The expanding curves and continuous cooling transformationcurve (dynamic CCT curve) of X60 pipeline steel were obtained by dilatometry and microscopic test under different cooling speed.
According to the tempering temperature and hardness curve, the redistribution of residual stress is associated with the transformation of residual austenite.
由回火温度与硬度变化曲线证实,残余应力重新分布是与残余奥氏体转变相关联。
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Then, two methods are discussed which are point-circle transformation and circular curve fitting for inspecting the bearing's circularity, dimension and concentricity.