Laser Cladding Samples Research Articles

A comparative study on corrosion and mechanical properties of laser-cladded X2CrNiMoN22-5-3 duplex stainless steel on 42CrMo4 steel substrate

Duplex stainless steel is an alloy that combines the advantages of austenitic stainless steel and ferritic stainless steel. It has excellent corrosion resistance, high strength, and good weldability. One of the main problems in marine shafts using X2CrNiMoN22-5-3 Duplex Stainless Steel (2205) is bending and warping over time. In this study, 42CrMO4 (MO40) steel was clad with 2205 dual-phase steel using direct metal deposition with wire to simultaneously utilize the mechanical properties, and corrosion resistance. Perform metallographic imaging, corrosion test, and tensile test, to maintain the quality of the cladding. The results show that the corrosion potential of 2205 cladding layer is −0.65 (including semi-passive zone), while the control sample of 2205 had a corrosion potential of −0.26, and the MO40 substrate had a corrosion potential of −0.1 (highlighting the advantage of the cladding in thermodynamics term). EIS results showed that the REISMO40=2325Ω, REIS2205=24315Ω, and REIS2205cladded=216133Ω. The corrosion rate for the substrate, control sample, and laser-clad sample were 0.33, 0.15, and 0.00095 mm/year, respectively, without significant loss in tensile properties. The final strength for MO40(with 2205 clad) reaches 672 MPa with a 14 % decrease from 788 for MO40. In this case, we still have a 36 % increase in strength compared to the 2205 sample. It seems that the bent problem of the pure 2205 marine shaft can be solved completely in this case and continues to be solved in our ongoing work.

Surface Modification and Corrosion Performance of Laser Cladded Co–Ni on Ti–6Al–4 V in 0.5 M H2SO4 Environment

This study investigates the laser cladding of Co and Ni powders onto Ti–6Al–4 V substrates, varying the admixed percentages while adjusting laser processing parameters. The influence of nickel and cobalt contents on the microstructure, phase composition, and electrochemical behavior of the laser-clad Ti–6Al–4 V coatings were analyzed. Coating morphology and phases were characterized using scanning electron microscopy (SEM) equipped with energy dispersive spectrometry (EDS), and X-ray diffractometry (XRD), respectively. The corrosion resistance of Ti–6Al–4 V, both with and without Ni–Co additions, in 0.5 M H2SO4 was evaluated using potentiodynamic polarization technique. Results indicated that the coatings exhibited excellent metallurgical compatibility with the substrate. Additionally, the high scan speed laser-clad samples showed enhanced corrosion resistance compared to those processed at low speeds. The potentiodynamic polarization analysis revealed passive behavior in all specimens, with higher cobalt content notably enhancing passivity and corrosion resistance by suppressing the anodic reaction.

COATING OF ST37 STRUCTURAL STEEL SURFACE WITH WC-ST6-ST21 AND FERRO55 USING LASER CLADDING TECHNIQUE AND INVESTIGATION OF SURFACE HARDNESS

Improving material properties such as surface hardness and wear resistance play a vital role in modern industrial applications. Surface coating techniques offer a practical approach to achieve these improvements. This study focuses on laser cladding as a method to coat ST37 structural steel material with WC, ST6, ST21 and Ferro55 powders and investigates the resulting surface hardness. ST37 structural steel with a base hardness of 120 HV was used as the starting material. Laser cladding was used to apply WC, ST6, ST21 and Ferro55 powders to the steel surfaces using various process parameters. Hardness measurements of the laser cladded samples were carried out using HV0.3 load for evaluation. The study examines the surface hardness differences between ST37 steel samples coated with different powders, highlighting the highest and lowest hardness values.

A comparative study on characteristics of composite (Cr3C2-NiCr) clad developed through diode laser and microwave energy

