scholarly journals PARAMETERS OF LASER PROCESSING AND THEIR INFLUENCE ON TRIBOLOGICAL CHARACTERISTICS OF IRON-BASED COATINGS

2018 ◽  
Vol 17 (1) ◽  
pp. 56-63
Author(s):  
O. V. Diachenko ◽  
M. A. Kardapolova
Keyword(s):  
Wear Resistance ◽  
Laser Beam ◽  
Melting Rate ◽  
Solid Particles ◽  
Structural Components ◽  
Structural And Phase Transformations ◽  
Beam Velocity ◽  
Overlapping Coefficient ◽  
Molybdenum Boride ◽  
Load Increase

The paper considers improvement of physic-mechanical and operational properties of adhesive coatings after laser infusion with additional alloying В4С, ТаВ and МоВ. Influence of the laser infusion with additional alloying on structure, microhardness and wear-resistance of adhesive coatings of the Fe–Cr–B –Si system has been studied in the paper. While increasing a laser beam velocity microstructure is changed from equilibrium to quasi-eutectic. Presence of molybdenum boride and tantalum increases sensitivity of the coating to specific features of laser remelting. In both cases heat exchange conditions have been changed, a number of iron and chromium borides has been increased and due to this molybdenum and tantalum have been partially passing to free state that contributes to a disintegration of structural components. While introducing solid particles B4C into a coating they are dissolved in an iron matrix while being heated by a laser beam and under cooling they are isolated in the form of separated Fe an Cr boride inclusions. Laser infusion and alloying increase coating wear-resistance. Load increase from 30 to 70 Н improves coating wear resistance averagely by 15–26 % and wear resistance of non-alloyed coatings is improved by 26–43 %. An increase of melting rate and laser spot diameter does not exert significant influence on wear but an increase in overlapping coefficient leads to reduction of coating wear. Presence of solid particles in a coating and an increase in rate of melting by laser beam reduce coating wear resistance. Such rather complicated dependence of coating wear rate on conditions of laser melting and wearing process is due to a complex of structural and phase transformations which have contributed to formation of secondary solid inclusions and increased microhardness.

Abrasive wear of polymer/steel gear drives

2008 ◽  
Vol 4 (1) ◽  
pp. 1-26
Author(s):  
Gábor Kalácska
Keyword(s):  
Wear Resistance ◽  
Abrasive Wear ◽  
Material Selection ◽  
Solid Particles ◽  
Soil Types ◽  
General View ◽  
Modern Engineering ◽  
Clean Environment ◽  
Engineering Polymers ◽  
Plastic Gears

Research was performed on the friction, wear and efficiency of plastic gears made of modern engineering polymers and their composites both in a clean environment (adhesive sliding surfaces) and in an environment contaminated with solid particles and dust (abrasive), with no lubrication at all. The purpose is to give a general view about the results of abrasive wear tests including seven soil types as abrasive media. At the first stage of the research silicious sand was applied between the meshing gears and the wear of plastic and steel gears was evaluated and analyzed from the point of different material properties (elongation at break, hardness, yield stress, modulus of elasticity) and its combinations. The different correlations between the experienced wear and material features are also introduced. At the second stage of the project the abrasive sand was replaced with different physical soil types. The abrasive wear of gears is plotted in the function of soil types. The results highlight on the considerable role of physical soil types on abrasive wear resistance and the conclusions contain the detailed wear resistance. The results offer a new tribology database for the operation and maintenance of agricultural machines with the opportunity of a better material selection according to the dominant soil type. This can finally result longer lifetime and higher reliability of wearing plastic/steel parts.

