Features of repair welding of power hydrocylinder elements

Abstract

At present, the use of power hydraulic cylinders is an integral part of most industrial equipment. They provide translational and horizontal movements, replacement of goods, fixation, etc. These devices are necessary elements of the equipment where application of the corresponding level of effort is applied. Often hydraulic cylinders are created specialized to perform certain types of work. It should be noted that part of the elements of the power cylinder in the manufacture is combined with welding. Such integral connections provide rigidity of installation, tightness of a design, fatigue strength at multicycle loadings. Difficult operating conditions, significant workloads, the presence of various external factors often leads to the destruction of individual elements of the cylinder. At the same time, the cost of repairing equipment that involves replacement with new power devices is quite high. This causes the implementation of repair and restoration work carried out at specialized enterprises. However, in the case of repairs, there are often a number of problems that require prompt resolution in the production environment. These should include the provision of basic materials with similar physical and chemical properties, the establishment of welding modes, the selection of the necessary welding materials, the use of appropriate techniques for conducting the arc process, etc. Therefore the repaired welded design of the case of the power hydraulic cylinder needs additional studying for weldability of separate elements among themselves, formation of a zone of thermodeformation influence. In general, the repaired hydraulic cylinder should meet the installation operating requirements depending on the purpose. The design of the considered hydraulic cylinder of the press installation is rather technological from the point of view of maintenance of automation of welding process. It contains long welds of a simple ring configuration. At the same time, the significant linear dimensions and the presence of a cylindrical surface cause some complexity in the implementation of processes. The construction material of the power hydraulic cylinder is low-carbon low-alloy steels. The analysis of technological weldability indicates a tendency to crack due to the thermal cycle of welding. The simulation of welds of the power hydraulic cylinder is performed in the work. The number of rollers was taken into account when obtaining butt welds. A comparative analysis of different electrode materials with different doping systems is done. The most applicable welding materials by chemical composition and properties of the weld metal are determined. According to the literature data and the results of comparative analysis, the optimal range of cooling rate of the main material of the hydraulic cylinder was established. The properties and structure of the zone of thermal influence of the butt welds of the power hydraulic cylinder have been studied. The magnitude of deformations and stresses caused by the thermal cycle of welding of the shell structure of the hydraulic cylinder liner is investigated. The admissible parameters of the zone of plastic deformations during butt welding are determined.

Ensuring the technological strength when welding the shaft with flange of auto-vehicles

“…4. Setting the parameters of the welding regime was carried out according to the recommendations of the specialized literature [7,8] and the construction of the welded structure (annular seam). The following regime parameters are recommended for automated welding of the shaft and flange in shielding gases (Table 2).…”

“…Therefore, when developing the welding technology of the shaft and flange, it is advisable to use methods that limit or eliminate the need for post-welding heat treatment; -limitation of the content of carbide-forming elements and their influence on the formation processes of structural heterogeneity. It was established [4,5,7,8] that structural heterogeneity is manifested depending on the content of alloying elements, their type and thermodynamic activity. In particular, the intensity of the influence increases with the increase in affinity to carbon of the remaining alloying elements.…”

Strengthening and reconstructionof drilling core pipe for engineeringand geological exploration

“…It is necessary to use various technological measures such as heating parts before surfacing and appropriate surfacing techniques to avoid residual deformation and reduce welding stresses, reduce the depth of the pipe worn wall penetration etc. [15][16][17].…”

“…We can well regulate the latest properties of the weld metal. Still, the diffusion processes of the elements are not so active that they also enable to affect the main metal properties [13][14][15]. In this case of core pipe surfacing, the thermal cycle will affect the structural-phase composition formation of the central metal thermal influence zone.…”

“…It determines a range of negative factors, including the transience of geyser arc surfacing processes, the existence of a significant temperature gradient (from maximal metal fusion to the surrounding workshop conditions) in a limited volume, the presence of cold pipe sections that hurt the temperature range of material, the fragility of availability temperature and residual stresses in the surfacing process, etc. [13][14][15]. The most critical factor that impacts the structural-phase composition formation of the material in the zone of welded core pipe thermal influence is at the same time a cooling speed.…”