We study the efficiency of application of the technology of high-frequency mechanical impacts (HFMI) aimed at increasing the fatigue resistance of butt welded joints in the stage of production of steel structures or after their long-term operation under the conditions of marine climate. Corrosion defects formed in welded joints were simulated in a KST-1 chamber filled with neutral salt fog for 1200 h at a temperature of 35 ± 2°C with dispersion of a sodium-chloride solution for 15 min every 45 min of testing for 1200 h. The concentration of sodium chloride in a solution was 50 ± 5 g/dm3 and pH = 6.5–7.2. The fatigue tests were carried out for four batches of butt welded joints of 15KhSND steel: in the aswelded state, after the HFMI treatment followed by holding in the KST-1 chamber; after operation for 2∙106 stress cycles and holding in the KST-1 chamber, and after operation for 2∙106 cycles and holding in the KST-1 chamber with subsequent HFMI hardening. It is experimentally demonstrated that the application of the HFMI technology noticeably increases the fatigue life of butt welded joints in metal structures under the conditions of variable loads and marine climate.

中文翻译：

---

海洋介质对高频机械冲击硬化15KhSND钢对接焊缝疲劳强度的影响

我们研究了高频机械冲击（HFMI）技术的应用效率，旨在提高钢结构生产阶段或在海洋气候条件下长期运行后的对接焊缝的抗疲劳性。焊接接头中形成的腐蚀缺陷在充满中性盐雾的 KST-1 室中模拟，在 35±2°C 的温度下进行 1200 小时，每 45 分钟测试一次，氯化钠溶液分散 15 分钟，持续 1200 小时. 溶液中氯化钠的浓度为 50 ± 5 g/dm3，pH = 6.5–7.2。对四批 15KhSND 钢的对接焊缝进行了疲劳试验：焊接状态，HFMI 处理后，在 KST-1 室中保持；在运行 2∙106 个应力循环并在 KST-1 室中保持后，以及在运行 2∙106 个循环并在 KST-1 室中保持并随后进行 HFMI 硬化后。实验表明，在可变载荷和海洋气候条件下，HFMI技术的应用显着提高了金属结构对接焊缝的疲劳寿命。