LIU Yu-rong
,
YE Dong
,
YONG Qi-long
,
SU Jie
,
ZHAO Kun-yu
,
JIANG Wen
钢铁研究学报(英文版)
The microstructures and mechanical properties of Cr13 super martensitic stainless steel after different heat treatments were studied. The results show that the structures of the steel after quenching are of lath martensite mixed with a small amount of retained austenite. With the raising quenching temperature, the original austenite grain size increases and the lath martensite gradually becomes thicker. The structures of the tempered steel are mixtures of tempered martensite and reversed austenite dispersed in the martensite matrix. The amount of reversed austenite is from 754% to 2249%. After different heat treatments, the tensile strength, the elongation and the HRC hardness of the steel are in the range of 813-1070 MPa, 101%-212% and 2133-3237, respectively. The steel displays the best comprehensive mechanical properties after the sample is quenched at 1050 ℃ followed by tempering at 650 ℃.
关键词:
super martensitic stainless steel
,
quenching
,
tempering
,
structure
,
property
,
reversed austenite
YANG Zhuoyue
,
SU Jie
,
WANG Yaming
钢铁研究学报(英文版)
Based on the fact that toughness degradation occurred in 1Cr21Ni5Ti duplex stainless steel during slow cooling in a temperature interval of 400-600 ℃ following brazed welding, a simulated embrittlement treatment was utilized to evaluate its embrittlement tendency. Accumulated experiences have shown that high Ti and Al contents led frequently to severe toughness deterioration. To elucidate this phenomenon, four heats with various Ti and Al contents were prepared in laboratoryscale melts, which were used to investigate the inherent embrittlement nature. The results have shown that 550 ℃ aging led only to a modest toughness reduction, whereas, aging around 475 ℃ resulted in ferrite embrittlement, regardless of Ti, Al levels. However, high Ti, Al levels reduced the austenite phase, which, in the case of its inferior shape and distribution due to insufficient hot deformation, failed to resist cleavagetype cracks initiated in the ferrite phase. Increasing hotforged areas reduction could modify the shape and distribution of austenite, resulting in the enhanced resistance of the austenite to the cleavagetype cracks, which have been confirmed to be beneficial for brittlement suppression of 1Cr21Ni5Ti duplex stainless steel.
关键词:
1Cr21Ni5Ti steel;embrittlement;Ti content;Al content;impact toughness
