铁路用热轧钢轨国内外标准比对分析

针对我国及国际国外铁路用热轧钢轨标准的尺寸外形、牌号、成分、残余氢氧氮含量、力学性能、非金属夹杂物、残余应力、表面质量等方面差异作了对比分析。     

化学组成和夹杂物对试验钢轨断裂韧性的影响

钢轨由于其自身特殊应用性,在标准中对其质量提出了较其它钢种更为严格的要求。钢轨需要完全满足质量标准,象标准中明确规定的断裂韧性、疲劳和残余应力限制。采用SENB试样,在MTS810伺服液压材料检测系统中完成了断裂韧性测试,研究了非金属夹杂物对断裂韧性值的作用。断裂韧性值也与钢轨化学组成和力学性能有关。在Klc值较低的试样中,发现了相当高的硫化物夹杂,经过光谱分析,结果表明氢含量较高。     

U75V钢轨轨腰探伤不合原因的分析

为查明U75V钢轨轨腰探伤不合原因,采用垂直探伤定位法准确定位缺陷后,利用光学显微镜、扫描电镜对定位的缺陷部位进行了非金属夹杂物、金相组织等检验分析.结果表明,在U75V钢轨轨腰探伤不合处存在长度超过2.0mm的异常大硅酸盐类非金属夹杂物和组织偏析,分析认为异常大硅酸盐类非金属夹杂物是导致探伤不合的主要原因.     

钢轨化学成分对力学性能影响的研究

为全面了解鞍钢生产的钢轨的化学成分和力学性能的情况,对2004年7月～2005年2月鞍钢生产的钢轨的化学成分和力学性能进行了统计分析.结果表明,鞍钢生产的钢轨化学成分范围较窄,力学性能相对稳定,成分的变化对性能有一定的影响.通过调整化学成分,可进一步提高钢轨的力学性能.     

钢轨钢微合金化及合金轨

介绍了微合金化元素对钢轨钢组织和力学性能的影响，国外生产的部分合金轨的成分和性能，超高强度钢轨的研制现状及合金元素对钢轨钢断裂韧性的影响。     

钢轨钢的现状和发展趋势

本文概述了钢轨钢的研究和发展，并论述了各类钢轨网的使用条件，化学成分，组织和力学性能的内在联系。根据重载高速铁路钢轨的特点，提出开发中碳多元合金化的高强度高韧性重轨钢。     

U75V 60kg/m钢轨接触疲劳裂纹伤损分析

针对U75V 60 kg/m钢轨在重载小半径线路中出现的探伤报警,对报警钢轨进行了宏观形貌、非金属夹杂物检验、低倍和显微组织检验等分析。分析结果表明,该钢轨在重载小半径曲线上,通过量达到4亿吨,使用状况良好。钢轨试样为接触疲劳裂纹伤损,与钢轨使用条件和线路运营情况有关,与钢轨材质无关。     

钢轨A类非金属夹杂的析出分析研究

通过对钢轨A类非金属夹杂进行不同深度、不同位置的取样检测,发现钢轨A类非金属夹杂评级结果存在一定偶然性。以U75V为例进一步采用Factsage热力学数值模拟及析出热力学理论对MnS非金属夹杂的析出过程进行分析;结合连铸过程钢液冷却凝固特性及实际统计、检测结果对MnS非金属夹杂的析出进行验证,最终得出MnS析出于钢液近乎完全凝固,且主要由于S、Mn偏析形成微区高溶质浓度而析出。以降低钢液氧、氮含量为基础,降低钢液硫含量、夹杂变性处理及铸坯内部质量优化可以抑制MnS非金属夹杂的析出及轧制形变。     

高洁净度钢轨钢的夹杂物控制技术

针对国内生产350 km/h高洁净度钢轨存在非金属夹杂物控制的核心问题,开展了相关研究.通过采用适宜的钢包底部吹氩模式和钢包渣组成,显著提高了钢中非金属夹杂物的去除率,T[O]去除率提高近40%;对硫化物夹杂的变性处理有效地控制了钢轨钢中夹杂组成和形态.这些技术在350 km/h高洁净度钢轨钢生产中的应用,不仅使钢轨的T[O]降到10.17×10-6,而且A类和B、C、D类非金属夹杂物评级分别≤2.0级和1.0级,实现了350km/h高洁净度钢轨钢的批量生产.     

