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净辐射系数是数值模拟中表征等离子体辐射属性最常用的参数.考虑了线谱、连续谱和分子带状谱等多种辐射机制,计算了3～25 kK 不同 Fe含量下[82% Ar-18% CO2]-Fe等离子体的净辐射系数,为GMAW电弧(82% Ar-18% CO2保护气,低合金钢焊丝)的数值模拟提供了完整的辐射属性数据.此外,通过分析发现,当Fe蒸汽加入到82% Ar-18% CO2混合物中,即使Fe含量极低,等离子体净辐射系数也会显著增大.同时,由于Fe的加入,原本辐射贡献率较高的分子带状谱和连续谱辐射相对线谱辐射可忽略不计.“,”Net emission coefficient (NEC) is the most implemented method in the numerical models developed for thermal plas-ma .This paper is devoted to the calculation of NECs for [82% Ar-18% CO2]-Fe plasmas with different iron contents between 3 and 25 kK .By considering various radiative mechanisms (spectral lines ,continuum and molecular bands) ,we developed a com-plet database of radiative proerty for the modelling of GMAW arcs (with 82% Ar-18% CO2shielding gas and a steel wire) .Also , it was found that the presence of iron vapour in the plasmas (even with very low content) can greatly improve the NEC and make the contribution of molecular bands and continuum ,which are considerable in the NEC of 82% Ar-18% CO2,negligible .