Effects Of The Technical Parameters On The Microstructure And Property Of BH-HSS Steel

The experiment in the laboratory and little lots site experiment for BH-HSS steel were carried out in this paper. The effect of different process parameters (C content, coiling temperature of hot rolling, cold rolling reduction, continuous annealing parameters and SPM’s elongation) on microstructure, properties and formation of final production. Meanwhile, on the base of those parameters we refined the process parameters of BH-HSS steel, and reached the customer’s requests with refined process parameters. The main contents are as following:(1) High reduction ration can increase the working-hard energy instored and in the production line,80%reduction ration was adopted.(2) In the same soaking temperature, as the soaking time increases, the solid carbon will precipited and the content will decrease. Considering the process speed, the adopted time is60s.(3) As the increased temperature, BH value will rise first and then down, at850～870℃can get wanted BH value and while the temperature is below790℃or more than870℃, BH value will become decrease.(4) For the detected micrograph of break places, it can be induced that the break is elastic fracture and the mixture of quasi-dissociation rupture and dimple rupture. High proportion of dimple rupture and large dimples shows the excellent plasticity of treated steels.(5) The processing parameters designed according to the experiments could satify the requirement of the product.