The total content of these additional alloying elements should not exceed 1.0 percent by weight, {HEAD ~ preferably not over 0.5 percent} by {TAIL ~ weight} 
by
The total content of these additional alloying elements should not exceed 1.0 percent by weight , { HEAD ~ preferably not over 0.5 percent } by { TAIL ~ weight }
OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD HEAD HEAD REL TAIL TAIL TAIL TAIL TAIL