PSI - Issue 40

A.V. Burnashev et al. / Procedia Structural Integrity 40 (2022) 90–96 Burnashev A.V. at al. / Structural Integrity Procedia 00 (2022) 000 – 000

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Combining the experimental results of shock and ultrasound studies, we constructed a correlation dependence of KCV (V) (Fig. 4). Areas of high values of impact strength and speed of sound correspond to an emergency reserve pipe, which has an equilibrium structure. The areas with low values of the studied quantities (shaded area) correspond to the samples of pipes after operation and after additional artificial ageing. The scatter of the values of these quantities is probably caused by the anisotropy of the structure of the material.

Fig. 4. Correlation of impact strength and speed of sound. (The shaded area is the range of limit values).

As the graph shows, there is not only a coincidence of the maxima but also a fairly good correlation of the curves. The similarity of the curves reduces to the linear dependences of KCV (V). The correlation equations obtained by the least squares method are: For the case of a surface wave, KCV =1.022 V- 3097.7  , (1) The correlation coefficient is 0.96. To supplement the developed method, we propose a method for estimating the residual life of the MG by changing the speed of sound by analogy to the method of estimating the residual life, by changing the toughness given in RD 12-411- 01 “Instructions for diagnosing the technical condition of underground steel gas pipelines”.