Ultrasonic Rolling Research Articles

Fabrication of AlTiN coatings deposited on the ultrasonic rolling textured substrates for improving coatings adhesion strength

This paper aims to provide a method in improving the adhesion strength of the AlTiN coating/steel substrate system, which is considerable for tribological applications. The surface pre-treatment was implemented by the ultrasonic surface rolling technology to fabricate linear micro-textures with different spacing. Then the AlTiN coatings were subsequently deposited on the polished and textured AISI 1045 steel surfaces. The scratch tests and reciprocating sliding wear tests were conducted to assess the adhesion strength and the wear performance of different coatings. Results revealed that the adhesion of AlTiN coatings deposited on textured substrates with the micro-groove spacing of 150 μm was improved and the anti-adhesive wear property of AlTiN coating against GCr15 steel ball was greatly improved with the aid of ultrasonic rolling texturing pre-treatment than that of the polished one. The contribution of ultrasonic rolling texturing was primarily providing a mechanical locking and a large interfacial contact area, a narrowing difference between the interactions in coating surface energy, an ideal surface residual compressive stress, and a highly active substrate, thus enhancing the adhesion strength and anti-adhesive wear performance of the hard coating/soft substrate system.

Fatigue behaviors of 2205 duplex stainless steel with gradient nanostructured surface layer

Fatigue behaviors of 2205 duplex stainless steel (initially composed of austenite and ferrite phase) with a gradient nanostructured (GNS) surface layer induced by the ultrasonic rolling process (USRP), are investigated in both strain-controlled high-cycle fatigue (HCF) and low-cycle fatigue (LCF) tests. Results showed that the fatigue life is improved in HCF (~5 times longer under 0.3% strain) but decreased in LCF (~53% under 0.8% strain). This is different from the simultaneous enhancement of fatigue behaviors in both HCF and LCF in other materials with GNS. The effect of martensite phase transformation (MPT), residual compressive stress as well as the GNS layers have been investigated to clarify the mechanisms of the fatigue behavior of the USRP samples. Besides the suppression of the surface crack initiation and propagation by residual compressive stress and GNS layers, the MPT during the USRP and cyclic loading processes greatly affects the fatigue behaviors. For HCF tests, not only the hard-brittle martensite phase induced by the USRP process improved the material strength but also the MPT process during cyclic loading absorbed the strain energy released from the crack growth, which increased the HCF life. However, for LCF tests, the hard-brittle martensite phase decreased the ductility of the GNS layer and accelerated the crack growth rate under higher strain amplitude, resulting in the decrement of LCF life. This work presents the first investigation on fatigue behaviors of duplex stainless steel with GNS structure.

Experimental and simulation requirements for residual stress of TC4 titanium alloy based on ultrasonic rolling

The residual compressive stress can improve the fatigue performance and strengthen the material surface. In this paper, TC4 titanium alloy is chosen as the material to measure surface residual stress under different static pressures by automatic gradient stress detection and analysis system. ABAQUS software is used to simulate the variation of residual stress in ultrasonic rolling process. The results reveal that the experimental values and the simulation values are consistent basically. The residual compressive stress reaches its maximum when the static pressure is 1000N. When the static pressure is 1100N ∼ 1200N, the depth of the residual compressive stress layer reaches its maximum.

Effects of ultrasonic rolling on the surface integrity of in-situ TiB2/2024Al composite

Mechanical surface modification is of great significance to the final engineering applications of particles reinforced aluminum matrix composites (PRAMCs) as structural materials. In the present study, in-situ 6 wt% TiB2/2024Al composite was surface-modified by ultrasonic rolling (UR). The surface integrity of the modified composite was comprehensively analyzed and assessed in terms of surface morphology, topography, microstructure, residual stress (RS), strain hardening (SH), and microhardness. Results showed that a single pass of UR treatment with a set of preselected parameters can directly improve the surface finish of the fine-turned samples by 1.5 orders of magnitude. The grain structure in the superficial layer can be effectively refined. High-level and profound compressive residual stress (RSc) and SH were introduced into the sample surface, which can be beneficial for the composite to resist multiple modes of mechanical failures. Besides, a sophisticated finite element (FE) simulation was conducted, which described the UR process fairly well from a numerical viewpoint. It is worth noting that the newly observed discretization mechanism of TiB2 clusters indicates the feasibility of modifying the surface distribution of the reinforcements, which brings about a brand-new and low-cost way to enhance the surface comprehensive mechanical properties of PRAMCs.

