scholarly journals Laser Surface Hardening of Ni-hard White Cast Iron

Metals ◽  
2020 ◽  
Vol 10 (6) ◽  
pp. 795
Author(s):  
Samar Reda Al-Sayed ◽  
Ahmed Magdi Elshazli ◽  
Abdel Hamid Ahmed Hussein
Keyword(s):  
Wear Resistance ◽  
Cast Iron ◽  
Impact Toughness ◽  
Surface Hardening ◽  
White Cast Iron ◽  
Laser Surface ◽  
Hard Alloys ◽  
The Core ◽  
Laser Surface Hardening ◽  
The Impact

Laser surface treatment on two different types of nickel–chromium white cast iron (Ni-hard) alloys (Ni-hard 1 and Ni-hard 4) was investigated. Nd:YAG laser of 2.2-kw with continuous wave was used. Ni-hard alloys are promising engineering materials, which are extensively used in applications where good resistance to abrasion wear is essential. The conventional hardening of such alloys leads to high wear resistance nevertheless, the core of the alloy suffers from low toughness. Therefore, it would be beneficial to harden the surface via laser surface technology which keeps the core tough enough to resist high impact shocks. A laser power of different levels (600, 800 and 1000 Watts) corresponding to three different laser scanning speeds (3, 4 and 5 m·min−1) was adopted hoping to reach optimum conditions for wear resistance and impact toughness. The optimum condition for both properties was recorded at heat input of 16.78 J·mm−2. The present findings reflect that the microhardness values and wear resistance clearly increased after laser hardening by almost three times due to laser surface hardening, whereas, the impact toughness was increased from five joules obtained from conventionally heat-treated samples to 6.4 J as gained from laser-treated samples.

Effects of CO2 Laser Surface Hardening in the Unlubricated Wear of Ductile Cast Iron Against Alumina

1996 ◽  
Vol 118 (4) ◽  
pp. 748-752 ◽  
Author(s):  
C. Papaphilippou ◽  
M. Vardavoulias ◽  
M. Jeandin
Keyword(s):  
Wear Resistance ◽  
Cast Iron ◽  
Co2 Laser ◽  
Surface Hardening ◽  
Normal Load ◽  
Ductile Cast Iron ◽  
Laser Surface ◽  
Sliding Velocity ◽  
Wear Coefficient ◽  
Laser Surface Hardening

The microstructure of a ferrito-pearlitic ductile cast iron has been modified by CO2 laser surface hardening. Analysis of the laser-processed surfaces showed a dramatic increase in microhardness. Dry sliding wear of laser-treated specimens against an alumina counterbody has been investigated by “ball-on-disk” testing. The evolution of the wear coefficient, as well as metallographic observations, revealed an oxidational wear mechanism. The wear resistance of the laser-treated samples was significantly enhanced. The laser-treated cast iron has a better resistance to abrasion and plastic deformation. The improvement of the wear resistance was due to the fine and homogeneous microstructure produced after laser-treatment. Wear plots showing the evolution of wear coefficient with normal load, sliding velocity, and humidity have been established. The wear of the laser-treated cast iron is not influenced by the variation of operating conditions (normal load, sliding velocity, and relative humidity).

Laser Surface Hardening of Gray Cast Iron Used for Piston Ring

2002 ◽  
Vol 11 (3) ◽  
pp. 294-300 ◽  
Author(s):  
Jong-Hyun Hwang ◽  
Yun-Sig Lee ◽  
Dae-Young Kim ◽  
Joong-Geun Youn
Keyword(s):  
Cast Iron ◽  
Surface Hardening ◽  
Piston Ring ◽  
Gray Cast Iron ◽  
Laser Surface ◽  
Gray Cast ◽  
Laser Surface Hardening

scholarly journals Enhancement of the Quality of the Shell-Core Bond Interface in Duplex Work Rolls Manufactured by Centrifugal Casting Used in Hot Strip Mills

Materials ◽  
2019 ◽  
Vol 12 (8) ◽  
pp. 1304 ◽  
Author(s):  
Alberto Cofiño-Villar ◽  
Florentino Alvarez-Antolin ◽  
Juan Asensio-Lozano
Keyword(s):  
Cast Iron ◽  
Impact Toughness ◽  
Centrifugal Casting ◽  
Complete Fusion ◽  
The Core ◽  
Hot Strip ◽  
Bond Interface ◽  
Hot Strip Mills ◽  
The Impact ◽  
Work Rolls

To ensure the formation of a sound shell-core bond interface free of defects between the shell and the core in work rolls used in the finishing stands of hot strip mills, a complete fusion of this interface must be achieved, avoiding excessive mixing of the two components and the formation of hard, fragile microstructures. The shell is made of white cast iron, alloyed with Ni and Cr, and the core is manufactured of grey cast iron spheroidal graphite in a pearlitic matrix. It is thus advisable to inoculate the shell with 0.6 kg/T SiCaMn, as this promotes discontinuity in the carbide network and leads to an increase in the impact toughness of the bond interface. Furthermore, inoculation of the shell with FeSi-La should be avoided, as this inoculant leads to an increase in graphite counts, promoting it with a lamellar morphology at the edge of the bond and hence reducing the impact toughness in this interface. Addition of Mg to the shell has been found to produce an increase in hardness in the regions adjacent to the bond interface.

