阴极极化对海洋工程用钢及其焊缝氢脆敏感性影响的研究

发布时间：2018-02-20 22:43

本文关键词： 海洋工程用钢阴极极化电位慢应变速率拉伸(SSRT) 氢脆　出处：《青岛科技大学》2015年硕士论文　论文类型：学位论文

【摘要】：E460、E500、E550和)XXX=等海洋工程用钢在海洋环境中服役时,会受到海水的腐蚀,因此对其施加阴极保护技术,以减小海水对钢结构的腐蚀作用。由于高强钢材料通常具有一定的氢脆敏感性,且随材料强度的增大,氢脆敏感性增强。当施加的阴极极化电位较负时,会导致金属材料表面析氢,氢扩散进入金属组织内部后,可能造成材料的氢脆断裂。因此,选择合理有效的阴极极化电位区间是对高强钢进行阴极保护设计时需要重点考虑的问题。本文采用电化学测试技术和慢应变速率拉伸试验等方法,研究了E460、E500、E550和XXXX等材料在不同极化电位下的氢脆敏感性,探讨了阴极极化电位对几种高强钢氢脆敏感性的影响规律。E460钢在Ecorr～-0.85V极化电位电位区间,主要表现为韧性断裂。在-0.85V～-0.95V电位区间内,断口出现了准解理组织的形貌特征。在-0.95V～-1.05V电位区间内,断裂方式变为了脆性断裂。E500钢在Ecorr～-0.85V电位区间,主要为阳极溶解型应力腐蚀,其断裂方式为韧性断裂。在-0.85V～-0.90V电位区间内,断口出现了准解理组织的形貌特征。在-0.95V～-1.05V电位区间内,断裂方式变为了脆性断裂。E550钢在Ecorr～-0.90V的阴极极化电位区间,其断裂方式主要表现为韧性断裂。当阴极极化电位负于-0.90V后,脆性断裂倾向增大。当电位进一步负于-1.00V后,断裂方式转变为脆性断裂。XXXX钢在Ecorr～-0.90V的阴极极化电位区间,断裂方式主要表现为韧性断裂。当阴极极化电位负于-0.90V后,有脆性断裂倾向。当电位进一步负移到负于-0.95V后,断裂方式转变为脆性断裂。XXXX钢焊接件在Ecorr～-0.875V的阴极极化电位区间,断裂方式主要表现为韧性断裂。当阴极极化电位负于-0.90V后,有脆性断裂的倾向。当阴极极化电位进一步负于-0.95V后,断裂方式转变为脆性断裂。
[Abstract]:Marine engineering steels such as E460, E500, E550 and XX = will be corroded by seawater when they are in service in the marine environment. Therefore, cathodic protection technology is applied to reduce corrosion of steel structures by seawater. High strength steel materials are usually sensitive to hydrogen embrittlement. The hydrogen embrittlement sensitivity increases with the increase of the material strength. When the applied cathodic polarization potential is negative, it will lead to hydrogen evolution on the surface of the metal material, and hydrogen diffusion into the metal structure may lead to the hydrogen embrittlement fracture of the material. The selection of a reasonable and effective cathodic polarization potential range is an important problem to be considered in the design of cathodic protection for high strength steel. In this paper, electrochemical measurement technique and slow strain rate tensile test are used. The hydrogen embrittlement sensitivity of E460 E500 E550 and XXXX at different polarization potentials was studied. The effect of cathodic polarization potential on the hydrogen embrittlement sensitivity of several high strength steels was discussed. In the range of -0.85 V ~ (-1) V ~ (-0.95) V potential, the morphology of quasi-cleavage structure appeared. In the range of -0.95 V ~ (-1) V ~ (-1.05V) potential, the fracture mode became brittle fracture. E500 steel changed into brittle fracture in Ecorr~-0.85V potential range, mainly anodic dissolved stress corrosion. The fracture mode is ductile fracture. In the range of -0.85 V ~ (-0.90) V potential, the fracture surface has the appearance of quasi-cleavage structure. In the range of -0.95 V ~ (-1.05V) potential, the fracture mode is changed into the cathodic polarization potential range of brittle fracture. E550 steel in Ecorr~-0.90V. When the cathodic polarization potential is negative at -0.90V, the brittle fracture tendency increases. When the potential is further negative at -1.00V, the fracture mode changes to the brittle fracture. XXXX steel changes to the cathodic polarization potential range of Ecorr~-0.90V. The fracture mode is mainly ductile fracture. When the cathodic polarization potential is negative to -0.90V, the fracture tends to brittle fracture. When the potential is further negative to -0.95V, the fracture mode changes into the brittle fracture. XXXX steel welds in the cathodic polarization potential range of Ecorr~-0.875V. The fracture mode is mainly ductile fracture. When the cathodic polarization potential is negative at -0.90V, the fracture tends to be brittle fracture, and when the cathodic polarization potential is further negative at -0.95V, the fracture mode changes to brittle fracture.
【学位授予单位】：青岛科技大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TG174.41;TG142

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