If somebody enquires to you about Alloy 718 Bar; they are definitely not suggesting that you meet them somewhere for a drink. They are likely to be an engineering based company and you would be working for one of their sub-contractors for supply of components and their meaning is that they want you to make something for them using Alloy 718 Bar as your raw material.
So; What Is It?
In this engineering context, an alloy is produced when two or more metallic elements are combined together to enhance the properties they possess on their own. When purchasing metal as a raw material; it comes in several forms or basic shapes and a bar is the description given to a long length of metal that has (usually) been rolled into a square shape (positively rectangular shape would be called beam and round shapes could be round bar – if solid all the way through – or pipe; tube; or hollow bar if they have a hole up the middle). Bearing in mind that metal being purchased in this form is to be the raw material from which something else is shaped; the cross sectional shape of the bar along with its basic dimensions should be chosen so as to minimize waste and cut down on finishing time (usually by machining the metal in some way).
Now, you might ask; what does the 718 stand for? As far as I am concerned; there must be some sort of logic behind naming something 718; but, I have never got to the bottom of it. However, I have learnt to take on proven trust that Rockwell high performance Alloy 718 Bar is actually the official way of talking about a metal bar produced from a non-ferrous, nickel based alloy in accordance with the chemical composition and physical properties spelt out in such specifications as ASTM B637 and/or AMS 5662 and also popularly known as Inconel 718 (Inconel being a registered trademark belonging to Special Metals Corporation of New York who acquired it from Inco Alloys).
Super Or High-Performance Alloys
This description is given to alloys that have been specifically formulated to meet the needs of equipment used in the aerospace (e.g. gas turbine blades); or, oil and gas (extremely corrosive environments and their effect on downhole tools and wellheads); or, refineries and petrochemical plants (extreme temperatures and highly explosive mixtures); or any other industry operating on the extreme edges of today’s technology (nuclear power plants would be another good example). This is the world where components made from superalloys like Alloy 718 Bar are a daily necessity.