美国对废旧钢轨的再生应用

美国对废旧钢轨的再生应用铁路钢轨是一种优质钢材，其材料组织致密，晶粒微细，含炭量高，力学性能优异，并且耐磨性好。当钢轨投入长期运用之后，由于轨道与车轮间的摩擦磨损，或者裂损，总有一天会报废。然而，钢轨报废后仍保持了新钢轨的潜在本质，其结构丝毫不变。过...     

Research progress on influence of inclusion on ductility and toughness of steel

The ductility and toughness of steel are inextricably linked with the non metallic inclusions, how to minimize the damage of inclusions on mechanical properties of steel is an important research priority in the metallurgy and materials field. The effects of inclusions on the ductility and toughness of steel were summarized from the perspective of type, size, number, distribution, and physical properties of inclusions. The fracture mechanism of steel caused by inclusion was also discussed. Then, the relationship between inclusion and mechanical properties of steel is prospected, which could provide a theoretical basis and technical reference for control technology of inclusions.     

夹杂物对钢塑性和韧性的影响研究进展

摘要：非金属夹杂物与钢的塑性和韧性有着必然的联系,如何降低夹杂物对钢性能的危害一直是冶金和材料领域关注的重点。从夹杂物类型、尺寸、数量、分布及其物理性能等角度归纳总结了夹杂物对钢塑性和韧性的影响,并分析了夹杂物引起材料断裂的机制。最后,对夹杂物与钢材性能的关系进行了展望,为钢铁企业非金属夹杂物的控制提供理论依据和技术参考。     

Effect of sulfur content on non metallic inclusions of heavy rail steel

Due to the inaccurate control of raw materials and operation in the actual production process, the sulfur content and non-metallic inclusions in the steel fluctuate greatly, which seriously affects the cleanliness of steel. To accurately control the size, shape and quantity of non-metallic inclusions such as manganese sulfide in heavy rail steel, the effect of sulfur content on non-metallic inclusions in heavy rail steel was studied in the laboratory. To investigate the changes of the number and morphology of non-metallic inclusions in steel under different sulfur contents, the sulfur content of test steel was increased to 70×10-6, 110×10-6 and 140×10-6, respectively. During the experiment, the test steel was heated and melted in a tubular furnace according to a certain heating rule, and then cooled naturally in the furnace. Subsequently, the non metallic inclusions in steel were scanned by automatic inclusions analyzer, and the relationship between sulfur content and the composition, size, form and quantity of non-metallic inclusions in steel was obtained. The results indicate that most of the inclusions in the steel are composite MnS with oxides as nucleating cores. With the increase of sulfur content, the quantity density of composite MnS, MnO-SiO2 and MgO-Al2O3-SiO2-CaO inclusions increase, while the CaO-SiO2 and MgO-CaO-SiO2 inclusions decrease. The average size of inclusions increases with the increase of sulfur content, and the number of inclusions with different sizes also increases, especially for inclusions with sizes of 2-10μm which increase obviously. During solidification, MnS can be separated from molten steel with sulfur content of (70-140)×10-6. In addition, the higher the sulfur content is, the earlier MnS inclusions precipitate and the more the MnS content is.     

硫含量对重轨钢中非金属夹杂物的影响

摘要：实际生产过程中由于原料和操作控制不精确,钢中硫含量和非金属夹杂物波动较大,严重影响钢的洁净度。为了准确控制重轨钢中硫化锰等非金属夹杂物的尺寸、形态和数量,在实验室开展了硫含量对重轨钢中非金属夹杂物的影响研究。钢中硫质量分数增至70×10-6、110×10-6、140×10-6后随炉冷却,采用全自动夹杂物分析仪对钢中非金属夹杂物进行统计,获得了硫含量与钢中非金属夹杂物成分、尺寸、形态和数量的关系。结果表明,钢中夹杂物大部分为以氧化物为形核核心的复合型MnS;随着硫含量的升高,复合型MnS、MnO-SiO2和MgO-Al2O3-SiO2-CaO型夹杂增多,CaO-SiO2和MgO-CaO-SiO2夹杂减少;夹杂物平均尺寸随硫含量的升高而增大,且不同尺寸的夹杂物均有所增加,尺寸为2~10μm增多最明显;硫质量分数为(70~140)×10-6的钢液凝固过程液相中都能单独析出MnS,且硫含量越高,MnS析出越早,含量越多。     