Modeling, simulation, and prediction of surface topography in two-dimensional ultrasonic rolling 7075 Al-alloy

Two-dimensional ultrasonic rolling (TDUR) is a kind of surface finishing and deformation strengthening technology, which can improve the surface quality and reduce the surface roughness of the workpiece so as to improve its fatigue resistance. In order to study the formation process of the surface topography of 7075 Al-alloy treated by TDUR, a dynamic model of the rolling system was established based on the principle of TDUR to obtain the dynamic force of the roller on the workpiece during the rolling process. The penetration depth model of the workpiece surface under the action of the static load and longitudinal ultrasonic impact was constructed based on the Hertz contact theory and the metal elastic-plastic deformation theory. Then, the simulation model of surface topography was established using the space transformation theory based on the penetration depth model and the trajectory of the roller. Sequentially, the surface topography was reconstructed with the Z-map method. Using the simulation results, the axial profile curve data was extracted, and the surface roughness was calculated by the surface roughness calculation model. Finally, a designed TDUR experiment was carried out to verify the theoretical surface topography and roughness models. And it shows that the simulated surface topography and predicted roughness are in good agreement with the experimental results. The maximum relative error between the predicted roughness and the experimental results is no more than 9%. Under the experimental conditions, the turning marks can be almost eliminated when the static load Fs is 215 N. At this time, the surface profile height was about 1.5 μm, and the roughness Ra is 0.413 μm, which is 78% lower than that of turning. Therefore, the surface topography and surface roughness models proposed in this work can be used to effectively predict the surface topography and surface roughness of 7075 Al-alloy treated by TDUR.

Effect of Surface Ultrasonic Rolling on Evolution of Surface Microstructure of EA4T Axle Steel

The effect of surface ultrasonic rolling (SUR) on the evolution of surface microstructure of EA4T axle steel is studied by using several microanalysis techniques. Fatigue life of samples after SUR is measured by means of rotary bending fatigue test. After SUR, the surface roughness of the sample is reduced, and the grain size in surface microstructure of the sample is obviously refined. With the increase in SUR passes, the fraction of high-angle grain boundary is increased and the size of ferrite grains is decreased. After SUR with 50 passes, the size of ferrite grains at sample surface is about 100 nm. The refinement mechanism of ferrite grains includes four steps: First, a large amount of dislocations is formed in ferrite. With the increase in strain, the tangled dislocations change into dislocation cells. As the strain continued to increase, the dislocation cells transform into low-angle grain boundary. Finally, the low-angle grain boundary gradually changes to high grain boundary to contribute to the refinement of ferrite grains. The fatigue life of the sample tested at 500 MPa after SUR with one pass is about 23 times higher than that of the sample after turning. However, after SUR with 10, 30 and 50 passes, the excessive plastic deformation reaches ductility limit to cause the surface damage during SUR. The surface damage, as the fatigue cracks initiation sites, can reduce fatigue life.

