【作者】 杨凯宇；

【导师】 惠虎；

【作者基本信息】 华东理工大学 ， 安全技术及工程， 2012， 硕士

【摘要】 奥氏体不锈钢应变强化技术通过冷拉伸产生一定的塑性变形来提高材料的屈服强度,实现了低温压力容器轻型化、减薄容器壁厚、节约制造成本的目的。本文将通过小冲杆实验技术研究奥氏体不锈钢应变强化容器焊接接头的力学性能。由于小冲杆实验技术所需试样很小,可以做到在不同部位取样,可分别在焊缝、母材部位取样,单独研究其力学性能。从而可为合理评价焊接接头提供第一手资料,同时可研究不同的焊接接头强弱匹配情况,为选择合理的焊缝材料提供科学依据。本论文主要的研究内容及取得的成果如下：1.本研究创新的将小冲杆技术运用于焊接接头力学性能的研究中。结果表明,本文所研究的应变强化焊接接头具有较好的冲击韧性、弯曲、延伸性能,此时焊缝屈服强度比母材高、抗拉强度比母材低；2.对于现在比较流行的两种应变强化控制方法,即9%应变控制以及σk应力控制,进行了有限元模拟研究。通过研究发现,当采用应变控制进行预拉伸时,焊缝处的名义应变量会随着拉伸试样标距的变大而变小；与应力控制相比较,在9%应变控制的情况下,焊缝处的名义应变要高出很多；3.通过有限元模拟分析了焊缝与母材在不同屈服强度匹配的情况下,应变强化过程对焊接接头变形量的影响。研究表明焊缝处的应变量会随着屈服强度匹配系数M的变大而减小。对带有余高的焊接接头进行了预拉伸模拟,研究表明焊余高能在一定程度上减少焊缝处材料的变形量。更多还原

【Abstract】 The light-weight of cryogenic pressure vessels from austenitic stainless steels can be carried out by using coldstretching technology, which may reduce the production costs. The yield strength of austenitic stainless steels can be significantly increased by coldstretching, thusing thinning the wall thickness of pressure vessels.The small punch technology was used to study the mechanical properties of coldstretched welding joints in this paper. Because the small punch specimen is very small, sampling from different parts of welding joint such as the weld or the base material can be got, which are used to study the mechanical properties of welding joint respectively.The reasonable evaluation of welding joint can be got, meanwhile, the strength match situation of the welding joint can be evaluated, which is benefit to selecting proper welding material.The main content and conclusions of the study are summarized as follows:1. The small punch test is innovatively used to study the mechanical properties of welded joints. The result shows that weld got good impact toughness, bending and elongation properties in the paper, while the welding material have high yield strength and low tensile strength;2. Finite element analysis method was used to analyze the specimen stretched by the stress control method and strain control method. It is found that when using the strain control method, the strain of the welding seam become smaller with a longer gauge. Compared with the stress control method, the strain of the welding seam is much higher than that with the 9% strain control method;3. Finite element analysis method is used to study the effect of stain strengthening on the deformation of welding seam with different yield strength matching factor M. It shows that the larger the factor M, the smaller the stain of welding seam. And to a certain extent, weld reinforcement can reduce the amount of deformation of the welding seam.更多还原