| 钢的氢腐蚀机理及检测技术的研究 | |
| 陈华 | |
| Subtype | 硕士 |
| Thesis Advisor | 柯伟 |
| 1993 | |
| Degree Grantor | 中国科学院金属腐蚀与防护研究所 |
| Place of Conferral | 中国科学院金属腐蚀与防护研究所 |
| Abstract | 本文以20G低碳钢和15CrMo钢为实验用材，经450 ℃和500 ℃18MPa氢气中分别暴露240，480和720小时，20G低碳钢发生不同程度氢蚀，15CrMo钢只表面脱碳。用表减法对氢蚀试样进行超声波检测，对检测结果进行统计分析，结果表明，超声衰减系数测定值呈正态分布，随氢蚀程度加深，正态分布均值μ增大，方差σ也增大。μ可以作为氢蚀程度的量度。缺陷反射法的回波率N也能衡量氢蚀程度。本文通过定氢分析、机械性能测定和扫描电镜观察，证实了在450 ℃和5MPa氢气中服役20000小时的304钢发生了氢蚀。透射电镜分析结果表明，氢蚀原因是Cr_(23)C_6碳化物析出。用SIMS和电镜对氢蚀机理进行研究后认为，扩散过程不是氢蚀气泡长大的控制因素，氢蚀气泡长大机制是位错蠕变型。本文对氢蚀前后低碳钢拉伸过程的声发射（AE）行为进行了研究。结果表明，氢蚀使低碳钢拉伸过程（AE）事件数明显减少，但高幅AE信号振铃数明显增加，声发射源以氢蚀显微裂纹的长大和连接为主。 |
| Other Abstract | 20G low carbon steel and 15CrMo steel was chosen for the experimental material and exposed in hydrogen gas at 18MPa at 450 ℃ and 500 ℃ for 240, 480 and 720 hours respectively in order to obtain different degrees of hydrogen attack. Ultrasonic attenuation measurements of hydrogen attack on HA samples were taken. The data obtained were analysed statistically. The results showed that the experimental values of ultrasonic attenuation coefficient at different placed on one sample obeyed the normal probability distribution. Both the mean value μ and the variance σ in the normal distribution increases with the exposure time. Therefor the values of μ could be used for prediting the degree of hydrogen attack. Flow echo ratio N also can be used to measure the degree of hydrogen attack. Hydrogen attack on 304 austenitic stainless steel in the service for 20000 h at 450 ℃ under 5MPa was detected to result from the occurrence of Cr_(23)C_6. The methane bubbles were formed preferentially along grain boundaries and twin boundaries, and some of them in grains. It is pointed ont that diffusion process is not the controlling factor of bubbles growth based on the observed results by SIMS and TEM. The mechanism of bubbles growth is belong to dislocation creep model. Acoustic emission (AE) behaviour during tensile in air has been studied for a low-carbon steel 20G which had been hydrogen attacked after exposed to hydrogen. The experimental results show that AE activity caused by hydrogen attack is decreased, but the counts of high amplitude AE signals is increased. The source of AE signals is a intergrainular fracture caused by coalescence of the micro-bubbles or microcracks on the grain boundaries. |
| Pages | 60 |
| Language | 中文 |
| Document Type | 学位论文 |
| Identifier | http://ir.imr.ac.cn/handle/321006/17586 |
| Collection | 中国科学院金属研究所 |
| Recommended Citation GB/T 7714 | 陈华. 钢的氢腐蚀机理及检测技术的研究[D]. 中国科学院金属腐蚀与防护研究所. 中国科学院金属腐蚀与防护研究所,1993. |
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