A typical ferrite/martensitic heat-resistant steel (T91) is widely used in reheaters, superheaters and power stations. Cr3C2-NiCr-based composite coatings are known for wear-resistant coatings at elevated temperature applications. The current work compares the microstructural studies of 75 wt% Cr3C2- 25 wt% NiCr-based composite clads developed through laser and microwave energy on a T91 steel substrate. The developed clads of both processes were characterized through a field emission scanning electron microscope (FE-SEM) attached with energy-dispersive X-ray spectroscopy (EDS), X-ray diffraction (XRD) and assessment of Vickers microhardness. The Cr3C2-NiCr based clads of both processes revealed better metallurgical bonding with the chosen substrate. The microstructure of the developed laser clad shows a distinctive dense solidified structure, with a rich Ni phase occupying interdendritic spaces. In the case of microwave clad, the hard chromium carbide particles consistently dispersed within the soft nickel matrix. EDS study evidenced that the cell boundaries are lined with chromium where Fe and Ni were found inside the cells. The X-ray phase analysis of both the processes evidenced the common presence of phases like chromium carbides (Cr7C3, Cr3C2, Cr23C6), Iron Nickel (FeNi3) and chromium-nickel (Cr3Ni2, CrNi), despite these phases iron carbides (Fe7C3) are observed in the developed microwave clads. The homogeneous distributions of such carbides in the developed clad structure of both processes indicated higher hardness. The typical microhardness of the laser-clad (1142 ± 65HV) was about 22% higher than the microwave clad (940 ± 42 HV). Using a ball-on-plate test, the study analyzed microwave and laser-clad samples' wear behavior. Laser-cladding samples showed superior wear resistance due to hard carbide elements. At the same time, microwave-clad samples experienced more surface damage and material loss due to micro-cutting, loosening, and fatigue-induced fracture.

Effect of laser shock peening on microstructure and mechanical properties of laser cladding 30CrMnSiNi2A high-strength steel

The effect of laser shock peening (LSP) on the microhardness and tensile properties of laser cladding (LC) 30CrMnSiNi2A high-strength steel was studied. After LSP, the microhardness of the cladding zone reached approximately 800 HV0.2, which was 25% higher than that of the substrate, while the cladding zone without LSP had an approximately 18% increase in its microhardness. Two strengthening processes were designed: groove LSP + LC + surface LSP versus LC + surface LSP. The former's tensile strength and yield strength were less than 10% weaker than those of forged materials, which is the best mechanical property recovery found in LC samples. The microstructural characteristics of the LC samples were analysed by scanning electron microscopy (SEM) and electron backscatter diffraction. Under the action of the laser-induced shock wave, the grain size of the LC sample surface was refined, the low-angle grain boundaries on the surface layer increased significantly, and the austenite grain length was reduced from 30–40 μm in the deep layer to 4–8 μm in the surface layer. In addition, LSP modulated the residual stress field, hence preventing the weakening effect of the LC process's thermal stress on the components' mechanical properties.

Corrosion Behavior of Coated Low Carbon Steel in a Simulated PEMFC Environment.

Here, potential metallic bipolar plate (BP) materials were manufactured by laser coating NiCr-based alloys with different Ti additions on low carbon steel substrates. The titanium content within the coating varied between 1.5 and 12.5 wt%. Our present study focussed on electrochemically testing the laser cladded samples in a milder solution. The electrolyte used for all of the electrochemical tests consisted of a 0.1 M Na2SO4 solution (acidulated with H2SO4 at pH = 5) with the addition of 0.1 ppm F-. The corrosion resistance properties of the laser-cladded samples was evaluated using an electrochemical protocol, which consisted of the open circuit potential (OCP), electrochemical impedance spectroscopy (EIS) measurements, and potentiodynamic polarization, followed by potentiostatic polarization under simulated proton exchange membrane fuel cell (PEMFC) anodic and cathodic environments for 6 h each. After the samples were subjected to potentiostatic polarization, the EIS measurements and potentiodynamic polarization were repeated. The microstructure and chemical composition of the laser cladded samples were investigated by scanning electron microscopy (SEM) combined with energy-dispersive X-ray spectroscopy (EDX) analysis.

Tool wear assessment when drilling AISI H13 tool steel multilayered claddings

Laser cladding is a layer-by-layer metal deposition technique often used to deposit high-quality metallic coatings on poorly performant metal alloy surfaces. Nevertheless, to reach the desired surface finish and geometrical tolerances, machining operations after laser cladding may become necessary, whose performances can be significantly affected by the deposition parameters. While the outcomes of milling operations carried out on multi-layered claddings in terms of tool wear and surface integrity have been recently investigated, the same is not available in literature in case of drilling, which is particularly challenging when the drilling operation intersects several layers. In this paper, C45 steel substrates were laser cladded with multiple AISI H13 tool steel layers using different powder size and laser power. The laser cladded samples were characterized on the basis of their microstructural features and micro-hardness. Afterward, drilling trials were conducted on these samples to evaluate the drill bit wear. The effect of the laser cladded-induced microstructure on the tool wear was then assessed at varying deposition parameters. Moreover, the quality of the drilled holes in terms of hole internal surface roughness and hole edge contour was investigated and related to the tool wear. The obtained results showed that, when drilling laser cladded AISI H13 tool steel, the microstructural features induced by the deposition process significantly affect the tool wear and, in turn, the hole quality.

