中间层及热处理对热轧钛—钢复合界面组织及结合性能的影响研究

发布时间：2018-01-09 00:18

  本文关键词：中间层及热处理对热轧钛—钢复合界面组织及结合性能的影响研究　出处：《钢铁研究总院》2017年硕士论文　论文类型：学位论文

  更多相关文章： 热轧钛-钢复合板 中间层 热处理 界面结构 剪切强度

【摘要】：热轧钛-钢复合板结合了钛耐蚀、密度小、比强度高及钢材较好的强度性能特点,在海洋工程、石油化工等领域应用前景广阔。现有关于热轧钛-钢复合板的研究,大多是探究轧制工艺参数对复合界面组织性能的影响,也有不少学者研究了Cu、Ni等中间层材料对复合界面的影响,但对Nb中间层、Nb+Ni双中间层的讨论较少。本文使用真空热轧复合法制备以Nb作中间层及Nb+Ni作双中间层的Q235-TA2复合板,利用OM、SEM观察复合界面显微结构,结合SEM-EDS说明复合界面元素扩散情况;通过压剪实验表征复合界面结合性能,并利用XRD结果对压剪断口进行物相分析。全文主要内容如下:首先分析了中间层对热轧钛-钢复合板复合界面的影响。轧制温度为875 ℃时,Nb中间层试样压剪强度最高(280 MPa),Nb+Ni双中间层试样次之(239 MPa),无中间层试样最低(231 MPa)。Nb中间层试样Q235-Nb界面存在Fe2Nb,压剪试样在Q235-Nb界面处发生断裂;Nb+Ni双中间层试样Nb-Ni界面存在Ni3Nb层及沿界面少量分布的微孔,压剪试样在Nb-Ni界面处发生断裂;无中间层试样Q235-Ti界面存在脆性TiC,压剪试样在Q235-Ti界面发生断裂。当轧制温度为925 ℃时,Nb中间层试样压剪强度仍高于Nb+Ni双中间层试样压剪强度。同轧制温度为875 ℃时的试样相比,轧制温度为925 ℃时Nb及Nb+Ni双中间层试样压剪强度均降低。Nb中间层试样Q235-Nb界面处脆性Fe2Nb相生成量增加,并伴随新相FeNb的生成。Nb+Ni双中间层试样Nb-Ni复合界面微孔尺寸增大数量增加,Ni3Nb金属间化合物层宽度增厚。其次,分别讨论正火及高温回火热处理对无中间层试样复合界面的影响。经650 ℃高温回火及900 ℃正火热处理后,试样压剪强度分别为138 MPa及143 MPa,试样Q235-Ti界面近Q235侧形成薄膜状TiC层,TiC厚度较轧态显著增加。高温扩散导致TiC层厚度增加是复合界面结合强度降低的主要原因。最后讨论热处理对Nb中间层试样复合界面的影响。高温回火试样Q235-Nb界面微孔的存在使得其压剪强度(162 MPa)略低于正火试样压剪强度(171 MPa)。高温回火及正火处理后,Q235-Nb界面均生成Fe2Nb,正火态试样Nb-Ti界面存在α-Ti+β-Ti两相混合组织。不同热处理条件下,试样压剪过程中均在Q235-Nb界面处发生断裂,Q235-Nb界面结合强度弱于Nb-Ti界面结合强度。
[Abstract]:Hot rolled Ti-steel composite plate combines the characteristics of titanium corrosion resistance, low density, high specific strength and better strength performance of steel in offshore engineering. The current research on hot rolled Ti-steel composite plate is mostly to explore the effect of rolling process parameters on the microstructure and properties of composite interface, and many scholars have also studied Cu. The effect of Ni and other interlayer materials on the composite interface, but on NB interlayer. There is little discussion about the double interlayer of NB and Ni. In this paper, the Q235-TA2 composite plate with NB as the interlayer and NB Ni as the double interlayer is prepared by vacuum hot rolling method, and OM is used. The microstructure of the composite interface was observed by SEM and the diffusion of elements at the composite interface was explained by SEM-EDS. The bonding properties of the composite interface were characterized by compression and shear experiments. The main contents of this paper are as follows: firstly, the effect of interlayer on the composite interface of hot-rolled Ti-steel composite plate is analyzed. The rolling temperature is 875 鈩，

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