【作者】 孙会魁；

【导师】 张金柱；

【作者基本信息】 贵州大学 ， 材料加工工程， 2009， 硕士

【摘要】 随着钢材需求量的不断加大,以废钢为主要原料的短流程炼钢被普遍看好。但在废钢的循环使用过程中,不可避免地将铅等低熔点金属带入到炼钢炉中。由于这些金属的氧化位比铁低,在常规的炼钢工艺中不能有效去除,且易在晶界富集,恶化钢的质量,使钢材发生表面裂纹、热处理回火脆性、高温持久强度和抗应力腐蚀强度明显下降等问题。因此,对钢中低熔点金属元素含量的控制及去除问题成为新的研究热点。稀土元素几乎是唯一能与钢中Pb、Sn等有害元素化合的元素,这是因为稀土元素电子结构特殊而具有极强的化学活性。稀土元素是钢液极强的净化剂和洁净钢夹杂物的有效变质剂。本文采用熔炼实验和力学性能试验两种实验方法研究稀土铈对含有低熔点金属铅的H08钢力学性能的影响。熔炼实验中,在H08钢中配加一定量的稀土铈和低熔点金属铅,在中频真空感应熔炼炉中进行冶炼。冶炼出的钢锭经过轧制,并进行热处理,加工成力学性能标准试样。通过对力学性能标准试样进行力学性能测试和扫描电镜分析,研究稀土铈对含铅H08钢抗拉强度、塑性和冲击韧性等力学性能的影响。实验结果表明:往含铅H08钢中加入一定量的稀土铈,在一定的热处理条件下,稀土元素铈可以减轻H08钢中低熔点金属元素铅对钢材力学性能的危害。更多还原

【Abstract】 With the increasing demand for steel,the short-rang steel made of scrap steel is more and more popular.However,during the period of circulation use of scrap steel,it causes the content increase unceasingly of the low melting point metallic elements such as Pb in the steel.Because the oxidation of the low-melting point metallic elements is lower than iron,they cannot be removed efficiently during the conventional steel-making. Many of them gather on the grain boundary, which deteriorate the quality of steel, produce the surface crackle on steel and temper brittleness of heat treatment, decrease high-heat rupture life and corrosion-proof strength.Therefore, it is necessary to discuss the method on how to remove the low melting point metallic elements. The RE elements are nearly only elements that can be compound with harmful elements such as Pb, Sn and so on in the steel. The reason is that the high chemical activity of RE elements depends on the character of their electro-construction of 4f. The RE elements are the scavenger for steel liquid and efficient modification for occlusion in pure steel.In this paper, influence of rare earth cerium on mechanical properties of lead bearing steel is studied through melting experiments and mechanical properties testing.During the experiments, cerium,lead and H08 steel are melted together. The steel is processed into standard samples for mechanical properties testing after rolling and heat treatment. Influence of rare earth cerium on mechanical properties such as tensile strength, plastic and impact toughness of lead bearing steel is studied through mechanical properties testing and scanning electron microscopy analysis.The experimental results show that: when a certain amount of rare earth cerium is added into lead bearing H08 steel, then in certain heat treatment conditions, rare earth element cerium can be able to reduce the harm caused by low melting point metallic element lead to mechanical properties of H08 steel.更多还原