冷轧深冲钢（即IF钢）的成形性能是其冲压加工时保证零件质量最重要的因素。通过静态拉伸、织构分析、成形极限等试验方法，分别研究了IF钢的基本成形性能和模拟成形性能。试验结果表明：IF钢具有优异的力学性能、高的延伸率、高的应变硬化指数、高的塑性应变比以及低的平面各向异性度。此外，IF钢的成形极限较高，深冲及复杂变形时有较高的安全裕度。

The formability of cold-rolled deep-drawing steel (IF steel) is considered to be the most im-portant factor in its stamping process to ensure the quality of machine parts .The basic formability and simulating formability of IF steel is studied by the static tensile test ,texture and forming limit test .The results show that IF steel has excellent mechanical properties ,high elongation ,strain hardening exponent (n-value) ,plastic strain ratio (r-value) and low degree of planar anisotropy .In addition ,IF steel has high level of the forming limit with high safety margin in the case of deep drawing and complex deformation .

针对济钢现场工艺条件下生产的Ti-IF钢,利用X’Pert ProxX射线衍射宏观织构分析方法,研究了中薄板坯热连轧轧制及随后的冷轧、退火工艺过程中织构的变化规律。IF钢冷硬板主要织构类型为{111}110、{111}112和{001}110,其中{111}110织构强度达到12;再结晶退火后的IF钢退火板,主要织构类型为{111}110和{111}112,{111}110织构强度提高到15.37。济钢生产的Ti-IF钢获得了对板材成形最有利的{111}//ND织构。

Based on the Ti-interstitial free steel produced by Jinan Steel, texture hereditary of Ti-interstitial free steel during JSP-double stands reversible cold rolling processes were studied by means of X’Pert Prox X-ray diffraction. The main texture of the cold rolled IF steel sheet was{111} ,{111} and{001} and the density of{111} was 12 in which. The main texture of the annealing IF steel sheet was{111} and{111} and the density of{111} was risen to 15.37. The{111}//ND texture which was the best to forming was obtained in the Ti-interstitial free steel produced by Jinan Steel.

系统研究了Ti-IF钢冶炼过程和铸坯中含Ti夹杂物的组成、分布与微观形貌,揭示了含Ti夹杂物的衍变规律.热力学分析和实验结果表明:在IF钢冶炼过程中无TiN生成,含Ti夹杂物的存在形式是以TiO_2为主的钛氧化物结合其他氧化物的复合夹杂:而在连铸凝固过程中,由于钢液温度降低和元素的偏析作用,TiN夹杂以异质形核的方式生成.IF钢铸坯中非金属夹杂物主要是大尺寸Al_2O_3颗粒和存在中间过渡层的TiN—Al_2TiO_5-Al_2O_3复合夹杂物,其形核长大过程是[Al]、[Ti]和[O]先在细小的Al_2O_3颗粒上反应生成一层Al_2TiO_5,然后TiN在Al_2TiO_5表面形核长大.根据连铸过程和铸坯中含钛夹杂物的研究得出,Ti-IF钢铸坯中TiN夹杂难以去除,但是可以使其变性以实现对钢中含钛夹杂物的控制.

The composition, distribution and microtopography of titaniferous inclusions in Ti- IF steel during steelmaking and in the casting billets were investigated systematically, and the evolution of the titaniferous inclusions was described subsequently. Both thermodynamic analysis and experimental results indicate that TiN could not precipitate in the steelmaking process, while the titanifer-ous inclusions exist in the form of a combination of titanium oxides which mainly consists of TiO2 and other oxides. In the solidification process of continuous casting, TiN inclusions precipitate in the heterogeneous nucleation way due to the decrease of liquid steel temper-ature and the segregation effect. The main non-metallic inclusions in the casting billets are large size Al2 O3 particles and TiN- Al2 TiO5-Al2 O3 triple-layer complex inclusions with the middle layer of Al2 TiO5 . The nucleation and growth process of TiN- Al2 TiO5- Al2 O3 complex inclusions is that [Al], [Ti] and [N] form the midd

以超低碳含磷高强IF钢为研究对象，在实验室条件下进行了冷轧及模拟退火试验。结果表明，随退火温度的升高及退火时间的延长，试验钢再结晶越完全，晶粒形状更趋近等轴晶；试验钢退火后具有较强的{111}＜110＞和{111}＜112＞织构；采用700～720℃退火4 h可使试验钢各项力学性能指标满足标准要求。

Taking a P-bearing high strength IF steel as an object of study, cold rolling and simulative annealing experiments were carried out in the laboratory. The results showed that recrystallization will be more complete along with annealing temperature rising and annealing time prolonging, and the grain shape tends to be equiaxial. Strong{111} and{111} texture components are found after annealing. All mechanical properties of tested steel meet the standard requirement after annealing between 700 and 720℃and 4 h.

采用ASPEX扫描电镜中的自动特征分析功能研究了交换钢包过程(取样浇次第4、5炉)对IF钢连铸板坯表层的洁净度的影响,且对比研究了交换钢包过程浇铸铸坯(交接坯)与正常浇铸铸坯(正常坯)的表层洁净度.结果表明:正常坯与交接坯中尺寸大于20μm的表层夹杂物可分为三类:(1)簇群状Al2O3(包括气泡+簇群状Al2O3);(2)簇群状TiOx--Al2O3夹杂物;(3)保护渣夹杂物.正常坯表层的大型夹杂物主要为簇群状Al2O3,没有检测到保护渣夹杂物.换包开浇后铸坯总氧质量分数从14×10-6增至17×10-6,交接坯表层检测到较多的第2夹杂物,说明钢包开浇后钢水被轻微氧化.此外,钢包开浇后剧烈的液面波动也导致了保护渣的卷入.在当前工艺下,换包对IF钢铸坯表层洁净度的影响长度约为11m.

The effect of ladle change process (the 4th heat to the 5th heat) on the surface cleanliness of IF steel continuous cast-ing slabs was investigated by total oxygen measurement and automatic feature analysis equipped on ASPEX. A comparison of surface cleanliness was performed between transition slabs ( cast during ladle change process ) and normal slabs ( cast under normal condi-tion). It is found that inclusions larger than 20μm are classified into three types:(1) cluster alumina (including bubble + cluster a-lumina inclusions);(2) cluster TiOx-Al2 O3 inclusions; and (3) mold powder inclusions. In terms of surface inclusions in normal slabs, most of the inclusions detected in the scanning area are cluster alumina, and no mold powder inclusions are found. While for transition slabs, the total oxygen content increases from 14 × 10 -6 to 17 × 10 -6 , and the number density of Type 2 inclusions goes up since the cast start of the 5th heat, indicating re-oxidation of the steel