Ultrasonic Surface Rolling Treatment Research Articles

Effect of ultrasonic surface rolling on the friction and wear properties of 8620H carburized steel at elevated temperatures

The surface strengthening treatment of 8620H carburized steel was carried out by ultrasonic surface rolling (USR) process, and the samples with and without the treatment were subjected to friction and wear experiments at 25°C, 100°C, and 150°C. The experimental results showed that the samples with USR treatment had higher surface hardness, lower surface roughness, deeper hardened layer depth, and higher surface residual compressive stress than the samples without USR treatment. Meanwhile, the wear degree of the samples deteriorated as the temperature increased, but the anti-wear performance of the samples with USR treatment increased by 52.9%, 29.8%, and 14.9% compared with the samples without USR treatment at 25°C, 100°C, and 150°C, respectively, indicating that the USR treatment still had a better strengthening effect at high temperatures.

Effect of Ultrasonic Surface Rolling on the Fretting Wear Property of 7075 Aluminum Alloy

This paper investigates the effect of ultrasonic surface rolling (USR) on the fretting wear properties of the 7075 aluminum alloy. A white light interferometer, Vickers hardness tester, and X-ray diffractometer were employed to comparatively analyze the variations in surface roughness, hardness. and grain size before and after the USR treatment. The fretting tests were carried out under oil lubricated and dry fretting conditions, using a ball-on-flat contact tangential fretting tester. The worn surface morphology, wear debris, and chemical composition were analyzed using an optical microscope (OM), a scanning electron microscope (SEM), and X-ray photoelectron spectroscopy (XPS), etc. The results revealed that after USR treatment, the surface roughness was reduced by 90%, the hardness was increased by 13HV, and the grains were refined. Moreover, the wear was reduced under oil lubrication conditions but increased under dry fretting conditions. It can be concluded that the microstructure and mechanical properties of the 7075 aluminum alloy surface can be enhanced by the USR treatment. The improved fretting performance in oil should be attributed to the increased surface hardness, which helps reduce abrasive wear and plastic deformation. However, under dry fretting conditions, the wear was increased due to the presence of hard debris particles that peel off from the USR-treated surface, leading to aggravated abrasion.

Study on Microstructure Evolution Mechanism of Gradient Structure Surface of AA7075 Aluminum Alloy by Ultrasonic Surface Rolling Treatment.

The materials with grain size gradient variation on the surface, which were prepared with mechanical-induced severe plastic deformation, always show high resistance to high and low cycle fatigue and frictional wear because of their good strength-ductility synergy. The ultrasonic surface rolling treatment (USRT) has the advantages of high processing efficiency, good surface quality, and large residual compressive stress introduced to the surface after treatment. The USRT was used to prepare aluminum alloy (AA7075) samples with a surface gradient structure; meanwhile, the microstructural evolution mechanism of the deformation layers on the gradient structure was studied with XRD, SEM, and TEM. The microstructure with gradient distribution of grain size and dislocation density formed on the surface of AA7075 aluminum alloy after USRT. The surface layer consists of nanocrystals with random orientation distribution, and high-density dislocation cells and subgrains formed in some grains in the subsurface layer, while the center of the material is an undeformed coarse-grained matrix. The results show that the dislocation slip dominates the grain refinement process, following the continuous cutting and refinement of dislocation cells, subgrains, and fragmentation of the second precipitates. This study systematically clarified the mechanism of grain refinement and nanocrystallization on the surface of high-strength aluminum alloys and laid a theoretical foundation for further research on mechanical behavior and surface friction and wear properties of high-strength non-ferrous materials with gradient structure.

Rolling contact fatigue behaviors of 25CrNi2MoV steel combined treated by discrete laser surface hardening and ultrasonic surface rolling