The roles of microstructural anisotropy in tribo-corrosion performance of one certain laser cladding Fe-based alloy

Because of the microstructural anisotropy for laser cladding materials, the tribo-corrosion performance can vary significantly with different directions. In this study, one certain Fe-based coating was fabricated by laser cladding. To study the effects of anisotropy, three working surfaces (0°, 45°, and 90° to the building direction) were machined from the laser cladding samples; as-cast samples with an approximately homogeneous structure were prepared as controls. The tribo-corrosion tests were conducted in a 3.5 wt% NaCl solution with varying normal loads (5, 10, and 15 N). The results demonstrated that the 45° surface has superior friction stability, corrosion resistance, and wear resistance. This was directly related to the crystal orientation and grain boundary density. In addition, a refined microstructure may enhance tribo-corrosion properties by increasing deformation resistance and decreasing surface activity.

Comparative study of coatings with different molybdenum equivalent on titanium alloy forged plate for laser cladding: Microstructure and mechanical properties

In this study, three types of titanium alloy powders (TA15, TC11 and TB2) with distinct molybdenum equivalent ([Mo]eq = 1.6, 3.4, 18.6, respectively) were deposited on the forged TC4 (Ti-6Al-4V, wt%) plates by laser cladding. The microstructure and mechanical properties of laser cladded samples were studied. The results show that coatings with fully martensitic α' phase (TA15 coating), fully lamellar (α + β) (TC11 coating), and fully β phase (TB2 coating) were obtained in the coating zone (CZ) under as-clad state. Compared with the ultimate tensile strength (UTS ~ 975 MPa) and elongation (EL ~ 14 %) of forged TC4 substrates, laser cladded samples under as-clad (D) and heat treatment (HT) states exhibited the comparable UTS (955–1180 MPa). The poor elongation (EL < 5 %) was obtained in the cladded samples with TC11 coating and heat treated TB2 coating, which was ascribed to the higher microhardness (440–460 HV) and more α/β interface led to the brittle tendency of coatings. The laser cladded samples of TA15 coating and TB2 coating under as-clad state respectively exhibited the elongation of 8.5 % and 14 %, which were acceptable for attaining 60 % and 100 % of the elongation of forged TC4 substrates. The improved elongation of laser cladded samples was mainly attributed to the decreased strength mismatch and relieved stress concentration at the interface of coating and heat affected zone (HAZ). This study provides a guidance for selecting appropriate alloy powder to achieve the better mechanical properties for repair of wrought Ti-alloys components by laser additive manufacturing.

Heterostructured alloys with enhanced strength-ductility synergy through laser-cladding

Heterostructuring has recently become a popular option to provide an excellent combination of strength and ductility in alloys. However, its production is a challenging multi-step process. In this study, we propose a simple process to develop heterostructured alloys by laser-cladding a thin layer of an identical material on the surface of the wrought material. The heterostructured laser-clad wrought samples exhibited enhanced strength and ductility compared to monolithic laser-clad and wrought 316L stainless steels. The enhanced twinning activity localized in the coating region generated high mechanical incompatibility. The hetero-deformation-induced strengthening of the heterostructured laser-clad samples resulted in an enhanced strength-ductility synergy. This approach is straightforward and viable for laser-clad available materials. This study presents a new direction for the use of laser-cladding to produce a heterostructurally-designed alloy with superior strength-ductility synergy.

