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实验研究了超低碳Ti-IF钢性能和析出相,结果表明:超低碳Ti-IF钢具有低的屈强比、高塑性、高应变硬化性能和高成形性能,其屈强比约为0.5,抗拉强度为310 MPa,屈服强度为155 MPa,伸长率47%~50%,应变硬化指数n值为0.26~0.28,塑性应变比r值均在2.0左右,最高r值达2.25。退火织构特征均表现为较强的γ纤维织构和较弱的α纤维织构,γ纤维织构主要为{111}<110>和{111}<112>,最强点在{111}<110>处,有利的{111}取向织构使Ti-IF钢具有优异的深冲性能。在超低碳钢中加入微量的Ti,形成碳化物、氮化物和氮碳化物,可以固定间隙原子(如C、N原子),获得无间隙原子钢,同时,适量固溶Ti,能显著提高钢的深冲性能。析出相主要有Ti(N,C)及TiC,Ti2CS,Ti3S4及很少量的AlN,而粗大稀疏的Ti2CS等析出相对晶界的钉扎力小,相应的促进了{111}再结晶织构的发展,从而获得较高的r值。
The results show that the ultra-low carbon Ti-IF steel has low yield ratio, high plasticity, high strain hardening and high formability. The yield ratio of the ultra-low carbon Ti-IF steel is about 0.5, tensile strength of 310 MPa, yield strength of 155 MPa, elongation of 47% ~ 50%, strain hardening index n value of 0.26 ~ 0.28, plastic strain ratio r value of about 2.0, the highest r value of 2.25. The annealed textures show strong γ fiber texture and weaker α fiber texture. The γ fiber texture is mainly composed of {111} <110> and {111} <112> <110>, the favorable {111} orientation texture gives Ti-IF steels excellent deep drawability. In the ultra-low carbon steel by adding a small amount of Ti, the formation of carbides, nitrides and nitrides, can fix interstitial atoms (such as C, N atoms) to obtain interstitial atomic steel, while the amount of solid solution Ti can be significantly increased Deep drawing of steel. Ti (N, C) and TiC, Ti2CS, Ti3S4 and a small amount of AlN are mainly precipitated, whereas coarse sparse Ti2CS and other precipitates have small pinning force with respect to the grain boundaries, correspondingly, the {111} recrystallization texture The development, thus obtains the higher r value.