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本文研究了9Ni低温钢经形变热处理后的室温力学性能及-196℃冲击韧性;观察了晶粒大小、断口形貌及组织结构。结果表明:高温形变热处理比普通热处理及a+γ两相区热处理有较好的低温韧性及强度,低温韧性提高12％左右,室温强度提高的最大值为107.8MPa。认为马氏体组织细化、回火组织中保留较多的位错亚结构、逆转变奥氏体均匀分布是提高强度和低温韧性的原因。
In this paper, the mechanical properties of 9Ni low temperature steel after deformation heat treatment at room temperature and -196 ℃ impact toughness; observed the grain size, fracture morphology and organizational structure. The results show that high temperature deformation heat treatment has better low temperature toughness and strength than ordinary heat treatment and a + γ heat treatment. The toughness of low temperature increases about 12% and the maximum value of room temperature strength increases 107.8MPa. It is considered that the martensite structure is refined and more dislocation substructures are retained in the tempering microstructure. The uniform distribution of retrograded austenite is the reason for improving the strength and the low-temperature toughness.