The high-temperature hardness test has a wide range of applications, but lacks test standards. The purpose of this study is to develop a finite element method (FEM) model of the relationship between the high-temperature hardness and high-temperature, quasi-static compression experiment, which is a mature test technology with test standards. A high-temperature, quasi-static compression test and a high-temperature hardness test were carried out. The relationship between the high-temperature, quasi-static compression test results and the high-temperature hardness test results was built by the development of a high-temperature indentation finite element (FE) simulation. The simulated and experimental results of high-temperature hardness have been compared, verifying the accuracy of the high-temperature indentation FE simulation.The simulated results show that the high temperature hardness basically does not change with the change of load when the pile-up of material during indentation is ignored. The simulated and experimental results show that the decrease in hardness and thermal softening are consistent. The strain and stress of indentation were analyzed from the simulated contour. It was found that the strain increases with the increase of the test temperature, and the stress decreases with the increase of the test temperature.

Cutting fluids are the most effective method to lower the cutting temperature and decrease the cutting tool wear. At the same time, the cutting fluids influence the corrosion resistance property of the machined surface. In this study, chlorinated paraffin (CP), which is a common additive in the cutting fluid, was selected as the research objective to study its corrosion resistance property. The passivation effect of CP with different concentrations on the machined surface of stainless steel was studied. Electrochemical measurements and surface morphology investigation were used to characterize the passivation effect of CP with different concentrations. The test results showed that the corrosion resistance of stainless steel in the cutting fluid was enhanced with the increase in CP additive. This reason is that the charge transfer resistance increases and the corrosion current density decreases with the increase in CP additive. The X-ray photoelectron spectroscopy (XPS) results show that the proportion of metal oxides on the processed surface of the stainless steel sample was increased from 20.4% to 22.0%, 32.9%, 26.6%, and 31.1% after adding 1 mL, 2 mL, 4 mL and 6 mL CP in the cutting fluid with a total volume of 500 mL, respectively. The oxidation reaction between CP and the stainless steel sample resulted in an increase in metal oxides proportion, which prevented the stainless steel sample from corrosion in cutting fluid.

Annelid-inspired robots exhibit excellent motion adaptability and structural compliance, enabling them to navigate confined, hazardous, or complex environments such as pipelines, soil, or the gastrointestinal tract. This review summarizes key developments in their bionic part design, actuation methods, material selection, and performance characteristics. Comparative analyses show that different actuation strategies (e.g., pneumatic, shape memory alloys, and electroactive polymers, etc.) need to be weighed in terms of their advantages, limitations, and applicable environments. Materials like silicone rubber and SMA are evaluated for their strength, flexibility, and energy performance. Quantitative benchmarks of velocity, load capacity, and energy consumption are presented to highlight design-performance correlations. Prospective research directions include the integration of multifunctional adaptive materials, real-time feedback sensing systems, and scalable architectures for autonomous operation in unstructured environments.

The surface integrity of grinding has a significant influence on the service performance and life of machined parts. In this study, the influence of grinding parameters and the grit size of the grinding wheel on the surface integrity of the hardened steel, including the roughness, microstructure, and hardness of the subsurface and the residual stress of the ground surface, was comprehensively investigated, and the corresponding mechanisms were revealed. The results show that the roughness perpendicular to the grinding direction was significantly larger than that parallel to the grinding direction due to serious side flow, and increasing the grinding speed or reducing the grinding depth was beneficial for reducing the side flow and thus decreasing the roughness. It was found that the grinding temperature dominated the formation of a harder white layer and a softer black layer, and workpiece speed had the smallest effect on the transition of subsurface microstructure compared to grinding speed and depth. It was also found that the increase in workpiece speed, grinding depth, or grinding speed resulted in a transition from compressive to tensile residual stress or an increase in tensile residual stress, and that grinding wheels with finer grit tended to induce compressive residual stress. This study may help to improve surface integrity by optimizing grinding parameters or facilitating the selection of the optimal grinding wheel.