New approach towards the machining process after laser cladding

As a chip-free and high-efficiency three-dimensional forming technology, laser cladding has been successfully applied in the green manufacturing and remanufacturing of some high-end engineering parts/components. However, in most cases, cladding coatings need to be machined due to the poor surface finishing by sole laser cladding technique. The study aims to explore an effective way to replace the current machining process after laser cladding, which is supposed to be incapable of satisfying the various technical requirements of some high-demand engineering parts/components. With this purpose, three new surface strengthening processes, i.e. ultrasonic roller burnishing at ambient temperature (URB), ultrasonic roller burnishing at warm temperature (UWB), and UWB coupled with continuous heat treatment (UWB/HT), were proposed and comparatively explored. The contact stresses between the contact pairs in URB were calculated and analyzed in theory. A set of ultrasonic roller burnishing equipment was self-manufactured to perform the experiment. Comparing with the conventional process, the three new processes were evaluated mainly from aspects of surface finishing, the adhesion behavior and corrosion resistance of the finished surface. Summarily, ultrasonic warm burnishing coupled with continuous heat treatment (UWB/HT) is considered to have the greatest potential to achieve the effective machining after laser cladding with excellent surface finishing over the other two strategies, which is expected to further advance the application of laser cladding technique particularly in the fabrication of some high-demand products serving in harsh conditions.

Effect of Surface Ultrasonic Rolling Treatment on Rolling Contact Fatigue Life of D2 Wheel Steel.

A GPM-30 fatigue machine was used to investigate the influence of surface ultrasonic rolling (SURT) on the rolling contact fatigue (RCF) life of D2 wheel steel. The experimental results present that the RCF life of the grinding processing sample is 4.1 × 105 cycles. During the RCF process, the flaking of the fine grain layer and high surface roughness of the grinding processing sample cause the production of RCF cracks. When the samples are treated by SURT with 0.2 MPa and 0.4 MPa, the RCF life is 9.2 × 105 cycles and 9.6 × 105 cycles, respectively. After SURT, the surface roughness of the samples is reduced, and a certain thickness of gradient-plastic-deformation layer and a residual-compressive-stress layer are produced. These factors lead to the improvement of the RCF property. However, when the static pressure increases to 0.6 MPa during SURT, the RCF life of the sample is reduced during RCF testing. The micro-cracks, which are formed during SURT, become the crack source and cause the formation of RCF cracks, decreasing of the RCF life.

The Optimal Processing Parameters of Radial Ultrasonic Rolling Electrochemical Micromachining-RSM Approach.

Radial ultrasonic rolling electrochemical micromachining (RUR-EMM) is a new method of electrochemical machining (ECM). By feeding small and rotating electrodes aided by ultrasonic rolling, an array of pits can be manufactured, which is called microstructures. However, there still exists the problem of choosing the optimal machining parameters to realize the workpiece machining with high quality and high efficiency. In the present study, response surface methodology (RSM) was proposed to optimize the machining parameters. Firstly, the performance criteria of the RUR-EMM are measured through investigating the effect of working parameters, such as applied voltage, electrode rotation speed, pulse frequency and interelectrode gap (IEG), on material removal amount (MRA) and surface roughness (Ra). Then, the experimental results are statistically analyzed and modeled through RSM. The regression model adequacies are checked using the analysis of variance. Furthermore, the optimal combination of these parameters has been evaluated and verified by experiment to maximize MRA and minimize Ra. The results show that each parameter has a similar and non-linear influence on the MRA and Ra. Specifically, with the increase of each parameter, MRA increases first and decreases when the parameters reach a certain value. On the contrary, Ra decreases first and then increases. Under the combined effect of these parameters, the productivity is improved. The experimental value of MRA and Ra is 0.06006 mm2 and 51.1 nm, which were 0.8% and 2.4% different from the predicted values.

