【摘要】：利用掃描電鏡(SEM)、透射電鏡(TEM)對(duì)Nb-Ti微合金化熱成形鋼的微觀組織進(jìn)行觀察,采用Kahn撕裂試驗(yàn)對(duì)其韌性和撕裂性能進(jìn)行了研究,并利用Thermo-Calc熱力學(xué)軟件對(duì)其析出行為和析出粒子成分進(jìn)行分析計(jì)算.結(jié)果表明,含碳質(zhì)量分?jǐn)?shù)0.13%的熱成形鋼在Nb-Ti微合金化后的組織為馬氏體,和傳統(tǒng)熱成形鋼(22MnB5)相比其奧氏體晶粒、板條塊和板條束都得到細(xì)化,并且其抗拉強(qiáng)度達(dá)到1500 MPa以上,撕裂強(qiáng)度和單位面積裂紋擴(kuò)展能分別達(dá)到1878 MPa、436 kN·m~(-1).在950℃奧氏體化時(shí),Nb-Ti合金元素幾乎全部以析出粒子形式存在,能有效阻止奧氏體晶粒長大.另外在基體中主要存在兩種析出物,一種是尺寸在100~200 nm的Ti(C,N);另一種是納米級(jí)別的鈦鈮復(fù)合碳氮化物,能有效強(qiáng)化基體,提高強(qiáng)度.
[Abstract]:The microstructure of Nb-Ti microalloyed hot formed steel was observed by scanning electron microscope (SEM),) transmission electron microscope (TEM). The toughness and tear properties of Nb-Ti microalloyed hot formed steel were studied by Kahn tear test. The precipitation behavior and the composition of precipitated particles were analyzed and calculated by Thermo-Calc thermodynamics software. The results show that the microstructure of hot forming steel with 0.13% carbon content is martensite after Nb-Ti microalloying. Compared with traditional hot forming steel (22MnB5), the austenite grain of hot formed steel is refined. The tensile strength is more than 1500 MPa, and the tear strength and crack growth energy per unit area are 1878 MPa,436 kN m-1, respectively. At 950 鈩，

本文編號(hào)：2402316