No abstract

Enough works in which positive action of the vibration fluctuations imposed both in the course of welding of a design and after it is specified are known. In the article features of influence of low-frequency vibration fluctuations in the course of a welding cycle on properties of welded connections from steel A 516-55 are considered. The conducted pilot studies of influence of vibration influence of a welding bathtub in the course of welding on structure and physico-mechanical properties of metal of welded connections have allowed to prove positive action of this technology which leads to increase in durability and fatigue endurance of welded connections. This fact will allow to expand using of technology of vibration processing in the course of welding for production of the welded equipment of various type.

An effective way to avoid heat treatment in the production of pipe beams of heat exchange apparatuses is to replace tungsten inert gas (TIG) welding with rotary RFW (RFW), but at the moment there is no information on the characteristics of welded joints of steel X10CRNITI18-10 obtained by RFW. In this article, the possibility of using RFW to obtain composite joints of a changed design was evaluated. To do this, studies were carried out on the structure of the metal, tests for static tension and impact bending of samples of X10CRNITI18-10 steel obtained by RFW.

The paper shows the possibility of using the technology of vibration treatment in the process of welding of high-temperature chromium steel of martensitic class P91 applied to the product to increase the technological strength of welded joints and the effect of this technology on mechanical properties before and after thermal treatment. Application of vibration action on welding bath and weld seam in process of manufacturing of welded structure may allow to reduce inhomogeneity of weld metal structure in liquid phase, as well as increase its microchemical inhomogeneity within crystallites during crystallization, reduce grain size due to more efficient heat removal and increase of number of crystallization centers. On the example of manufacturing the turbine support housing of the gas turbine drive, it is shown that it is necessary to replace part of the heat treatment operations with other more energy - efficient and less labor-intensive operations. Results of studies of influence of vibration treatment of welded joint on tendency of welded joint metal to form cold cracks, strength, hardness and impact toughness are given. Based on the obtained results, diagrams of average values of parameters are constructed and conclusions are drawn on the possibility of using the technology of vibration treatment of the turbine casing in the process of welding in order to reduce the number of heat treatment operations during its manufacture.

In this work, one of the main methods of strengthening the hole in the apparatus is considered - strengthening with overhead rings, the advantages and disadvantages of using reinforcing rings are indicated. An analysis of the main methods of strengthening the openings of pressure vessels and devices shows that the difficulties in designing and installing the reinforcing rings are in the technology of assembly, detection of weld defects and detection of the local location of this defect. The work shows the possibilities of using locally rib-reinforced nozzle assemblies, which in some cases can serve as an alternative to reinforcing rings, and are also more technological in manufacture, repair and control. Calculations show that the use of two stiffening ribs oriented along the generatrix of the shell to strengthen the hole allows reducing stresses in the area of welding of the nozzle to the body of the apparatus under static load. Practical experiments carried out at the same time showed that in conditions of dynamic loading, it is categorically not recommended to use the strengthening of the nozzle with local stiffening ribs oriented along the generatrix of the shell.