Multi-component White Cast Iron Research Articles

Effect of V Content on Microstructure and Heat Treatment Behavior of Multi-component White Cast Iron used for Hot Work Roll Applications

Effect of V Content on Microstructure and Heat Treatment Behavior of Multi-component White Cast Iron used for Hot Work Roll Applications

Influence of Tempering Temperature on Abrasive-Wear Performance of High-Chromium-Based Multicomponent White Cast Iron

Recently, high-Cr multicomponent white cast iron after quenching is known to have superior abrasive-wear resistance. However, this material is prone to cracking due to the precipitation of very hard carbides resulting in very limited application. However, the cracking tendency might be reduced by appropriate tempering temperature. Therefore, the three-body abrasive-wear resistance of 18 wt.% and 27 wt.% Cr based on 3 wt.% Mo, W, V, and Co with different temperatures of tempering was studied. These are abbreviated as 18Cr MCCI and 27Cr MCCI. The tempering temperature range was 653–813 K with an interval of 20 K after the quenching process. The quenched specimens were used as comparison materials, and three tempered specimens were selected. Thus, there are quenched (Q), quenched-tempered at low temperature (TLT), quenched-tempered at medium temperature (TMT), and quenched-tempered at high temperature (THT) specimens. From the results, it can be known that the wear resistance of the material decreases as Cr percentage and tempering temperature increase. Therefore, the 18Cr MCCI Q has better wear performance than specimens of other conditions. Yet, different results occur in the group of 27Cr MCCI. The material is more wear-resistant after tempering despite the lower hardness of the material. This might be owing to the higher fracture toughness of the M7C3 carbide, which is higher after the tempering process compared with quenching only. Therefore, it can be said that it is important to maintain the hardness of the material to achieve better wear resistance. However, in materials containing large M7C3 carbides, the fracture toughness of carbides should also be considered.

Three-Body Abrasive Wear-Resistance Characteristics of a 27Cr-Based 3V-3Mo-3W-3Co Multicomponent White Cast Iron with Different Ti Additions

A multicomponent white cast iron containing 5 wt.% each of Cr, V, Mo, W, and Co (MWCI) is known to have excellent wear-resistance properties due to the precipitation of some very hard carbides, such as MC, M2C, and M7C3. However, it seems possible to improve the wear resistance of MWCI by increasing the carbide volume fraction (CVF). Thus, 27 wt.% Cr based on 3 wt.% each of V, W, Mo, and Co was simultaneously added into the white cast iron. To avoid the tendency of carbides to crack due to high M7C3 precipitation levels, titanium (0–2 wt.% Ti) was also added. A rubber wheel abrasive machine test according to the ASTM G65 standard with two different abrasive particle sizes (average: 75 and 300 μm) was used to evaluate the wear characteristics of the alloy. The results show that the wear resistance of these new alloys (0Ti, 1Ti, and 2Ti) is lower than that of MWCI in small silica sand, owing to the lower hardness. However, a different condition is present in large silica sand, for which the abrasive wear resistance of MWCI is lower than that of the 0Ti and 1Ti specimens. In addition, TiC precipitation effectively refined the size of M7C3 carbides and reduced their cracking tendency. Thus, the wear resistance of 1Ti is comparable to that of 0Ti, although it has a lower hardness factor. However, the wear resistance of the alloy significantly decreased following the addition of Ti by more than 1 wt.% due to the lower hardness and CVF. Therefore, it can be said that the abrasive wear characteristics of the alloy are not only affected by the hardness, but also by the micro-structural constituents (type, size, and volume fraction of carbides) and silica sand size.

