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研究了四炉不同碳、氮含量的253MA不锈钢(21Cr11NiO.17NO.05Ce)的蠕变性能。在600,750和900℃进行了蠕变试验。结果发现253MA钢的蠕变强度至少有三分之一是由它高的碳含量(0.1％)及氮量作出的贡献。碳含量增加到0.16％并不再进一步提高其强度。750℃和900℃的蠕变塑性显著高于600℃,这与沉淀相的大小、分布有关。600,750℃主要沉淀相是π-氮化物,M_(23)C_6碳化物及σ相,高的氮和碳含量相应地促使π相与M_(23)C_6的形成,而σ相受到抑止。900℃时钢中主要沉淀相是Cr_2N和M_(23)C_6相。
The creep properties of 253MA stainless steel (21Cr11NiO.17NO.05Ce) with different carbon and nitrogen contents in four furnaces were studied. Creep tests were performed at 600, 750 and 900 ° C. As a result, it has been found that at least one-third of the creep strength of 253MA steel is contributed by its high carbon content (0.1%) and nitrogen content. Increasing the carbon content to 0.16% does not further increase its strength. The creep ductility at 750 ℃ and 900 ℃ is significantly higher than 600 ℃, which is related to the size and distribution of precipitates. The major precipitates at 600 and 750 ℃ are π-nitrides. The M_ (23) C_6 carbides and σ phase, and the high nitrogen and carbon contents promote the formation of π phase and M_ (23) C_6, while the σ phase is inhibited. The major precipitates in steel at 900 ℃ are Cr_2N and M_ (23) C_6 phases.