中文摘要：

研究了高Cr铁素体耐热钢时效过程中的组织演变与力学性能。600℃时效后（最长至3000h），高Cr铁素体耐热钢在室温和600℃下的拉伸强度随时效时间基本不变；增加耐热钢中的W含量可以提高时效前后的600℃高温拉伸强度，添加Co则无显著影响；耐热钢的室温冲击功在500h的短时时效后快速降低，随后逐渐趋于稳定，加Co可以提高该水平；Laves相的形成是耐热钢冲击功快速降低的主要原因，其向晶界的聚集还会引起冲击断口上沿晶断裂的发生；在相同时效时间下，加Co、增W会促进Laves相的形成，增大Laves相的体积分数；耐热钢中不加Co和降低W含量可以有效抑制时效过程中Laves相的形成，从而维持耐热钢的冲击功基本不变。

英文摘要：

Structural evolution and mechanical properties of high Cr ferritic heat-resistant steel in ageing process are studied. The tensile strengths of high Cr ferritic heat resistant steels at room temperature and 600℃ remained stable during aging at 600 ℃ （up to 3000h）. The tensile strength at 600℃ could be enhanced by increase of W while the addition of Co can not. The impact toughness if the steel at room temperature decreased rapidly only after 500h short-time ageing and later tended to be a constant level which could be raised by addition of Co. Formation of Laves phase was considered as the main reason for the deterioration of the impact toughness after ageing. Clusters of laves phase along the prior austenite grain boundaries would result in intergranular cracks on the impact fracture surface. Both increase of W and addition of Co in the same condition would promote the formation of Laves phase and increase its volume fraction. However, elimination of Co and reduction of W were effective to inhibit the formation of Laves phase and maintain the impact toughness.