Influence of laser cladding parameters on slurry erosion performance of NiCrSiBC + 50WC claddings

Various components employed in hydro machines are rigorously affected by the presence of sand particles throughout their operation which leads to degradation of the target surface. To counteract this menace, laser cladding has been emerged as a prominent technique to produce dense coatings along with enhanced surface properties like hardness and wear resistance. Therefore, in this study, hard layers of NiCrSiBC + 50WC powder were deposited on SS410 steel by laser cladding. Further, the effect of laser beam power, scanning speed, and powder feed rate on quality of clads was investigated. The laser cladded samples were examined for their micro structural characteristics, micro-hardness, and slurry erosion. Performance of NiCrSiBC + 50WC coatings under slurry erosion was evaluated for harsh conditions of various factors namely sand particle size, slurry concentration, impingement velocity, and impingement angle. Laser cladding parameters namely scanning speed and laser beam power were found to have a significant influence on micro-hardness of developed clads, while powder feed rate did not exhibit a significant effect on micro-hardness variations. Owing to higher hardness of deposited materials, slurry erosion resistance of NiCrSiBC + 50WC clad surfaces was greatly enhanced as that of uncoated SS410 steel. From SEM images, plastic deformation, micro-cutting, crater formation, and ploughing were observed as the major wear mechanisms for the slurry eroded clads. Further, from the obtained results, it has been noticed that a blend of high scanning speed, high laser beam power, and intermediate powder feed rate is suitable to develop coatings having superior wear resistance.

Self-Grinding Silage Knife Strengthened with Ni–WC Alloy Prepared by Laser Cladding

The working environment of agricultural cutting tools is poor, and the operational quality and efficiency are reduced after they become blunt. This study aimed to develop a high wear-resistant agriculture knife with a long life. A Ni–WC alloy, wear-resistant layer was prepared using laser cladding technology on one side of the cutting edge of a 65 Mn silage knife. A self-grinding edge was formed when the cladded knife was used, which improved the cutting quality and service life of the knife. The microstructure, phase, composition, and hardness distribution of the cladding layer were detected and analyzed. The impact toughness and wear resistance of the laser-cladded samples were analyzed, and the cladded knife was tested in the field. The results show that a cladded layer with a dense microstructure formed metallurgical bonds with the substrate. The microhardness was uniform across the cladded layer, and the average hardness of the micro Vickers was approximately 1000 HV(0.2), which was approximately three times the hardness of the substrate. The impact toughness and wear resistance of the coated knife were obviously higher than those of uncoated knives. The field tests showed that compared with a conventional 65 Mn knife, the self-grinding knife with laser cladding could maintain its sharp cutting shape after operation for 76 h, which greatly extended the service life of the knife. This study improved the service life of an agricultural cutting tool, which enhanced the cutting performance and efficiency at the same time.

Manufactural Investigations on Dissimilar Laser Cladding and Post-Clad Heat Treatment Processes of Heat-Resistant Ni Alloy on Cu Substrate

Hardness of dissimilar laser clad samples of NiCrBSi alloy on a Cu substrate was investigated, with the aim of optimizing the manufacturing process for high-durability continuous casting molds for steelmaking. The performance of the clads is compared with that of samples prepared by thermal spray coating, and an optimal process is proposed. Dissimilar laser cladding between NiCrBSi alloy and Cu was achieved with a hardness of ~450 HV using a high-power diode laser, and no cracks and pores were observed. Post-clad heat treatment performed below the melting point of the Cu substrate (1357 K) using a furnace (1223 K for 500 min) resulted in a decrease in the hardness to 142 HV, which was attributed to the dilution of the alloy with the soft Cu substrate and changes to the microstructure; the solidification microstructure was almost homogenized during the heat treatment, and secondary boride phases were formed and almost dissolved in the matrix phase. Laser surface heat treatment of the clad metal at 1323 K resulted in a decrease in the hardness (to 359 HV near the surface), with a heat treatment depth of ~1.3 mm. In contrast, the hardness of the as-sprayed coatings was 730–750 HV, which drastically increased to ~1200 HV after laser fusing because of the formation of finely distributed secondary phases. Therefore, to achieve high-durability continuous casting mold components, minimization of Cu dilution is preferentially recommended for the laser cladding of NiCrBSi alloy on Cu substrate. Furthermore, when it is difficult to minimize the Cu dilution during the laser cladding, thermal spraying in conjunction with laser fusing treatment appears to be sufficiently applicable for high-durability continuous casting molds.