In this paper, the effect of a novel surface treatment method that combing the discrete laser surface hardening (DLSH) and ultrasonic surface rolling (USR) on the material properties (surface roughness, microstructures, microhardness and residual stress) and rolling contact fatigue (RCF) behaviors of 25CrNi2MoV steel were investigated. A continuous-wave diode laser with a maximum output power of 2 kW was used to fabricate four different types of DLSH density samples with a size of Φ42 mm × 6 mm. The results showed that the combined USR treatment improved the surface quality (including roughness and oxide layer) of the DLSH samples, increased surface hardness, and obtained a beneficial surface compressive residual stress of up to 1240 ± 91 MPa. The severe plastic deformation introduced a gradient nano/ultrafine grain layer on both hardened zone (HZ) and substrate zone (SZ) surfaces of DLSH group samples, and the deformation depth decreased with the increase of DLSH density within 24.3–65.3 μm. Accumulation of plastic deformation below and around the HZ edge resulted in a gradient drop in hardness from HZ to SZ, which helps to relieve the occurrence of stress concentration at the surface HZ edge. Benefit from favorable factors, the RCF life of combined treated samples with hardened spot densities of 28%, 50%, 79% and 100% was increased by 82.2%, 123%, 143.6% and 171.9% compared with that of the untreated samples, respectively. After USR treatment, the failure mode within the SZ changed from spalling to delamination, but it remained as spalling failure within the HZ.

Effect of ultrasonic surface rolling on microstructural evolution and fretting wear resistance of 20CrMoH steel under different quenching temperatures

The influence of ultrasonic surface rolling (USR) treatment on microstructures, residual stress, microhardness and fretting wear behaviors of 20CrMoH steel under different quenching temperatures (740, 840 and 940 °C) was systematically investigated. The results indicated that the maximum hardening layer depth of the USR treated specimen quenched at 740 °C was about 130 μm, accompanied by grain refinement and high-density dislocations. Simultaneously, the microhardness was mostly increased by 212 HV0.2 and the highest surface residual compressive stress (RCS) was up to −649 MPa. The fretting wear mechanisms of the specimens in different treatment states were mainly delamination and oxidative wear. The volume wear loss of the USR treated specimen quenched at 940 °C was reduced by 48% compared with the untreated specimen quenched at 740 °C. This could be benefited from the protection of the oxide layer and the effective prevention of cracks source by the higher surface RCS, as well as the grain refinement and the increase in dislocations caused by USR treatment.

Effects of ultrasonic surface rolling and plasma nitriding on microstructure and properties of 690TT alloy

To enhance surface mechanical properties of 690TT alloy, a surface hardening layer was obtained by ultrasonic surface rolling treatment (USRT) and plasma nitriding (PN). The surface morphology, mechanical properties, wear performances and corrosion performance were investigated by XRD, TEM, using a hardness tester, tensile tester, wear tester and electrochemical workstation in simulated sea water, respectively. The results showed that USRT as the pre-treatment can strengthen the performance of PN treatment samples. The USRT + PN treated sample showed existence of dislocation tangles and twin grains. Corrosion resistance in simulated sea water was enhanced. The surface microhardness increased by 180% compared with the untreated sample, the cross-sectional hardness gradually decreased till the depth of 1 mm. The tensile strength increased by a factor of 90% while the elongation decreased by only 40%. The wear scar was narrower and shallower than the untreated sample and the wear rate was significantly dropped. This paper aims at providing a new method for surface strengthening of 690TT alloy.

Experimental study on aluminum bronze coating fabricated by electro-spark deposition with subsequent ultrasonic surface rolling

Aluminum bronze coatings were prepared on the as-cast substrate of the same material by electro-spark deposition (ESD), and the coatings were treated by ultrasonic surface rolling (USR). The effects of USR on the microstructural, mechanical, and tribological properties of the ESD coatings were investigated. The microstructure, phase composition, nanoindentation, microhardness, surface residual stress, and tribological properties of the coatings were experimentally determined and characterized in detail. The USR treatment with different static pressures (1.0 MPa, 2.5 MPa, 4.0 MPa) was employed to reveal the mechanism of microstructure evolution and surface modification. The results showed that the original columnar crystal structure of the coatings treated by USR was deflected, elongated, and even broken, resulting in the grain refinement of the coatings. The hole defects were healed after USR2.5 treatment. The phase composition of the coatings changed from β′ (Cu3Al) phase to α (Cu) and κ (Fe3Al) phase because of the heat released at USR. The nanohardness, static creep resistance, and microhardness of the ESD coatings were effectively promoted by USR. The nano-hardness of the ESD coating after USR4.0 treatment (4.4 GPa) was 1.38 times and 2.2 times that of the ESD coating and the as-cast alloy respectively, and the creep displacement (5.193 nm) was 27.2% and 18.5% that of the ESD coating and the as-cast alloy respectively. The residual tensile stress of the ESD coatings was eliminated after USR treatment and converted into the residual compressive stress. The surface residual stress of the ESD coating after USR2.5 was −337.16 MPa. After USR2.5 treatment, the wear loss of ESD coating reduced by about 1/2, which was attributed to the healing of hole defects, residual compressive stress, and the increase of the hardness.