RUUKKI RAEX 300

Alloy Digest ◽  
2012 ◽  
Vol 61 (2) ◽  
Keyword(s):  
Fracture Toughness ◽  
Wear Resistance ◽  
Shear Strength ◽  
Impact Toughness ◽  
Yield Strength ◽  
Physical Properties ◽  
Tensile Properties ◽  
High Strength ◽  
Structural Components ◽  
Wear Resistant

Abstract RUUKKI RAEX 300 (typical yield strength 900 MPa) is part of the Raex family of high-strength and wear-resistant steels with favorable hardness and impact toughness to extend life and decrease wear in structural components. This datasheet provides information on composition, physical properties, hardness, elasticity, tensile properties, and shear strength as well as fracture toughness. It also includes information on wear resistance as well as forming, machining, and joining. Filing Code: SA-643. Producer or source: Rautaruukki Corporation.

Experimental Investigation of Convective Melting of Granular Packed Bed Under Microgravity

2000 ◽  
Author(s):  
J. Jiang ◽  
Y. Hao ◽  
Y.-X. Tao
Keyword(s):  
Experimental Investigation ◽  
Average Particle Size ◽  
Particle Diameter ◽  
Vertical Direction ◽  
Packed Bed ◽  
Melting Rate ◽  
Control Flow ◽  
Solid Particles ◽  
Average Particle ◽  
Ice Particles

Abstract To improve the understanding of convective melting of packed solid particles in a fluid, an experimental investigation is conducted to study the melting characteristics of a packed bed by unmasking the buoyancy forces due to the density difference between the melt and solid particles. A close-loop apparatus, named the particle-melting-in-flow (PMF) module, is designed to allow a steady state liquid flow under a specified temperature. The module is on board NASA’s KC-135 reduced gravity aircraft for the experiments. In the test module, water is used as the fluid, and ice particles are fed to the test section at the beginning of the test. As the liquid flows though the bed, the solid grains melt. A perforate plate, through which liquid can flow while the ice particles are retained, bounds the downstream of the packed bed. From the digital video images the local packed bed thickness is measured under control flow rate, and the melting rate is determined. The temperature distribution along the horizontal direction and vertical direction is measured using 19 thermocouples. An infrared camera is mounted to record the local temperature variation between liquid and solid. The melting rates are presented as a function of upstream flow velocity, temperature and initial average particle size of the packed bed. It is found that the melting rate is influenced mainly by the ratio of the Reynolds number (Re, based on the initial particle diameter) to the square of the Froud number (Fr), and me Stefan number (Ste). In general, the dimensionless melting rate decreases as Re/Fr2 increases and increases as Ste increases. With the absence of gravity, i.e., Froud number approaches infinity, a maximum melting rate can be achieved for otherwise the same test conditions. The increase in the melting rate with the increase in Stephan number also becomes more pronounced under the zero gravity condition.

Microstructural and Mechanical Characterization of Gray Cast Iron and AlSi Alloy after Laser Beam Hardening

2010 ◽  
Vol 638-642 ◽  
pp. 769-774 ◽  
Author(s):  
Waldemar Alfredo Monteiro ◽  
E.M.R. Silva ◽  
L.V. Silva ◽  
W. de Rossi ◽  
S.J. Buso
Keyword(s):  
Wear Resistance ◽  
Laser Beam ◽  
Automotive Industry ◽  
Automobile Industry ◽  
Gray Iron ◽  
Beam Hardening ◽  
Localized Source ◽  
Alsi Alloy ◽  
Hardening Treatment

A localized source of heat, such as that of laser beam, can provide a convenient means of producing a surface layer of altered microstructure. By using surface hardening treatment, wear resistance can be increased. Experiments were performed using a Nd:YAG pulsed laser under different processing conditions. Scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS) and X-ray mapping (SEM) were employed to observe the effect of laser melting treatment on the microstructural properties of the samples. Depending on the selected laser treatment working conditions, different microstructures characteristics of surface melting can be achieved in the treated zone. Higher microhardness values were found at the treated area showing a superficial hardening of the sample and, consequently, an improvement of the wear resistance of these automotive alloys. The aim of this work is to find the optimal process parameters and to evaluate the characteristics of the laser superficial hardening (LSH) in a pearlitic gray iron and Al-Si alloy used in an automobile industry (bearing and piston materials in automotive industry).

