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35CrMo高强度钢在海洋大气中的氢渗透行为与环境致脆机理研究

The Research of Hydrogen Permeation Behaviors and Environment Sensitive Fracture Mechanism of High Strength Steel 35CrMo in Marine Atmosphere

【作者】 于青

【导师】 黄彦良;

【作者基本信息】 中国科学院研究生院(海洋研究所) , 海洋化学, 2008, 博士

【摘要】 海洋大气腐蚀环境是海洋腐蚀环境之一。金属材料在海洋大气环境下会发生环境敏感断裂。在环境敏感断裂中,氢脆是其中的一个重要类型。氢脆是合金中存在过量的氢,并在拉应力协同作用下造成的一种脆断。氢渗透已被证明是金属材料失效的主要原因之一。氢脆导致了材料强度降低,在较低载荷下会导致材料的灾害性破坏,因此研究海洋用钢在海洋大气中的致脆机制与氢渗透行为是十分必要的。本文所做工作主要有以下几点:一、采用Devanathan-Stachurski氢渗透技术,研究了35CrMo高强度钢未受力试样在海洋大气腐蚀环境中的氢渗透及腐蚀失重行为。主要分为两个部分:(1)干湿循环实验;(2)模拟海洋大气腐蚀实验。实验结果表明,在海洋大气腐蚀环境中,35CrMo高强度钢存在着明显的氢渗透现象,在不同腐蚀环境中现象有所不同。Cl-离子、H2S、SO2等污染物对氢渗透产生了明显的促进作用。另外,氢渗透量与腐蚀失重存在着明显的线性关系。二、采用慢应变速率拉伸实验法(SSRT),在海洋大气腐蚀环境中对35CrMo试样进行力学性能测试,研究氢渗透对35CrMo应力腐蚀开裂敏感性的影响。实验结果表明,在各种腐蚀条件下,氢渗透会增加35CrMo的应力腐蚀开裂敏感性,使得最大载荷、断裂时间及应变值均减小。三、采用Devanathan-Stachurski氢渗透技术与慢应变速率拉伸实验法,进行了35CrMo高强度钢受力试样在海洋大气环境中的氢渗透实验,研究材料形变对氢渗透的影响。实验结果表明,在弹性变形阶段,氢渗透电流逐渐增大,在塑性变形阶段开始后,氢渗透逐渐减小,在塑性变形阶段后期,随着形变的增大,氢渗透电流增大。

【Abstract】 Marine atmospheric corrosion environment is one of the marine corrosion environment. Metal and its alloy can occur environment sensitive fracture in marine atmosphere. Hydrogen embrittlement(HE) is one of the important forms of the environment sensitive fracture and it is induced by the interaction of the extra hydrogen in the metal and the stress. It is confirmed that hydrogen permeation is one of the primary causations of the metal failure. Hydrogen embrittlement makes the material strength descend and brings the disastrous accident. It is necessary to research the embrittlement mechanism and the hydrogen permeation behaviors of the metals in marine atmosphere. The research works are listed in below:1. The hydrogen permeation behaviors and corrosion weight losses of 35CrMo specimens with no stress were researched by using Devanathan-Stachurski’s hydrogen permeation technique. This research works were composed with two parts. (1) the wet– dry cycle experiments; (2) the simulated marine atmosphere experiments. Experimental results showed that obvious hydrogen permeation behaviors can be observed and differed with the experimental conditions. Cl- ions, H2S and SO2 promoted the hydrogen permeation obviously. There was a clear linear correlation between the amount of hydrogen permeated and the corrosion weight loss.2. The effect of hydrogen permeation to the environment sensitive fracture of 35CrMo in the marine atmosphere environment was researched by using slow strain rate tensile test(SSRT). Experimental results showed that hydrogen permeation can increase the degree of environment sensitive fracture of 35CrMo and made the maximum load, fracture time and the strain of the specimens descend.3. The effect of the stress to the hydrogen permeation behavior in marine atmospheric corrosion environment was researched by using Devanathan-Stachurski’s hydrogen permeation technique and slow strain rate tensile test. Experimental results showed that, hydrogen permeation current increased with stress under elastic deformation range, the earlier period of the plastic deformation, while decreased with the onset of plastic deformation and then reached a critical point after which increased.

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