CAJ | 학술논문

采用物理化学相分析、高分辨透射电镜等手段研究V-N微合金化钢在正火过程中第二相行为,并进行相应的理论计算,讨论该行为对材料性能产生的影响.正火加热保温过程中,V-N钢有约32.9%的V( C,N)未溶解,阻止奥氏体晶粒长大.在正火冷却过程中,未溶解的V( C,N)诱导晶内铁素体形核,细化铁素体晶粒,而溶解的V( C,N)重新析出,起到析出强化作用. V( C,N)析出相行为的变化导致材料力学性能的改变.与热轧态V-N钢相比,正火态V-N钢细晶强化贡献值增加31 MPa,而析出强化贡献值减少45 MPa.
채용물이화학상분석、고분변투사전경등수단연구V-N미합금화강재정화과정중제이상행위,병진행상응적이론계산,토론해행위대재료성능산생적영향.정화가열보온과정중,V-N강유약32.9%적V( C,N)미용해,조지오씨체정립장대.재정화냉각과정중,미용해적V( C,N)유도정내철소체형핵,세화철소체정립,이용해적V( C,N)중신석출,기도석출강화작용. V( C,N)석출상행위적변화도치재료역학성능적개변.여열알태V-N강상비,정화태V-N강세정강화공헌치증가31 MPa,이석출강화공헌치감소45 MPa.
The precipitation behavior of V-N microalloyed steel at the normalizing process was studied by physicochemical phase analysis and high resolution transmission electron microscopy. The effect of this precipitation behavior on the mechanical properties of the steel was discussed by theoretical calculations. At soaking of the normalizing process, 32. 9% of V(C,N) precipitations keep undissolved into austenite, and they prevent austenite from growing up. At the subsequent cooling process, the undissolved V( C,N) precipitations induce intra-granular ferrite nucleating, which can refine ferrite grains; besides, the dissolved V( C,N) precipitations re-precipitate and play the role of precipitation strengthening. Compared with the hot-rolled steel, the normalized steel gains a 31 MPa increment in grain-refined strengthening but a 45 MPa decrease in precipitation strengthening.