Ultrasonic Rolling Research Articles

Ultrasonic rolling surface roughness study of shaft parts based on three-dimensional morphology reconstruction

Ultrasonic rolling surface roughness study of shaft parts based on three-dimensional morphology reconstruction

Enhancement of the tool performance of circular saw blades by improving the microstructure and residual stress field using an ultrasonic rolling tensioning process

Enhancement of the tool performance of circular saw blades by improving the microstructure and residual stress field using an ultrasonic rolling tensioning process

Simulation study of turning-ultrasonic rolling compound processing for 42CrMo steel

The ultrasonic rolling processing technology has been shown to significantly reduce surface roughness and enhance the residual stress of parts, thereby improving their surface properties and extending their service life. This technology is particularly effective for the precision machining and surface strengthening of ultra-high-strength steel 42CrMo. This study aims to investigate the impact of turning pre-processing on the distribution of residual stress during ultrasonic rolling, a simulation model incorporating turning pre-processing was developed and used to conduct ultrasonic rolling simulation experiments, enabling the analysis of residual stress distribution patterns. Concurrently, ultrasonic rolling strengthening experiments were performed to validate the accuracy of the simulation model. The results confirm that with increasing rotational speed and feed rate, residual stress decreases, whereas with increasing static pressure and amplitude, residual stress increases. The residual stress variation obtained from the simulation of combined turning and ultrasonic rolling closely matched the results of experimental ultrasonic rolling tests. This consistency validates the accuracy of the simulation model. This study offers a novel approach for simulating and experimentally validating ultrasonic rolling processes, particularly for shaft-like parts that undergo turning as a pre-processing step.

Surface fatigue characterization and its enhancement by the engineered ultrasonic rolling process for 300 M ultrahigh strength steel

The fatigue life of surface layer (FSL) is innovatively characterized to accurately capture the effect of surface integrity on the fatigue behavior of the components. The sensitivity of FSL of 300 M ultrahigh strength steel to the surface integrity indexes induced by representative manufacturing processes was analyzed by analytical modeling and fatigue tests from the perspective of engineering fracture mechanics. The ultrasonic surface rolling process (USRP) was introduced to optimize the fatigue limit of 300 M steel, and the improvement in fatigue life was experimentally quantified. Besides, the fracture analysis was conducted to provide the reason why USRP can enhance the fatigue behavior of 300 M steel. The results show that FSL occupies a majority with percentage of over 95 % in the entire fatigue life and a strong relation with the machined surface defects, especially the surface machining marks. The excellent surface finishing effect and high compressive residual stresses induced by engineered USRP could transfer the crack source from surface machining marks into subsurface inclusions, which greatly prolongs the fatigue crack initiation life and thereby the entire fatigue life. To be specific, the fatigue life was elevated by more than 40 times and the fatigue strength was increased by 34.7 % after USRP for the tested 300 M steel.

Effect of ultrasonic vibration on the roll bending deformation behavior of ultra-thin-walled corrugated sheets

The ultra-thin-walled corrugated sheet is a crucial component of metal honeycomb structures. Due to the size effect, the traditional roll bend forming process often leads to significant dimensional deviations in ultra-thin-walled corrugated sheets. To address this issue, an ultrasonic vibration-assisted roll bend forming process was proposed. First, an ultrasonic vibration-assisted roll bend forming device was designed, which had a special drive roller structure that can alter the original axial direction of ultrasonic vibration to produce a radial vibration with an amplitude of 0–2 µm. Under the high-frequency impact and acoustic softening effect of ultrasonic vibration, the ultra-thin-walled corrugated sheets formed numerous plastic penetration zones. As a result, the influence of individual grain heterogeneity was weakened and the stress distribution states underwent an interchange. Therefore, the ultra-thin-walled corrugated sheets demonstrated improved edge length uniformity, increased hardness in the deformed areas, reduced surface roughness, and decreased springback angle. However, excessive ultrasonic amplitude resulted in severe thinning or even rupture. Ultimately, high-quality ultra-thin-walled corrugated sheets were successfully fabricated using pure titanium foil with a t/d of 5.4 and an ultrasonic amplitude of 1.6 μm.

