Metallurgy

Metals can be segregated in ferrous and non-ferrous, offering different properties, and requiring different process routes.

Ferrous materials are iron based metals including steel and cast iron. Steel alloys represent a major segment from the vacuum perspective with secondary metallurgy as the first vacuum treatment applied in the steel production chain.

Non-ferrous metal alloys cover a very wide range of metals such as nickel, titanium, aluminum among many others. These metals are selected according to their physicochemical properties depending on the application. Like carbon makes iron harder, alloying elements are very often added to achieve desired metal alloy properties.  

The types of processes: Metallurgical processes are used to adjust the metallographic structure, chemical composition, shape and join metal parts in process sequences down the production route. Typical terminology for these processes includes melting, refining, alloying, casting, molding, heat treatment and joining. 

Steel degassing and refining

This uses vacuum to remove hydrogen, nitrogen from molten steel to make the steel stronger and less brittle or carbon through an oxygen decarburization process. Edwards offers innovative mechanical vacuum systems that can meet the large performance requirements and handle the process gas with Argon and dust. This steel widely is used for construction steel either plates or long bars. 

Special Metallurgy

This process involves using vacuum for production of special material qualities and/or shapes. Tertiary Metallurgy considers remelting under vacuum to improve homogeneity of (ferrous) materials e.g for use in aircraft industry. Special metallurgy is the main process route for superalloys production, typically nickel or cobalt based. Superalloys benefit from high mechanical strength, operative temperatures, corrosion resistance making them suitable for using in ships, submarines, hot metals working dies, reactors, or turbines.

Powder Metallurgy 

This is another growing field of metallurgy for manufacturing of metals and ceramics parts with complex shapes and new material compositions that cannot be achieved by any other casting technologies. The latest development is 3D printing as a new area and emerging area of powder metallurgy. Typical applications include refractory materials (i.e. tungsten, tantalum) hard materials, wear resistant materials, permanent magnets, porous metals, mixtures of dissimilar metals. Vacuum technology is used in several processes such as atomisation, injection moulding, debinding, sintering, Hot Isostatic Pressing (HIP). 

Heat Treatment

This process is applied further downstream in the production chain to the material in solid state, without changing the chemical composition of the bulk. Heat treatment with vacuum can be used to either the entire metal structure (bulk heat treatment) or only the surface of a work piece (surface heat treatment) which is typically used to achieve a harder surface. Further heat treatments under vacuum are joining processes like brazing and welding. Vacuum plays an important role to create optimal conditions for thermal treatments such as clean and oxygen-free environment.