scholarly journals Influence of Thermal Processing Factors, Linked to the Destabilisation of Austenite, on the Microstructural Variation of a White Cast Iron Containing 25% Cr and 0.6% Mo

Metals ◽  
2020 ◽  
Vol 10 (6) ◽  
pp. 832 ◽  
Author(s):  
Alejandro González-Pociño ◽  
Florentino Alvarez-Antolin ◽  
Juan Asensio-Lozano ◽  
Hugo Alvarez-Perez
Keyword(s):  
Cast Iron ◽  
Thermal Processing ◽  
White Cast Iron ◽  
Erosive Wear ◽  
Unit Cell ◽  
Cast Irons ◽  
Tempering Temperature ◽  
Eutectic Carbides ◽  
Processing Factors ◽  
Non Equilibrium

Hypoeutectic white cast irons containing 25% Cr are used in ore-processing industries due to their high resistance to erosive wear. Applying a Design of Experiments (DoE), the aim of this study is to analyse the influence of thermal processing factors on the microstructural variation of a white cast iron containing 25% Cr and 0.6% Mo. The carbides present in the as-cast state are of the M7C3, M2C, and M3C types. M2C carbides precipitate on the eutectic M7C3 carbides favoured by heterogeneous nucleation conditions. Two kinetics compete during the destabilisation of austenite. One dissolves those eutectic carbides precipitated as a result of non-equilibrium solidification (M7C3 and M2C), while the other enables the precipitation of secondary M7C3 and M23C6 carbides. The M7C3 carbides begin to precipitate first. Low destabilisation temperatures and short dwell times are insufficient to dissolve the precipitated eutectic carbides from non-equilibrium conditions, thus favouring the presence of M2C carbides, which are associated with Mo. The factor that has the greatest influence on hardness is the tempering temperature. The optimal tempering temperature is found to be 500 °C. Short tempering times maintain the distortion of the ferrite unit cell. The precipitation of Cr carbides during tempering requires a temperature of 500 °C and the prior dissolution of the carbon precipitated during the initial stages of said tempering. With short tempering times, the Cr atoms still remain dissolved in the ferrite, distorting its unit cell and increasing the hardness of the matrix constituent of the alloy.

scholarly journals The Joint Effects of Nitriding and Parameters Related to the Destabilisation of Austenite on Wear Resistance in White Cast Iron with 25% Cr

Metals ◽  
2021 ◽  
Vol 11 (1) ◽  
pp. 85
Author(s):  
Alejandro González-Pociño ◽  
Florentino Alvarez-Antolin ◽  
Juan Asensio-Lozano
Keyword(s):  
Wear Resistance ◽  
Cast Iron ◽  
White Cast Iron ◽  
Nitrided Layer ◽  
Erosive Wear ◽  
Air Cooling ◽  
Cast Irons ◽  
Eutectic Carbides ◽  
Noticeable Increase ◽  
Ionic Nitriding

In this article, the effects of an ionic nitriding treatment are analysed, together with deliberate variation of different thermal parameters associated with the destabilisation of austenite, on erosive wear resistance of white cast irons with 25% Cr. The methodology followed in this research was an experimental design, where six factors were analyzed by performing eight experiments. The thickness of the nitrided layer is much smaller than in white cast iron with lower percentages in Cr, never reaching 20 microns. The nitriding treatment entails considerable softening of the material underneath the nitriding layer. This softening behaviour becomes partially inhibited when the destabilisation temperature of austenite is 1100 °C and dwell times at such temperature are prolonged. This temperature seems to play a significant role in the solubilization of non-equilibrium eutectic carbides, formed during industrial solidification. The nitriding treatment leads to additional hardening, which, in these cases, favours a second destabilisation of austenite, with additional precipitation of secondary carbides and the transformation of retained austenite into martensite. Despite softening of the material, the nitriding treatment, together with air-cooling after destabilisation of the austenite, allows a noticeable increase in resistance to erosive wear.

Influence of Ni Content on Erosive Wear and Destabilization Heat Treatment Conditions Behavior of Multi Component White Cast Iron

2020 ◽  
Vol 998 ◽  
pp. 48-54
Author(s):  
Kenta Kusumoto ◽  
Kazumichi Shimizu
Keyword(s):  
Heat Treatment ◽  
Wear Resistance ◽  
Cast Iron ◽  
White Cast Iron ◽  
Erosive Wear ◽  
Wear Property ◽  
Eutectic Carbides ◽  
Secondary Carbides ◽  
Ni Content ◽  
Ni Addition

This study investigated the influence of nickel (Ni) addition on erosive wear property of multi-component white cast iron with good erosive wear resistance. Multi-component white cast irons (MWCIs) with 2 mass % of carbon (C), 5 mass % of chromium (Cr), molybdenum (Mo), tungsten (W), niobium (Nb) and 0, 3, 5 mass % of Ni were prepared as experimental materials. The heat treatment condition was quenching by forced air cooling after keeping the specimens at 1123K for 3.6ks. Specimens with size of 50mm×50mm×10mm were tested using a suction-type blasting machine. The test was conducted with impact angle of 30, 60 and 90 deg. at room temperature. Collision particles were irregular steel grids with average particle diameter of 770μm and hardness of 810HV1. The speed of air flow was about 100m/s while the speed of impact particles was around 20.0g/s and the total time of each experiment was 3600 sec.. According to the result, erosion rate was decreased with the increase of Ni content in all of the impact angles. Especially, MWCIs which contain 5 mass % Ni showed the most excellent erosive wear resistance. As reasons, it can be considered that with Ni addition, the volume fraction of eutectic carbides and secondary carbides was increased which enhanced the matrix structure and suppressed the surface deformation of the experimental surface. Therefore, the increasing of eutectic carbides and secondary carbides can be considered as the reason of erosive wear resistance increased.

