Keyword: «mechanical properties»

The article presents the results of a study on multi-pass welded joints made at subzero and ambient air temperatures. Experimental multi-pass welding of low-alloy bridge steel 10HSND (Grade 3) was performed using WN 62U electrodes with registration of the welding thermal cycles. The research results confirm the possibility of producing high-quality welded joints in 10HSND steel under subzero temperature conditions without significant degradation of its performance characteristics.

The article presents the results of studies on the microstructure and mechanical properties of weld metal modified with a natural concentrate of rare-earth elements from the Tomtor rare-metal deposit. It is shown that the structural changes that occur when a complex modifier is added into the charge of coated high-strength ANP-2 type E70 electrodes lead to a 15% increase in the impact toughness of the weld metal at positive test temperatures, and a 50% increase in the test range from –40 to –60 °C.

The technology of obtaining and complex properties of polyurethane composites reinforced with carbon fiber are investigated. The key problems of modern research (insufficient interfacial adhesion, low thermal and moisture resistance, and uneven fiber distribution) are identified, and a comprehensive approach to their solution is proposed, including optimization of the polyurethane matrix formulation, pre-treatment of carbon fiber, and regulation of molding/curing parameters. Mechanical (stretching, bending, impact strength) and thermal (DSC, TGA) studies have evaluated the properties of composites with different carbon fiber content. It is shown that at 15 wt. % fiber content composites demonstrate optimal mechanical properties, and the regulation of curing significantly improves their thermal stability. The study provides a theoretical and technical basis for a wide range of engineering applications of the results obtained.