scholarly journals Thermodynamics and Industrial Trial on Increasing the Carbon Content at the BOF Endpoint to Produce Ultra-Low Carbon IF Steel by BOF-RH-CSP Process

2019 ◽  
Vol 38 (2019) ◽  
pp. 822-826
Author(s):  
Guo Jing ◽  
Cheng Shu-Sen ◽  
Guo Hanjie
Keyword(s):  
Carbon Content ◽  
Liquid Steel ◽  
Low Carbon Steel ◽  
Metal Loss ◽  
Content Increase ◽  
If Steel ◽  
Low Carbon ◽  
Rh Process ◽  
Bof Slag ◽  
Final Steel

AbstractThermodynamic analysis was performed to obtain the relation between the carbon content at the BOF endpoint and the dissolved oxygen content in liquid steel and the (FeO + MnO) content in the slag with the help of thermodynamic calculation software FactSage. It finds that both the [O] and (FeO + MnO) content increase with decreasing the carbon content at the BOF endpoint and the increasing rate is larger when the carbon content is lower. In addition, in the case of the higher temperature at the BOF endpoint the [O] in liquid steel increase and the (FeO + MnO) in the slag increase as well. The consumption of O2 for decarbonization at the BOF endpoint is much more than that in RH degasser since the majority of the blowing O2 at the BOF endpoint will produce FeO into the slag, thus it increase the metal loss and deteriorate the steel cleanness during the consequent refining process. As a result, the carbon content at the BOF endpoint should be properly increased within the RH decarbonization ability. At last, industrial trials were carried out and confirmed that total oxygen consumption decrease obviously and the (FeO + MnO) of final BOF slag decline as well with increasing carbon content at BOF endpoint from 0.042% to 0.081%. In addition, it almost does not slow down the RH process and the carbon content in final steel all met the demand of the ultra-low carbon steel. In addition, mechanical properties of IF steel with higher carbon content at the endpoint of BOF are almost all more superior to those of heat with lower carbon content at BOF endpoint.

Effect of Soaking Time on Paste Carburizing of Carburized Low Carbon Steel

2017 ◽  
Vol 740 ◽  
pp. 93-99
Author(s):  
Muhammad Hafizuddin Jumadin ◽  
Bulan Abdullah ◽  
Muhammad Hussain Ismail ◽  
Siti Khadijah Alias ◽  
Samsiah Ahmad
Keyword(s):  
Carbon Steel ◽  
Carbon Content ◽  
Low Carbon Steel ◽  
Case Depth ◽  
Carbon Steels ◽  
Low Carbon ◽  
Soaking Time ◽  
Low Carbon Steels ◽  
Carburized Steel ◽  
Carburizing Process

Increase of soaking time contributed to the effectiveness of case depth formation, hardness properties and carbon content of carburized steel. This paper investigates the effect of different soaking time (7-9 hours) using powder and paste compound to the carburized steel. Low carbon steels were carburized using powder and paste compound for 7, 8 and 9 hours at temperature 1000°C. The transformation of microstructure and formation carbon rich layer was observed under microscope. The microhardness profiles were analyzed to investigate the length of case depth produced after the carburizing process. The increment of carbon content was considered to find the correlation between types of carburizing compound with time. Results shows that the longer carburized steel was soaked, the higher potential in formation of carbon rich layer, case depth and carbon content, which led to better hardness properties for carburized low carbon steel. Longer soaking time, 9 hours has a higher dispersion of carbon up to 41%-51% compare to 8 hours and 7 hours. By using paste carburizing, it has more potential of carbon atom to merge the microstructure to transform into cementite (1.53 wt% C) compare to powder (0.97 wt% C), which increases the hardness of carburized steel (13% higher).

scholarly journals Characterization of Microstructure in High-Hardness Surface Layer of Low-Carbon Steel

Metals ◽  
2020 ◽  
Vol 10 (8) ◽  
pp. 995
Author(s):  
Haitao Xiao ◽  
Shaobo Zheng ◽  
Yan Xin ◽  
Jiali Xu ◽  
Ke Han ◽  
...  
Keyword(s):  
Surface Layer ◽  
Carbon Steel ◽  
Yield Strength ◽  
Carbon Content ◽  
Acicular Ferrite ◽  
Lath Martensite ◽  
Low Carbon Steel ◽  
Low Carbon ◽  
Upper Bainite ◽  
Mixed Microstructure

Surface hardening improves the strength of low-carbon steel without interfering with the toughness of its core. In this study, we focused on the microstructure in the surface layer (0–200 μm) of our low-carbon steel, where we discovered an unexpectedly high level of hardness. We confirmed the presence of not only upper bainite and acicular ferrite but also lath martensite in the hard surface layer. In area of 0–50 μm, a mixed microstructure of lath martensite and B1 upper bainite was formed as a result of high cooling rate (about 50–100 K/s). In area of 50–200 μm, a mixed microstructure of acicular ferrite and B2 upper bainite was formed. The average nanohardness of the martensite was as high as 9.87 ± 0.51 GPa, which was equivalent to the level reported for steel with twenty times the carbon content. The ultrafine laths with an average width of 128 nm was considered to be a key cause of high nanohardness. The average nanohardness of the ferrites was much lower than for martensite: 4.18 ± 0.39 GPa for upper bainite and 2.93 ± 0.30 GPa for acicular ferrite. Yield strength, likewise, was much higher for martensite (2378 ± 123 MPa) than for upper bainite (1007 ± 94 MPa) or acicular ferrite (706 ± 72 MPa). The high yield strength value of martensite gave the surface layer an exceptional resistance to abrasion to a degree that would be unachievable without additional heat treatment in other steels with similar carbon content.

