scholarly journals Evaluation of Hardness, Sliding Wear and Strength of a Hypoeutectic White Iron with 25%Cr after Heat Treatments

Metals ◽  
2021 ◽  
Vol 11 (6) ◽  
pp. 947
Author(s):  
Alejandro González-Pociño ◽  
Juan Asensio-Lozano ◽  
Florentino Álvarez-Antolín ◽  
Ana García-Diez
Keyword(s):  
Thermal Treatment ◽  
Retained Austenite ◽  
Sliding Wear ◽  
Adhesive Wear ◽  
Lower Bainite ◽  
White Iron ◽  
Cast Irons ◽  
Rupture Stress ◽  
Resistance To Sliding ◽  
Industrial Mining

Hypoeutectic white cast irons with a high chrome content are commonly used in the industrial mining sector where there is a demand for both high resistance to adhesive wear and an acceptable toughness for the absorption of impacts and falls of diverse materials. Through the application of a design of experiment (DoE) technique, factors related to thermal treatment are analyzed with respect to resistance to sliding wear, maximum rupture stress and toughness. The results show that, in order to increase resistance to adhesive wear, it is convenient to use destabilization temperatures of 1050 °C and tempering of two hours at 400 °C. This foments a very hard martensite and a high proportion of highly alloyed retained austenite, which, with low tempering, achieves a precipitation of carbides from this austenite with hardly any loss of hardness of the martensite. In order to increase the energy which this material is capable of absorbing until breakage, furnace cooling set at 150 °C followed by tempering at 550 °C would be favorable. Slower cooling implies a greater quantity of conditioned retained austenite, so that, following this, it may be transformed into lower bainite with a high density of finely dispersed precipitated carbides. Furthermore, this tempering also allows the transformation of martensite into ferrite with finely dispersed carbides.

scholarly journals Dry Sliding Wear Behaviours of Valve Seat Inserts Produced from High Chromium White Iron

2014 ◽  
Vol 34 (7) ◽  
pp. 635-641
Author(s):  
Ali Kalyon ◽  
Dursun Özyürek ◽  
Mustafa Günay ◽  
Hasan Aztekin
Keyword(s):  
Sliding Wear ◽  
Dry Sliding Wear ◽  
White Iron ◽  
X Ray Diffraction ◽  
Valve Seat ◽  
Cast Irons ◽  
High Chromium ◽  
Service Conditions ◽  
Valve Seat Inserts ◽  
Pin On Disk

Abstract In this present study, wear behaviours of high chromium white iron valve seat inserts and tappets used in the automotive sector were investigated. Wear behaviours of three different rates of high chromium white cast irons (containing 10, 12 and 14% chromium) were examined under heavy service conditions. For that purpose, the produced valve seat inserts were characterized through Scanning Electron Microscopy (SEM), Energy Dispersive Spectroscopy (EDS), X-ray diffraction (XRD) and hardness measurements. They were tested at a sliding speed of 1 ms−1, under 120 N load and for six different sliding distances (500, 1000, 1500, 2000, 2500, 3000 m) by using a standard wear apparatus (pin-on-disk type). The result showed that as the amount of Cr increased in the alloys, their hardness decreased. The decrease in the hardness were considered to be as the result of transformation of M7C3 carbides into M23C6 carbides in the structure. This decrease in hardness with increasing chromium content also increased the weight loss. Thus, it was determined that the white iron with 14% Cr (which had a greater amount of M23C6 carbides) was subjected to the highest wear.

Microstructure, Mechanical Properties and Wear Resistance of WC/Co Nanocomposites

1996 ◽  
Vol 457 ◽  
Author(s):  
Kang Jia ◽  
Traugott E. Fischer
Keyword(s):  
Mechanical Properties ◽  
Wear Resistance ◽  
Sliding Wear ◽  
Adhesive Wear ◽  
Liquid Phase Sintering ◽  
Binder Phase ◽  
Slow Cooling ◽  
Diamond Indenter ◽  
Grain Fragmentation ◽  
Spray Conversion

