Effect of composition and thermomechanical processing on the ageing characteristic of copper-bearing HSLA steel

3 alloys of copper-bearing steels with or without boron have been studied i n different thermomechanical controlled processing (TMCP) conditions. The i nfluence of TMCP schedules onto the ageing behaviour in boron-treated and b oron-free steels is examined. The structure property analysis of these stee ls is also carried out. It is found that when the finish rolling is carried out above Ar,, the steels direct cooled after TMCP are able to retain a hi gher amount of copper in solid, leading to higher ageing response. Boron is found to delay the precipitation of copper and the best ageing effect is r ecorded in B-Cr steel.