【作者】 甘晓龙；

【导师】 徐光；

【作者基本信息】 武汉科技大学 ， 材料加工工程， 2010， 硕士

【摘要】 热轧带肋钢筋是建筑结构中广泛应用的建筑用钢材,在我国约占长材产量的30%。长期以来,我国建筑结构中使用的钢筋基本上是Ⅱ级螺纹钢HRB335,造成矿石等资源的浪费。而国外早在20世纪70年代就已经普遍采用屈服强度400MPa以上级别钢筋作为建筑结构的主导受力钢筋。随着我国国民经济的不断发展,冶金、建筑等行业与国际接轨步伐加快。我国有关部门多次下文要求推广建筑用Ⅲ、Ⅳ级高强钢筋。目前,国内钢铁企业生产和使用的主要是20MnSi系列的Ⅱ级和添加少量微合金元素的Ⅲ级螺纹钢。而国外钢铁企业主要产品为Ⅳ级螺纹钢。国内多家企业均生产过屈服强度500MPa以上的Ⅳ级螺纹钢。采取的技术线路是添加Nb、V等微合金元素。这种技术路线由于添加了价格昂贵的微合金元素,生产成本较高,Nb、V微合金化生产Ⅳ级螺纹钢筋的利润空间越来越小。同样作为微合金添加元素的Ti的价格比Nb、V要低很多,为此,结合企业实际研发新的低成本、高强度的Ⅳ级螺纹钢就显得十分迫切,具有巨大的经济价值和社会效益。本文对Ti微合金化Ⅳ螺纹钢进行实验室研究,研究了Ti微合金化Ⅳ螺纹钢成分对组织和性能的影响,确定了Ti微合金化Ⅳ螺纹钢的最佳成分,研究了钢中夹杂物属性,确定了Ti微合金化Ⅳ螺纹钢析出强化机理以及Ti微合金化Ⅳ螺纹钢冶炼工艺和轧制工艺,为实际生产提供了理论依据。更多还原

【Abstract】 Hot rolled ribbed steel bars are widely used construction steels in building structures and other constructions. The output of rebar in China accounts for about 30% of long products. For a long time, rebar used in building structures is basically HRB355 in China, result in a waste of ore resource etc. On the other hand, the rebars with yield strength of more than 400MPa have been widely used in 70s in the 20th century as a main structural steel. With the continuous development of China’s national economy, metallurgy, construction and other industries are speeding up the pace with international standards. Relative authorities in China have repeatedly requested to promote the use ofⅢandⅣgrade high-strength construction rebars. At present, the products in iron and steel plants are mainlyⅡgrade rebar of 20MnSi series orⅢgrade rebar with a small amount of microalloy elements, while the main products of foreign steel companies areⅣgrade rebar.Domestic enterprises have produced gradeⅣrebar with the yield strength of more than 500MPa. The production route is to add Nb, V and other microalloy elements. The production costs are relatively high by this technical route because of higher price of addition element Nb and V, which makes the profits of gradeⅣrebar is becoming less and less. Contrary, the price of addition Ti is lower than that of Nb and V, so it is important to develop new low-cost, high-strength gradeⅣrebar with Ti-addition.In this paper, Ti microalloyed gradeⅣrebar was developed in laboratory. The effects of compositions on microstructure and properties were studied and the optimum chemical compositions were decided. In addition, the inclusions in steel were investigated and the mechanism of precipitation strengthening in Ti microalloyed gradeⅣrebar was analyzed. The refine and rolling technologies are also studied in the paper.更多还原