We construct diagrams of fatigue crack growth for St3ps steel placed in demineralized water and in saturated solutions of the Nurelle D insecticide and UN-32 complex liquid fertilizer and evaluate the corresponding values of threshold and critical stress intensity factors. It is established that, in a Nurelle D solutions, the fatigue crack-growth rate increases, whereas in UN-32 solutions, it decreases as compared with its value in air. For the demineralized water, there exists a characteristic value below which the crack-growth resistance of steel increases and above which it decreases. The obtained results may serve as a basis for the numerical analyses aimed at prediction of the serviceability and residual service life of the frames of sprayer booms.

我们构建了St3ps钢在软化水中以及Nurelle D杀虫剂和UN-32复合液体肥料的饱和溶液中的疲劳裂纹扩展图，并评估了阈值和临界应力强度因子的相应值。可以确定的是，在Nurelle D解决方案中，疲劳裂纹扩展速率增加，而在UN-32解决方案中，其疲劳裂纹扩展速率与其在空气中的值相比降低了。对于软化水，存在特征值，在该特征值以下，钢的抗裂纹扩展性增加，在其之上，其降低。获得的结果可以作为数值分析的基础，该数值分析旨在预测喷杆的框架的使用寿命和剩余使用寿命。