航天气瓶用超高强度钢应力腐蚀应力强度门槛值的试验研究  

EXPERIMENTAL STUDY ON K_(ⅠSCC) OF ULTRA-HIGH STRENGTH STEEL GAS-TANK USED FOR SHUTTLES

作　　者：白铁钧[1] 陈怀宁[1] 陈亮山[1] 

机构地区：[1]中国科学院金属研究所

出　　处：《机械强度》2004年第1期67-71,共5页Journal of Mechanical Strength

摘　　要：应力腐蚀门槛值是评价超高强度钢制航天气瓶安全性的重要性能参数。如何合理地获得航天气瓶用超高强度钢应力腐蚀门槛值的正确值 ,以及气瓶验证和使用过程中过载对该参数的影响是本文研究的重点。文中针对超高强度钢提出在正火热处理后即开始预制疲劳裂纹 ,然后再进行淬火和回火 ,以达到材料最终性能的方法 ,测定超高强度钢3 7SiMnCrNiMoV钢的 (条件 )KⅠSCC值 ,避免采用传统方法测定KⅠSCC时由于裂纹尖端产生塑性变形和残余应力而造成测试结果的不准确性。在此基础上研究一次和多次过载以及不同过载水平对超高强度钢应力腐蚀性能的影响 ,发现在一定的过载应力条件下适当的过载次数可以显著提高材料的KⅠSCC值 ,这种作用与裂纹尖端的残余应力和材料硬化发生的性变有关 。Stress corrosion stress intensity threshold ( K ⅠSCC ) is an important performance in evaluating the safety of gas tanks for shuttles made of ultra high strength steel. Nevertheless, there are some problems in traditional method of measuring K ⅠSCC using pre cracked fatigue specimens. In this article, K ⅠSCC of 37SiMnCrNiMoV ultra high strength steel was determined with a new preparing method of cracked specimens,that is, fatigue cracks were made just after annealing and then conducted final queeching and tempering heat treatment. The influence of over loading normally from the proof test and operation of a tank on K ⅠSCC performance of super strength steels was detemined by changing the level and cycles times of over loading. The results show that over loading could significantly improve the value of K ⅠSCC , which is mainly related to the compressive residual stress and plastic deformation including workharding at the crack tip. These results will give an orientation to establish a valuable evaluation technique of fracture safety for astrogate gas tanks.

关 键 词：航天气瓶 超高强度钢 应力腐蚀 应力强度门槛值 试验研究 过载 疲劳裂纹 

分 类 号：V252.1[一般工业技术—材料科学与工程] O346[航空宇航科学与技术—航空宇航制造工程]