This article aims to optimise the structure of a press machine to enhance its stability and accuracy, as well as reduce the frame deformation during processing. The outer supporting frame of the JH31-250 press machine (Zhejiang Weili Forging Machinery Co., Ltd, Shaoxing, China) is used as a typical sample for exploring optimisation. Commercial software is utilised to conduct a finite element analysis on the three-dimensional model of the press machine frame. A topological optimisation algorithm using the solid isotropic microstructures with penalisation (SIMP) method is then applied to improve the structure of the press frame. The size of the topological structure is further refined with the response surface method and particle swarm optimisation method to ensure it is more relevant to engineering application. The analysis results indicate that the initial frame’s deformation under the static conditions is 0.4229 mm, and after optimisation, the deformed structural displacement is 0.2548 mm, a decrease of 39.75%. Additionally, a simplified experimental method is designed to effectively validate the simulation and the proposed design.

The local corrosion resistance of forging and selective laser melting (SLM) 304 steels was explored by intergranular corrosion analysis, double-loop electrochemical potentiodynamic reactivation, dynamic polarization experimentation, structural analysis, and passivation film characteristics analysis. The ability to resist sensitization of SLM 304 steel is greater than that of forging 304 steel at a temperature of 650 °C for 9 h. Moreover, the pit corrosion resistance of forging and SLM 304 steels is weakened by sensitization, while the pit corrosion resistance of SLM 304 steel is much greater than that of forging steel. Therefore, SLM technology can improve the ability to resist sensitization and pit corrosion of 304 steel. Analysis showed that the ability to resist corrosion of the passivation film of SLM 304 steel is greater than that of forging steel. In addition, corrosion pits are easier to generate at the interface of forging steel and SLM 304 steel. The grain boundary corrosion of SLM 304 steel intensified while the corrosion of the melt pool boundaries weakened after the sensitization treatment, resulting in a decrease in pit corrosion resistance. The coupling effect of these different structures and passivation films decides the pit and sensitization resistance of forging and SLM 304 steels. Clarifying the corrosion mechanism of forging and SLM steels is of great significance for scientific research and the widespread use of SLM technology.

This article conducts intermittent tensile deformation on 304 stainless steel; observes the microstructure, mechanical properties, and corrosion performance evolution of stainless steel under different deformation conditions; and reveals its mechanisms. The results indicate that the performance of 304 stainless steel is significantly affected by the degree of intermittent deformation. Small intermittent deformation can produce a good microstructure with uniform distribution, low martensite content, and weak texture, optimizing comprehensive mechanical properties by improving ductility, yield strength, and tensile strength. On the contrary, excessive intermittent deformation increases martensitic transformation and enhances texture, leading to a transition from ductile fracture to brittle fracture. In addition, small intermittent deformations improve corrosion resistance by promoting the formation of a stable passivation film. The microstructural changes affect the deformation mechanism and surface passivation film of stainless steel, making its mechanical strength and corrosion resistance superior to larger intermittent deformation amounts. Small intermittent deformation can improve the mechanical and corrosion properties of 304 stainless steel. This study provides a reference for the formation and performance control of metal materials and has certain practical value.

Steam generator equipment is widely used in both industrial and domestic applications. However, during service, the coils in such equipment are prone to cracking. This paper analyzes the cause of coil leakage in steam generators using methods such as macroscopic inspection, metallographic analysis, chemical composition analysis, scanning electron microscopy (SEM), and energy-dispersive spectroscopy (EDS). Results show that excessive temperature leads to chemical reactions between the coil material and water. The reaction products undergo physical changes upon heating, which damage the metal product film and corrode the inner wall of the coils. This ultimately leads to failure due to corrosion. This research provides a theoretical basis for designing high-quality steam generators.