Metal Casting and Casting Alloys

Metal casting is one of the oldest and most versatile manufacturing processes in existence. At its core, casting involves pouring or injecting molten metal into a mould, allowing it to solidify into a precise shape, and then removing the finished part. The process is capable of producing components ranging from simple brackets to highly complex, thin-walled geometries that would be difficult or impossible to achieve through other manufacturing methods.

Modern casting technology — and high pressure die casting in particular — has made the process faster, more repeatable, and more precise than ever, making it a cornerstone of mass production across the automotive, aerospace, electronics, industrial, and consumer goods sectors.

Metal Casting

Molten metal is injected into a hardened steel mould under high pressure, producing parts with tight tolerances, excellent surface finish, and high repeatability. High pressure die casting is best suited to high-volume production of complex components in aluminium and zinc alloys. This is Norfran’s core process — available for both zinc and aluminium die casting.

Casting Alloys

The choice of alloy has a significant impact on the properties, performance, and cost of a finished casting. The most widely used casting alloys are outlined below.

Aluminium alloys

Aluminium is the most widely specified die casting material, valued for its combination of low density, good strength, excellent corrosion resistance, and thermal and electrical conductivity. Aluminium alloys are used extensively in the automotive, aerospace, and electronics sectors, and are fully recyclable without loss of mechanical properties.
Common aluminium casting alloys include LM2 (EN AC 46100), LM6 (EN AC 44100), EN AC 43400, EN AC 44300, each offering slightly different balances of castability, strength, and corrosion resistance. Norfran’s aluminium die casting service uses cold chamber machines ranging from 180 to 800 tonne, suited to a wide range of component sizes.

Zinc alloys

Zinc is the easiest of the common metals to cast and offers excellent dimensional accuracy, a fine surface finish, and the ability to cast very thin walls and intricate detail. Its lower melting point compared to aluminium makes it well suited to hot chamber die casting, resulting in faster cycle times and longer tool life.
Zinc alloys are widely used for small, complex components in the automotive, electrical, and consumer goods industries. Common alloys include Zamak 3, Zamak 5, and ZA-8, which offer varying balances of strength, creep resistance, and castability. Norfran’s zinc die casting service accommodates castings from 0.002 kg to 9.00 kg.

Choosing the Right Alloy

Selecting the most appropriate casting alloy depends on a number of factors, including the required mechanical properties, the operating environment, the complexity of the component geometry, the production volume, and the target cost. In many cases, switching alloy or casting process can deliver significant benefits in terms of weight, performance, or unit cost.

Norfran’s engineering team is experienced in advising customers on alloy and process selection from the earliest stages of a project. Our design and project management service is available to help ensure the right decisions are made before tooling is committed to.

For detailed technical guidance on die casting tolerances and design considerations, visit our technical resources section.