Optimizing the technology for making steel 08Yu with a carbon content below 0.03%

Ferrite and cementite grain growth is seen on some heats of steel 08Yu when it is made by the standard technology in accordance with GOST 9045-93. A study was made of the effect of the chemical composition of the steel and the parameters of the hot-and cold-rolling operations on the microstructure of steel 08Yu. It was found that a low carbon content in the steel is the main factor affecting its microstructure. __________ Translated from Metallurg, No. 1, pp. 56–59, January, 2007.     

钢中液态夹杂物聚并行为的数学物理模拟

基于相似原理,采用水模拟钢液,用有机试剂模拟钢液中液态非金属夹杂物,同时采用数值仿真方法共同研究了夹杂物种类、两相间界面张力及黏度对于液滴聚并过程的影响规律.结果表明,夹杂物液滴间的聚合趋势与其自身的物理性质有紧密联系,其中液滴相与连续相之间的界面张力会促进其相互聚并,而液滴相的黏度则正相反,在液滴聚并过程中起抑制作用.因此,通过改变液态夹杂物与高温钢液之间的界面参数以及黏度参数,有望达到聚合或分散的控制目标,进而实现夹杂物尺寸的灵活控制.      

Nonuniform structure and properties in hot-rolled low-carbon steel coils

The austenite phase transitions in the industrial production of hot-rolled steel coils are studied magnetometrically. Nonuniformity of the structure and mechanical properties of low-carbon steel strip over its length and width may be attributed to incomplete phase transitions in the strip on the output roller conveyer and nonuniformity of the subsequent coil cooling in regular production conditions. Inheritance of the structural inhomogeneity formed after hot rolling may be responsible for the thickness variation observed after cold rolling of the strip. Recommendations are made for reducing or eliminating the structural inhomogeneity so as to improve product quality.     

Technology for chemical preheating of automotive-grade and tube steels in the ladle

The converter shop at the Severstal’ Metallurgical Combine has developed and introduced a unit for the chemical preheating of steel in pouring ladles. When the filled ladle arrives at the steel-finishing unit, the steel is blown with argon in accordance with existing procedures. Measurements of temperature are then used to evaluate the need for chemical heating of the steel. The mass of aluminum to be used for this purpose and the total consumption of oxygen are calculated based on the steel’s temperature and aluminum content. The chemical heating technology can be used in the production of ordinary steels, automobile sheet 08Yu, and tube steel 22GYu. When IF-type automobile sheet is being made, the amount of oxygen used for chemical preheating should be limited to 100 m³. __________ Translated from Metallurg, No. 2, pp. 45–47, February, 2007.     

Production of cold-rolled sheet of increased strength

In sheet-rolling shop 5 at OAO Magnitogorskii Metallurgicheskii Kombinat (MMK), a production technology for 0.8–3.0 × 1180–1250 mm cold-rolled annealed strip made of 08γCЮT steel (strength class 275 according to Technical Specifications TU 14-1-3764-84) has been developed. Such sheet is used in stamping auto components. Technological parameters such that the product meets customer requirements on surface quality and mechanical properties are established.     

大型原油储罐用B610E(08MnNiVR)高强度调质钢板研制

介绍了在宝钢分公司厚板厂产线上开发成功的大型原油储罐用B610E（08MnNiVR）高强度钢板的成分和性能特点、生产工艺,列举了典型厚度钢板的实物性能,试验和分析了其大热输入焊接的适应性。研究结果表明,宝钢分公司厚板厂产线工业批量生产的B610E（08MnNiVR）钢板性能稳定。完全满足10万m。大型原油储罐用大热输入焊接高强度钢板技术要求,已成功地用于建造10万m。原油浮顶储罐。     

ML08Al冷镦钢连铸坯质量的研究

利用转炉冶炼生产ML08Al冷镦钢,通过冶炼工艺的优化,改善了钢中非金属夹杂物的形态和行为,提高了钢的质量.还对ML08Al冷镦钢连铸坯进行了必要的检测分析,并对其中非金属夹杂物的形态与行为做了深入的研究.提出了改善产品质量的措施和提高钢的纯净度的手段和方法.     

