Key technological parameters of the stable production of interstitial free (IF) grade steel sheet with the bake hardening (BH) effect have been studied. The features of ultralow-carbon IF grade steels and IF steels with the BH effect, as well as the process flowchart for hardening IF-BH steel during hot drying of a car body after painting are described. Data concerning the chemical composition of IF and IF-BH steels produced at Russian and foreign enterprises are presented. The causes of slip band defects in steel sheet occurring when the yield plateau is observed in the tensile diagram of steel samples are analyzed. Requirements for the shelf life of IF-BH steel grades are presented and analyzed. A calculation formula of effective carbon content in steel is proposed based on the content of total carbon, niobium, titanium and nitrogen in steel. The range of effective carbon content in steel required for achieving the optimal BH effect magnitude is presented based on the papers published earlier. The industrial IF-BH steel production results have been analyzed for Russian enterprise conditions. In addition, the following criteria are recommended: the optimum range of carbon content in solid solution, the recommended maximum total concentrations of carbon and nitrogen in steel, and the BH effect magnitude that provides a high yield of IF-BH steel sheet fit for production. The calculations of various IF-BH steel microalloying with titanium and niobium have been performed. Criteria have been formulated that for obtaining a given BH effect magnitude in cold-rolled ultralow-carbon steels. A two-stage scheme for microalloying with titanium and niobium is proposed. The grain size influence in sheet steel upon the presence and BH effect magnitude, as well as upon the presence or absence of a yield plateau observed in the sheet metal’s tensile diagram in the initial state, is described.

中文翻译：

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在深冲用超低碳钢中实现 BH 效应的标准参数

研究了稳定生产具有烘烤硬化 (BH) 效应的无间隙 (IF) 级钢板的关键技术参数。描述了超低碳IF级钢和具有BH效应的IF钢的特点，以及IF-BH钢在喷漆后热干燥过程中硬化的工艺流程图。介绍了俄罗斯和外国企业生产的 IF 和 IF-BH 钢的化学成分数据。分析了在钢试样的拉伸图中观察屈服平台时钢板出现滑移带缺陷的原因。提出并分析了 IF-BH 钢种的保质期要求。根据钢中总碳、铌、钛和氮的含量，提出了钢中有效碳含量的计算公式。实现最佳 BH 效应量级所需的钢中有效碳含量范围是根据早先发表的论文提出的。工业 IF-BH 钢生产结果已针对俄罗斯企业条件进行了分析。此外，推荐以下标准：固溶体中碳含量的最佳范围，钢中推荐的最大碳和氮总浓度，以及提供适合生产的高产率的 IF-BH 钢板的 BH 效应大小. 已经进行了钛和铌微合金化的各种 IF-BH 钢的计算。已经制定了在冷轧超低碳钢中获得给定 BH 效应量级的标准。提出了钛和铌微合金化的两阶段方案。