Abstract: There is disclosed a softening method for a high-strength Q & P steel hot-rolled coil, comprising: after heating a Q & P steel ingot, subjecting it to rough rolling, finish rolling, laminar cooling and coiling to obtain a hot-rolled coil; after unloading the coil, covering the coil on-line with an insulating enclosure and moving it into a steel coil warehouse along with a transport chain; after a specified period of insulating time, removing the coil from the insulating enclosure, and cooling it to room temperature in air, wherein the coiling is performed at a temperature of 400-600° C.; said covering on-line with an insulating enclosure means each hot-rolled coil is individually covered with an independent, closed insulating enclosure unit within 60 minutes after unloading; the insulating time of the steel coil in the insulating enclosure is ?60 minutes. The inventive method replaces the intermediate annealing step in the production process of cold-rolled Q & P steel.

Abstract: There is provided a production method for on-line improving precipitation strengthening effect of Ti microalloyed hot-rolled high-strength steel, comprising: casting a molten steel with microalloying element Ti added to obtain an ingot; after heating the ingot, subjecting it to rough rolling, finish rolling, laminar cooling and coiling to obtain a hot-rolled coil; after unloading the coil, covering the coil on-line with an insulating enclosure and moving it into a steel coil warehouse along with a transport chain; after a specified period of on-line insulating time, removing the coil from the insulating enclosure, and cooling it to room temperature in air, wherein the microalloying element Ti has a content of ?0.03 wt %; the coiling is performed at a temperature of 500-700° C.; said covering on-line with an insulating enclosure means each hot-rolled coil is individually covered with an independent, closed insulating enclosure unit within 60 minutes after unloading; the on-line insulating time is ?60 minutes.