Effect of B4C nanoparticles on microstructure and properties of laser cladded IN625 coating

IN625 is a nickel-based super alloy with remarkably high temperature corrosion resistance, which makes it a good choice for marine and chemical industry applications. However, its relatively low hardness and low wear resistance limit its applications in many areas. In order to increase hardness and wear resistance of laser cladded IN625 coating, B4C nanoparticles were used to reinforce the cladded coating. B4C nanoparticles and IN625 powder were alloyed mechanically under the work of high-energy ball milling. Laser cladded samples were tested for hardness and high temperature friction and wear. OM, XRD, SEM, EDS and EPMA were used for analyzing the microstructure, elemental distribution and wear morphology. The B-C-Cr phase of the powder was produced by high-energy ball milling. The precipitation of Ni3B and Cr3C2 phases in the interdendritic region, refined dendritic structure. The results demonstrated that cladded coating without cracks can be obtained when the B4C nanoparticles content is less than 2 wt%. Elemental analysis showed that the boride reinforced phase was distributed uniformly along a boundary in a molten pool to form B-enriched belts. Mechanical tests showed that the hardness of reinforced layers were increased by about 64% and the high temperature wear volume of B4C nanoparticles reinforced coating was decreased by about 86% compared to the pure IN625 coating.

Effects of laser cladding on crack resistance improvement for aluminum alloy used in aircraft skin

In order to improve the damage tolerance ability of aircraft skin, the superiority of laser cladding aluminum alloy structures for crack resistance is investigated by establishing a three-dimensional (3D) finite element simulation model based on the double ellipsoid heat source and sequentially coupled thermal-mechanical analysis (SCTMA) method. The temperature field and residual stress field under different laser power, laser scanning velocity, laser cladding length, laser cladding patterns and laser cladding angles are investigated to evaluate the effectiveness of fatigue life improvement. Stress intensity factors are calculated by M-integral method and fatigue life is estimated by Paris equation, respectively. The results show that the laser cladding samples achieve the best crack resistance performance at laser power of 1400 W and laser scanning velocity of 10 mm/s. The fatigue life for the sample of cladding coating length of 50 mm is 2.93 times than that of the untreated sample. The linear pattern shows a better crack resistance performance than other patterns and the best crack resistance performance is achieved when the cladding angle of linear pattern is “0”. The results demonstrate that the fatigue life of samples after being laser cladding treated is significantly higher than that of untreated samples, which benefits from the residual compressive stress induced by laser cladding process. The higher laser power or lower laser scanning velocity can improve the fatigue life of laser treated samples. The fatigue life of samples can be affected by laser parameters, laser cladding patterns and angles.

Laser cladding of Stellite 6 on EN8 steel – A fuzzy modelling approach

Laser cladding is a very popular technique for the process of providing protection to the surface of materials that are subjected to extreme working conditions. This article describes the process where Stellite 6 alloy is added on to the surface of EN8 steel in a controlled manner. EN8 steel is the material that is used as a base material as it the commonly used material in the manufacturing sector. Stellite 6 is a cobalt base super alloy which is characterized by extreme wear resistance and high hardness. The laser cladding process is done whilst considering parameters like laser scanning speed, laser focus height, laser power and powder feed. The laser cladded samples are corrosion tested in an acidic environment and the electron images of the samples are taken. From the electron microscopy images the corrosion is classified in order to be fed to a fuzzy logic model. This fuzzy logic model is used to deduce a corrosion index and this corrosion index is further optimized using Taguchi method and the results have been reported.

Microstructures and mechanical behavior of beta-type Ti-25V-15Cr-0.2Si titanium alloy coating by laser cladding

Preparing a flame-resistant coating with high adhesion to the titanium substrate is a feasible method to prevent “titanium fire”. In this work, Ti-25V-15Cr-0.2Si, which is a beta stabilized titanium alloy with excellent flame-resistant properties, was fabricated on a Ti-6Al-4V substrate by laser cladding with aim to improve the flame resistance of the Ti-6Al-4V substrate. The microstructure, mechanical properties and strengthening mechanisms of the laser cladded samples were studied. An excellent metallurgical bond is formed between the substrate and the cladded layers and a reasonable transition of composition and microhardness from the substrate to the Ti-25V-15Cr-0.2Si cladded layers is obtained. An effective relationship between dilution ratio and composition was established to predict the composition evolution of transition zone in the cladded layers. Microstructural characterization confirmed a direct transformation from α+β bi-phase in Ti-6Al-4V substrate to single β phase in Ti-25V-15Cr-0.2Si laser cladded zone throughout the cladding interface. The room-temperature tensile testing along both parallel and vertical to cladding interfaces showed that the cladded samples exhibit tensile strength exceeding 900 MPa and elongation of >9% (reaching 90% and 70%, respectively, the corresponding ones of wrought Ti-6Al-4V substrate), indicating the very good mechanical performance of the laser cladded samples.

