The stress-corrosion cracking (SCC) of X70 type steel of a controllable rolling for manufacture of pipes was studied in the conditions of complex influence of factors such as full immersion into the solution and periodic wetting, open circuit potential and cathodic polarization potentials (−0.75 V_s.c.e., −1.0 V, −2.0 V), accumulated cyclic stresses simulating a long operation of the gas pipeline, presence of stress concentrator in the form of a notch, influence of protective polymeric coatings with different transition resistance and their combinations. Different combinations of stress-corrosion factors were simulated in the laboratory, their influence on the X70 type steel of a controllable rolling for manufacture of pipes was investigated and the susceptibility of that steel to SCC under these conditions was estimated. The K_S coefficient (the ratio of the relative reduction of the sample in air to its relative reduction in the solution) was proposed for estimating the sensibility to SCC. The results of investigations confirmed that mechanical stresses, corrosion-aggressive medium and protective potential are the main factors, while other ones are additional and can increase or decrease the influence of the main factors, without changing the process mechanism.

在完全浸入溶液和定期润湿，开路电势和阴极极化电势等因素综合影响的条件下，研究了管材可控轧制X70型钢的应力腐蚀开裂（SCC）。 0.75伏_秒，-1.0 V，-2.0 V），累积的循环应力，模拟天然气管道的长期运行，存在缺口形式的应力集中器，具有不同过渡电阻的保护性聚合物涂层的影响及其组合。在实验室中模拟了应力腐蚀因子的不同组合，研究了它们对管材可控轧制X70型钢的影响，并评估了这些条件下该钢对SCC的敏感性。在K_小号为了估计对SCC的敏感性，提出了系数（样品在空气中的相对减少与其在溶液中的相对减少的比率）。研究结果证实，机械应力，腐蚀介质和保护电位是主要因素，而其他因素是附加因素，可以在不改变工艺机理的情况下增加或减少主要因素的影响。