Parameters prediction for Low-Plasticity ultrasonic rolling strengthening process of blades based on Few-Shot Genetic Bayesian-Back Propagation intelligent learning

This study aims to reduce titanium alloy blade surface roughness and enhance compressive residual stress (CRS) using the low-plasticity ultrasonic rolling strengthening process (URSP). Due to the URSP’s multifactorial complexity and characteristics of few and irregular test samples, this study proposes a Genetic Bayesian-Back Propagation neural network (GB-BP) for a few sample parameters optimization for low-plasticity URSP of the blade, which combines a back propagation (BP) neural network with genetic algorithm (GA) and Bayesian Optimization (BO). The proposed approach establishes a robust correlation between processing parameters, blade surface roughness, and CRS. Firstly, an orthogonal test with three factors, rolling depth, feeding speed, and rolling distance, is designed. The signal-to-noise ratio (S/N) analysis and mean value analysis identify rolling distance and depth as the primary factors influencing surface roughness and CRS. Furthermore, BP complement with BO is employed to predict blade surface roughness and CRS after URSP. Finally, GB-BP is proposed to predict parameters, and experimental validation demonstrates the superior predictive accuracy of the GB-BP network. Compared to traditional BP models, the mean error percentages for GB-BP prediction dropped by 51.286% for surface roughness and 69.818% for CRS. The root mean square error (RMSE) decreased by 51.864% for surface roughness and 71.982% for CRS. This network model can provide accurate parameters optimization for low-plasticity URSP of blades.

Enhanced electrochemical corrosion resistance of 316L stainless steel manufactured by ultrasonic rolling assisted laser directed energy deposition

Enhanced electrochemical corrosion resistance of 316L stainless steel manufactured by ultrasonic rolling assisted laser directed energy deposition

A novel ultrasonic rolling assisted direct energy deposition method with semi-solid thixo-forming characteristics for AA6061

In order to overcome the defects during the process of additive manufacturing for AA6061, a novel ultrasonic rolling assisted direct energy deposition method with semi-solid thixo-forming characteristics was proposed in this study, which used cold deformed AA6061 wire as raw material, and a corresponding process platform was established. The results showed that under the conditions of laser heating temperature of 750 ℃ and heating plate temperature of 200 ℃, the sample could achieve continuous multi-pass deposition while retaining some of the cold-drawn plastic deformation energy. When the vertical deformation rate was 0.153 and the ultrasonic amplitude was 20 μm, the microstructure of deposition sample after semi-solid heat-treat exhibited typical equiaxed grain characteristics, corresponding to average grain diameter of 95.6 μm and shape coefficient of 1.263. Thin-walled samples with different shapes were formed to verify the capability of process platform. The inference of the formation mechanism of semi-solid microstructure was revealed at last: the introduction of ultrasonic rolling supplemented the plastic deformation energy, and semi-solid heat-treat provided temperature and time for the incubation of equiaxed grains, both of which were crucial for the formation of the semi-solid microstructure.

Formation mechanism of blade surface integrity based on hybrid process of cryogenic minimum quantity lubrication and ultrasonic rolling strengthening process

This study proposes a hybrid process method based on Cryogenic Minimum Quantity Lubrication and Ultrasonic Rolling Strengthening Process (CMQL-URSP) to improve the surface integrity and enhance the mechanical properties of blade surface. First, the principle of the CMQL-URSP hybrid process was described. Second, the TEM experiments were conducted to clarify the influence of the CMQL-URSP hybrid process on aircraft engine blades. Finally, the blade processing experiments were performed to demonstrate the effectiveness of the CMQL-URSP hybrid process on the blade surface micro-morphology, micro-hardness and residual stress. The results indicate that the CMQL-URSP hybrid process effectively overcomes the limitations inherent to the solitary application of URSP. The CMQL process inhibits work hardening, thereby allowing the URSP to achieve better low-plastic surface improvement. Grain refinement governed by the continuous dynamic recrystallization mechanism leads to the formation of nanocrystals, which significantly improves mechanical properties of blade surface. The CMQL-URSP hybrid process results in a reduction in surface roughness from Ra 2.644 μm to Ra 0.055 μm, an increase in surface residual compressive stress from 321 MPa to 657 MPa, and the formation of a reinforced layer with a depth of 3.7 mm on the blade, thereby enhancing the surface integrity of the blade.

