This is made from hot rolled or cold reduced strip, sheet or plate. Small and medium diameters are produced in continuous, multiple-roll mills that progressively bend incoming, unheated strip into a circular cross-section prior to welding along the longitudinal seam. Tube may subsequently be cold-drawn through dies to achieve precise dimensions and finish. This is cheaper than the seamless process but welded tube generally has a lower mechanical and pressure performance.

This method of joining metals is essential for certain types of pipemaking and is widely used in structural steel fabrication, shipbuilding etc. The workpieces are melted at the point where they are to be joined using a very localised, high temperature energy source, and a filler material is added to create a small additional amount of molten metal. When this cools the workpieces fuse together to form a strong joint.

These heavy duty structural sections are often referred to as H-beams and I-beams (because of their cross-sectional appearance). They are mainly used in the frames of industrial and hi-rise structures, are internationally traded and are a stockholder item in standard lengths. Dimensions are in metric, except in the USA where they are sold as “W” shapes in inches.

This is a type of iron, which unlike hard, brittle pig iron – such as is tapped from a blast furnace – is tough and malleable, allowing it to be forged and welded. It has a high tensile strength and is more corrosion resistant than steel. Wrought iron has a very low carbon content – lower than many steels – but importantly it has traces of manganese/sulphur/phosphorus/silicon-containing slag which give it a fibrous structure and which contributes to its desirable properties. 

Metals which after melting, casting and solidifying have been further worked in a hot or cold condition to alter their shape and/or dimensions by rolling, forging, extruding and drawing.