Metal Ingots for Foundries and Melt Shops

There are two kinds of ingot on this page. Lead, zinc and tin are sold as nearly pure metals, graded by minimum purity. A buyer chooses the grade by how much impurity the end use can tolerate: battery oxide and zinc die-casting alloys need high-purity metal, while some alloying and general uses accept a lower grade.

LM4 and LM6 are different. They are aluminium casting alloys, made to a specified recipe of silicon, copper and other elements, and melted directly into castings. The foundry is buying a ready-made alloy rather than a pure metal it will alloy itself.

Lead ingots go into batteries, radiation shielding, cable sheathing, ballast and lead alloys; details on the lead ingots page. Zinc goes into hot-dip galvanising kettles, zinc die-casting alloys, brass making and chemicals. Tin is the base of most solders and the alloying addition in bronze and gunmetal. LM6 is the aluminium alloy for thin-walled, pressure-tight and corrosion-resistant castings, and LM4 is the general-purpose, heat-treatable casting alloy.

Purity is checked by chemical analysis, usually optical emission spectrometry on a sample cut or drilled from the ingot, or by wet chemical methods for some elements. A good report lists every element the standard limits, not just the main metal.

Each lot from Jubilant Impex can be supplied with a test certificate through a Government-recognised test house. Look for the grade designation, the minimum purity, and the impurity values against the limits of the standard. Our guide to reading a test certificate explains the layout.

Give the metal, the grade or minimum purity, the quantity and the end use. The end use matters more than people think. Zinc for a galvanising kettle and zinc for die-casting alloy can both be quoted as 'pure zinc', yet the alloy maker needs the lowest lead, cadmium and tin, which only the top grade guarantees. Lead for a battery workshop and lead for ballast are a similar story. If a customer specification or approval names a standard, such as IS 27 or BS 1490, quote that number and we will match the certificate to it.

Keep ingots dry and off the floor. Moisture on an ingot charged into molten metal turns to steam instantly and can throw metal out of the pot, so preheat ingots near the furnace before charging. Lead needs extra care: wear gloves, do not eat or drink in the work area, and control fumes when melting.