Corrosion behaviour of nanocrystallines alloy 690 at high-temperature and high-pressure in simulated PWR secondary environment

The influence of ultrasonic surface rolling treatment (USRT) on the corrosion behaviour of nanocrystallines (NC) alloy 690 at high temperature and high pressure in simulated PWR secondary environment was performed by using Raman spectrometer, X-ray photoelectron spectrometer (XPS) and scanning electron microscopy (SEM). After USRT, the average size and the thickness of NC surface layer could reach 55 nm and 1 μm, respectively. Electrochemical measurements showed that the oxide film on the surface of NC alloy 690 was denser and more complete compared with coarse grained (CG) samples. The corrosion tests in ethanolamine (ETA) solution illustrated that the fine oxide particles were evenly distributed on the oxide film of NC alloy 690. The corrosion potential increased from −364 mV to −229 mV, while the corrosion current density dropped from 18.07 × 10−8 mm2 A cm−2 to 8.842 × 10−8 mm2 A cm−2 after USRT. By analysis, the inner layer of oxide film consisted of Cr2O3, NiFe2O4, and FeCr2O4, while Ni hydroxides formed the major part of the outermost layer of film. A growth model of oxide films on alloy 690 at high-temperature and high-pressure in stimulated PWR secondary environments was proposed and discussed.

Effect of Ultrasonic Surface Rolling on Dry Sliding Tribological Behavior of Ductile Iron Under Different Normal Loads

This study emphasizes the effect of ultrasonic surface rolling (USR) on the surface roughness, hardness, and tribological properties of ductile iron under different normal loads. Results revealed that surface roughness was reduced by 96% and surface hardness increased by 37.8% after USR treatment. By increasing normal load, the average friction coefficient of the USR-treated specimens decreased, but the wear rate of both USR-treated and untreated specimens increased, mainly because the dominant wear mechanism changed. The average friction coefficient of the untreated specimen (~ 0.32) was much higher than the USR-treated specimen (~ 0.24) when the normal load was 30 N. However, the wear rate of the USR-treated specimen was larger than that of the untreated specimen when the normal load was greater than 20 N because the higher hardness abrasive particles on the worn surface of the USR-treated specimen not only accelerated abrasive particle wear, but also caused more severe adhesive wear.

Microstructure and high-temperature wear behaviour of Inconel 625 multi-layer cladding prepared on H13 mould steel by a hybrid additive manufacturing method

To improve the high-temperature performance of a hot-working mould, high-temperature wear-resistant multi-layer laser cladding was prepared on the forming surface of the mould by a hybrid additive manufacturing (HAM) method. First, an Inconel 625 multi-layer cladding was fabricated on the H13 mould steel by laser cladding. Then, the multi-layer laser cladding was milled by CNC. Finally, the milled multi-layer cladding was subjected to ultrasonic surface rolling (USR) treatment. The microstructure and high-temperature wear behaviour of the multi-layer cladding prepared by HAM were studied using SEM, EDS, and a high-temperature tribometer. The results show that the multi-layer laser cladding after USR has a smooth nanolayer. The surface roughness is below 0.15 μm. The multi-layer cladding has better high temperature wear resistance than the substrate. The microstructure of the multi-layer cladding from the surface to the substrate is composed of coaxial, columnar, and dendritic grains. After USR treatment, the dendritic grains are grown in the processing direction and significantly refined.

Effects of ultrasonic surface rolling on fretting wear behaviors of a novel 25CrNi2MoV steel

In this work, the ultrasonic surface rolling (USR) with different rolling loads were introduced to 25CrNi2MoV steel. And the microstructure and fretting wear behaviorswere evaluated. Results showed that USR treatment can significantly generate plastic deformation in material surface layer. The sample treated by 1000 N showed the lowest coefficient of friction and wear volume in the USR treated samples. The wear mechanism of untreated sample was adhesive wear, and the USR treated samples were abrasive wear.

