scholarly journals Optimization for Morphology of Grinding Layer on Textured Laser Cladding Grinding Tool

Author(s):  
Xufeng Zhao ◽  
Changhe Li ◽  
Tianbiao Yu

Abstract In order to improving the grinding performance of laser cladding textured grinding tool (LCTGT) under high speed grinding process, the topography shape (height, width and height/width ratio) of laser cladding grinding layers on LCTGT were designed with RSM (response surface method) through optimizing laser cladding processing parameters and laser cladding layers structure parameters that based on Archimedes helix coefficients. The LCTGTs were produced with optimized laser cladding parameters and structural parameters for laser cladding grinding layers. The results showed that laser cladding parameters of 397W of laser power, 3.56 mm/s of the laser scanning speed and 0.91 r/min of powder feeding rate and structure parameters of laser cladding layers of 6-10-10 can meet requirement.

2013 ◽  
Vol 395-396 ◽  
pp. 1127-1131 ◽  
Author(s):  
Wei Zhang

The experiments of laser cladding on the surface of 20 steel were made. High-chromium (Cr) cast iron powder was used as cladding material. The microstructure and hardness of laser cladding layers under different scanning speed were studied. The experiments showed that high-Cr cast iron cladding layer had better properties such as minute crystals, high density, no crack, no gas cavity and good metallurgical bonding with base metal. When the scanning speed was low, such as 10mm/min, the microstructure of cladding layer was cellular dendrite. There were much carbide with the shape of fish-bone distributing among cellular grains. Under higher scanning speed (from 100mm/min to 300mm/min), needle-shaped primary cementite would come into being. When laser scanning speed was 500mm/min, the carbide of cladding zone was very thin. With the increasing of laser scanning speed, the average hardness of cladding zone increased from 388HV0.2 to 580 HV0.2.


2011 ◽  
Vol 686 ◽  
pp. 646-653 ◽  
Author(s):  
Jing Liang ◽  
Sui Yuan Chen ◽  
Chang Sheng Liu ◽  
Feng Hua Liu

Two kinds of mixed powders:Ti-6Al-4V/B/C and Ti-6Al-4V/B4C which are pre-pasted or synchronized fed on Ti-6Al-4V substrates separately were scanned by a 500W pulsed YAG laser to induce in situ formation of titanium composite coatings contained TiBxand TiC ceramic reinforced phases. The influences of laser processing parameters including Pulse Frequency (PF), Pulse Width (PW), Laser Power (P) and Scanning Speed (V) together with the powder proportions on the microstructure and properties of the coatings were investigated. Microstructures, phase components of the coating were analyzed by OM, SEM, TEM and XRD respectively. Experimental results show that two and more kinds of ceramic reinforcements were in situ formatted in the matrix of Ti-6Al-4V. TiB and TiC ceramics were formed evenly with the morphology of needle, tiny dendrites and disperse particles in the prepasted single path specimens. For the powder feed laser cladding layers, the ceramic reinforcements were TiB (needlelike), TiB2(hexagonal prism or rodlike), a small amount of TiC (disperse particles) and non fully reacted B4C. The microhardness increased with the increase of the amount of B4C and B+C additions. When the added B and C contents are the same, the microhardness of the coating with B4C addition is higher than that of the coating with B+C addition. The average micro-hardness of a powder prepasted (with 20 wt.% B4C addition) multi-path laser cladding layer formed under the optimized processing parameters is up to 800HV, which is more than 2 times of that of the substrate (340Hv), and the wear weight loss of the layer decreased nearly 3 times that of the substrate.


2011 ◽  
Vol 138-139 ◽  
pp. 732-736
Author(s):  
Ba Sheng Ouyang ◽  
Run Juan You

Cladding experiment with parameter variations was presented to manufacture the better processing property coating by laser cladding self-fused Ni-based ceramic powder of ZrO2 composite on the excircle surface of 304 SUS. The influence of the laser process parameters on macroscopic view, microstructure and micro-hardness of the laser cladding layers were investigated. The results show that we can get better coating when laser power is 1.5KW, and that the cladding layer microstructure has the trend of refined framework with the growing of scanning speed; micro-hardness will be higher and distribution from substratum to surface with little fluctuate by optimizing scanning speed.