Laser cladding of Mg–Zn–Y–Zr alloy using Al with different ratios of micro- and nano-SiC powder

In this study, a Mg–Zn–Y–Zr alloy was laser cladded with Al–SiC powder using different weight percentages and different grain sizes of SiC to improve its surface properties. We observed that the laser-cladded layer primarily comprised α-Mg, Mg2Si, Mg17Al12, Al2Y and Al3Y phases. Moreover, the cladded layer exhibited a progressive microstructure and composition, and the volume fraction and size of the Mg17Al12, Al2Y and Al3Y phases decreased with the increase in depth. Because of the formation of these hardened phases, the average hardness of the sample with 10% of nSiCp was 4.06 times that of the substrate. In comparison with four laser-cladded samples, the sample cladded with 5% of nSiCp had the lowest friction coefficient and the highest wear resistance. The potentio-dynamic polarisation curves, measured in an aqueous NaCl (3.5 wt%) solution, demonstrated that for samples with a cladding of 10% nm, the corrosion potential increased from − 1.63 V for the untreated Mg–Zn–Y–Zr alloy to − 1.32 V for the laser-cladded alloy. The corrosion current density significantly decreased from 3.60 × 10−5 to 4.03 × 10−6 A cm−2. These results demonstrate that laser cladding with nano-SiC is an effective method to significantly improve the surface properties of Mg-rare earth alloys.

Effect of nickel-based laser coatings on phase composition and corrosion behaviour of titanium alloy for offshore application

Recent advances in titanium alloy applications in the offshore industry have been realized through the development of laser surface modification technique. The distinctive outcome of this technique has provided increase in the utilization of titanium in offshore drilling risers for special drilling operations and various subsea and tubing applications. In this work, surface mitigation and corrosion degradation of titanium alloy in aggressive sulfuric acid were investigated using electrochemical technique (linear potentiodynamic polarization) while the surface characterization (morphology) and phases of the resultant coatings were analyzed using X-ray diffractometry (XRD) and scanning electron microscopy (SEM). Prior to that, laser surface technique was used to fabricate Nickel-based powder on the substrate (Ti-6Al-4V). Results revealed that laser clad sample with high scan speed was more effective in improving the corrosion resistance compared to low scan speed. The enhanced corrosion resistance with high laser scan speed has been attributed to the presence of hard intermetallic compounds in the metallic coating.

Microstructure and mechanical properties of laser cladded Cr[sbnd]Ni alloy by hard turning (HT) and ultrasonic surface rolling (USR)

The CrNi alloy powder was deposited by laser cladding (LC) on the surface of 1045 and then processed by hard turning (HT) and combined HT with ultrasonic surface rolling (USR). USR was introduced to improve surface properties of LC layer by exerting severe plastic deformation. Microstructure, surface roughness, surface residual stress, and mechanical properties (microhardness, elastic modulus and surface fracture toughness) of the cladding layer after LC, HT and combined HT with USR were investigated by optical microscope, scanning electron microscopy, X-ray diffraction, roughness measuring instrument and nano-indenter. The results reveal that USR can neither change the element distribution on the surface of laser cladding layer nor induce the formation of new phase. After USR, the 〈111〉 texture on the surface is weakened. Fine particles layers with thickness of 2.5 μm and 2 μm are observed on the topmost surface of USR and HT samples, but not on the surface of LC samples. However, obvious grain refinement and change of grain morphology in the subsurface and interior of cladding layer are not observed in this work. The surface properties of the USR samples are greatly improved. Compared with HT samples, the surface roughness decreases by 88.5%, the surface microhardness increases by 34.6%, the surface residual stress changes from tension (449.6 MPa) to compression (−334 MPa), the surface elastic modulus changes little, and the surface fracture toughness increases by 106%. Nevertheless, USR has weak effect on the properties of y-z cross section. The elastic modulus of y-z cross section along the depth does not increase significantly and regularly. Under the experimental parameters, the hardened depth of y-z cross section is about 140 μm. Above results indicate that USR can improve the surface properties of laser cladding layer as a post-treatment process, which has a certain grain refinement and work hardening effect.