Abstract: The    radiant    tubes    of    HP40    steel(0.35~0.45C,24~27Cr,34~37Ni,≤0.5Mo)cracked    and    failed    af- ter  serveed  for 2 years  and nine months  at ≤980  ℃.The  analysis results  showed that the  g phase precipitation which  led  to brittleness of materials was main cause for cracking of radiant tubes, the served temperature at cracking region was higher than that  at non-cracking region, in  cracking region the precipitated g phase was  coarse,the  amount  of σ phase increased,  and the plasticity and toughness of this region obviously decreased led to cracking and failure.

Key words: Heat Resistant Steel HP40,Centrifugal Casting Radiant Tubes,Cracking and Failure,σ Phase

摘要： HP40钢(%:0.35~0.45C、24~27Cr,34~37Ni、≤0.5Mo)辐射管在≤980 ℃服役2年9个月后开裂 失效。分析结果表明，服役过程σ-相的析出导致材料脆化是辐射管开裂的主要原因，开裂区服役温度高于未开裂 区，开裂区析出σ-相粗大、数量增多、塑韧性显著降低，致使该区开裂失效

关键词: HP40耐热钢 , 离心铸造辐射管 ,  , 开裂失效 ,  , σ-相