In the present study, laser shock peening (LSP) was employed to enhance the rotating bending fatigue life of 1Cr12Ni3Mo2VN martensitic stainless steel used in steam turbine blades, addressing the issue of insufficient fatigue performance in these components. The aim of this study was to investigate the effect of LSP on the microhardness, residual stress, and rotating bending fatigue life of 1Cr12Ni3Mo2VN steel samples. The microhardness of LSP-treated samples was increased by 10.5% (LSP-3J sample) and 15.3% (LSP-4J sample), respectively, compared to high-frequency hardening samples. The residual compressive stress of the LSP-4J sample was the largest, reaching −689 MPa, and the affected layer depth was about 800 μm. Fatigue tests showed that the number of cycles at the fracture point for the LSP-3J and LSP-4J samples increased by 163% and 233%, respectively. The fatigue fracture morphology of the four samples showed that the microhardness and residual compressive stress distribution introduced by LSP could effectively inhibit the initiation of surface cracks, slow down the crack growth rate, and improve the rotating bending fatigue life of 1Cr12Ni3Mo2VN.

Steel wheels, consisting of rims and spokes, are important load-bearing parts of vehicles, and the fatigue fractures’ life estimation accuracy directly determines the stability and safety when applied in the transportation industry. The most common form of failure is fatigue fracture. The strong elastic–plastic deformation during the rim roll-forming process generates a residual stress field in its surface layer, which changes the actual stress distribution in the rim when it is loaded and thus affects the fatigue life of the steel wheel. In this paper, ABAQUS software was used to establish a rim-rolling simulation model to obtain the residual stress field distribution after forming and compare it with the actual residual stress on the formed surface of the rim to verify the reliability of the model. On the basis of this model establishment, the service hazard areas and maximum stresses of steel wheels with or without superimposed residual stress fields were calculated separately, and their fatigue lives were predicted separately using the local stress-strain method. The simulation results show that the maximum stress of the rim before and after the superimposed residual stress occurs in the area of the bottom of the groove, which is consistent with the actual failure location. However, the maximum stress after superposition increased from 120.7 MPa to 332.9 MPa, and the corresponding calculated life decreased from 158,340,000 to 459,500 cycles, which is closer to the actual test results. The results of the study can provide a theoretical basis for the lightweight design and process improvement of automotive steel wheels.

Laser shock peening (LSP) process parameters have an important influence on the strengthening effect. In this study, theoretical calculations were used to determine a suitable range of stress wave peaks (5.09 GPa–6.36 GPa) for laser shocking, which consider the material properties of alloy steel 40Cr. In addition to theoretical calculations, the finite element numerical simulation of a single-point laser shock was also performed. The residual stresses of specimens under different shock pressure waves were simulated, and then the optimal pulse width was determined as 20 ns and the optimal pulse energy was determined as 10 J. Finally, the influences of different pulse energies on the microhardness, residual stress, microstructure, and shock-affected layer thickness of metallic materials were comprehensively investigated through experiments, and the optimization of the laser shock energy was proved to be 10 J. An optimized combination of parameters of a single-point laser shock for 40Cr was obtained, in which the spot diameter was 3 mm, the pulse width was 20 ns, and the pulse energy was 10 J. The study has implications for the selection of LSP process parameters for alloy steels.

Many micro-scraps are generated when a micro-triangular pyramid array (MTPA) is machined by the fly-cutting method. Micro-scraps are generally not removed quickly enough; therefore, these residual micro-scraps participate in the cutting process again, scratching the workpiece surface and accelerating diamond tool wear. To remove micro-scraps rapidly, a fly-cutting method to produce MTPAs on vertically oriented working surfaces was developed during this study. The results show that an MTPA produced by fly cutting on a vertical workpiece had a clearly outlined structure, high dimensional accuracy, and a low surface roughness. There was no micro-scrap residue on the workpiece surface and the diamond tool wear was small. The cutting inlet edges had no burrs, and the cutting outlet edges had only a small number of burrs. This method of fly cutting MTPAs on vertically oriented working surfaces provides a foundation for the development of high-precision micro-triangular pyramid optical elements.

The copper mold of the micro-triangular pyramid (MTP) is a key component of MTP plastic film manufacturing, and its optical functional surface comprises micro-triangular pyramid arrays (MTPAs). The edge burrs of MTPAs severely affect the optical properties of MTP plastic film. To solve the problem of excessive edge burr of MTPA machining using the fly-cutting method, the orthogonal experimental method was used to optimize the four influencing factors: fly-cutting speed, feed speed, cutting depth, and cooling mode. The results show that the impact of these influencing factors on surface roughness, the projected area of the exit edge burr, and exit edge burr thickness are ranked from largest to the smallest as follows: fly-cutting speed, feed speed, cutting depth, and cooling mode. The factors affecting tool nose wear in descending order are fly-cutting speed, feed speed, cooling mode, and cutting depth. The optimal conditions for minimizing the thickness of the edge burr were a fly-cutting speed of 7.85 m/s, a feed speed of 50 mm/min, a finishing cutting depth of 15 μm, and using compressed air with oil mist for cooling. This study lays a foundation for improving the anti-reflection performance of MTP plastic film.

Micro-pyramid copper molds are critical components in the preparation of high-precision optical elements, such as light-trapping films and reflective films. Their surfaces are composed of micro-pyramid arrays (MPAs). The surface roughness and edge burrs of MPAs seriously affect the optical properties of optical elements. To reduce the surface roughness, as well as the sizes of the edge burrs, the longitudinal ultrasonic vibration-assisted planing (LUVP) method for processing MPAs was developed during this study. In addition, an experiment was conducted to compare the precision planing and LUVP methods of MPA generation. The results show that the tool nose amplitude of the LUVP experimental platform constructed during this study was 3.3 μm, and that the operating frequency was 19.85 kHz. An MPA processed by LUVP had a smaller surface roughness than that of an MPA produced by precision planing; it also had fewer and smaller edge burrs, and there was slightly less diamond tool wear. The MPA cut using the LUVP method had no corrugation on its surface. This research lays a foundation for developing higher-precision micro-pyramid plastic films.