Study on theory and finite element simulation of ultrasonic rolling extrusion process

Study on theory and finite element simulation of ultrasonic rolling extrusion process

Fatigue Strength Improvement of Laser-Directed Energy Deposition 316L Stainless Steel with In Situ Ultrasonic Rolling by Preliminary Investigation.

In this study, to improve the fatigue strength of the LDED (laser-directed energy deposition) 316L stainless steel, an in situ ultrasonic rolling technology is developed to assist the laser-directed energy deposition process (LDED-UR). The microstructural characteristics and fatigue behavior are comprehensively discussed. The results show that the average size of pores of the LDED-UR alloy is about 10.2 μm, which is much smaller than that of the LDED alloy (34.1 μm). Meanwhile, the density of the LDED alloy is also enhanced from 98.26% to 99.27% via the in situ ultrasonic rolling. With the application of the in situ ultrasonic rolling, the grains are transformed into fully equiaxed grains, and their average grain size is greatly reduced from 84.56 μm to 26.93 μm. The fatigue limit of the LDED-UR alloy is increased by 29% from 210 MPa (LDED alloy) to 270 MPa, which can be ascribed to the decreased porosity and the fine grains. In particular, the crack initiation site of the LDED alloy is located at the surfaces, while it is nucleated from the sub-surface for the LDED-UR alloy. This is mainly attributed to the compression residual stress induced by the in situ ultrasonic rolling. This research offers a valuable understanding of the failure mechanisms in additively manufactured metals, guiding the development of effective strategies to improve their fatigue threshold under severe operating conditions.

The tribological properties of PPS-PTFE/SiO2 coating deposited on the textured surfaces processed by ultrasonic rolling

In this paper, ultrasonic rolling textures were fabricated on 42CrMo steel substrates, and the polyphenylene sulfide-polytetrafluoroethylene/silicon dioxide (PPS-PTFE/SiO2) lubricating coatings were deposited on the textured surfaces to improve the tribological properties of the coating-substrate system. The influences of textures with different shapes (spiral, linear, wavy textures) and step distances (100, 150, 200, 250 μm) on the surface morphologies and strengthening effects of the substrates were investigated. The results showed the wavy texture with a step distance of 200 μm had the best strengthening effect, which increased the surface hardness and residual compressive stress by 126.1% and 5.1 times compared to the substrate, respectively. The influences of different textures on the friction and wear properties of lubricating coatings were studied by dry reciprocating friction testings. The results showed that the coating on the spiral textured surface with a step distance of 250 μm had the best tribological properties, and the average friction coefficient and wear rate were reduced by 45.5% and 49.5% compared to the coating on the substrate. The influence of ultrasonic rolling texture on the tribological properties of the lubricating coating was a combined result of the strengthening effect and texture structure. The strengthening effect provided a steady gain, while the texture structure provided either a gain or a deterioration.

Multi-Objective Process Parameter Optimization of Ultrasonic Rolling Combining Machine Learning and Non-Dominated Sorting Genetic Algorithm-II.

Ultrasonic rolling is an effective technique for enhancing surface integrity, and surface integrity is closely related to fatigue performance. The process parameters of ultrasonic rolling critically affect the improvement of surface integrity. This study proposes an optimization method for process parameters by combining machine learning (ML) with the NSGA-II. Five ML models were trained to establish relationships between process parameters and surface residual stress, hardness, and surface roughness by incorporating feature augmentation and physical information. The best-performing model was selected and integrated with NSGA-II for multi-objective optimization. Ultrasonic rolling tests based on a uniform design were performed, and a dataset was established. The objective was to maximize surface residual stress and hardness while minimizing surface roughness. For test specimens with an initial surface roughness of 0.54 µm, the optimized process parameters were a static pressure of 900 N, a spindle speed of 75 rpm, a feed rate of 0.19 mm/r, and rolling once. Using optimized parameters, the surface residual stress reached -920.60 MPa, surface hardness achieved 958.23 HV, surface roughness reduced to 0.32 µm, and contact fatigue life extended to 3.02 × 107 cycles, representing a 52.5% improvement compared to untreated specimens and an even more significant improvement over without parameter optimization.