2013 ◽  
Vol 668 ◽  
pp. 283-287
Author(s):  
Sheng Feng Zhou ◽  
Xiao Qin Dai

In order to characterize the dissolution of cast WC particles in Ni-based WC coatings by laser induction hybrid rapid cladding, NiCrBSi+50 wt.% WC coatings are produced on A3 steel by low and high speed laser induction hybrid cladding (LIHC). When laser scanning speed is only 600 mm/min, the crack-free coating has pores and its dilution is as high as 45%. At the bottom of coating, the cast WC particles are dissolved completely and the herringbone M6C eutectics are precipitated. In the center of coating, the cast WC particles are also dissolved completely and the acicular, blocky and dendritic carbides with relatively low hardness are precipitated. At two sides of coating, some cast WC particles are dissolved partially and interact with Ni-based alloy to form an alloyed reaction layer, while others preserve the primary eutectic structure and high hardness. When laser scanning speed and powder feeding rate are increased to 1500 mm/min and 85.6 g/min, the coating has cracks but no pores. Its dilution can be markedly decreased to 7.8%. Moreover, a majority of WC particles are still composed of primary eutectic structure and keep their high hardness, which can play a positive role in strengthening Ni-based metallic matrix.


2019 ◽  
Vol 33 (01n03) ◽  
pp. 1940014
Author(s):  
Ruifeng Li ◽  
Yi Qiu ◽  
Yanyan Zhu

A Ni–Fe–B–Si–Nb amorphous alloy was deposited on a steel substrate surface via a laser cladding process, and a laser cladding plus laser remelting process. The wear behavior of the laser processed samples and the bulk metallic glass (BMG) sample with the same nominal composition were tested using a pin-on-disc type testing machine. The nano-mechanical properties of the samples were measured with a nano-characterization system. The friction wear tests showed that deep grooves and wear debris were formed on the worn surface of the laser cladded coating, while only shallow grooves for the laser remelted coatings. The friction coefficients of laser remelted coatings and BMG were lower than the laser cladded coating. The wear mass losses of the laser remelted coating were less than the BMG when the laser remelting scanning speed was higher than 6 mm/min. The nano-hardness and elastic modulus of the remelted coating is higher than that of the laser cladded coating. Also, they increase with the increasing laser scanning speed with 1227.9 HV and 277.4 GPa when the remelting scanning speed is 8 m/min. Based on the nano-indentation and friction wear tests results, it was found that the friction wear properties of the laser cladded coating, laser remelted coatings and BMG related well to the ratio of H3/E2. A higher value of H3/E2 can lead to a better wear resistance property.


2019 ◽  
Vol 813 ◽  
pp. 185-190 ◽  
Author(s):  
Fazati Bourahima ◽  
Anne Laure Helbert ◽  
Vincent Ji ◽  
Michel Rege ◽  
Arnaud Courteaux ◽  
...  

In glass industry, laser cladding is an innovative surfacing technique allowing to deposit a layer of nickel to protect glass mold against corrosion, abrasion and thermal fatigue. This method (powder fusion by projection), well known in additive manufacturing represents a real technological leap for the glass industry. But during laser cladding of Ni-based powder on gray cast iron, cracks can be observed for some process conditions. These cracks are often due to the Heat Affected Zone that creates structural stresses linked to the development of a martensitic structure in the ferritic matrix of the lamellar graphite cast iron. The aim of this work is to observe the impact of laser cladding (without substrate pre-heating usually employed to limit cracking) on the coating behavior but also on the flake-graphite cast iron substrates. The microstructure and the mechanical properties were studied (SEM and microanalysis, microhardness) around the interface cladding/substrate. Also, the impact of the processing parameters (power P (1500-2300 W), scanning speed v (2.5-10 mm/s) and powder feeding rate PFR (24.5-32.5 g/min) was studied by using the ANOVA (ANalysis Of VAriance) technique. It has been observed that laser cladding on graphite cast iron is possible without cracks by limiting the linear energy induced by the process. Also, an optimization of the processing parameters (P, v, PFR) in order to obtain the industrial expected geometry of the coating has been proposed.