scholarly journals MICROSTRUCTURE AND PROPERTIES OF HIGH CHROMIUM WHITE CAST IRONS ALLOYED WITH BORON

2021 ◽  
Vol 3 ◽  
pp. 137-141
Author(s):  
Julieta Kaleicheva ◽  
Krasimir Kirov ◽  
Valentin Plamenov Mishev ◽  
Zdravka Karaguiozova
Keyword(s):  
Mechanical Properties ◽  
Cast Iron ◽  
Impact Toughness ◽  
Boron Content ◽  
Bending Strength ◽  
White Cast Iron ◽  
Metallographic Analysis ◽  
Cast Irons ◽  
High Chromium ◽  
The Impact

The microstructure and mechanical properties of high chromium white cast iron with composition: 2,6÷3,4% C; 0,9÷1,1% Si; 0,8÷1,1% Mn; 1,0÷1,3% Mo; 12,3÷13,4% Cr, additionally doped with boron in an amount of 0,18% to 1,25% is investigated. The microstructure of six compositions of white cast irons is studied by means of an optical metallographic analysis - one without boron, and the others contain 0,18%; 0,23%; 0,59%; 0,96% and 1,25% boron. A test is performed to determine: hardness by the Rockwell method; microhardness; bending strength and impact toughness. It was found that at a boron content of 0,18%; 0,23% and 0,59%, the structure of white cast irons is subeutectic, with impact toughness in the range of 1,80÷1,52 J/cm2; with a boron content of 0,96%, the structure of white cast iron is close to the eutectic, with impact toughness 0,98 J/cm2 ; at a boron content of 1,25% the structure of white cast iron is supereutectic and the impact toughness decreases to 0,68 J/cm2. With a change in the boron content from 0,8% to 1,25%, the amount of carbide phase in the structure of white cast iron increases, which leads to an increase in hardness from 53 to 59 HRC. The highest bending strength (Rmi=660,85 MPa) was obtained in white cast irons with a boron content of 0,23%. 

Experiments of Laser Surface Engineering for the Green Remanufacturing of Railway Coupler

2008 ◽  
Vol 373-374 ◽  
pp. 354-357 ◽  
Author(s):  
C.Y. Liu ◽  
L.Y. Yu ◽  
W. Tian ◽  
J.C. Tang
Keyword(s):  
Wear Resistance ◽  
Surface Hardening ◽  
Surface Engineering ◽  
Impact Resistance ◽  
Laser Surface ◽  
Rolling Stock ◽  
Laser Surface Hardening ◽  
Class Steel ◽  
Laser Transformation Hardening ◽  
Improve Wear Resistance

To achieve sustainable development and to solve the question of resource recycling and environment protection, green remanufacturing should be considered in the life cycle of the used railway rolling-stock components. These invalidated components resulting from fatigue and wear, such as coupler, could be remanufactured using laser surface hardening technology as the key processing. The objective was to harden the coupler backend pinhole interface, and to repair the layer with wear and fatigue crack on the wall of pinhole. Laser transformation hardening and laser melt-solidification hardening was used to the new manufacturing process to improve wear resistance of the surface of coupler backend pinhole. Laser surface cladding was used to repair lost material area for the reason of wear or fatigue, in order to offset the geometry size and satisfy the assembly relationship, and to increase the strength, the hardness and the wear resistance of the substrate. To the E class steel, typical coupler metal, the related laser process variables and materials were test and optimized. For the sake of verification these tests, related hardening area mechanical behaviors examinations including hardness, wear resistance, impact resistance and metallographic examinations were given. The result of the examinations show that the laser hardening area joins with the substrate being metallurgic join, and the behaviors examined were equal or best than the substrate. These means that laser surface hardening technology could be applied to the green remanufacturing of railway couplers as key processing.

A Study on the Structures and Properties of B-Bearing Cast Steel for Wear Resistance

2010 ◽  
Vol 34-35 ◽  
pp. 878-882 ◽  
Author(s):  
Zhi Qiang Jiang ◽  
Xi Lan Feng ◽  
Xian Zhang Feng
Keyword(s):  
Wear Resistance ◽  
Cast Iron ◽  
Impact Toughness ◽  
Grain Boundary ◽  
White Cast Iron ◽  
Cast Steel ◽  
Lath Martensite ◽  
Solidification Structure ◽  
High Chromium ◽  
Structures And Properties

The microstructures of B-bearing cast steel containing 0.8-1.2 wt.%B, 0.8-1.2 wt.%Cr, 1.0-1.5 wt.%Mn, 0.6-1.0 wt.%Si and 0.10-0.25 wt.%C have been characterized by means of optical OM, SEM, EPMA and XRD. The solidification structure of B-steel consists of pearlite, ferrite, martensite and boride (Fe2B), while the hardness is 1430-1480 HV. Borides distribute along the grain boundary in the form of eutectic. Fine lath martensite and eutectic Fe2B can be obtained by water quenching at 1223 K-1273 K. The hardness and impact toughness of the B-steel exceed 55 HRC and 150 kJ/m2, respectively. The abrasion resistance determined using a pin abrasion tester is obviously higher than that of the martensitic cast steel and nears to the high chromium white cast iron.

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