Tribological Characteristics of High-Chromium Based Multi-Component White Cast Irons

It has been evaluated the relationship between the microstructure and three-body abrasive wear behavior of high-chromium (18 and 27 mass % Cr) based (3 mass % each of V, Mo, W, and Co) multicomponent white cast iron materials (high-Cr MWCIs). It was also compared to MWCI to determine the service life of the materials. The results indicate that the microstructure of the material is composed of mainly martensite matrix and different types of precipitated carbides. The wear resistances of both the high-Cr MWCIs are higher than MWCI owing to the higher hardness (4–18% increment in hardness), although they contain fewer carbide types. The carbide volume fraction of high-Cr MWCI increases with increase in the Cr content, but the hardness decreases, leading to a reduction in wear resistance. This is because the transition metal significantly consumes C atoms to form more eutectic carbides during solidification, which is exacerbated by the depletion of C in the matrix during heat treatment to form coarser secondary carbides. This means that increasing the addition of Cr does not always lead to an increase in the hardness or wear resistance of the material. In addition, the wear resistance of 27Cr MWCI after tempering (wear rate: 8.80 × 10−5 g/m) is higher than that after quenching (wear rate: 9.25 × 10−5 g/m) owing to the increase in the fracture toughness of M7C3 carbide. This is contrary to the case of 18Cr-MWCI; the wear resistance after tempering (wear rate: 5.29 × 10−5 g/m) is worse than that after quenching (wear rate: 5.11 × 10−5 g/m) owing to the reduction in hardness as a stress-relieving effect.

Comparison of Three-Body Abrasion Behaviors of High-Cr-Mo- and High-Cr-Based Multicomponent White Cast Irons

Comparison of Three-Body Abrasion Behaviors of High-Cr-Mo- and High-Cr-Based Multicomponent White Cast Irons

Effect of boron addition on three-body abrasive wear characteristics of high chromium based multi-component white cast iron

This study aims to systematically investigate the influence of boron (0–3.0 wt % B) on microstructure and abrasive wear characteristics of high chromium based multi-component white cast iron (Hi-Cr MWCI).As result, the microstructure is mainly composed of martensite matrix and carborides such as M7(C, B)3, M2(C, B), M23(C, B)6. At low load, B can increase the wear resistance of Hi-Cr MWCI owing to the higher volume fraction of M2(C, B). However, it reduces the wear resistance of material due to low the fracture toughness of primary M7C3 or M7(C, B)3 at high load. Therefore it can be concluded that B addition can improve the abrasive wear resistance of Hi-Cr MWCI at low load, but, the opposite tendency will occur at high load.

Erosive wear characteristics of high-chromium based multi-component white cast irons

Erosive wear characteristics of (18 and 27) wt.% Cr based multicomponent (3 wt% V, Mo, W, and Co) white cast iron have been systematically investigated with three conditions: as-cast (AC), as-quenched (Q), and as-quenched tempered (QT).The result shows that Q specimens has the better erosive wear resistance compared to AC due to the transforming of the austenite matrix to be martensite and precipitation of secondary carbide. However, the erosive wear resistance of Q specimens was slightly reduced by the tempering process due to a significant increment of M7C3 carbide fracture toughness. Therefore, it can be concluded that the excessive Cr addition can be a negative factor on erosive wear-resistance in heat-treated condition and the tempering process should be ignored.

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

This research investigated wear resistance characteristics of hard carbide cast-in insertion cast iron by high-temperature erosive test. Moreover, good bonding conditions between cast iron and hard carbide alloy were examined by using casting simulation CAE. Two types of multi-component white cast iron with Cr, Mo, W, V, and Nb for base metal, tungsten carbide (WC) and titanium carbide (TiC) for insert were prepared. High-temperature erosion tests were conducted using alumina ball (average diameter: 1.16 mm, hardness: 1140 HV) with impact angle of 30, 60, and 90 deg. at 873 K.The air velocity of 100 m/s (particle velocity about 30 m/s). The total particle loading was 8 kg. The mass of the test specimen was measured before and after each test to evaluate the erosive wear property by erosion rate which is volumetric removal divided by the total feed of impact particles.As a result of erosion tests, WC cast-in insertion multi-component white cast iron showed good wear resistance characteristics compared with TiC one. TiC cast-in insertion multi-component white cast iron increased wear amounts due to cracking on insert surfaces that occurred by heat shock when pouring.Temperature history of interfacial molten cast iron and insert on solidification process were acquired by using solidification analysis to compere condition of molten steel and insert at the bonding interface. To longer liquid phase contact time is the thicker diffusion and reaction layer of each cast-in insertion sample. Both diffusion and reaction layers were created in the bonding interface of WC cast-in insertion sample. On the other hand, only diffusion layer was created in TiC cast-in insertion sample. These differences in bondability are due to diffusion coefficient of insert elements and gibbs standard free energy of carbides.

