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Applications in Iron and Steel Making
Published in Nirupam Chakraborti, Data-Driven Evolutionary Modeling in Materials Technology, 2023
Decarburization of steel is another very important aspect related to steel that received limited attention from the researchers who use evolutionary algorithms. The term decarburization is used in two different contexts. In many steels, depending on the carbon content, temperature of application and the amount of oxygen in the environment, carbon tends to diffuse to the surface and the physical and mechanical properties of the steel deteriorates because of that. As per Fick’s second law of diffusion this is a time dependent process (Geiger and Poirier, 1973) and the deterioration takes place over the time. On the other hand, in stainless steelmaking processes, decarburization often refers to removal of carbon in the steel making vessel.
Metallurgical Defects in Cast Slabs and Hot Rolled Products
Published in Vladimir B. Ginzburg, Metallurgical Design of Flat Rolled Steels, 2020
The carbon-depleted zone is usually known as the decarburization zone and is located between the interior of the steel and the oxide-metal interface. Decarburization has a detrimental effect on subsequent processing of certain high-carbon special steels. It usually produces no quality problems in low-carbon steels.
Metal Forming
Published in Sherif D. El Wakil, Processes and Design for Manufacturing, 2019
Decarburization may also occur in steels, especially when hot forming high-carbon steel. The scales, oxides, and decarburized layers must be removed by one or more machining processes. This slows down the production, adds machining costs, and yields waste material, resulting in lower efficiency of material utilization. A further limitation of hot forming is reduced tool life due to the softening of tool surfaces at elevated temperatures and the rubbing action of the hot metal while flowing. This actually subjects the tools to thermal fatigue, which shortens their life.
A novel approach to prevent decarburisation through electroless plating
Published in Surface Engineering, 2019
R. Johari Teymoori, M. Shahidi, I. Taji, Z. Sharifalhoseini, B. Beidokhti
Decarburisation as an undesirable consequence of the heat treatment cycle occurs when the atoms at the steel surface interact with furnace atmosphere and are removed from the surface. This phenomenon is a serious problem because the surface properties are inferior to core properties, resulting in poor wear resistance and low fatigue. In hot work tool steels, decarburisation affects the formation of martensite in a certain depth under the surface of steel. Therefore, the improper microstructure containing ferrite is formed at the surface and reduces the wear resistance of hot work tool steels [3].
Detection of Decarburising Depth in Hadfield Steels Using a Multi-magnetic NDE Method
Published in Nondestructive Testing and Evaluation, 2022
Saeed Kahrobaee, Iman Ahadi Akhlaghi, Claire Davis, Lei Zhou
The recommended ISO 3887 method for measuring the decarburised depth determines the micro-hardness profile on a cross-section of the steel sample after polishing. Therefore, the relationship between the microstructure in the decarburised zone and micro-hardness value has been evaluated in the present work. According to ISO 3887, the depth of decarburisation is considered as the distance between the surface of the sample and the point at which the hardness is at the level where the performance would be unaffected by a reduction in hardness, which is equivalent to the bulk hardness for the Hadfield steels. Figure 2 presents the hardness profiles of the four steel samples, subjected to different austenitising times. Contrary to what is expected in the decarburisation process for conventional carbon steels where hardness decreases in the decarburised region, in all the Hadfield steel samples, an increase in the hardness is observed towards the surface than in the core of the material. The thickness of decarburised layers has been determined by considering a depth where hardness becomes constant and equal to the bulk hardness. Figure 2 indicates the heat-treating process in the absence of an inert atmosphere increases the hardness of the surface by at least 300 HV compared to the bulk (for the sample austenitised for 1 hour) due to the decarburisation process. An increase in the austenitising time increases the hardness in the surface region (from 590 to 900 HV) and increases the hardening depth (from 35 to 110 µm) for the samples. This is expected to be due to the amount and depth of the hard martensite phase formed at the surface. It should be noted that a gradually decreasing trend in micro-hardness values indicates the existence of a martensite-austenite mixture in the decarburised layer where the amount of austenite phase increases with depth.
Nondestructive examination of decarburised layer of steels using eddy current and magnetic Barkhausen noise testing techniques
Published in Nondestructive Testing and Evaluation, 2018
S. Falahat, S. Ghanei, M. Kashefi
Decarburisation, which is widely observed during different heat treatments process of steels, leads to a gradient in both microstructure and hardness because of the produced gradient in the carbon content from the surface to the core. As carbon content loss near the surface in a steel leads to negative effects on the mechanical and physical properties of the alloy, determining of the decarburised depth is vital for quality control during production of steel part [1].