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4. Gases In Steel : (a). Hydrogen ( H2 ) (Most Detrimental Element). Causes brittlenes without increasing tensile strength, easily penetrates the steel as an ion (diffusion) and by increasing its volume forms blowholes when pickling, flaking and internal cracks when welding. Nitrogen ( N2 ) (Partially Detrimental, partially alloying element). Causes brittlenes in construction steel though nitride formation (ageing, blue brittleness) and increases tensile strength in austenitic corrosion resistant steels (added < 0.20 % N, but can boiling with increasing content during welding). Oxygen ( O2 ) ( Detrimental ). Manifest itself during manufacture in the form of non metallic inclusions (NMI) and also in the free condition ; form, size and distribution of the oxide inclusions which are formed during the Deoxidation phase from element such as Si, Mn, Al, Ti, Mg, Ca etc. Which combine with O2 are the cause of various brittleness factor (red shortness, fibrous fracture). These non metallic inclusions can never be entirely removes from the melt. (b). (c). D:\Private\Article\Material\Alloying.doc Farid 11:16 PM Page 5 21/08/2009...
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This note was uploaded on 03/17/2010 for the course ME ME78212 taught by Professor Prof.sulis during the Spring '10 term at Institut Teknologi Bandung.
- Spring '10