scholarly journals Influence of Microstructure and Chemical Composition on Microhardness and Wear Properties of Laser Borided Monel 400

Materials ◽  
2020 ◽  
Vol 13 (24) ◽  
pp. 5757
Author(s):  
Mateusz Kukliński ◽  
Aneta Bartkowska ◽  
Damian Przestacki ◽  
Grzegorz Kinal
Keyword(s):  
Wear Resistance ◽  
Laser Beam ◽  
Wear Test ◽  
Beam Power ◽  
Iron Particles ◽  
Wear Properties ◽  
Beam Scanning ◽  
Scanning Velocity ◽  
Monel 400 ◽  
Laser Beam Scanning

In this study, wear properties of Monel 400 after laser alloying with boron are described. Surfaces were prepared by covering them with boron paste layers of two different thicknesses (100 µm and 200 μm) and re-melting using diode laser. Laser beam power density was equal to 178.3 kW/cm2. Two laser beam scanning velocities were chosen for the process: 5 m/min and 50 m/min. Surfaces alloyed with boron were investigated in terms of wear resistance, and the surface of untreated Monel 400 was examined for comparison. Wear tests were performed using counterspecimen made from steel 100Cr6 and water as a lubricant. Both quantitative and qualitative analysis of surfaces after wear test are described in this paper. Additionally, microstructures and properties of obtained laser alloyed surfaces are presented. It was found that the wear resistance increased from four to tens of times, depending on parameters of the laser boriding process. The wear mechanism was mainly adhesive for surfaces alloyed with initial boron layer 100 µm thick and evolves to abrasive with increasing boron content and laser beam scanning velocity. Iron particles detached from counterspecimens were detected on each borided surface after the wear test, and it was found that the harder the surface the less built-ups are present. Moreover, adhered iron particles oxidized during the wear test.

Experimental Investigation of Convective Melting of Granular Packed Bed Under Microgravity

2002 ◽  
Vol 124 (3) ◽  
pp. 516-524 ◽  
Author(s):  
J. Jiang ◽  
Y. Hao ◽  
Y.-X. Tao
Keyword(s):  
Experimental Investigation ◽  
Reynolds Number ◽  
Froude Number ◽  
Average Particle Size ◽  
Particle Diameter ◽  
Packed Bed ◽  
Melting Rate ◽  
Solid Particles ◽  
Average Particle ◽  
Stefan Number

To improve the understanding of convective melting of packed solid particles in a fluid, an experimental investigation is conducted to study the melting characteristics of a packed bed by unmasking the buoyancy forces due to the density difference between the melt and solid particles. A close-loop apparatus, named the particle-melting-in-flow (PMF) module, is designed to allow a steady-state liquid flow at a specified temperature. The module is installed onboard NASA’s KC-135 reduced gravity aircraft using ice particles of desired sizes and water as the test media. Experimentally determined melting rates are presented as a function of upstream flow velocity, temperature and initial average particle size of the packed bed. It is found that the melting rate is influenced mainly by the ratio of the Reynolds number (Re, based on the initial particle diameter) to the square of the Froude number (Fr), and the Stefan number (Ste). In general, the dimensionless melting rate decreases as Re/Fr2 increases and increases as Ste increases. With the absence of gravity, i.e., as the Froude number approaches infinity, a maximum melting rate can be achieved. The increase in the melting rate proportional to the Stefan number also becomes more pronounced under the zero gravity condition. The trend of average and local Nusselt number of the melting packed bed under microgravity, as a function of Reynolds number and Prandtl number, is discussed and compared with the case of nonmelting packed bed.