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

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.

Investigation of Prediction Method for Crack and Deformation of Cemented Carbide Cast-in Insertion Multi-Component White Cast Irons by Thermal Stress Analysis

Investigation of Prediction Method for Crack and Deformation of Cemented Carbide Cast-in Insertion Multi-Component White Cast Irons by Thermal Stress Analysis

Three body type abrasive wear characteristics of multi-component white cast irons

Abrasive wear can occur on tooth and suspension parts such as construction machinery power shovels and bulldozers. In order to reach high safety and low cost, it is important to develop wear resistant material and estimate of life service during abrasion.The amount of alloy element dissolved in the matrix is changed by the type of carbide and microstructure due to the addition content of alloy. However, it is important to consider the relationship the actual wear situation with environment reproducible testing machine.In the present study, nickel (Ni) which will encourage the carbides formation by suppressed the solid solution of the carbide-forming elements into the matrix was added into the traditional Fe-2C-5Cr-5Mo-5W-5 Nb-5Co system multi-component white cast iron. The effect of Ni on the three type of abrasive wear characteristics of this new material was investigated. A rubber wheel type abrasion tester was used for the abrasion tester. Test piece was pressed against the circumferential portion of the rubber wheel rotating at 100 ± 1 rpm with a load of 196 N. Silica sand of 170–220 µm was supplied at a rate of about 4.2 g/s from the popper between them, an abrasion test was conducted for 5 min.As a results, in both 0Co and 5Co type specimens, the specimens added with 3% Ni showed good three body type abrasive wear characteristics. In particular, the hardness of 3Ni-5Co showed a high value of 790 HV, showing the most excellent three type abrasive wear characteristics. With or without addition of Co, there was no difference in wear loss for 0Ni and 5Ni specimens. This is because there was no significant difference in hardness between 620 and 690 HV. Thereby, it can be concluded, the wear loss tended to decrease with increasing hardness of specimens.

Improvement of Durability for Low Speed Hot Rolling Rolls by Controlling Microstructures of Multi-component White Cast Iron

Improvement of Durability for Low Speed Hot Rolling Rolls by Controlling Microstructures of Multi-component White Cast Iron

Erosive Wear Characteristics of High-Cr Based Multi-Component White Cast Irons

Erosive Wear Characteristics of High-Cr Based Multi-Component White Cast Irons

Abrasive Wear Characteristics of Multi-Component White Cast Iron and Effect of C Content

Abrasive Wear Characteristics of Multi-Component White Cast Iron and Effect of C Content

Effect of C Content on High Temperature Erosive Wear Characteristics of Fe-Based V Containing Multi-Component Cast Steel with Ni

