MASTER ALLOYS
plants and products for foundries
Aluminum master alloys
In the world of alloy manufacturing and foundry, aluminum master alloys are usually divided into several groups.
There are those used as additions in the composition correction to achieve the final chemical specification. They are often added to harden alloys and are consequently called "hardener". Examples of these are AlMn, AlFe, AlCr, AlCu, AlV etc. both in the form of shaped ingots and in the form of compacted powders, i.e. alligant tablets and briquettes.
Another important group is that of grain refiners, alloys that are added to control the crystal structure. A grain refiner influences the aluminum alloy during the solidification phase. The aim is to prevent cracking, combat shrinkage porosity and increase casting speed. An example is boron titanium aluminum called AlTiB. Sometimes they are also called with the commercial brand Tibor or TiBAl. Another example is titanium carbon aluminum called AlTiC, sometimes also called Ticar or TiCAl. These alloys are mainly used in the form of coiled wire rod for continuous inoculation during casting. A wire rod feeding unit (wire rod feeder) ensures the correct inoculation rates.
For alloy foundries an important MASTER ALLOYS is strontium aluminum called AlSr. The inoculants change the structure of the eutectic alsi from a needle shape to a globular shape thus making the alloy much more ductile. Strontium inoculation nowadays has largely replaced nitrogen inoculation and is an essential part of modern molten bath treatment technology.
Finally some MASTER ALLOYS are added for specific purposes other than those mentioned above. For example, boron aluminum or AlB or Boral is added to increase the electrical conductivity of electrically conductive aluminum, a procedure often called: boron treatment. Beryllium aluminum or AlBe and today also aluminum calcium (AlCa) are added to minimize the formation of oxides and spinels in AlMg alloys; furthermore, for example, zirconium aluminum is used to increase the recrystallization temperature of the 7000 series alloys.
Aluminum-antimony8%, 10%, 15% AlSb
Aluminum-beryllium2.5%, 5% AlBe
Aluminum-bismuth10% AlBi
Aluminum-boron 3%, 4%, 5%, 6%, 8%, 10% AlB
Aluminum-calcium 6%, 10% AlCa
Aluminum-cerium 10% AlCe (MM)
Aluminum-chromium 5%, 10%, 20%, 80% AlCr
Aluminum-cobalt 5%, 10% AlCo
Aluminum-copper 33%, 50%, 80% AlCu
Aluminum-copper-phosphorus AlCuP
Aluminum-iron 10%, 20%, 25%, 30%, 45%, 80% AlFe
Aluminum-magnesium 20%, 25%, 50%, 65%, 75% AlMg
Aluminum-magnesium-boronAlMgB
Aluminum-magnesium-siliconAlMgSi
Aluminum-manganese10%, 15%, 20%, 25%, 30%, 60%, 80% AlMn
Aluminum-nickel20%, 50% AlNi
Aluminum-silicon20%, 25%, 30%, 50% AlSi
Aluminum-silicon-calciumAlSiCa
Aluminum-silicon-ironAlSiFe
Aluminum-silicon-strontiumAlSiSr
Aluminum-silver10% AlAg
Aluminum-strontium3.5%, 5%, 10%, 15% AlSr
Aluminum-strontium-titanium-boronAlSrTiB
Aluminum-tantalumHigh
Aluminum-titanium5%, 6%, 10%, 80% AlTi
Aluminum-titanium-boron5/1, 3/1, 5 / 0.2, etc. AlTiB
Master alloys of copper
In copper, brass and bronze a similar division can be made into "hardener", "grain refining" and "special alloys". Manganese copper (CuMn), copper aluminum (CuAl) and copper iron (CuFe) are added to correct the composition. Boron copper (CuB), boron aluminum copper (CuAlB), zirconium copper (CuZr), titanium copper (CuTi) and in some cases copper iron (CuFe) are used as grain refiners for copper and for some types of brass and bronze . Magnesium copper (CuMg), lithium copper (CuLi), calcium copper (cuCa) and phosphorus copper (CuP, PCu) are established deoxidizers. Finally, high phosphorous deoxidized DHP copper is used for decorative copper plating and as a substrate for plating.
Cupellation assays according to ISO 11426
The most precise method for determining the gold title is represented by the cupellation test as described in the ISO 11426: 2000 standard, used by the sage offices all over the world.
The principle of the method is based on the removal of all non-precious metals from a small weighed sample, by oxidation with lead in the cupellation phase, which leaves a pure gold-silver alloy, followed by the removal of silver by dissolution with nitric acid for leave a residue of pure gold, which is weighed in order to calculate the gold content.
99.99% min pure lead is used in the cupellation phase in the form of a tape or weighed tablets.
