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Differences in the nature of the thermal cycle run under welding conditions in comparison to that during conventional heat treatment are shown. The methods of investigations into microstructural changes of austenite under welding thermal cycles conditions developed and used at the Welding Institute in Gliwice are discussed. The investigation results, in the form of CTPC-S diagrams for construction steels of grades X12CrCoWVNbl 2-2-2 (VM12-SHC), 7CrMoVTiB10-10 (P24) and 10CrMo9-10 (P22), are presented and compared with those in the form of CTPC diagrams plotted for metallurgical conditions.

AbstractDiffusion of oxygen and nitrogen in the cold sprayed commercially pure Ti (CS CP Ti) deposits profoundly impacts their mechanical properties. One plausible approach to additively manufacture a malleable (wrought) and high-density Ti is optimizing CS deposition parameters considering a reduction in porosity for the following heat treatment. Herein, we examined porosity, bulk density, and hardness characteristics of CS CP Ti deposits produced at varying processing gas temperatures (700, 800, and 900°C), which significantly influences the interactions of CP Ti with oxygen and nitrogen. Post-processing heat treatments at 800, 900, and 1000°C were performed in a high vacuum furnace, respectively, which diminished splat boundaries and submicron pores with increasing grain size. SEM images revealed that CS CP Ti had a dense microstructure with low porosity. According to LECO research, low spraying temperatures (i.e. 700°C) maintained oxygen and nitrogen levels in the CS CP Ti deposits at the same level as the stock powders. The bulk density of CS CP Ti produced at 900 °C matched that of wrought CP Ti metal. In addition, to improve the mechanical properties of CS CP Ti deposits, we looked at the link between CS conditions and heat treatment.

This paper investigates a novel cooperative guidance law for the task of salvo attack based on efficient information. The concept of efficient information is first introduced as the basis of a multi-missile cooperative structure in a nominal engagement situation. The effective time of the efficient information, which can be regarded as an important parameter to indicate the ability of a missile to attack a given stationary target, is estimated by modifying the current time-to-go estimation method in the presence of a lateral acceleration constraint. Utilizing the effective time, a novel cooperative guidance law with better adaptiveness and robustness is proposed for multi-missile systems to realize the simultaneous attack. Finally, the effectiveness of the proposed cooperative guidance law is demonstrated via simulations.

The origin of stains on the surface of anodized aluminium profile was investigated. Stains were visible on the surface under the specific angle of observation. Anodized surface and layer were investigated by scanning electron microscopy, metallography of cross section of the layer was performed and EDS analyses were done. Presented are results of investigation. No difference was observed by scanning microscope between the surface with and without stain. The metallography of cross section of anodized layer revealed prevailing compact layer, only in the region with the stain a small pores were observed below the surface. The pores were not connected to the surface. The EDS analyses detected in the pores the presence of oxygen, sulphur, fluorine and nickel. Sulphur confirmed the sulphuric acid was used as electrolyte at anodizing process, but fluorine and nickel are evidence that pores were cold sealed in solution containing NiF2. Investigations confirmed that apparent stains were an optical effect, a consequence of different refraction of the light due pores in the layer. The main reason for the rests of pores in anodized layer was not optimised anodizing process.

Because high positioning accuracy of industrial robots requires high stiffness at the price of high robot mass and energy consumption relative to the payload of the robot, this paper describes a kind of service robot dual-arm constructed by lightweight reconfigurable modules. After analyzing the composition characteristics of service robot dual-arm, the type selection of robot arm modules is accomplished, and the hardware platform of robot dual-arm composed by modular joint is builded. According to the modularization characteristics of arm joints, the distributed control system is designed.

In this paper, through the process of designing complex products, by combining a model of collaborative optimization with robust design, we built the model of robust collaborative optimization with mixed-discrete variables. And the model was validated by an actual engineering case, which was a typical Multidisciplinary design optimization (MDO) case. In the meantime, we analyzed the result and compared it with the result got from the collaborative optimization model with mixed-discrete variables to verify the effect by robust design.

Abstract A software package has been developed to describe high speed machining applied to a number of metal cutting operations. The formulations of the model and program are described and an example is presented applied to milling. This modular system incorporates a structured database that can be updated by the user in a dialogue operational mode and allows the user to obtain process parameters for changing cutting conditions in both conventional and high-speed machining. The model described here also incorporates workpiece/tool thermal and mechanical properties amongst its input variables. This allows the outputs to be more representative of real life cutting and the outputs of the model are useful for both conventional and high speed machining.

Abstract Possible existence of a dynamic version of the quasi-static Saint-Venant's principle (DSVP) has been raised by Boley five decades ago. Since then, relatively few papers have been dedicated to the possible validity of a DSVP. These papers are reviewed in the first part of a present communication. An apparent observation is the absence of any consensus on whether there is a dynamic counterpart to the classical Saint-Venant's principle (SVP) with the same generality and validity. On the other hand, there is experimental support (and numerical simulations) regarded by several researchers as evidence for the existence and validity of a DSVP in conservative systems. Nevertheless, no coherent versions of SVP for dynamic problem in non-dissipative systems have been proposed, and those proposed, are proved to be not valid. The historical account emphasizes the apparent gap between the theoretical approach and the experimental insights. In the second part of the present communication a new definition of a dynamic version of SVP is suggested, bridging over the apparent gap between the theoretical approach and experimental insights. This is achieved by introducing the concept of “dynamically equivalent system of loads” analogous to the “statically equipollent system of loads” introduced by Saint-Venant.

In recent years, non-traditional machining processes have been growing in popularity and their applications have continued to increase. However, very limited research work has been carried out to investigate their economic implications on tolerance allocation. This paper reports on cost-tolerance relationships for non-traditional processes, namely, electrical discharge wire machining and laser beam machining. Medium carbon steel plates are machined using the two processes to obtain cost-tolerance data which are fitted to various mathematical models. A third-degree polynomial function has been found which gives the most representative fit to the data obtained. An example is presented to illustrate the application and to compare the cost implication of the two machining processes.