ABSTRACTThe microstructure, mechanical properties, abrasion and wear resistance of WC-Co nanocomposites synthesized by the spray conversion technique by McCandlish, Kear and Kim have been investigated. The binder phase of WC-Co nanocomposites is enriched in W and C, compared to conventional cermets. Small amorphous regions exist in the binder despite the slow cooling after liquid phase sintering. Few dislocations are found in the WC grains. The increased WC content and the amorphous regions modify (i.e. strengthen) the binder phase of the composites. Vickers indentation measurements show a hardness of the nanocomposites reaching 2310 kg/mm2. While the toughness of conventional cermets decreases with increasing hardness, the toughness does not decrease further as the WC grain size decreases from 0.7 to 0.07 μm. but remains constant at 8 MPam1/2. Scratches caused by a diamond indenter are small, commensurate with their hardness. These scratches are ductile, devoid of the grain fracture that is observed with conventional materials. The abrasions resistance of nanocomposites is about double that of conventional materials, although their hardness is larger by 23% only. This is due to the lack of WC grain fragmentation and removal which takes place in conventional cermets. Sliding wear resistance of WC/Co is proportional to their hardness; no additional benefit of nanostructure is obtained. This results from the very small size of adhesive wear events in even large WC grains.

Sliding Wear of Cu-Ag Alloy in Cu Cladding Al Contact Wire

2012 ◽  
Vol 538-541 ◽  
pp. 1924-1928
Author(s):  
Ying Hui Zhang ◽  
Bin Yang ◽  
Jing Qin ◽  
Hong Bo Sui
Keyword(s):  
Plastic Deformation ◽  
Surface Morphology ◽  
Sliding Wear ◽  
Adhesive Wear ◽  
Wear Behavior ◽  
Contact Wire ◽  
Sliding Direction ◽  
Black Oxide ◽  
Worn Surface

The sliding wear behavior of Cu-Ag alloy in Cu cladding Al contact wire against 45# steel or bronze block was tested, then surface morphology was investigated in different load and velocity. The results indicated that the worn surface had plastic deformation and many clear furrows and cutting traces along the sliding direction. There were black oxide of copper on the worn surface. The oxide was both abrasive and lubrication. The mechanisms transformed from abrasive attrition into adhesive wear. Spalling pits and adhesive blocks with bronze friction were significantly bigger than that of steel, and the mechanisms was adhesive wear.

Electrochemical Corrosion Behavior of Different Graphite Shapes Cast Irons in Acidic Solution

2014 ◽  
Vol 906 ◽  
pp. 275-282
Author(s):  
Zhu Huan Yu ◽  
Jun Feng Qiang ◽  
Hui Lu Li
Keyword(s):  
Electron Microscopy ◽  
Corrosion Resistance ◽  
Corrosion Behavior ◽  
Driving Force ◽  
Acidic Solution ◽  
Electrochemical Corrosion ◽  
White Iron ◽  
Cast Irons ◽  
The Matrix ◽  
Electrochemical Corrosion Behavior

The effect of graphite shapes on the electrochemical corrosion behavior of cast iron was studied by means of weight loss tests, electrochemical measurements and electron microscopy. It was found that the electrochemical corrosion behavior of graphite is significantly different from one other, and the corrosive potential difference between carbide ad the matrix is the main driving force of the different phase corrosions. Among them, the center A type and edge D type graphite exhibited the highest corrosion resistance. The corrosion of white iron is worst, because there are so many type carbides in white iron and so there is an obvious tendency to produce micro-cell in white iron.

scholarly journals Wear Resistance of High C High Si Steel with Low Retained Austenite Content and Kinetically Activated Bainite

Metals ◽  
2020 ◽  
Vol 10 (5) ◽  
pp. 672 ◽  
Author(s):  
Bojan Podgornik ◽  
Mihael Brunčko ◽  
Peter Kirbiš
Keyword(s):  
Wear Resistance ◽  
Retained Austenite ◽  
Adhesive Wear ◽  
Cold Work ◽  
High Hardness ◽  
Bearing Steel ◽  
Austenite Content ◽  
Surrounding Matrix ◽  
Aisi D2 ◽  
Wear Mode

A novel high C high Si carbide free bainitic steel was developed for the production of cold work tools, knives, and rolls, requiring high hardness, toughness, as well as abrasive/adhesive wear resistance and resistance to galling at low costs. The steel was tribologically tested in dry sliding conditions under abrasive and adhesive wear mode, facilitated by using alumina and bearing steel ball as a counter-material, respectively. It was determined that carbide dissolution occurs under high contact pressures, thereby enriching the surrounding matrix with carbon and locally increasing the retained austenite content. The high retained austenite at the sliding interface increases the steels work hardening capacity and promotes superior wear resistance when compared to much more alloyed cold work tool steel, such as AISI D2. The steel has a high resistance to galling as determined by sliding against a soft steel bar due to its chemical composition.