稀释剂对原位合成TiC_p/钢基硬质涂层组织和性能的影响

为提高钢基硬质涂层的表面质量和显微硬度,采用真空消失模铸造法引发自蔓延高温合成(SHS)反应,在铸件表面制备原位合成TiC颗粒增强钢基硬质涂层。通过X-ray、OM、SEM、EDS及显微硬度测试等方法,研究了稀释剂TiC的加入量对钢基硬质涂层微观组织和力学性能的影响。结果表明:硬质涂层与基材之间呈冶金结合,涂层组织由TiC颗粒和α-Fe基体相构成;随外加TiC含量的增加,可降低燃烧反应温度,提高涂层组织致密度,原位合成的TiC颗粒细小呈圆球或近圆球形状,均匀分布在基体组织中,显著提高了TiC颗粒总体积分数和硬质涂层显微硬度,其中TiC加入量为10%(质量分数)时,涂层的综合性能最佳。     

H08A焊条钢的开发

河北敬业集团从市场需求和集团的实际情况出发,开发了H08A焊条钢。介绍了H08A焊条钢冶炼的主要设备、工艺流程,针对该钢低碳低硅的特点,转炉冶炼时尽量一次拉碳出钢、一次拉碳多倒渣,做到温度与化学成分双命中;采用挡渣塞和挡渣锥挡渣出钢,加铝镁钙、中碳锰铁等合金脱氧、去除夹杂物;钢包到站后,在包底分别于软吹氩和钙处理后测温、取样,控制钢水的化学成分达到目标值;全程保护浇铸,防止钢水出现二次氧化。从试生产检测试样结果后,H08A焊条钢连铸坯未发现裂纹和气泡,连浇炉次由3～4炉上升到目前的15炉以上,铸坯成品合格率达到98.3%。     

Influence of impurities on the solid-solution hardening of low-carbon steel

The influence of impurities on the solid-solution hardening of cold-rolled low-carbon steel components is considered, by calculation and experiment. To confirm the results, data regarding the influence of the chemical composition on the properties of cold-rolled 08?? steel components (produced by Cherepovets Metallurgical Works, OAO Severstal??) are subjected to statistical analysis, with the formulation of a regression model. The factors that underlie the influence of impurities on the properties of 08?? steel are investigated, and the optimal impurity contents for products of the highest extrusion category are established.     

新型锯片基体用钢51CrV4的研究与开发

 51CrV4钢因具有良好的热处理性能与力学性能,广泛用作为高等级弹簧钢。为改善现有锯片钢的不足,根据51CrV4特有的化学成分,创新性地将其用于制造金刚石焊接锯片基体。通过研究动态CCT曲线,卷取温度对显微组织与第二相析出物的影响,淬火与回火工艺对碳化物尺寸、晶粒尺寸、力学性能的影响,评估了51CrV4钢用于制造金刚石焊接锯片基体的可行性。结果表明：卷取温度升高,先共析铁素体尺寸与珠光体片层间距变大,10 nm粒径以下的(V,Cr)C析出物在MC相析出物中所占的比例减少;淬火温度由800提高到900 ℃时,奥氏体晶粒尺寸先缓慢变化,随后快速长大,固溶的碳化物质量分数增多,回火后锯片硬度增强,而回火温度由450提高到550 ℃时,马氏体板条界片层状渗碳体逐步球化,强度明显下降,塑性小幅提高;设定合适的卷取温度控制热轧态中第二相碳化物的尺寸,并在850～900 ℃淬火、约450 ℃回火是生产高硬度、高韧性51CrV4金刚石焊接锯片的关键工艺。     

Revealing the Role of Cerium on Precipitation Behavior of In Situ TiC Particles and Wear Resistance of High-Titanium Wear-Resistant Steels

Compared to conventional martensitic wear-resistant steels of the same hardness, high-titanium wear-resistant steels with in situ TiC particles can significantly improve wear resistance. However, micron-sized TiC particles will decrease the toughness of high-titanium wear-resistant steels. Here, in order to improve wear resistance without reducing impact toughness, we incorporate 0.0025% cerium elements into high-titanium wear-resistant steels. Compared with no cerium steel, the steel containing cerium is demonstrating comparable mechanical properties, with the yield strength of 1283 MPa and impact toughness of 35.6 J, and the wear performance of the steel containing cerium is 1.78 times that of the steel with no cerium. The results show that with the addition of cerium the effective grain size of the steel decreases, and yield strength and toughness increase. The addition of cerium can form intermetallic compounds of Ce₂O₂S, which are used as heterogeneous nuclear particles in TiC to form rare earth composite particles calculated by the 2D mismatch theoretical model of Bramfitt. As the average spacing of the reinforcing phase particles in the steel decreases, the effective grain size of the steel decreases, and the number of reinforcing phase particles increases, the wear resistance of the steel with the addition of cerium is optimized.     

稀土铈对内生TiC型超级耐磨钢组织性能的影响

作为耐磨钢研究的新领域,引入高体积分数TiC粒子的超级耐磨钢,虽然能够提升钢的耐磨性,但会降低材料的韧塑性.为了提升超级耐磨钢的综合性能,研究稀土铈对超级耐磨钢组织性能的影响,采用真空感应炉冶炼出不同铈质量分数的试验钢,通过扫描电镜(SEM)、电子背散射衍射(EBSD)、电子探针(EPMA)、硬度测试、低温冲击性能测试...     

