The ultra-fine bainitic microstructure of a 900 MPa low carbon bainitic Cu-Ni-Mo-B steel was obtained by a newly developed relaxation precipitation control （RPC） phase transformation processing. In a pan-cake like p...The ultra-fine bainitic microstructure of a 900 MPa low carbon bainitic Cu-Ni-Mo-B steel was obtained by a newly developed relaxation precipitation control （RPC） phase transformation processing. In a pan-cake like prior-austenite grain, the micro- structure consisted of lath bainite, a little of abnormal granular bainite, and acicular ferrite. The effect of zirconium carbonitrides on the austenite grain coarsening behavior was studied by transmission electron microscopy （TEM）. The results show that, the lath is narrower with increasing cooling rate. The ratio of all kinds of bainitic microstructure is proper with the intermediate cooling rate; and Zr-containing precipitates distribute uniformly, which restrains austenite grain growing in heat-affected welding zone.展开更多
To develop high strength, good toughness, and weldable steel plate, a steel composition was designed. It was an ultra-low-carbon microalloyed steel. TMCP （thermal mechanical control process） and RPC （relaxation pre...To develop high strength, good toughness, and weldable steel plate, a steel composition was designed. It was an ultra-low-carbon microalloyed steel. TMCP （thermal mechanical control process） and RPC （relaxation precipitation control） were employed to ensure fine lath bainite microstructure. This kind of microstructure could induce higher strength and better toughness.展开更多
基金supported by the National High-Technology Research and Development Program of China (No.2003AA331020)
文摘The ultra-fine bainitic microstructure of a 900 MPa low carbon bainitic Cu-Ni-Mo-B steel was obtained by a newly developed relaxation precipitation control （RPC） phase transformation processing. In a pan-cake like prior-austenite grain, the micro- structure consisted of lath bainite, a little of abnormal granular bainite, and acicular ferrite. The effect of zirconium carbonitrides on the austenite grain coarsening behavior was studied by transmission electron microscopy （TEM）. The results show that, the lath is narrower with increasing cooling rate. The ratio of all kinds of bainitic microstructure is proper with the intermediate cooling rate; and Zr-containing precipitates distribute uniformly, which restrains austenite grain growing in heat-affected welding zone.
基金Item Sponsored by National Key Basic Research and Development Program of China (2006AA03Z507)
文摘To develop high strength, good toughness, and weldable steel plate, a steel composition was designed. It was an ultra-low-carbon microalloyed steel. TMCP （thermal mechanical control process） and RPC （relaxation precipitation control） were employed to ensure fine lath bainite microstructure. This kind of microstructure could induce higher strength and better toughness.
