A study for predicting the creep deformation behavior of a MERT (mixing element radiant tube) type KHR45A steel is carried out. To this end, a modification of the theta projection model is proposed by incorporating a statistical analysis technique especially with a nonlinear mixed-effect model. The model is applied for predicting the creep deformation behavior of a KHR45A steel. Creep curve data used for prediction was obtained by creep test in the stress range of 20.2–73.7 MPa and the temperature range of 816–1093 °C. The proposed model is demonstrated to be more accurate and practically meaningful than the existing theta projection model for predicting the creep deformation behavior. The prediction accuracy of the proposed model is confirmed using mean absolute percentage error (MAPE) and symmetric MAPE (SMAPE) calculations.

进行了预测MERT（混合元素辐射管）型KHR45A钢的蠕变变形行为的研究。为此，通过结合统计分析技术，特别是非线性混合效应模型，提出了theta投影模型的修改方案。该模型用于预测KHR45A钢的蠕变变形行为。通过蠕变试验在20.2-73.7 MPa的应力范围和816-1093°C的温度范围内获得了用于预测的蠕变曲线数据。与现有的用于预测蠕变变形行为的theta投影模型相比，所提出的模型被证明更加准确和实用。使用平均绝对百分比误差（MAPE）和对称MAPE（SMAPE）计算来确认所提出模型的预测准确性。