Heat Treatments of Chromium-Manganese White Cast Irons for an Optimum Combination of Wear Resistance and Impact Strength

1984 ◽  
Vol 34 ◽  
Author(s):  
A. Basak ◽  
J. Penning ◽  
J. Dilewijns
Keyword(s):  
Wear Resistance ◽  
Cast Iron ◽  
Impact Strength ◽  
White Cast Iron ◽  
Heat Treatments ◽  
Optimum Combination ◽  
Austenitic Matrix ◽  
Cast Irons ◽  
Martensitic Matrix ◽  
Eutectic Carbides

As cast microstructures of chromium-manganese white cast iron containing about 2.5 % carbon, 0.7 % silicon, 4.5 % manganese and 11.5 % chromium reveal discontinuous plate like eutectic carbides embedded in a mainly austenitic matrix[1](Fig.1). This austenitic matrix accounts for a higher impact strength and a lower wear resistance. It has been reported elsewhere [2] that a martensitic matrix containing uniformly distributed fine alloy carbides exhibits a very good wear resistance, but lower impact strength.

High-temperature erosive wear characteristics and bonding requirements of hard carbides cast-in insertion multi-component white cast iron

Wear ◽  
2021 ◽  
pp. 203672
Author(s):  
Kenta Kusumoto ◽  
Kazumichi Shimizu ◽  
V.G. Efremenko ◽  
Hiroya Hara ◽  
Masato Shirai ◽  
...  
Keyword(s):  
Cast Iron ◽  
High Temperature ◽  
White Cast Iron ◽  
Erosive Wear ◽  
Wear Characteristics

Effect of the Morphology, Size, Distribution and Homogeneity of Carbides and Matrix on Wear Resistance in High Cr-Alloys White Cast Iron

2021 ◽  
Vol 1016 ◽  
pp. 56-62
Author(s):  
Carlos Camurri ◽  
Jasmín Maril ◽  
Eric Romero
Keyword(s):  
Wear Resistance ◽  
Cast Iron ◽  
White Cast Iron ◽  
Wear Behavior ◽  
Hardness Test ◽  
Mining Equipment ◽  
Cast Irons ◽  
Loss Of Mass ◽  
Ultimate Purpose ◽  
Wear Tests

The aim of this work was to study the wear behavior of high-chromium white cast iron of families ASTM A-532 II (B, D) and III A, used in mining equipment, in order to establish relationships between the wear resistance, hardness and microstructure of the alloys, with the ultimate purpose of predicting their resistance to abrasion. Samples from these cast irons were subjected to mechanical wear tests by rotating drum, then their micro/macro hardness was measured and microstructure analyzed by optical and scanning electron microscopy .It was found that when the macroscopic hardness differences were significant there was a strong correlation between the hardness and the loss of mass due to abrasion-impact wear. By contrast, when the alloys had similar hardness, the wear resistance was determined by morphology, size, and the distribution and connectivity of carbides and matrix and therefore was not predictable by an only simple hardness test.

White Cast Irons with Acoustic Properties

2014 ◽  
Vol 659 ◽  
pp. 81-84
Author(s):  
Alexandru Ioan Girnet ◽  
Daniela Lucia Chicet ◽  
Mihai Axinte ◽  
Sergiu Stanciu ◽  
Ion Hopulele
Keyword(s):  
Cast Iron ◽  
Experimental Determination ◽  
Elastic Energy ◽  
Physical Theory ◽  
Scientific Explanation ◽  
White Cast Iron ◽  
Musical Instruments ◽  
Acoustic Properties ◽  
Sound Waves ◽  
Cast Irons

There is the opinion, imprinted by tradition, that only bronze alloyed with tin may be used to build bells, musical instruments or sound transmitters, without the need to bring a scientific explanation. Starting from the physical theory and experimental determination that sound travels only through bodies with elastic proprieties, a study over acoustic white cast iron was proposed. After convincing experiments, it results that white cast irons have good properties for producing and transmitting sound waves. The measurements focused two fundamental aspects, the elastic energy available for producing and transmitting sounds and amortization, resulting that white cast irons can substitute with success bronze with tin or even better properties.

scholarly journals Effect of Co Addition on High Temperature Erosive Wear Characteristics of Fe-C-Cr-Mo-W-V Multi-Component White Cast Iron

2017 ◽  
Vol 58 (6) ◽  
pp. 927-931
Author(s):  
Yao Zhang ◽  
Kazumichi Shimizu ◽  
Kenta Kusumoto ◽  
Kazuhiro Tamura ◽  
Hiroya Hara ◽  
...  
Keyword(s):  
Cast Iron ◽  
High Temperature ◽  
White Cast Iron ◽  
Erosive Wear ◽  
Wear Characteristics ◽  
Co Addition

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%. 

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