Percentage Of Carbide Research Articles

Effect of actual WC content on the reciprocating wear of a laser cladding NiCrBSi alloy reinforced with WC

This paper studies the tribological improvement of a NiCrBSi laser cladding coating reinforced with different weight percentages of WC (0–50%) in a powder feeder. During the laser cladding process, it was observed that WC particles tend to precipitate to the bottom of the melted coating, the percentage of carbides hence increasing with depth of the coating. The actual concentration of WC in the surface was therefore determined in order to evaluate its influence on their tribological behaviour, instead of relating it to the concentration adjusted in the feeder.Wear decreases exponentially with the actual percentage of WC, and a significant decrease in wear does not occur above actual 30% WC on the surface. Non-significant variations in the coefficient of friction were observed. The main wear mechanisms observed were adhesive, oxidative and abrasive wear.

Investigating the effect of electric current flow on the wear behavior of 1.2080 tool steel during the deep cryogenic heat treatment

Deep cryogenic heat treatment is a supplementary process, which is performed in tool steels after quench and before temper regularly. In this study, the effect of the electric current flow through the deep cryogenically treated samples was investigated via the X-ray diffraction (XRD), scanning electron microscope (SEM), energy dispersive spectroscope (EDX), hardness test, and pin-on-disk wear testing machine. Results showed that the deep cryogenic heat treatment improves the carbide percentage, distribution, hardness and wear resistance of the 1.2080 tool steel, as compared with those of the conventionally treated. Further improvement in the wear resistance and hardness were also observed due to the formation of some newly formed nano-sized carbides in the structure. It was also observed that the electric current flow leads to a decrease in this improvement due to its effect on the as-quench vacancies, which were ignored as powerful places for carbide nucleation during the deep cryogenic heat treatment. It was also shown that the predominant wear mechanism is a combination of adhesive and tribo-chemical wear.

Effects of applying an external magnetic field during the deep cryogenic heat treatment on the corrosion resistance and wear behavior of 1.2080 tool steel

This work concerns with the effect of applying an external magnetic field on the corrosion behavior, wear resistance and microstructure of 1.2080 (D2) tool steel during the deep cryogenic heat treatment. These analyses were performed via scanning electron microscope (SEM), optical microscope (OM), transmission electron microscope (TEM) and X-ay diffraction (XRD) to study the microstructure, a pin-on-disk wear testing machine to study the wear behavior, and linear sweep voltammetry to study the corrosion behavior of the samples. It was shown that the deep cryogenic heat treatment eliminates retained austenite and makes a more uniform carbide distribution with higher percentage. It was also observed that the deep cryogenic heat treatment improves the wear behavior and corrosion resistance of 1.2080 tool steel. In comparison between the magnetized and non-magnetized samples, the carbide percentage decreases and the carbide distribution weakened in the magnetized samples; subsequently, the wear behavior and corrosion resistance attenuated compared in the magnetized samples.

Investigating the effect of holding duration on the microstructure of 1.2080 tool steel during the deep cryogenic heat treatment

This study concerns the effect of the holding time at liquid nitrogen temperature during the deep cryogenic heat treatment on the microstructural changes, carbide distribution, carbide percentage, hardness and microhardness of 1.2080 tool steel. These analyses were performed via the scanning electron microscope (SEM), optical microscope (OM), transmission electron microscope (TEM) and X-ay diffraction (XRD). The obtained results showed that there is an optimum holding duration in which the carbides exhibit a maximum percentage and the most homogenous distribution as compared to the other soaking durations. It was also shown that by increasing the holding duration beyond the optimum holding duration, the hardness, microhardness, carbide percentage, carbide distribution homogeneity and particle size reach a constant value and do not change.

