High strength rebar

Abstract

A high mechanical strength reinforcement steel comprising, in addition to iron, at most about 0.5% by weight carbon, at most about 0.5% by weight vanadium and/or niobium, and the usual residual elements of scrap steel. A method of reinforcing a dwelling from damage resulting from seismic activity, the method comprising providing, as a component of the dwelling, at least one rebar of a composition comprising, in addition to iron, at most about 0.5% by weight carbon, at most about 0.5% by weight vanadium and/or niobium, at most 1.7% by weight of manganese, at most 0.5% by weight of silicon, and the usual residual elements of scrap steel.

We claim: 
     
         1 . A high mechanical strength reinforcement steel consisting essentially of, in addition to iron: at most about 0.5% by weight carbon; at most about 0.5% by weight vanadium and/or niobium; at most about 1.7% by weight of manganese; at most about 0.5% by weight of silicon; and the usual residual elements of scrap steel. 
     
     
         2 . A high mechanical strength reinforcement steel of  claim 1 , consisting essentially of, in addition to iron: at least about 0.1% and at most about 0.5% by weight carbon; at least about 0.1% and at most about 0.5% by weight vanadium and/or niobium; at most about 1.7% by weight of manganese; at most about 0.5% by weight of silicon; and the usual residual elements of scrap steel. 
     
     
         3 . A high mechanical strength reinforcement steel of  claim 1 , consisting essentially of, in addition to iron: at most about 0.4 wt % carbon; at most about 0.3% by weight vanadium and/or niobium; at most about 1.7% by weight of manganese; at most about 0.5% by weight of silicon; and the usual residual elements of scrap steel. 
     
     
         4 . A high mechanical strength reinforcement steel of  claim 1 , consisting essentially of, in addition to iron: between 0.3-0.4 wt % carbon; at most about 0.2% by weight vanadium and/or niobium; at most about 1.7% by weight of manganese; at most about 0.5% by weight of silicon; and the usual residual elements of scrap steel. 
     
     
         5 . A high mechanical strength reinforcement steel of  claim 1 , consisting essentially of, in addition to iron: at most about 0.5% by weight carbon; at most about 0.5% by weight vanadium and/or niobium; at most about 1.7% by weight of manganese; at most about 0.5% by weight of silicon; and usual residual elements of scrap steel of at most about 0.05% by weight of molybdenum; at most about 0.7% by weight of copper and/or nickel; at most about 0.1% by weight of phosphorous and/or sulfur; at most 500 ppm of nitrogen. 
     
     
         6 . A reinforcing bar having the composition of  claim 1 . 
     
     
         7 . The reinforcing bar of  claim 6 , wherein the rod is of a size between size #3 rebar to size #18 rebar with a yield strength of at least 90 ksi, preferably a rebar of size #5 or size #6 with a yield strength of at least 90 ksi. 
     
     
         8 . A concrete form comprising at least one rebar having a composition defined by  claim 1 . 
     
     
         9 . A method of fabricating a high strength rebar, the method comprising
 providing a scrap metal melt comprising substantially iron and residual elements;   analyzing a sample of the scrap metal melt;   adjusting the elemental composition of the scrap metal melt based on the analysis wherein the adjusted composition provides a size #3 rebar to size #18 rebar, with a yield strength of at least 90 ksi.   
     
     
         10 . The method of  claim 9 , wherein the melt is adjusted to a composition consisting essentially of, in addition to iron: at most about 0.5% by weight carbon; at most about 0.5% by weight vanadium and/or niobium; at most about 1.7% by weight of manganese; at most about 0.5% by weight of silicon; and the usual residual elements of scrap steel. 
     
     
         11 . The method of  claim 9 , wherein the melt is adjusted to a composition consisting essentially of, in addition to iron: at least about 0.1% and at most about 0.4% by weight carbon; at least about 0.1% and at most about 0.5% by weight vanadium and/or niobium; at most about 1.7% by weight of manganese; at most about 0.5% by weight of silicon; and the usual residual elements of scrap steel. 
     
     
         12 . The method of  claim 9 , wherein the melt is adjusted to a composition consisting essentially of, in addition to iron: at most about 0.4 wt % carbon; at most about 0.3% by weight vanadium and/or niobium; at most about 1.7% by weight of manganese; at most about 0.5% by weight of silicon; and the usual residual elements of scrap steel. 
     
     
         13 . The method of  claim 9 , wherein the melt is adjusted to a composition consisting essentially of, in addition to iron: between 0.3-0.4 wt % carbon; at most about 0.2% by weight vanadium and/or niobium; at most about 1.7% by weight of manganese; at most about 0.5% by weight of silicon; and the usual residual elements of scrap steel. 
     
     
         14 . The method of  claim 9 , further comprising hot rolling the melt. 
     
     
         15 . A method of reinforcing a dwelling from damage resulting from seismic activity, the method comprising;
 providing, as a component of the dwelling, at least one rebar of a composition consisting essentially of, in addition to iron: at most about 0.5% by weight carbon; at most about 0.5% by weight vanadium and/or niobium; at most about 1.7% by weight of manganese; at most about 0.5% by weight of silicon; and the usual residual elements of scrap steel.   
     
     
         16 . The method of  claim 15 , wherein the rebar composition consists essentially of, in addition to iron: at least about 0.1% and at most about 0.5% by weight carbon; at least about 0.1% and at most about 0.5% by weight vanadium and/or niobium; at most about 1.7% by weight of manganese; at most about 0.5% by weight of silicon; and the usual residual elements of scrap steel. 
     
     
         17 . The method of  claim 15 , wherein the rebar composition consisting essentially of, in addition to iron: at most about 0.4 wt % carbon; at most about 0.3% by weight vanadium and/or niobium; and the usual residual elements of scrap steel. 
     
     
         18 . The method of  claim 15 , wherein the rebar composition consisting essentially of, in addition to iron: between 0.3-0.4 wt % carbon; at most about 0.2% by weight vanadium and/or niobium; and the usual residual elements of scrap steel. 
     
     
         19 . The method of  claim 15 , wherein the component of the dwelling comprises a concrete construction element comprising the at least one rebar. 
     
     
         20 . The method of  claim 15 , wherein the rebar is of size of one of size #3 rebar to size #18 rebar, with a yield strength of at least 90 ksi, preferably a rebar of size #5 or size #6 with a yield strength of at least 90 ksi.