Tribological properties of textured surfaces fabricated on AISI 1045 steels by ultrasonic surface rolling under dry reciprocating sliding

This paper aims to demonstrate an effective surface texturing fabrication approach in improving the tribological properties of AISI 1045 hardened steel surface. Ultrasonic surface rolling technology was employed to fabricate strengthened surface and line array textured surface on substrates. Characterizations such as morphology, surface residual stress, microhardness, elasticity modulus and surface roughness with different surfaces were examined. Ball-on disk reciprocating sliding dry friction tests were performed. Results indicate that textured surfaces with good quality and accuracy were fabricated by ultrasonic rolling treatment. Increased microhardness and residual compressive stress of surfaces treated by ultrasonic rolling were obtained. Textured surfaces played a positive role in improving tribological performance. The surface with line array textures presented the best efficiency of anti-friction and anti-wear while sliding against GCr15 steel ball, the friction coefficient and sliding ball wear rate decreased by 79% and 98%, respectively, compared with the polished ones. Additionally, the possible tribological mechanism of ultrasonic rolling texturing was discussed. Multistage structure with mm/micro/nano-textures combined with a strengthened layer caused by ultrasonic rolling technology, increased the mechanical and tribological properties of surfaces. The synergistic combination of strengthened layer and texture structure could contribute to prolonging the friction and wear life of materials.

Influence of Surface Ultrasonic Rolling on Microstructure and Corrosion Property of T4003 Ferritic Stainless Steel Welded Joint

In this paper, the effect of surface ultrasonic rolling treatment (SURT) on surface properties of T4003 cold metal transfer (CMT) welded joints was studied. Surface topography and microstructure changes of the welded joint surface before and after SURT were observed by optical microscope and scanning electron microscope. The hardness and residual stress distribution of welded joint were measured by a microhardness tester and X-ray diffractometer. The change of corrosion resistance of welded joints was studied by electrochemical polarization curve measurement. The results show that surface roughness (Ra) of the weld zone, heat affect zone (HAZ), and base metal after SURT was reduced to 0.320 μm, 0.156 μm, and 0.227 μm, respectively, and surface morphology became smooth. The plastic deformation layer and working hardening layer were formed at the welded joint. The degree of plastic deformation of the weld zone was more serious than that in the base metal, and grains in weld zone was obviously refined. The thickness of plastic deformation layer was about 100 μm. The surface hardness in the weld zone was highest, which is about 420 HV. The refinement of grains and the increase of surface hardness can improve the fatigue life of welded joint. After SURT, the residual stress in the welded joint changes from residual tensile stress to residual compressive stress, which can also improve fatigue life of the welded joint. Surface corrosion resistance of welded joints after SURT was improved due to smooth surface and the formation of fine grains layer.

Microstructure and mechanical properties of high entropy CrMnFeCoNi alloy processed by electopulsing-assisted ultrasonic surface rolling

In this paper, the CrMnFeCoNi high entropy alloy has been processed by electopulsing-assisted ultrasonic surface rolling. The strength of the high-entropy alloy has been greatly improved while it still has good plasticity, attributing to the approximate gradient structure can be formed by ultrasonic rolling, and the plastic deformation can be adjusted by electric pulse.

Residual stresses in high-speed two-dimensional ultrasonic rolling 7050 aluminum alloy with thermal-mechanical coupling

In order to achieve the high-efficiency and high-quality anti fatigue manufacturing of 7050 aluminum alloy, high speed ultrasonic machining was introduced into two-dimensional ultrasonic rolling, the simulation and experiment of high-speed two-dimensional ultrasonic rolling (HTUR) 7050 aluminum alloy were carried out. The evolution of temperature field, stress field and strain field in HTUR process were simulated, and the evolution of the surface flow stress with thermal-mechanical coupling was analyzed. The surface residual stress and microstructure of the cross section of sample after HTUR treatment were characterized by X-ray diffraction and scanning electron microscope (SEM). The results show that HTUR treatment can form a gradient strengthened layer and introduce beneficial residual compressive stress in the surface layer of 7050 aluminum alloy. In HTUR process, the surface temperature field, equivalent stress and equivalent strain field are non-uniformly distributed, and the changes of the temperature, equivalent stress and equivalent strain are not completely synchronous with time. The residual stress with thermal-mechanical coupling is slightly less than that of without thermal-mechanical coupling, and close to the experimental results. The temperature has a little negative effect on the residual stress. The performance of the specimen still mainly depends on the cold plastic deformation in HTUR process, so such technology can realize high-efficiency ultrasonic hardening treatment of 7050 aluminum alloy on the premise of ensuring fatigue strengthening.

