesium with the 4xxx series fillers. The higher magnesium base materials are only welded with 5xxx filler alloys, which generally match the base alloy composition.
6XXX Series Alloys – (heat treatable – with ultimate tensile strength of 18 to 58 ksi) These are the aluminum / magnesium - silicon alloys (magnesium and silicon additions of around 1.0%) and are found widely throughout the welding fabrication industry, used predominantly in the form of extrusions, and incorporated in many structural components. The addition of magnesium and silicon to aluminum produces a compound of magnesium-silicide, which provides this material its ability to become solution heat treated for improved strength. These alloys are naturally solidification crack sensitive, and for this reason, they should not be arc welded autogenously (without filler material). The addition of adequate amounts of filler material during the arc welding process is essential in order to provide dilution of the base material, thereby preventing the hot cracking problem. They are welded with both 4xxx and 5xxx filler materials, dependent on the application and service requirements.
7XXX Series Alloys – (heat treatable – with ultimate tensile strength of 32 to 88 ksi) These are the aluminum / zinc alloys (zinc additions ranging from 0.8 to 12.0%) and comprise some of the highest strength aluminum alloys. These alloys are often used in high performance applications such as aircraft, aerospace, and competitive sporting equipment. Like the 2xxx series of alloys, this series incorporates alloys which are considered unsuitable candidates for arc welding, and others, which are often arc welded successfully. The commonly welded alloys in this series, such as 7005, are predominantly welded with the 5xxx series filler alloys.
Summary
Today’s aluminum alloys, together with their various tempers, comprise a wide and versatile range of manufacturing materials. For optimum product design and successful welding procedure development, it is important to understand the differences between the many alloys available and their various performance and weldability characteristics. When developing arc welding procedures for these different alloys, consideration must be given to the specific alloy being welded. It is often said that arc welding of aluminum is not difficult, “it’s just different”. I believe that an important part of understanding these differences is to become familiar with the various alloys, their characteristics, and their identification system.
Additional Information Sources
There are a number of excellent reference sources available exclusively addressing aluminum welding; One being the Aluminum Association’s “Welding Aluminum Theory and Practice” and another, is the American Welding Society Document D1.2 – Structural Welding Code – Aluminum. Other documents available from the Aluminum Association that assist with the design of aluminum structures are the Aluminum Design Manual and Aluminum Standards and Data. These documents along with the alloy designation documents mentioned earlier in the article can be obtained directly from the AWS, or The Aluminum Association as appropriate.
AWS Tel: 1 800 443 9353 Web Site:www.aws.org
The Aluminum Association Tel: (301) 645-0756 Web Site: www.aluminum.org