▁as ▁G 5 5 0 ▁for ▁all ▁sections . ▁( G reg ▁Han cock ) ▁Building ▁Code : ▁Building ▁Code ▁of ▁Australia ▁ ▁( National ▁document ) ▁calls ▁AS / N Z S ▁ 4 6 0 0 : 2 0 0 5 ▁ ▁New ▁Zealand ▁Spec ification : ▁AS / N Z S ▁ 4 6 0 0 ▁ ▁( same ▁as ▁Australia ) ▁▁ ▁Common ▁section ▁profiles ▁and ▁applications ▁▁ ▁In ▁building ▁construction ▁there ▁are ▁basically ▁two ▁types ▁of ▁struct ural ▁steel : ▁hot - rolled ▁steel ▁shapes ▁and ▁cold - formed ▁steel ▁shapes . ▁The ▁hot ▁rolled ▁steel ▁shapes ▁are ▁formed ▁at ▁elev ated ▁temper atures ▁while ▁the ▁cold - formed ▁steel ▁shapes ▁are ▁formed ▁at ▁room ▁temperature . ▁Cold - formed ▁steel ▁struct ural ▁members ▁are ▁shapes ▁commonly ▁manufact ured ▁from ▁steel ▁plate , ▁sheet ▁metal ▁or ▁strip ▁material . ▁The ▁manufact uring ▁process ▁involves ▁forming ▁the ▁material ▁by ▁either ▁press - bra king ▁or ▁cold ▁roll ▁forming ▁to ▁achieve ▁the ▁desired ▁shape . ▁ ▁When ▁steel ▁is ▁formed ▁by ▁press - bra king ▁or ▁cold ▁rolled ▁forming , ▁there ▁is ▁a ▁change ▁in ▁the ▁mechanical ▁properties ▁of ▁the ▁material ▁by ▁virtue ▁of ▁the ▁cold ▁working ▁of ▁the ▁metal . ▁When ▁a ▁steel ▁section ▁is ▁cold - formed ▁from ▁flat ▁sheet ▁or ▁strip ▁the ▁yield ▁strength , ▁and ▁to ▁a ▁less er ▁extent ▁the ▁ult imate ▁strength , ▁are ▁increased ▁as ▁a ▁result ▁of ▁this ▁cold ▁working , ▁particularly ▁in ▁the ▁b ends ▁of ▁the ▁section . ▁ ▁Some