Effect of Ultrasonic Rolling Pretreatment on Corrosion Resistance of Micro-arc Oxidation Coating of Mg-alloy

Effect of Ultrasonic Rolling Pretreatment on Corrosion Resistance of Micro-arc Oxidation Coating of Mg-alloy

Surface characteristics and corrosion behavior of TC11 titanium alloy strengthened by ultrasonic roller burnishing at room and medium temperature

A roller tip was utilized in a set of self-fabricated ultrasonic burnishing equipment. Ultrasonic roller burnishing with/without heat treatment was proposed and investigated in the surface strengthening of TC11 titanium alloy material. Experimental research together with finite element analysis were carried out to perform the study. Three treatments, including conventional turning, ultrasonic roller burnishing at ambient temperature (URB) and ultrasonic roller burnishing at medium temperature (URB/HT), were comparatively evaluated in term of surface integrity and corrosion resistance of the treated sample. As a result, compared with URB, the surface of TC11 alloy treated by URB/HT had better surface finishing, which significantly improved corrosion resistance, and thus the surface of TC11 alloy was strengthened. The good performance of URB/HT was attributed to the combined effect of the high frequency dynamic impact from URB and the thermoplastic effect of the heat treatment. Owing to the excitation of the ultrasonic vibration during URB, an oscillating stress wave formed and propagated deep inside the being treated material, and the heat treatment in URB/HT case was supposed to accelerate this sort of stress propagation. Meanwhile, both the heat treatment and the dynamic oscillating stress wave facilitated the deformation of the surface layer.

Experiment and simulation study on influence of ultrasonic rolling parameters on residual stress of Ti-6Al-4V alloy

In order to optimize the process parameters of high residual stress on the surface of Ti-6Al-4V alloy sheet which is obtained after ultrasonic rolling, the effects of static pressure, ultrasonic rolling amplitude and time on surface residual stress are investigated. Firstly, the ultrasonic rolling experiment was carried out under different static pressure conditions, and then the distribution of residual stress on the specimen surface was measured. Further, based on Abaqus/Explicit, a three-dimensional finite element (FE) model was established to simulate the ultrasonic rolling process. The distribution of residual stress on the surface was also analyzed with different static pressure, ultrasonic rolling amplitude and time. The reliability of the model under different static pressure parameters was verified in the aspects of residual stress, size and thickness of the hardening layer. The simulation results were in good agreement with the experimental results. The FE results show that the compressive residual stress increased first and then decreased along with the rolling depth direction, and then transformed into tensile residual stress. The residual stress increased with the increase of static pressure and amplitude, and it decreased first and then increased with the increase of time. According to the FE results, higher residual stress is obtained when the static force, ultrasonic amplitude and time are set to 1100 N, 10 μm and 0.065 s, respectively, which contributes to the improvement of fatigue life. This study could guide the selection of the processing parameters of the ultrasonic surface rolling in Ti-6Al-4V alloy.

Effects of Ultrasonic Bending Vibration Introduced by an L-Shaped Ultrasonic Rod on the Microstructure and Properties of a 1060 Aluminum Alloy Strip Formed by Twin-Roll Casting.

