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.

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.

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.

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.

scholarly journals A New Look at Cast Iron Microstructure

2003 ◽  
Vol 11 (5) ◽  
pp. 42-45
Author(s):  
Janina M. Radzikowska
Keyword(s):  
Wear Resistance ◽  
Cast Iron ◽  
Ductile Iron ◽  
White Cast Iron ◽  
Equilibrium Diagram ◽  
Damping Properties ◽  
Cast Irons ◽  
Malleable Iron ◽  
Alloy Cast ◽  
Grey Iron

Cast irons belong to a family of iron-carbon (Fe - C) alloys with free carbon in the form of graphite, a very soft constituent of iron microstructures, that improves machinability and damping properties of castings, or combined carbon, in the form of cementite, that improves wear resistance. Graphitic cast irons include grey iron, compacted iron, malleable iron, and ductile iron, Cementite irons include white cast iron and alloy cast irons. Solidification of graphite directly from molten metal takes place between 1145°C (2093 °F) and 1152 °C (2105 °F), according to the Fe-C equilibrium diagram. The above considerations regard only pure Fe - C alloys.

scholarly journals Heat Treatment in High Chromium White Cast Iron Ti Alloy

2014 ◽  
Vol 2014 ◽  
pp. 1-9 ◽  
Author(s):  
Khaled M. Ibrahim ◽  
Mervat M. Ibrahim
Keyword(s):  
Heat Treatment ◽  
Tensile Strength ◽  
Wear Resistance ◽  
Cast Iron ◽  
Impact Toughness ◽  
White Cast Iron ◽  
High Chromium ◽  
Eutectic Carbides ◽  
Secondary Carbides ◽  
Ti Addition

The influence of heat treatment on microstructure and mechanical properties of high chromium white cast iron alloyed with titanium was investigated. The austenitizing temperatures of 980°C and 1150°C for 1 hour each followed by tempering at 260°C for 2 hours have been performed and the effect of these treatments on wear resistance/impact toughness combination is reported. The microstructure of irons austenitized at 1150°C showed a fine precipitate of secondary carbides (M6C23) in a matrix of eutectic austenite and eutectic carbides (M7C3). At 980°C, the structure consisted of spheroidal martensite matrix, small amounts of fine secondary carbides, and eutectic carbides. Titanium carbides (TiC) particles with cuboidal morphology were uniformly distributed in both matrices. Irons austenitized at 980°C showed relatively higher tensile strength compared to those austenitized at 1150°C, while the latter showed higher impact toughness. For both cases, optimum tensile strength was reported for the irons alloyed with 1.31% Ti, whereas maximum impact toughness was obtained for the irons without Ti-addition. Higher wear resistance was obtained for the samples austenitized at 980°C compared to the irons treated at 1150°C. For both treatments, optimum wear resistance was obtained with 1.3% Ti.

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 Erosive Wear Resistance Regarding Different Destabilization Heat Treatments of Austenite in High Chromium White Cast Iron, Alloyed with Mo

Metals ◽  
2019 ◽  
Vol 9 (5) ◽  
pp. 522 ◽  
Author(s):  
Alejandro Gonzalez-Pociño ◽  
Florentino Alvarez-Antolin ◽  
Juan Asensio-Lozano
Keyword(s):  
Wear Resistance ◽  
Retained Austenite ◽  
Erosive Wear ◽  
Sharp Decrease ◽  
Heat Treatments ◽  
Structural Refinement ◽  
Cast Irons ◽  
Eutectic Carbides ◽  
Secondary Carbides ◽  
The Matrix

With the aim of improving erosive wear resistance in hypoeutectic white cast irons with 18% Cr and 2% Mo, several samples of this grade were subjected to different heat treatments at 1000 °C to destabilize the austenite. The dwell times at this temperature varied from 4 to 24 h and the samples were cooled in air or oil. The existing phases were identified and quantified by applying the Rietveld structural refinement method. The results were correlated with the hardness of the material and with the microhardness of the matrix constituent. The greatest resistance to erosive wear was achieved in those samples that had a higher percentage of secondary carbides. The longer the dwell time at the destabilization temperature of austenite, the greater the amount of precipitated secondary carbides. However, the percentage of dissolved eutectic carbides is also higher. These eutectic carbides were formed as a result of non-equilibrium solidification. Low cooling rates (in still air) can offset this solution of eutectic carbides via the additional precipitation of secondary carbides in the 600–400 °C temperature range. A sharp decrease is observed in the percentage of retained austenite in those treatments with dwell times at 1000 °C equal to or greater than 12 h, reaching minimum values of around 2% volume. The percentage of retained austenite was always lower after oil quenching and the hardness of oil quenched samples was observed to be greater than those quenched in air. In these samples, the maximum hardness value obtained was 993 HV after a 12 h dwell, which result from the optimum balance between the percentages of retained austenite and of precipitated carbides.

Research on the Wear Resistance of High-Chromium White Cast Iron and Multi-Component White Cast Iron

2013 ◽  
Vol 859 ◽  
pp. 64-69
Author(s):  
Chien Lung Yen ◽  
Fu Je Chen ◽  
Yung Ning Pan
Keyword(s):  
Wear Resistance ◽  
Cast Iron ◽  
Linear Relationship ◽  
White Cast Iron ◽  
Wear Test ◽  
Specimen Surface ◽  
Testing Time ◽  
Cast Irons ◽  
High Chromium ◽  
Treatment Conditions

The pin-on-disk wear test and solid particle erosion test were used to investigate the wear resistance property of both high chromium white cast iron and multi-component white cast iron with optimal alloy compositions and heat treatment conditions. Experimental results indicate that a linear relationship between the wear lose and the testing time exists for high chromium white cast irons. Apparent scratch grooves and sheared pits appeared on the specimen surface. Subsurface observations found pit depths of some 4.5~8.0 mm. Crack propagation routes were clearly visible along the martensitic grain boundaries for alloys in the as-quenched state. Tempering treatment increases the toughness of the alloy, resulting in an increase in the resistance to crack formation. On the other hand, the multi-component white cast irons exhibited a non-linear relationship between the wear lose and the testing time. Relatively shallow scratches were found on the specimen surface, and pit depths of about 4.0 mm were observed through subsurface observations. Tempering at 570°C caused a reduction in hardness of the alloy, and therefore, the fracture mode tends to be ductile. As a result, deformation only occurred in crater regions with no clear evidence of spreading.

ALMANITE W

Alloy Digest ◽  
1974 ◽  
Vol 23 (3) ◽  
Keyword(s):  
Heat Treatment ◽  
Fracture Toughness ◽  
Impact Strength ◽  
Surface Treatment ◽  
High Hardness ◽  
Heat Treating ◽  
Austenitic Matrix ◽  
Matrix Type ◽  
Martensitic Matrix ◽  
Cast Condition

Abstract ALMANITE W comprises a series of three types of austenitic-martensitic white irons characterized by high hardness and relatively good impact strength. Type W1 has a pearlitic matrix. Type W2 has a martensitic matrix, Type W4 is highly alloyed to provide an austenitic matrix in the as-cast condition which may be further modified to give a martensitic matrix by heat treatment or by refrigeration. This datasheet provides information on composition, hardness, elasticity, and tensile properties as well as fracture toughness. It also includes information on casting, heat treating, machining, and surface treatment. Filing Code: CI-42. Producer or source: Meehanite Metal Corporation.

Sign in / Sign up

Export Citation Format

Share Document