通过透射电镜观察了低氮低钒D36船板钢的析出相特征,并讨论了其沉淀强化作用。结果表明：实验用钢的组织均为铁素体-珠光体组织,珠光体中未见析出相,仅在铁素体中观察到析出相。VCx析出相为矩形片状形貌,在铁素体基体上均匀弥散沉淀,析出相以{100}α-Fe为惯习面,与基体存在Baker-Nutting取向关系;少量球状V6C5析出相（单斜结构）与铁素体基体存在一定取向关系,可能是共格VCx相通过碳原子重新分布转变而成。低氮低钒钢中加入0.05%V,沉淀强化值约为63 MPa,加入微量铌后在铁素体内形成一定密度的位错能有效发挥钒的沉淀强化作用。
Characteristics of precipitates in low-nitrogen and low-vanadium D36 ship plate steel was observed by tansmission electron microscopy and the effect of precipitation strengthening was discussed.The results indicate that the microstructure of the steel consists of ferrite and pearlite.Precipitates are observed in ferrite but have not been detected in pearlite.Within ferrite the precipitates of VCx with rectangular platelet shape present a uniform and dispersive distribution.The precipitates,with a（001）α-Fe habit plane exhibit the Baker-Nutting orientation relationship with matrix.The TEM observation also reveals the existence of a few sphericall shaped precipitate of V6C5（monoclinic system） having an orientation relationship with ferrite.It appears that the V6C5 phase is transformed from the coherent VCx by redistribution of carbon atoms.The precipitation strengthening increment is about 63 MPa in the low-nitrogen and low-vanadium steel containing 0.05%V.The strengthening effect of vanadium can be enhanced by high density dislocations in ferrite with addition of small amounts of niobium.
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