Nickel is a chemical element that is a silvery-white lustrous metal with a slight golden tinge. It is an important constituent of stainless steel, and increases the tensile strength of carbon steel. It is also essential to some other alloys capable of operating at very high temperatures and/or in very aggressive environments. 

Nickel-based alloys are developed for very high temperature service where relatively high stresses are encountered and where high surface stability is frequently required. Typical applications are aircraft turbine and land-based turbine components.

Non-prime usually describes steel which is unsuitable for its originally intended application – either because of its metallurgy or physical condition – or is in excess of the tonnage required to fulfil a particular contract (over-rolled). Much non-prime is the result of defects created during steelmaking and downstream processing – and as a result this steel does not have the mill certification associated with prime material. 

Normalising is a process where a heat treatment is applied to steel for relief of internal stress, based on heating and subsequent air cooling. This is a process similar to annealing, where metal is heated to a high temperature and held at this temperature for several hours to improve grain structure. Unlike annealing, however, where the metal is cooled slowly in the furnace, here it is cooled more swiftly by removing it from the furnace to cool in air. This makes the metal stronger and harder than it would be after annealing, and because of this the normalising process is often employed to treat steel plate used for pressure vessel fabrication.