Study on Cleanliness of Ultra-Low Carbon Steel First Slab

2012 ◽  
Vol 524-527 ◽  
pp. 2037-2043
Author(s):  
Qi Chun Peng ◽  
Xue Sen Yu ◽  
Wei Xiong ◽  
Liu Yang ◽  
Liang Zhou Zhang ◽  
...  
Keyword(s):  
Comparative Analysis ◽  
Carbon Steel ◽  
Liquid Steel ◽  
Steel Slag ◽  
Low Carbon Steel ◽  
Low Carbon ◽  
Metallographic Examination ◽  
Ultra Low Carbon Steel ◽  
Casting Length ◽  
Slag Entrapment

By means of Oxygen and Nitrogen Analyzer, Metallographic Examination, SLIME, SEM, EDS, etc, the cleanliness of ultra-low carbon steel first slab produced by LD-RH-CC, and the comparative analysis with the cleanliness of normal slab is studied. The results show that T[O] and [N] are obviously decreasing with the increasing of casting length. The micro-inclusions and large-inclusions are generally decreasing with the increasing of casting length. The micro-inclusions of the first slab are mainly from deoxidization products and reoxidation of liquid steel. And the sources of large-sized inclusions mainly are reoxidation of liquid steel, slag entrapment in mould or tundish and stuffing sand. The cleanliness of ultra-low carbon steel first slab is closed to those normal slabs at the length of 3.5m.

scholarly journals Fracture Toughness Properties of Savannah River Site Storage Tank ASTM A285 Low Carbon Steel

2002 ◽  
Author(s):  
K. H. Subramanian ◽  
A. J. Duncan ◽  
R. L. Sindelar
Keyword(s):  
Fracture Toughness ◽  
Carbon Steel ◽  
Carbon Content ◽  
Storage Tank ◽  
Low Carbon Steel ◽  
Savannah River Site ◽  
Low Carbon ◽  
Savannah River ◽  
High Carbon ◽  
River Site

A materials test program was developed to measure mechanical properties of ASTM A285 Grade B low carbon steel for application to structural and flaw stability analysis of storage tanks at the Department of Energy (DOE) Savannah River Site (SRS). Under this plan, fracture toughness and tensile testing are being performed at conditions that are representative of storage tank conditions on steels that span compositions within ASTM A285 specifications. The testing is being done within the framework of a statistical test matrix and the data collected will be used to develop a predictive model for materials properties. The results presented herein are limited to a subset of data comparing for comparison of a recent vintage steel versus an older steel for fracture resistance behavior. These preliminary results indicate that dynamic loading rates result in a greater increase in the fracture toughness response in the case of the recent vintage steels of lower carbon content when compared to the archival heat of high carbon content. In addition, ductile tearing in the archival, high carbon steel was more likely to be interrupted by cleavage fracture at lower fracture energies than the modern, low carbon steel.

scholarly journals Improvement of ASTM A53 Steel Durability Using Agrowastes as Carburizing Agent

2021 ◽  
Vol 13 (6) ◽  
Author(s):  
S. A. Afolalu ◽  
◽  
O. M. Ikumapayi ◽  
M.E. Emetere ◽  
T.S. Ogedengbe ◽  
...  
Keyword(s):  
Carbon Content ◽  
Control Sample ◽  
Palm Kernel ◽  
Low Carbon Steel ◽  
Grain Structure ◽  
Past Century ◽  
Low Carbon ◽  
Environment Impact ◽  
The Past ◽  
Carburized Steel

The importance of steel in manufacturing and construction over the past century cannot be over-emphasized and easy accessibility couple with excellent mechanical properties make it preferable over others. However, the problem of durability has posed a serious concern as majority of steel application are meant for long term use. Several attempts have been made to improve the durability of steel in the past and increase of carbon content in low carbon steel was found to be a suitable agent. Although getting carbon is not the challenge rather obtaining it from a sustainable source that has zero environment impact. This research identified two separate agrowaste that has high carbon content the issue of sustainability brought about the development of carburizing agent from agrowaste that are easily accessible namely palm kernel and eggshell which is employed in this research. The use of agrowaste was found to be effective as there was notable increase in grain structure of the carburized steel when compared to the control sample without carburized agent in it.

