热冲压高强钢B1500HS的淬火-碳分配试验研究

Study on quenching & partitioning heat treatment for hot-stamped high-strength steel B1500HS

为克服现行热冲压制件塑性较差的缺点,研究将淬火-碳分配(Quenching-Partitioning)工艺与热冲压工艺结合的可行性。通过热冲压高强钢B1500HS的全马氏体转变、Q&P一步法和Q&P两步法的热模拟试验、拉伸试验、显微组织观察等方法,研究了不同Q&P热处理工艺参数对材料性能的影响。结果表明,在合适的工艺参数下,Q&P一步法能获得恰当的马氏体和残留奥氏体组织,在基本保证热冲压制件超高强度的同时有效提高其伸长率,从而提升制件的综合力学性能。试验结果显示,与代表现行热冲压工艺的全马氏体转变相比,Q&P一步法提高强塑积约24%。

In order to overcome the disadvantage of poor plasticity of present hot-stamped parts,the feasibility of realizing quenching &partitioning( Q&P) heat treatment of B1500HS steel by the hot stamping process was investigated.The effects of full martensitic transformation,one step Q&P treatment and two steps Q&P treatment on properties of high-strength steel B1500HS were studied by a series of thermal simulation experiments,tensile tests and microstructure observations.The results show that the one step Q&P treatment with appropriate process parameters result in dual-phase microstructure of martensite and retained austenite,which can improve the elongation effectively as maintaining the high-strength.The experimental results show that the product of strength and elongation after one step Q&P treatment is about 24% higher than that of by using present hot stamping process.