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| Vacuum Arc Remelting (VAR) |
| A process in which a metallic alloy in the form of an electrode, and which may be in either as-cast or wrought condition, is remained in vacuum, by means of a DC arc, and is then resolidified within a water-cooled copper mould. The primary benefits of the process are the removal of dissolved gases, the minimising of the content of undesired trace elements that have a high vapour pressure, improved cleanliness with respect to oxide inclusions and the avoidance of macrosegregation and the minimising of microsegregation. |
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| Vacuum Degassing |
| A secondary refining process for liquid steel in which it is exposed to a low pressure environment with the aim of achieving one or more of the following: reduction of dissolved gases - improved cleanliness - greater uniformity control of chemical composition. |
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| Vanadium (V) |
| Used in small amounts, up to 0.15% for grain refining and strengthening of microalloyed high strength structural steels and up to 0.2% in certain hot forging steels for improving hardenability. A strong carbide former, giving rise to secondary hardening, so is used in tool steels for use at elevated temperatures and in creep resistant steels. |
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| Vee (Single/Double) |
| Preparation for welding. |
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| Vickers Hardness Test |
| Also known as the diamond pyramid test, as the indenter used in the test is a pyramid shaped diamond. This is forced under a given load into the metal specimen for a fixed time. On removal of the load the diagonals of the diamond-shaped indentation are measured under a low-power optical microscope. The average value of the two readings together with the applied load is then used to determine from standard tables, a hardness number for the metal. The load used is varied according to the softness or hardness of the metal being tested, and also its thickness. |