Hydrostatic Collapse Tests of Full-Scale Pipeline Specimens With Thickness Metal Loss

2020 ◽  
Author(s):  
Divino J. S. Cunha ◽  
Caroline Ferraz ◽  
Theodoro A. Netto ◽  
J. C. Diniz ◽  
Diego G. G. Rosa ◽  
...  
Keyword(s):  
Failure Modes ◽  
Low Carbon Steel ◽  
External Pressure ◽  
Full Scale ◽  
Metal Loss ◽  
Internal Diameter ◽  
External Diameter ◽  
Low Carbon ◽  
Extensive Research Program ◽  
Simple Equations

Abstract The present paper deals with the subject of failure of deep-sea pipelines that have thickness metal-loss areas caused by corrosion and are subjected to high external hydrostatic pressure. An extensive research program was launched to observe failure modes, to examine existing and to develop prediction collapse equations, and to determine their accuracy. The program uses finite element modeling and external hydrostatic collapse tests of full-scale specimens. This paper presents and discusses the results of the first 20 collapse tests, which were performed in a new 103 MPa (15 ksi) hyperbaric chamber (760 mm internal diameter and 7200 mm length). The test results obtained with full scale specimens (324 mm external diameter and 23 mm thickness) made of low carbon steel API 5L X60 with external machined metal loss defects are used to verify the level of accuracy and conservatism of four analytical simple equations used to predict collapse of pipes with corrosion subjected to high external pressure.

scholarly journals Anti-carburizing Coating for Resin Sand Casting of Low Carbon Steel Based on Composite Silicate Powder Containing Zirconium

2018 ◽  
Vol 142 ◽  
pp. 03007
Author(s):  
Chunyi Zhan ◽  
Shengshan Feng ◽  
Shuzhong Xie ◽  
Chunjing Liu ◽  
Yunhua Gao ◽  
...  
Keyword(s):  
Stainless Steel ◽  
Carbon Steel ◽  
Carbon Content ◽  
Low Carbon Steel ◽  
Powder Coating ◽  
Sand Casting ◽  
Low Carbon ◽  
Casting Surface ◽  
Upper Limit ◽  
Zircon Powder

This paper studied the structure and properties of anticarburizing coating based on composite silicate powder containing zirconium by X-ray diffraction analyzer, thermal expansion tester, digital microscope and other equipment. It is introduced that the application example of the coating in the resin-sand casting of ZG1Cr18Ni9Ti stainless steel impeller. The anti-carburizing effect of the coating on the surface layer of the cast is studied by using direct reading spectrometer and spectrum analyzer. The change of the micro-structure of the coating after casting and cooling is observed by scanning electron microscope. The analysis of anti-carburizing mechanism of the coating is presented. The results indicate that the coating possesses excellent suspension property, brush ability, permeability, levelling property and crackresistance. The coating exhibits high strength and low gas evolution. Most of the coating could be automatically stripped off flakily when the casting was shaken out. The casting possesses excellent surface finish and antimetal penetration effect. The carburizing layer thickness of the stainless steel impeller casting with respect to allowable upper limit of carbon content is about 1mm and maximum carburizing rate is 23.6%. The anticarburizing effect of casting surface is greatly improved than that of zircon powder coating whose maximum carburizing rate is 67.9% and the carburizing layer thickness with respect to allowable upper limit of carbon content is greater than 2mm. The composite silicate powder containing zirconium coating substantially reduces the zircon powder which is expensive and radioactive and mainly dependent on imports. The coating can be used instead of pure zircon powder coating to effectively prevent metal-penetration and carburizing of resin-sand-casting surface of low carbon steel, significantly improve the foundry production environment and reduce the production costs.

scholarly journals Detection and Determination of Solute Carbon in Grain Interior to Correlate with the Overall Carbon Content and Grain Size in Ultra-Low-Carbon Steel

2013 ◽  
Vol 19 (S5) ◽  
pp. 66-68 ◽  
Author(s):  
Jiling Dong ◽  
Yinsheng He ◽  
Chan-Gyu Lee ◽  
Byungho Lee ◽  
Jeongbong Yoon ◽  
...  
Keyword(s):  
Grain Size ◽  
Electron Microscope ◽  
Carbon Content ◽  
Three Dimensional ◽  
Low Carbon Steel ◽  
Atom Probe ◽  
Optical Microscope ◽  
Low Carbon ◽  
Transmission Electron ◽  
Solute Carbon

AbstractIn this study, every effort was exerted to determine and accumulate data to correlate microstructural and compositional elements in ultra-low-carbon (ULC) steels to variation of carbon content (12–44 ppm), manganese (0.18–0.36%), and sulfur (0.0066–0.001%). Quantitative analysis of the ULC steel using optical microscope, scanning electron microscope, transmission electron microscope, and three-dimensional atom probe revealed the decrease of grain size and dislocation density with the increase of carbon contents and/or increase of the final delivery temperature. For a given carbon content, the grain interior carbon concentration increases as the grain size increases.

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