某火箭发动机燃烧室表面缺陷分析

Defects Analysis of Combustor Surface in Rocket-engine

某火箭发动机燃烧室原材料经酸煮后出现裂纹和“灰条”,旋压成型后出现表面起皮。本文对裂纹、“灰条”和起皮三种缺陷的形貌进行了观察,并对缺陷处的金相组织和微区成分进行了检测,分析了缺陷的性质及其形成原因。结果表明,“灰条”是因燃烧室局部Cr、Mo元素偏聚导致周围基体贫铬,从而在酸煮过程中被腐蚀形成的凹坑,表面裂纹为金属铸造收缩裂纹,表面起皮是由壳体表层和心部金属的变形差异所致,与旋压变形过程有关。

Cracks and ＂grey strips＂ after bailing in the acid and peelings after spinning were found on combustor surface of some rocketengines. In this paper, on the basis of macro observation, metallurgical structure inspection and energy spectrum analysis of micro areas, characteristics and cause of defects were carried out. ＂Gray strips＂ were matrix eroding by the acid where content of Cr was low. Surface crack was caused by the shrinkage in the casting of the metal. Surface peelings were caused by different deformation beween the surface and interior metal which related to spinning.