|Cu||Melting point 1083 °C||Copper|
Copper is added to very few steel alloys, as it concentrates under the layer of scale and through penetrating into the grain boundary, causes high surface sensitivity in hot forming processes, for which reason it is regarded as a steel parasite. The yield point and the yield point/strength ratio are increased. Contents above 0.30% can cause precipitation hardening. Hardenability is improved. Weldability is not affected by copper. In alloy and low alloy steels, Cu produces significant improvement in weathering resistance. In acid resistant high alloy steels, a Cu content above 1% produces improvement in resistance to hydrochloric acid and sulphuric acid.