Rolling contact fatigue properties of ultrasonic surface rolling treated 25CrNi2MoV steel under different lubricant viscosities

Ultrasonic surface rolling (USR) treatment was subjected to the 25CrNi2MoV shaft steel surface. The rolling contact fatigue (RCF) properties of treated samples under different lubricant viscosities were investigated. Results showed that the USR treatment significantly refined the surface grains, improved the surface hardness and generated a compressive residual stress (CRS) field in the subsurface layer. Reduced surface roughness changed the lubrication regime between contact pairs and relieved the local surface stress concentration. USR treatment is an effective way to improve the RCF life under high lubricant viscosity. Moreover, the dominant failure mode of USR treated sample was delamination.

Microstructures and rolling contact fatigue behaviors of 17Cr2Ni2MoVNb steel under combined ultrasonic surface rolling and shot peening

A novel surface treatment method of combining ultrasonic surface rolling (USR) and shot peening (SP) in different sequences was proposed. The microstructures and rolling contact fatigue (RCF) behaviors of 17Cr2Ni2MoVNb steel were investigated after USR treatment, SP treatment and combined (USR + SP + USR) treatment. Results showed that the combined treatment can significantly generate ultra-fine grains, improve surface microhardness and induce high intensity residual compressive stress in material surface layer. The samples after combined treatment with the lowest surface roughness exhibited the maximum mean RCF life of 6.610 × 106 cycles and the fatigue damage mechanism was spalling.

Effect of Ultrasonic Surface Rolling Treatment on Corrosion Behavior of Alloy 690

The nanograins (NG) on the top surface layer of alloy 690 were successfully prepared by ultrasonic surface rolling treatment (USRT). The average grain size of NG alloy 690 was 55 nm, and the thickness of the NG surface layer was about 1 μm. Meanwhile, the surface roughness was significantly reduced after surface nanocrystalliztion. The corrosion behavior of alloy 690 before and after USRT was studied in a secondary side environment containing chloride. Electrochemical corrosion experiments demonstrated that the passive film generated by USRT was denser than that formed on coarse-grained (CG) alloy 690. Pitting corrosion was prone to occur in grain boundaries of CG alloy 690, and the pits on the surface of NG alloy 690 were smaller than those generated on CG alloy 690 after 1000 h of an immersion experiment.

Enhanced Corrosion Behavior and Mechanical Properties of Al-Zn-Mg-Cu Sheet Alloy by Ultrasonic Surface Rolling Treatment

An outstanding enhancement of corrosion resistance and mechanical properties of Al-Zn-Mg-Cu alloy was achieved by ultrasonic surface rolling treatment (USRT). The results showed that the precipitates were dissolved into Al matrix, the deformation texture was weakened, and the nanometer/micron/nanometer lamination structure was formed after USRT, which enhanced the corrosion resistance and provided the alloy with an excellent ultimate tensile strength of 578.1 MPa, tensile yield strength of 517.6 MPa and elongation to fracture of 8.5 pct.

Effects of ultrasonic rolling on surface performance of 7B85-T6 alloy

ABSTRACTSurface nanocrystallization (SNC) of 7B85-T6 alloy was obtained through ultrasonic surface rolling treatment (USRT) to improve the surface comprehensive performance of the alloy. The effects of USRT parameters on microhardness, surface roughness, and corrosion behavior of the 7B85-T6 alloy were investigated systemically. The optimal process parameters were obtained in the USRT process with the pressure of 0.3 MPa and the preloading depth of 0.2 mm. The microhardness and surface roughness of the alloy increased by 60.96% and reduced by 79% compared to the original alloy, respectively. Meanwhile, the corrosion resistance was improved in the 7B85-T6 alloy after USRT. The corrosion product film of the alloy after USRT was denser than that of the original alloy, which was attributed to the combined action between microstrain and nanograin. The phenomenon led to the enhanced surface activity and the formation of continuous dense Al2O3 oxides of the alloy.

