以碳钢为例，将ISO9223：2012标准中的单个剂量响应函数分解为对应多个腐蚀等级的分段式剂量响应函数。采用关联规则理论，以置信度的形式建立了二氧化硫含量、氯离子含量、润湿时间等大气环境因子与碳钢腐蚀等级之间的关联规则。最后，用分段式剂量响应函数加权求得腐蚀速率，进而得到确定的腐蚀等级。分别采用分段式剂量响应函数和ISO9223：2012标准对国内外腐蚀试验站点40条碳钢大气腐蚀数据进行腐蚀等级判定。结果表明：与ISO9223：2012标准相比，采用分段式剂量响应函数得到的腐蚀等级与碳钢真实的腐蚀等级更接近，该方法能更准确地评估大气环境的腐蚀性等级。

Taking carbon steel as a sample, the single dose-response function in ISO9223:2012 standard was decomposed into sectional dose-response function corresponding to several corrosion categories. The association rules between atmospheric environmental factors (sulfur dioxide concentration, chloride concentration, wetting time) and corrosion categories were established as confidence coefficients by association rules theory. On this basis, corrosion rates were calculated by weighting the sectional dose-response function to determine the certain corrosion category. The atmospheric corrosion data of carbon steel from 40 domestic and foreign test sites were used to judge the corrosion categories by the sectional dose-response function and ISO9223:2012 standard respectively. The results show that the corrosion categories evaluated by the sectional dose-response function were closer to real corrosion categories, compared with ISO9223:2012 standard. The proposed method is more accurate than ISO9223:2012 standard to evaluate the corrosion categories of atmospheric corrosivity.