2012 ◽  
Vol 581-582 ◽  
pp. 467-470
Author(s):  
Bao Hong Tian ◽  
Yi Zhang ◽  
Yong Liu

The laser surface alloying for metallic materials has been applied widely to improve the wear resistance, corrosion resistance and other required properties. The studies of laser surface alloying on copper-base materials are becoming more and more important. This work using two methods of pretreated coatings, i.e., chemical bonded 50%Cr-50%Cu and pure Cr powders and electroplating chromium coating respectively, on pure copper substrate surface to prepare laser alloyed Cu-Cr alloy coatings was investigated. The samples were treated with different laser scanning speed. Using scanning electron microscopy (SEM), micro-hardness indentor and wear tester, the effects of different coating processing parameters on the microstructure and properties of Cu-Cr coatings were determined and analyzed respectively.


2020 ◽  
Vol 976 ◽  
pp. 9-14 ◽  
Author(s):  
Wei Zhang ◽  
Qiu Hong Feng ◽  
Wei Zhong Zhang

Aiming at the problem of poor high-temperature wear-resistance of rope clamp used in super-high speed elevators, the experiments of laser cladding to prepare carbide reinforced composite coating were made. nanoTiC powder, Ni-based alloy powder were used as cladding material. The microstructure and hardness of composite coating were tested by relevant equipments. The research results show that the composite coating is made up of TiC, Cr3C2, Fe3C and Fe-Ni-Cr-C HYPERLINK "javascript:void (0);" solid solution. When the content of TiC is 10%, 30%, the morphology of TiC is presented as dendrite-like and the morphology of HYPERLINK "javascript:void (0);" solid solution is presented as cellular-like. When the content of TiC is 50%, the morphology of TiC is presented as block-like, lath-like. There are some microcracks on grain boundaries. At the content of 30%, laser power 1.5KW, scanning speed 600mm/min, the laser cladding has no crack and hole. The average hardness of composite coating is 701HV0.2. Using this technology to the surface strengthening of elevator parts, the wear resistance and service life can be greatly improved.


Coatings ◽  
2020 ◽  
Vol 10 (3) ◽  
pp. 300 ◽  
Author(s):  
Haijiang Wang ◽  
Wei Zhang ◽  
Yingbo Peng ◽  
Mingyang Zhang ◽  
Shuyu Liu ◽  
...  

FeCoCrNi-Mo high entropy alloy/diamond composite coatings were successfully prepared by high speed laser cladding. A high scanning speed was adopted (>30 mm/s), and the effects of laser power, scanning speed, and diamond content on the microstructure and wear resistance of the composite coating were studied. The processing parameters of laser cladding had significant influence on the dilution ratio, graphitization of diamond, and wear resistance of the composite coatings. When the laser cladding parameters were 3000 W of laser power and the high scanning speed of 50 mm/s, the composite coating exhibited a uniform microstructure, the lowest dilution ratio, and the best wear resistance. The wear resistance of the composite coating was enhanced with the addition of diamond, but microcracks also increased. When the amount of diamond was 15 wt.%, the best combination of microstructures and wear resistance was obtained.


2009 ◽  
Vol 628-629 ◽  
pp. 679-684 ◽  
Author(s):  
Hong Yu Wang ◽  
Dun Wen Zuo ◽  
Yong Jun Chen ◽  
H. Ma

The green presetting of powders was performed on the substrate by introducing a novel technique namely squash presetting method, and cladding coatings were prepared by crosscurrent CO2 laser in this work. Based on the concept of laser energy efficiency which being accepted generally by insider, the energy efficiency of squash presetting laser cladding was determined. Meanwhile, effects of processing parameters including specific energy, laser power, scanning speed and spot diameter on energy efficiency were investigated through an orthogonal test. The results show that the energy efficiency increases at first and then decreases with the increase of specific energy, and the energy efficiency is relatively higher when laser specific energy ranged from 90 J/mm2 to100 J/mm2. Among three single-factors, the effects of spot diameter on energy efficiency are most significant, laser power takes second place, and scanning speed comes next. It is considered through analysis that the relationship between energy efficiency and processing parameters is closely related to powders melting and heat-conduction course of squash presetting laser cladding.


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