大壁厚ZG230-450H铸件强度预测方法

Strength Forecasting Method for ZG230-450H Castings with Heavy Wall Thickness

对存在严重偏析的1 000 mm大壁厚ZG230-450H铸钢件取样进行小试样正火+不同温度回火热处理,采用主成分分析方法和强度数据多元线性回归法分析测试数据发现, C含量和回火温度是影响铸钢强度的两个主要因素。通过分析大壁厚ZG230-450H的合金元素、回火温度与一定晶粒度下铸钢强度的关系,建立了晶粒度为8.5级时铸钢强度预测模型以及基于HallPetch关系的不同晶粒度下强度的换算公式。考虑到铸钢壁厚的影响,并结合生产数据,对模型进行了修正和检验。结果显示,该强度预测方法具有一定的实用价值。

Heavy wall thickness in ZG230-450 H steel castings make segregation more serious. In order to forecasting the strength property of castings, ZG230-450 H samples with size 1 000 mm×1 000 mm×20 mm and 1 000 mm×1 000 mm×1 000 mm were cut and tempered at different temperatures after annealing and normalizing treatments in the present study. Through analysis of the composition and strength data using principal component analysis method and multivariate linear regression method, respectively, it was found that carbon content and tempering temperature were the major factors influencing the strength property of ZG230-450 H steel castings with heavy wall thickness. After analysis of the relationship between chemical composition,tempering temperature and the strength of ZG230-450 H with certain grain size, a strength forecasting model was established to describe the strength of ZG230-450 H castings with the grain size number of 8.5 level, and a conversion equation was developed based on Hall-Petch relation to calculate the strength of ZG230-450 H of castings with different grain size numbers. The forecasting model was adjusted and verified with considering the effect of wall thickness and combining with the production data. Results showed that the method had some value in practical applications.