Improving the fretting wear resistance of titanium alloy by laser beam quenching

Wear ◽  
1997 ◽  
Vol 213 (1-2) ◽  
pp. 135-139 ◽  
Author(s):  
Z.D. Dai ◽  
S.C. Pan ◽  
M. Wang ◽  
S.R. Yang ◽  
X.S. Zhang ◽  
...  
Keyword(s):  
Wear Resistance ◽  
Titanium Alloy ◽  
Laser Beam ◽  
Fretting Wear

scholarly journals EFFICIENCY OF HARDENING OF METALLURGICAL EQUIPMENT SPARE PARTS BY HARD ALLOY

2019 ◽  
Vol 61 (12) ◽  
pp. 939-947
Author(s):  
V. А. Bystrov
Keyword(s):  
Wear Resistance ◽  
High Temperature ◽  
Service Life ◽  
Hard Alloy ◽  
Solid Particle ◽  
Thermal Stresses ◽  
Spare Parts ◽  
Solid Particles ◽  
High Temperature Wear ◽  
Hardening Process

Composite  materials  (CM)  are  widely  used  for  hardening  of  wearing parts operating at high temperature wear types. They are based  on  high-melting  hard  alloys,  as  which  are  used  carbides  of  transition  metals  of  IV – VI  groups A  determining  the  physics  of  high-temperature wear. For these purposes baked TiC of TN 20 type on the basis  of (Ti, Mo)C – Ni – Mo is used that has a ring structure preventing the  formation of complex alloyed structures on the bounda ry of solid particle-matrix. Due to the minimal solubility of the sintered hard alloy of  TN 20 type in the alloy-bond, at the interface of solid particle – matrix  practically does not stand out complex structural phases causing embrittlement and growth of residual thermal stresses and strains. It leads  to increased wear resistance and longer service life of hardened parts.  In order to increase the opera ting efficiency of metallurgical units due  to  hardening  of  spare  parts  with  a  composite  material  based  on  sintered hard alloy of the TN 20 type using electroslag surfacing (ESW),  a comprehensive program has been developed to control the efficiency  of hardening parts. In the management of hard alloy surfacing the special  attention  is  given  to  heat  and  high  temperature  wear  resistance  determined  by  the  set  of  CM  properties  of  solid  particles.  Therefore,  maintaining of high mechanical, thermal and energy characteristics of  carbides and decrease of the solubility of solid particles in a CM matrix  at surfacing is a priority for improving efficiency in hardening process  of spare parts. Integrated ESW management program for CM is based  on  effects,  aimed  to  prevent  the  formation  of  complex  alloyed  structures on surface of the solid section of particle-matrix; to reduce thermal stresses and deformations (leading to the cracks formation, chipping and deleting solid particles in abrasive wear) and to improve high  temperature wear resistance. Use of the developed control systems for  hardening  process  of  metallurgical  equipment  wearing  parts  has  significantly  increased  the  service  life  of  spare  parts  and  producti vity  of  the metallurgical units, which ensured a certain economic effect.

scholarly journals Investigation of the Technological Possibility of Laser Hardening of Stainless Steel 14Cr17Ni2 to a Deep Depth of the Surface

Metals ◽  
2021 ◽  
Vol 12 (1) ◽  
pp. 5
Author(s):  
Vladislav Somonov ◽  
Igor Tsibulskiy ◽  
Ruslan Mendagaliyev ◽  
Alexander Akhmetov
Keyword(s):  
Stainless Steel ◽  
Laser Beam ◽  
Laser Processing ◽  
Quantitative Estimation ◽  
Hardened Layer ◽  
Laser Hardening ◽  
Structural Components ◽  
Technological Possibility ◽  
Deep Depth ◽  
Number Of Passes

The article presents the results of a research of the process of laser hardening of steel 14Cr17Ni2 (AISI 431) by radiation of a high-power fiber laser LS-16. Assessment of the theoretically possible maximum depth in laser processing without additional beam transformations, the use of additional coatings and devices were shown. The results of experiments on increasing the depth of the hardened layer during laser processing by using scanning of the laser beam and optimally selected mode parameters without scanning are demonstrated. The influence of the number of passes on the depth of the hardened layer is investigated. The microstructure of hardened samples was studied and quantitative estimation of structural components was carried out. The microhardness of hardened samples at different modes of laser hardening was measured.

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