Achieving high strength 316L stainless steel by laser directed energy deposition-ultrasonic rolling hybrid process

Laser directed energy deposition (LDED) has attracted as a progressive additive manufacturing technique in fabricating the stainless steel components. The rapid melting and solidification velocity under LDED process induces the appearance of pores and the columnar dendritic, which degrades the strength of alloys. Here, a self-developed LDED-UR (ultrasonic rolling) synchronous manufacturing equipment is developed to fabricate the 316L stainless steel, and the characterization of microstructure and mechanical properties are studied. Results show that the size and fraction of pores are significantly reduced by LDED-UR processing, and fine equiaxed grains are obtained under the combined effects of ultrasonic vibration and roller pressure. With the severe plastic deformation, the average grain size of LDED-UR sample is decreased from 76.10 μm to 26.23 μm (LDED sample), and high angle grain boundaries transforms to low angle grain boundaries. Meanwhile, the dislocation density in LDED-UR sample is increased compared to the LDED sample. Owing to the grain refinement and dislocation strengthening, the average microhardness, yield strength, ultimate tensile strength and elongation of the LDED-UR sample reach 268.18 ± 13.90 HV0.2, 442 MPa, 771.2 MPa, and 49.8 %, respectively, which are larger than those of LDED sample (214.13 ± 13.76 HV0.2, 396 MPa, 682 MPa, and 45.5 %). This implies that the superior mechanical properties are obtained by employing in-situ ultrasonic rolling under LDED process. The insight of the influence of microstructure on mechanical properties extends a new approach for enhancing the mechanical properties of LDED alloys.

Ultrasonic rolling strengthening of TC11 titanium alloy surface: Corrosion and wear properties under extreme conditions

The surface of TC11 titanium alloy was polished and strengthened using ultrasonic rolling process (USRP) technology. The effects of USRP on the surface quality, friction and wear properties, corrosion resistance, and wear mechanisms of TC11 titanium alloy at room temperature, low temperature (−60 °C), high temperature (400 °C), and in corrosive environments were investigated by using optical microscope, microhardness tester, electrochemical workstation, multifunctional friction and wear tester, SEM, EDS, XRD, and XPS. The results indicate that USRP can effectively refine the surface grains of titanium alloy, reducing its surface roughness parameter by 80.4 % and increasing surface hardness and residual compressive stress by 21.7 % and 97.1 %, respectively. USRP is advantageous for producing a layer of TiO2 on the surface of titanium alloys, effectively enhancing the corrosion resistance of titanium alloy surfaces. USRP technology can improve the stability of surface hardness values of titanium alloys in harsh environments. The results of dry friction and wear tests using GCr15 steel balls as the counter material show that the USRP technology can effectively reduce the friction coefficient and wear loss at room, high and low temperatures. The results of corrosion and wear tests using Si3N4 as the counter material indicate that the USRP technology can effectively reduce the friction coefficient and wear volume in seawater corrosion environments. The USRP technology is most effective in reducing the high-temperature friction coefficient of titanium alloys and improving their wear resistance in low-temperature and corrosive environments. The primary wear form of TC11 titanium alloy after USRP has shifted from adhesive wear to abrasive wear.

Formation mechanism of surface gradient microstructure and mechanical properties evolution of Mg–Y-Nd-Gd-Zr alloy by ultrasonic rolling

The evolution mechanism of the microstructure and mechanical properties of a Mg–Y-Nd-Gd-Zr alloy subjected to different numbers of passes of the ultrasonic surface rolling process (USRP) was investigated. The results demonstrated an initial decrease followed by an increase in the surface roughness of the alloy. The optimal surface roughness was achieved after four passes, with a contour mean deviation of 0.06 μm and micro-roughness 10-point height of 0.55 μm. After the USRP, the alloy exhibited a composite gradient structure characterized by increased grain size and decreased dislocation, lamination, and twin densities. The depth of the gradient layer increased with each additional USRP pass, ranging from 650 μm (1 pass) to 910 μm (8 passes). Furthermore, the USRP treatment effectively enhanced the alloy strength; compared with the untreated samples; the yield strength increased by 34.2% in the gradient sample after one pass. No significant change was observed in the YS with an increasing number of rolling passes for Mg alloys, whereas both the tensile strength and elongation showed improvements. High-density twinning played a crucial role in enhancing the YS of the gradient samples without significant variation across different numbers of rolling passes, thus following a consistent pattern. The formation of more nanocrystals on the surface of Mg alloys after multiple rolling cycles is key to preventing premature fracture failure and improving the work-hardening rate.