Study on the tensile and fatigue properties of the heat-treated HIP Ti-6Al-4V alloy after ultrasonic surface rolling treatment

This paper was mainly study on the tensile and fatigue performance change of HIP Ti-6Al-4V alloy treated by heat treatment combined with ultrasonic surface rolling (USR). Based on the use of heat treatment process to improve the microstructure and increase the mechanical properties, then USR treatment was used to further refine the grains in material surface modification layer and increase the residual stress and microhardness. The results showed that the plastic deformation layer of material surface was comparatively thin, and had a poorer grain refining effect. The SAED had the discontinuous ring spot pattern. Compared with the cut sample, the compressive residual stress value was −724 ± 23 MPa and increased by 50%, surface roughness was reduced to 0.17 ± 0.025 μm and decreased by 74.6%, and surface microhardness were increased to 467 ± 7.4 HV and increased by 43.6%. Finally, the tensile and yield strength increased by 3.6% and 3%, and the rate of reduction in area and the elongation decreased by 12.9% and 3.4% respectively. The fatigue strength at the high-cycle mechanism changed from 530 MPa to 570 MPa. The fatigue lifetime was increased by several times at the cycle stress of 700 MPa, and the only initial point of fatigue crack was located at the subsurface of the sample. Therefore this method could effectively improve tensile strength, fatigue strength and fatigue lifetime of HIP Ti-6Al-4V alloy.

Corrosion behaviour of nanocrystallines 304 stainless steel in simulated secondary side environment

Surface nanocrystallisation (SNC) was prepared on the top-surface layer of 304 stainless steel by ultrasonic surface rolling treatment (USRT). Meanwhile, martensite transformation also occurred during grain refinement, and the surface microhardness increased more than tripled after USRT. The corrosion resistance of nanocrystallines (NC) 304 stainless steel was notably better than that of untreated samples in simulated pressurised water reactor (PWR) secondary water by potentiodynamic polarisation curves, electrochemical impedance spectroscopy and Mott-Schottky curves. Meanwhile, the corrosion mechanism was discussed before and after USRT by X-ray photoelectron spectroscopy (XPS). The main reason is due to the formation of denser Cr(OH)3 protective film and the reduction of the porous structure Fe2O3 content in the NC 304 stainless steel.

Effect of ultrasonic surface rolling on microstructure and rolling contact fatigue behavior of 17Cr2Ni2MoVNb steel

Ultrasonic surface rolling (USR) treatment with different rolling loads (600, 800, 1000 and 1200 N) was introduced to the 17Cr2Ni2MoVNb steel. The microstructure and rolling contact fatigue (RCF) behavior after USR treatment were investigated. Results pointed out that grain refinement existed in the surface-modified layer of the material after USR treatment. The treatment with rolling load at 1200 N could produce a best surface enhancement effect, compared to the untreated sample, the microhardness of USR treated sample (25 kHz, 1200 N) was increased from 795 HV0.2 to 905 HV0.2, with an increase by 13.8%. The surface residual compressive stress was increased from −334 MPa to −527 MPa, with an increase by 57.8%. However, the samples treated at 1200 N increased the surface roughness and caused some surface cracks on the rolled surface, which was an important factor to reduce the fatigue life. The results from RCF tests showed that USR treatment with rolling load at 1000 N exhibited the maximum mean life of 3.71 × 106 cycles.

Enhanced corrosion resistance of a Cu[sbnd]10Ni alloy in a 3.5 wt% NaCl solution by means of ultrasonic surface rolling treatment

Cu10Ni alloy with a gradient nano-structured surface layer was synthesized by ultrasonic surface rolling process (USRP). The microstructure and mechanical properties of the nanosurface layer were characterized by X-ray diffractometry (XRD), microhardness testing, scanning electron microscope (SEM) and transmission electron microscope (TEM). The corrosion behavior of the USRPed and coarse-grained (CG) Cu10Ni alloy in a 3.5 wt% NaCl solution was investigated. The results showed that the topmost surface possessed an average grain size of 70 nm, and the corresponding surface hardness increased by 80% after USRP treatment. Additionally, the electrochemical test results showed that the USRPed Cu10Ni alloy exhibits enhanced corrosion resistance relative to that of the CG sample in a 3.5 wt% NaCl solution. The higher corrosion resistance of the nanograined Cu10Ni alloy was attributed to the nanograined surface promoting the formation of a passivation film on the surface during the corrosion process, which can effectively prevent further corrosion. This study demonstrates that the hardness properties and corrosion resistance of Cu10Ni alloys can be improved simultaneously by means of surface nanocrystallization.