采用光学显微镜、扫描电镜分析,表面硬度和残余应力测试,研究了P91高合金连铸钢坯在凝固后显微组织与残余应力的变化规律。结果表明:影响铸坯组织结构的主要因素是冷却速率及其在坯体中的位置。铸坯中心的组织为铁素体和马氏体,其硬度相对较低;远离中心,铁素体逐渐减少、消失,马氏体逐渐增多,其硬度也相应地逐渐增大。通过iXRD便携式残余应力测量仪测量出铸坯的残余应力,其结果为在中心受740 MPa的拉应力,边缘受435 MPa的压应力。 The microstructure and residual stress of P91 high-alloy continuous casting billet were studied by optical microscopy, scanning electron microscopy, surface hardness and residual stress test. The results show that the main factors affecting the structure of slab are the cooling rate and its position in the green body. The center of the slab is composed of ferrite and martensite, and its hardness is relatively low. When it is far from the center, the ferrite gradually decreases and disappears, and the martensite gradually increases and its hardness increases correspondingly. The residual stress of slab was measured by iXRD portable residual stress meter. The result was a tensile stress of 740 MPa at the center and a compressive stress of 435 MPa at the edge.