Wear Behavior of Laser Surface-Hardened Gray and Ductile Cast Irons: Part 1—Sliding Wear

1986 ◽  
Vol 108 (3) ◽  
pp. 326-333 ◽  
Author(s):  
P. A. Molian ◽  
Mark Baldwin
Keyword(s):  
Sliding Wear ◽  
Continuous Wave ◽  
Wear Behavior ◽  
Test System ◽  
Case Depth ◽  
Laser Surface ◽  
Dramatic Improvement ◽  
Cast Irons ◽  
Severe Wear ◽  
Depth Analysis

The influence of laser surface transformation hardening on the sliding wear characteristics and mechanisms of ASTM class-40 gray and 80-55-06 ductile cast irons was investigated. A 1.2 kw, continuous wave, CO2 gas laser was employed to scan the beam successively across the surfaces of cast irons to generate hardened and tempered layers with various case depths. A pin-on-disk wear test system was then used to study the wear behavior as functions of case depth, microstructure, hardness, and surface roughness. As expected, a dramatic improvement in resistance to scuffing and sliding wear was obtained. However, the most significant result was the occurrence of negligible oxidational wear for a load range that increased with an increase in case depth. Resistance to mild and severe wear, mild-to-severe wear transition load, and frictional heating were increased with an increase in case depth. Analysis of worn surfaces and wear debris revealed that negligible oxidational wear in laser-hardened irons is due to two mechanisms: oxidation and adhesion of oxide to the substrate. In contrast, the mild oxidational wear of untreated irons occurs through the formation of loose oxide debris. The mechanisms of severe wear were plastic deformation, delamination, and adhesion; the rate process was controlled by adhesion for laser hardened irons and delamination for untreated irons.

Phosphorus Content Dependent Sliding Wear Behaviors of Electroless Ni-P Deposits

2010 ◽  
Vol 663-665 ◽  
pp. 1187-1191
Author(s):  
Yan Hai Cheng ◽  
Zhen Cai Zhu ◽  
Zheng Tong Han ◽  
Yong Zou
Keyword(s):  
Sliding Wear ◽  
Phosphorus Content ◽  
Adhesive Wear ◽  
Wear Behavior ◽  
High Phosphorus ◽  
Heat Treated ◽  
Before And After ◽  
Electroless Ni ◽  
Wear Tests ◽  
High Phosphorus Content

In this work, the deposits of electroless Ni-P deposits prepared by different process were studied by means of EPMA, mirohardness tester, friction-wear instrument. The experimental results showed that the microhardness of the deposits was directly affected by the phosphorus content, which was depended on the processes of electroless. The friction-wear tests showed that the Ni-P deposits composing of less phosphorus content exhibited lower friction coefficient before and after being heat treated. The conclusion was drawn that the lower phosphorus content deposits could improve the wear resistance under the condition of both as-plated and after being heat treated Ni-P deposits. The wear behavior was typical of a pure adhesive wear mechanism for the high phosphorus content deposit at as-plated and after being heat treated at 200oC. However, for the high phosphorus content deposit after being heat treated at 400oC, the alternate friction mechanisms were emerged from adhesive wear to abrasive wear with the precipitating of hard Ni3P particles during Ni-P deposits suffering friction tests

Dry Sliding Wear Behavior of A356-ZrO2 Metal Matrix Composite

2015 ◽  
Vol 1125 ◽  
pp. 116-120
Author(s):  
Hamidreza Ghandvar ◽  
Saeed Farahany ◽  
Mohd Hasbullah Idris ◽  
Mohammadreza Daroonparvar
Keyword(s):  
Metal Matrix ◽  
Sliding Wear ◽  
Adhesive Wear ◽  
Wear Behavior ◽  
A356 Alloy ◽  
Matrix Alloy ◽  
Dry Sliding Wear ◽  
Dry Sliding ◽  
Friction Behavior ◽  
Wear And Friction

Dry sliding wear and friction behavior of cast A356 Al-Si alloy and composite containing 5wt. % ZrO2 particles were studied by means of a pins-on-disk apparatus over loads of 5N, 20N and a sliding speed of 0.628m/s. The experimental results showed that the composites exhibited a higher wear resistance in comparison to that of the unreinforced A356 alloy. The friction coefficient of tested materials increased with increasing applied load from 5 to 20 N. FESEM investigations revealed that the wear mechanism of the A356 matrix alloy changed from sever abrasive, adhesive wear into mild abrasion and adhesive wear with addition of 5wt. % ZrO2 reinforcement particles.

Sign in / Sign up

Export Citation Format

Share Document