Surface chemistry and porosity of nitrogen-containing activated carbons produced from acrylic textile waste

Acrylic textile waste was pyrolysed in a fixed bed reactor in a nitrogen atmosphere at three different temperatures, 700, 800 and 900°C. Steam activation of the chars generated at these temperatures was carried out for different durations of activation time up to 4h at 900°C temperature to produce activated carbons. The BET surface area and the pore structure of the pyrolysis chars and activated carbons were evaluated from nitrogen adsorption data at 77K in relation to process conditions. The BET surface area of the pyrolysis chars were all less than 2m2g−1, but significantly increased with steam activation to produce a maximum surface area of 752m2g−1 for the activated carbon produced from the char generated at 700°C and steam activated at 900°C for 2h. The porosity of the product activated carbon was mainly microporous with an increase in mesopore fraction at higher degrees of burn-off. The effect of burn-off on the acid/base properties and the surface chemistry of the activated carbon, in terms of carbon, nitrogen and oxygen functionalities, were studied in detail using titration method and X-ray photoelectron spectroscopy (XPS) respectively. The results showed that, for all activated carbon samples, the concentrations of basic groups are always much higher than that of acidic groups. Higher degrees of burn-off leads to a lower percentage of graphite, higher percentage of carbide, an increase in C-oxygen functionalities and the percentage of quaternary nitrogen, while the ratio of the N-5 functionality decreased.

Influence of Mold Preheating and Silicon Content on Microstructure and Casting Properties of Ductile Iron in Permanent Mold

Abstract The effects of the mold preheating and the silicon content of ductile iron on the percentage of carbides, graphite nodule counts and shrinkage volume were investigated. The results showed that the percentage of carbides and the shrinkage volume decreased when the mold preheating increased. The ductile iron with the carbon equivalent of 4.45% and the silicon content of 2.5% without any porosity defects was achieved when the mold preheating was 450 °C. Increasing the silicon content in the range of 2.1%—3.3% led to the increase in graphite nodule count and graphite size and the decrease in percentage of carbides. It is due to the increase in induced expansion pressure during the graphite formation with the increasing of silicon content. The suitable condition for casting a sound product of ductile iron without the riser at the mold preheating temperature of 300 °C is the silicon content of 3.3% and carbon equivalent of 4.7%.

Influence of different cryotreatments on tribological behavior of 80CrMo12 5 cold work tool steel

This experimental study investigated the effect of cryogenic treatments on the wear behavior of 80CrMo12 5 tool steel. For this purpose, two different cryogenic temperatures were used: −80 °C as the shallow cryogenic temperature and −196 °C as the deep cryogenic temperature. The results showed that the cryogenic treatments decrease retained austenite, which is more effective in the case of the deep cryogenic treatment (DCT). As a result, a remarkable improvement in the wear resistance of the cryogenically treated specimens was observed. In addition, DCT increases the percentage of carbides and their homogeneity in distribution. An optimum holding time was found in the deep cryogenic temperature, in which the hardness and wear resistance show maximum values. Moreover, the wear debris and worn surfaces showed that the dominant mechanism in the wear test is adhesive.

The effect of molybdenum upon the transformations in the matrix of high‐speed steels during austenitizing and quenching

Analysis of the transformations during austenitizing and quenching on model alloys imitating, by means of chemical composition, the matrices of the quenched high‐speed steels of various relations Mo/W. Analysis of the volume percentage of carbides, grain size, the temperature of the beginning of partial meltings and retained austenite. Results of the model alloy tests in comparison with the high‐speed steels of the 18‐0‐1 and 6‐5‐2 types.

The composition of steel and the percentage of carbide phase

1. The percentage of carbides in annealed steel is directly proportional to the carbon concentration of the steel and inversely proportional to the carbon content of the carbide. 2. In multiphase alloys the carbon concentration of the carbide is determined as the sum of the products of the weight percentages of each carbide by the weight per cent of their carbon content.

Strength and ductility of chromium-manganese austenitic steel

1. Alloying of steel Kh10G14 with 0.26–3.01% Si has a negligible effect on the ductility after quenching from 1120°C, which ensures solution of the carbides in austenite. After quenching from 850°C the amount of M23C6, carbide increases with the concentrations of silicon and carbon; in this case the ductility decreases. 2. An increase of the carbon and silicon concentrations in the γ solid solution raises the yield strength in direct proportion. The increase of the yield strength due to the carbide particles is directly proportional to the cube root of the percentage of carbide.