3Cr2W8V钢高温高载下的干摩擦滑动磨损特性

对３Ｃｒ２Ｗ８Ｖ钢高温高载下的干摩擦滑动磨擦滑动磨损性及磨损面形貌、磨损面表层和次表层的组织和硬度进行了试验和分析。结果表明：高载下３Ｃｒ２Ｗ８Ｖ钢的力学性能是决定材料磨损特性的低载下磨损面上形成氧化物磨屑的覆盖,而在国高载和高温下都未形成氧化物磨屑的覆盖;高温高载下,主要因３Ｃｒ２Ｗ８Ｖ钢本身承能力下降,氧化物磨屑未能覆盖于磨损面上,故对磨损面起不到保护作用。     

Study on microstructure and properties of cold-rolled high strength steel for enameling

With its superior comprehensive properties,cold-rolled enameling steel is widely applied in many fields.However,its low yield stress greatly limits its application.This study aims to improve the yield stress of cold-rolled enameling steel under the premise of meeting formability and enameling properties by strengthening the ferrite matrix via solid strengthening of Mn.The grain size of ferrite before and after enameling,mechanical properties of annealed steel,and precipitation behavior of second-phase precipitates are obtained through studying the microstructure and properties of enameling steel at different stages.The microstructure of the steel investigated at room temperature is found to contain equiaxial ferrite and bunchy cementite particles;the ferrite grains have grown to some extent after enameling.The fine dispersed TiC particles and cementite particles contained in the annealed steel are the main factors improving the hydrogen storage capability.Finally,the result of a falling-ball impact test shows that the steel has achieved excellent adherence.     

Modelling of Charpy V test rejection probability

Abstract

The purpose of this study was to develop a product design model for estimating the impact toughness of low alloy steel plates. The rejection probability in a Charpy V test is predicted with process variables and chemical composition. Joint modelling of the mean and deviation was used in order to improve the results. The proposed method is suitable for the whole production line, including all grades of steel in production and it is not restricted to a few test temperatures. Using the proposed model the product design group could have recognised most of the rejections before production. Next, the developed model will be implemented into a graphical simulation tool that is in daily use in the product planning department and already contains some other mechanical property models. The model will guide designers in predicting the related risk of rejection and in producing desired properties in the product at lower cost.     

厚规格热轧带钢高精度卷取温度控制模型

卷取温度是影响带钢组织性能的重要工艺参数.在生产实践中,如何提高厚规格带钢卷取温度的控制精度是一个难点.针对厚规格带钢在层流冷却过程中的工况特点,提出了温度场计算模型和对流换热系数模型的改进方法,并开发了一种全新的基于相似策略的自适应模型,以改善卷取温度前馈控制效果.经现场应用证明,本文提出的方案能有效提高厚规格带钢的卷取温度控制精度,其中厚度大于12 mm的带钢平均命中率可达到94.9%.      

微合金元素B对轻质TWIP钢组织及力学性能的影响

摘要：将质量分数为0.002%的微合金元素B加入至Fe-28Mn-9Al轻质TWIP钢中，以期改善其强塑积及室温冲击性能。利用X射线衍射、扫描电镜、电子万能拉伸试验机和金属摆锤冲击试验机对热轧TWIP钢的物相组成、微观组织、力学拉伸性能及室温冲击韧性进行了研究与分析。结果表明，微合金元素B的添加具有延缓奥氏体向铁素体转变的作用，细化了奥氏体晶粒，提升了钢的力学性能，TWIP钢的塑性、强塑积和冲击韧性均有明显的提高。     

H08焊条钢连铸坯质量的研究

转炉用准沸腾钢生产工艺冶炼H08焊条钢,生产过程中钢水的脱氧程度决定了钢中非金属夹杂物的形态和行为,会直接影响到钢的质量。为改善H08焊条钢的质量,特别对连铸坯进行了必要的检测分析．并对H08焊条钢连铸坯中非金属夹杂物的形态与行为作了深入的研究。     

A New Pb-free Machinable Austenitic Stainless Steel

 In the present paper, the machinability tests were conducted by using various processing parameters on a CA6164 lathe with a dynamometer. The metallurgical properties, machinability and mechanical properties of the developed alloy were compared with those of an austenite stainless steel 1Cr-18Ni-9Ti. The results have shown that the machinability of the austenitic stainless steels with free-cutting additives is much better than that of 1Cr-18Ni-9Ti. This is attributed to the present of machinable additives. The inclusions might be composed of MnS. Sulfur and copper addition contributes to the improvement of the machinability of austenitic stainless steel. Bismuth is an important factor to improve the machinability of austenitic stainless steel, and it has a distinct advantage over lead. The mechanical properties of the free cutting austenitic stainless steel are similar to that of 1Cr-18Ni-9Ti. A new Pb-free austenitic stainless steel with high machinability as well as satisfactory mechanical properties has been developed.