Hot hardness and oxidation property of target material influences greatly on the erosion behavior at elevated temperature. The correlation between hot hardness and oxidation property of multi component white cast irons and its erosion resistance were investigated, and try to estimate the high temperature erosion behavior in the study. Nine kinds of multi component white cast iron and cast steel were used in this study. Specimen were machined into a flat plate with dimension of 50×50×10 mm. High temperature erosion test machine was used to investigate the erosive wear property of experimental materials at 1173K. Alumina grits (average diameter: 1.16 mm, hardness: 1250 HV1) which were used as impact particles were heated to 1073K and shoot on the heated specimen by hot air at the velocity of 100 m/s. The total particle loading was 2 kg. In order to clarify the correlation of hot hardness, oxidation property and the erosion resistance of specimens, hot hardness test was carried out specimens, to estimate erosion damage caused by solid particle. Hot hardness of specimens showed a value comparable to 200～250HV1. Result of erosion and oxidation tests, erosion rate and amount of oxidation of the specimen were suppressed by Ni addition. It suggested that the more amount of Ni contents, the lower the erosion rate and the less the amount of oxidation.

Influence of Microstructures on Abrasive Wear Characteristics of Multi-component White Cast Iron

Influence of Microstructures on Abrasive Wear Characteristics of Multi-component White Cast Iron

Fe-C-Cr-Mo-W-V-10%Co多合金白鋳鉄のシャー切断試験による摩耗評価

Fe-C-Cr-Mo-W-V-10%Co多合金白鋳鉄のシャー切断試験による摩耗評価

Fe-C-Cr-Mo-W-V系多合金白鋳鉄の高温エロージョン摩耗特性に及ぼすCo添加の影響

Fe-C-Cr-Mo-W-V系多合金白鋳鉄の高温エロージョン摩耗特性に及ぼすCo添加の影響

Abrasive wear characteristics of Fe-2C-5Cr-5Mo-5W-5Nb multi-component white cast iron

Recently, many researchers have studied on the variety of alloys and tempt to develop wear resistant materials. Multi-component white cast iron has been reported to exhibit good erosive wear and abrasive wear resistance. Niobium (Nb) is also one of the carbide-forming elements in the same manner as vanadium (V), but not much is known about the effect on the wear resistance by Nb addition into the cast irons. Therefore, multi-component white cast irons with about 2 mass% carbon (C) and about 5 mass% chromium (Cr), molybdenum (Mo), tungsten (W) and V or Nb with 0, 5 mass% cobalt (Co) were prepared as the experimental materials in this study.As results, the amount of wear loss of the multi-component white cast irons containing Nb is less compared to that of the multi-component white cast irons containing V, showing good abrasive wear resistance. Especially, material 5Nb-5Co showed the best abrasive wear resistance. Area ratio of eutectic carbides and secondary carbides in any of the specimens were at the same level. However, eutectic MC carbide of multi-component cast iron containing Nb was larger as compared to that of multi-component cast iron containing V, showing higher resistance to the contact with the abrasive grains. Therefore, it was suggested that by adding Nb as an alternative to V, it's possible to develop a new wear resistant material.

Influence of Ni addition on erosive wear characteristics of multi-component white cast iron at elevated temperature

Comparing to the carbide-forming elements such as chromium (Cr), molybdenum (Mo) and tungsten (W), nickel (Ni) has a feature of preferentially dissolved into the matrix instead of forming carbides. The carbide-forming elements which were suppressed to dissolve into the matrix would then be encouraged to form more carbides. Hence, the improvement of erosive wear performance of the materials can be expected.In this study, approximately 0, 3, 5 mass % of Ni was added into the Niobium (Nb)-containing multi-component white cast iron and the influence of Ni on the erosive wear characteristics was investigated at elevated temperature (1173K). Alumina balls which hardness is 1140 HV (average diameter: Ø1.16 mm) were used as impact particles at velocity of 30m/s. As results, the oxidation amount was suppressed at the same level, and the amount of eutectic carbides was increased with the addition of Ni as expected. The high temperature hardness was increased with Ni addition due to the high hardness carbides, resulting in the improvement of the erosive wear property and material 5Nb-5Ni exhibited the most excellent erosive wear characteristics at 1173K. Therefore, by promoting the formation of carbides and remaining the heat resistant property, the addition of Ni is an effective method to improve the erosive wear characteristics of Nb-containing multi-component white cast irons at 1173K.