- Rolled homogeneous armour
Rolled homogeneous armour, or RHA, is a basic type of steel plate, used as a baseline to compare the effectiveness of military
vehicle armour .Through the end of
World War II , the type of armour for almost alltank s and other armoured vehicles was sheets ofsteel . Increasing the protection on a vehicle meant adding thicker sheets of steel, increasing the vehicle's weight and reducing its mobility. Since then, other forms of armour, incorporating empty spaces and materials such asceramic s ordepleted uranium in addition to steel, have been developed. Made ineffective by modern weapons using high-impact or high-temperature cutting jets, RHA itself is obsolete due to advances in vehicle armor.The more recent term RHAe (Rolled Homogeneous Armour equivalency) is used when giving a rough estimate of either the penetrative capability of a
projectile or the protective capability of a type ofarmour which may or may not besteel .Because of variations in armor shape, quality, material, and case-by-case performance, the usefulness of RHAe in comparing different armour is debatable.
pecifications
For current
United States Army use, RHA steel is produced to Military standard MIL-A 12560 by several manufacturers. The newest standard used is MIL-A-46100. [ [http://www.intlsteel.com/PDFs/armor.pdf http://www.intlsteel.com/PDFs/armor.pdf] , accessed Sept 21, 2006] It is very similar to but not identical to standard high strength steel alloy 4340 in theAISI steel grades , though mechanical properties are very similar to that alloy. [ [http://www.eng-tips.com/viewthread.cfm?qid=159941&page=6 http://www.eng-tips.com/viewthread.cfm?qid=159941&page=6] , accessed Sept 21, 2006]ee also
*
Sloped armour
*Composite armour
*Reactive armour
*Vehicle armour References
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