攀钢连铸板坯非金属夹杂物现状调查

根据对攀钢连铸板坯中非金属夹杂物现状的调查，了解了０９ＣｕＰＲｅ－Ｂ钢连铸坯中夹杂物的状况及在生产过程中的变化情况，得到的结果可作为攀钢生产洁净钢的依据。     

A Comparison of a Two‐Dimensional and a Three‐Dimensional Method for Inclusion Determinations in Tool Steel

To produce clean commercial tool steel the non‐metallic inclusions characteristics have to be known, since they influence the mechanical properties of steel. In this work, inclusion characteristics in steel samples from plant trials were studied. The samples were collected in the steel plant according the two following methods: (a) 2D investigations of inclusions by a cross sectional method and (b) 3D investigations of inclusions collected on a film filter after electrolytic extraction. More specifically, the chemical composition, morphology, number and size distribution of inclusions in tool steel samples taken from ladle during melt treatment were determined by both methods. In both methods SEM equipped with EDS was used for compositional analysis of inclusions. In addition, in the cross sectional method an automated detection program called ‘INCAFeature’ was used to collect more statistics of non‐metallic inclusions. The composition of inclusions larger than 5 µm was found to contain 49% CaO based on the results from both methods. However, for smaller inclusions it was found that the accuracy of the 2D method was less than that of the 3D method due to the influence of the metal matrix on the results. In addition, it was found that a critical inclusion size of 4 µm could be defined for the 3D method, above which the standard deviation in composition determination was very low.     

50MnVS非调质易切削钢的生产实践

用EBTEAF—LF工艺生产非调质易切削50MnVS钢，S的回收率大幅度提高，且完全满足用户对机械性能、晶粒度、非金属夹杂物及低倍的要求。     

含钙钡合金脱氧和非金属夹杂物控制技术研究

采用MoSi2电阻炉在1〖KG-*9〗873 K下开展了含钙钡合金脱氧和非金属夹杂物控制技术研究。结果表明，各组实验终点钢中夹杂物平均长度均小于8 μm，并都有纯三氧化二铝夹杂物存在。采用含钙钡合金的复合脱氧工艺，终点钢中未发现含钡夹杂物，有较多以CaO Al2O3为主要成分的复合夹杂物，w（T.O）＞50×10-6。用AlMnCa脱氧，终点钢样w（T.O）＝37×10-6，含氧化钙夹杂物较少，大于20 μm的夹杂物数量占总夹杂物数量的1.2%。     

去除钢水中非金属夹杂物方法研究

介绍了一种去除钢水中非金属夹杂物的方法,探讨了它对中间包内腔结构改进的作用。经过计算,本方法能够满足10μm以上非金属夹杂物的上浮时间要求。实验证明,通过整流的作用,降低了钢水流动速度,流动更加平稳,可降低注流区的湍流强度,同时使钢液流动路线延长,钢液平均停留时间增加,夹杂物上浮增多,利于提高钢液洁净度。钢水均匀慢速流动减轻了钢水短路流动造成的耐火材料熔损,由耐火材料熔损造成的夹杂物减少。     

薄带连铸304不锈钢凝固过程中生成的氧化物夹杂

 采用透射电镜(TEM)对双辊薄带连铸AISI304不锈钢凝固过程中生成的非金属夹杂物进行了研究,发现在薄带的晶界存在许多球型的微细氧化物夹杂,其成分主要是MnO Al2O3 SiO2类复合夹杂物,直径均小于1 μm,并采用数学模型对薄带连铸304不锈钢凝固过程中析出的氧化物夹杂的大小进行了计算,预测值与实验中观察到的结果吻合较好。与传统连铸相比,双辊薄带连铸AISI304不锈钢凝固过程中生成的非金属夹杂物数量增多,尺寸明显减小。