In order to achieve the industrial application of ultrasonic energy in the continuous casting and rolling production of aluminum alloy, a new type of L-shaped ultrasonic rod was used to introduce an ultrasonic bending vibration into the aluminum melt in the launder during the horizontal twin-roll continuous casting and rolling process of a 1060 aluminum alloy. The effects of the ultrasonic bending vibration on the microstructure and properties of the 1060 aluminum alloy cast rolling strip and its subsequent cold rolling strip were studied experimentally, and the effect of the ultrasonic-assisted refining with different amounts of Al-Ti-B refiner was explored. The results show that under the same addition amount of Al-Ti-B refiner, the ultrasonic bending vibration can refine the grains of the cast rolling strip, make the distribution of precipitates more uniform, reduce the slag inclusion defects, and improve the mechanical properties to a certain extent. The microstructure and properties of the ultrasonic cast rolling strip with 0.18 wt% Al-Ti-B refiner or 0.12 wt% Al-Ti-B refiner are better than those of the conventional cast rolling strip, but the microstructure and properties of the ultrasonic cast rolling strip with 0.09 wt% Al-Ti-B refiner are slightly worse than those of the conventional cast rolling strip. Moreover, after cold rolling, the effect of the ultrasonic bending vibration on the improvement of the microstructure and properties of the aluminum alloy strip is inherited. A comprehensive analysis shows that the use of ultrasonic energy in this paper cannot completely replace the effect of the Al-Ti-B refiner, but it can reduce the addition amount of the Al-Ti-B refiner by 1/3.

Experimental study on surface integrity of ultra-high-strength steel by ultrasonic hot rolling surface strengthening

Ultrasonic hot rolling, a newly developed technology of surface modification and multi-field strengthening, is used for surface treatment of ultra-high-strength steel (45CrNiMoVA) at different temperatures, with the temperature as high as 300 °C. Based on the thermal softening and strain rate sensitivity of ultra-high-strength steel, the formation and evolution of surface integrity including surface topography, residual stress and microstructure were analyzed after ultrasonic hot rolling. It is found that ultrasonic hot rolling can still achieve good surface finishing effect, in which rolling pressure and ultrasonic impact play a key role. The residual stress amplitude and the depth of the affected layer are larger under the ultrasonic hot rolling, which is the influence of the ultrasonic impact and the thermal field together. In the temperature range of 150 °C–200 °C, the surface integrity after ultrasonic hot rolling is the best. The reason for the more stable residual stress after ultrasonic hot rolling is work hardening, age hardening, and precipitation hardening.

Simulation Design of 30KHz Ultrasonic Rolling Tool Head

In order to explore the types of ultrasonic rolling tool head used in ultrasonic rolling and finishing processing device, ANSYS Workbench is taken as a tool to simulate the machining process of ultrasonic rolling processing through transient dynamic analysis, and the maximum residual stress distribution and stress concentration of 45 steel workpiece are analyzed. Based on the simulation result, the ball-type ultrasonic rolling tool head is selected in this work. In addition, the transient dynamics module of ANSYS Workbench is also used to simulate the ultrasonic rolling tool head of different structure parameter, in that way, the accurate and reasonable structure parameters of rolling components of ultrasonic rolling tool head can be achieved. The results of this work show that a ball-type ultrasonic rolling tool head of a diameter of 8mm can make the maximum residual stress minimum and stress concentration slightest under the condition of normal processing of the 45 steel workpiece. In other words, it suggests that this ultrasonic rolling tool head can produce the best surface quality of 45 steel workpiece.

Effect of surface nanocrystallization on low-temperature gas carburization for AISI 316L austenitic stainless steel

In this paper, the effect of surface nanocrystallization on low-temperature gas carburization (LTGC) for AISI316L austenitic stainless steel was studied. Surface ultrasonic rolling processing (SURP) was used to prepare the nanostructured surface layers and then the un-SURP and SURP specimens were treated by LTGC at 430 and 470 for 10 h, 20 h and 30 h. After the SURP treatment, the thickness of plastic deformation layer was about 350 μm and the compressive residual stress generated on the surface was −857.67 ± 55.54 MPa. In addition, the surface roughness decreased obviously. The SURP treatment has a negative effect on the thickness of the carburized layer but it significantly increases the carbon concentration, nanohardness, elastic modulus and compressive residual stress of the outer surface of the carburized layer. However, these parameters then rapidly decreased along the depth of the carburized layer. Both SURP and LTGC could significantly strengthen the surface of AISI316L steel and the combination of the two would achieve better surface properties.