Effect of ultrasonic rolling on the fatigue performance of laser-welded TC4 titanium alloy joints

Effect of ultrasonic rolling on the fatigue performance of laser-welded TC4 titanium alloy joints

Study on the mechanical properties and deformation mechanism of copper with different volume fractions of gradient structure

In this study, ultrasonic rolling process (USRP) were performed on the rolled copper samples (with an initial grain size of 11.4 μm) to obtain the gradient structure (GS), which comprises nanocrystalline layer (NL), deformed layer (DL), and center layer (CL). The different GS layer (NL and DL) volume fractions of samples were obtained by performing different passes of USRP after rolling, and the effect of the GS layer volume fractions on the mechanical properties was further studied. The morphology and structure of (unrolled, rolled and rolled + USRP) samples were characterized by electron backscattering diffraction (EBSD) and transmission electron microscope (TEM). In-situ tensile testing was used to investigate the tensile deformation behavior of the GS sample. The results show that the rolled + USRP (12 passes) sample with the thickest GS layer (volume fraction of 42%) has the greatest strength (yield strength (YS) 262 MPa and ultimate tensile strength (UTS) 325 MPa). The fine grains, dislocations and textures jointly strengthen the GS sample by increasing the force required for dislocation slip, and their contribution to YS is 51.3%, 44.4% and 4.3%, respectively. In addition, the nanocrystalline grains of GS layer make microcracks evenly distributed and hard to gather, to efficiently hinder cracks propagation and result in good ductility of GS samples. This study provides an effective method to obtain GS materials with good comprehensive properties and a deeper understanding of their deformation behavior and strengthening mechanism.

Experimental Research of Ultrasonic Cavitation Evolution Mechanism and Model Optimization of RUREMM on Cylindrical Surface

Micro-pits are widely used in the aerospace and tribology sectors on cylindrical surfaces and electrochemical micromachining which are of great significance for the high material removal rate, absence of tool wear, and mechanical stress, while facing significant challenges such as stray corrosion and low machining efficiency. Aiming at the above problems, this paper proposes a comprehensive method called radial ultrasonic rolling electrochemical micromachining (RUREMM) in which an ultrasonic field has been added onto the cylindrical surface. First, a theoretical model was created to gain the rules of the formation and collapse of bubbles in the liquid medium. Second, to analyze the optimal size of the cathode electrode, the COMSOL5.2 simulation software was proposed to research the influence of the electric field on the different dimensions, and the influences of different parameters in RUREMM on material depth/diameter ratio and roughness are explored through processing experiments. Research results found that the cavitation bubble undergoes expansion, compression, collapse and oscillation, where the max deviation is less than 12.5%. The optimized size was chosen as 200 × 200 μm2 and an electrode spacing of 800 μm through a series of electric field model simulation analyses. Relevant experiments show that the minimum pits with a width of 212.4 μm, a depth of 21.8 μm, and a surface roughness (Ra) of 0.253 μm were formed due to the optimized parameters. The research results can offer theoretical references for fabricating micro-pits with enhanced surface quality and processing precision on cylindrical surfaces.

Enhancing interface bonding strength of Ti/Al laminated composites via periodic surface nano-crystallization pretreatment

Ti/Al laminated composites have high strength and excellent corrosion resistance, while the relatively low interface bonding strength has still restricted its wide usage. This paper proposes a new method to improve the interface bonding strength of Ti/Al laminated composites through surface nano-crystallization pretreatment using ultrasonic rolling technique. The mechanical property, interface characteristics and interface bonding mechanism are thoroughly studied. The results show that ultrasonic rolling surface pretreatment enables the strong interface bonding of Ti/Al laminated composites and greatly reduces the rolling reduction threshold. It is revealed that ultrasonic rolling surface pretreatment can generate periodic grooves and nanocrystalline layer with low ductility on the Ti surface, which can effectively promote cracking of the Ti hardening layer and increase the contact area of virginal Ti and Al metals during rolling process. Besides, ultrasonic rolling forms nanocrystals and high-density defects on the top surface of the titanium layer, which promote the migration, exchange and rearrangement of atoms under severe plastic deformation and eventually lead to the formation of amorphous structures in the transition layer of the Ti/Al interface. Therefore, the Ti/Al laminated composites pretreated using ultrasonic rolling technique exhibit outstanding interface bonding strength, especially at relatively low rolling reduction conditions.