scholarly journals Improvement of Longitudinal Performance Uniformity of Hot-Rolled Coils for Cold-Rolled DP980 Steel

Metals ◽  
2020 ◽  
Vol 10 (3) ◽  
pp. 382 ◽  
Author(s):  
Haijun Li ◽  
Tianxiang Li ◽  
Chaofei Li ◽  
Zhaodong Wang ◽  
Guodong Wang

Cold-rolled DP980 steel is widely used in the automobile industry. Hot-rolled coil is the raw material of cold-rolled DP980 steel, the head and tail parts of which are usually obviously stronger than the body part. The objective of this study is to improve the longitudinal performance uniformity of hot-rolled coils. The material properties of this steel, such as the dynamic continuous cooling transformation, the influence of the cooling mode before coiling, the cooling rate during coil cooling on the microstructure, and mechanical properties of cold-rolled DP980 steel were investigated through thermal simulation experiments and hot rolling experiments. Meanwhile, the temperature field of hot-rolled coil was analyzed using ABAQUS software, which was used to survey the cause of the longitudinal performance fluctuations of hot-rolled coils, combined with an investigation of the aforementioned material properties. The results illustrate that the average cooling rate of the head and tail parts are higher than that of the body part during coil cooling, which causes the longitudinal performance fluctuation of hot-rolled coils. Based on the temperature field of hot-rolled coil, obtained by FEM, the parameters of the U-shaped cooling process were optimized and used in industrial applications.

2015 ◽  
Vol 639 ◽  
pp. 243-248 ◽  
Author(s):  
Tobias Konrad ◽  
Peter Feuser

Tailored press-hardening processes are used to reduce both production costs and component weight. The aim of these development methods is to generate regions zones in the component with both high and low tensile strengths. The B-pillar, for instance, needs high tensile strength in the region of the roof frame to prevent deformation. However, the connection to the body should have lower tensile strength to absorb the energy of a crash.Regarding the production process for tailored welded blanks, the tailored press-hardening processes for monolithic sheets need no joining operation. As an addition to recent publications, this paper presents a modified tailored press-hardening process, with a modified time-temperature process. Starting from the required tailored material properties of the part, with a sheet thickness of 1.5 mm, research has been done on the process window and process design.This contribution concentrates on modifications to the time-temperature profile. After heating the hot-dip galvanized, heat-treatable 22MnB5 steel above its austenitic temperature, the aim is to adjust the material’s mechanical properties within the cooling process.Based on the continuous TTT diagram, the cooling rate has an impact on the material’s mechanical material properties. Different proportions of constituents such as Bainite, Ferrite or Perlite are created by varying the cooling rate. Furthermore, during an intermediate stage in the cooling-down period, the holding temperature has an even stronger effect on the material’s microstructural composition and the corresponding mechanical properties. The rate of the transformation process changes, depending on the intermediate temperature. The third parameter investigated is the holding time at this intermediate temperature. As the holding time is increased a transformation, progressing from austenite to other constituents, can be observed.The results of this parametric study could be transferred to a prototype environment.


2014 ◽  
Vol 1028 ◽  
pp. 50-54
Author(s):  
Yuan She ◽  
Wei Ming Kong ◽  
Zhao Hui Zhang

The tests were conducted on 400MPa hot-rolled ribbed bar (HRB400). The cool bending fracture appeared frequently in the production was analyzed. The research result showed that the cool bending fracture of rebar were caused by element segregation of C, Mn, inclusions, the existence of banded structure, widmannstatten structure and bainite structure in the center and edge of rebar. The inclusions are the root cause of internal crack and one of the reasons to fracture. Reasonable cooling rate can refine grain size, while the overquick cooling speed could result in the formation of widmannstatten structure in acicular or plume, increased the brittleness of steel and reduce its cold bending properties. On this basis, some improvement opinions were put forward: using the raw material with low Mn, S and P; reducing the S content with pretreatment of hot metal; controlling the content of C and Mn respectively in C: 0.18 ~ 0.23%, Mn:1.20~1.30%; extending argon blowing time at argon flushing station, using electromagnetic stirring technology; controlling the cooling rate at 15 °C/s.


2021 ◽  
pp. 46-49
Author(s):  
Николай Борисович Кондратьев ◽  
Лариса Валентиновна Зайцева ◽  
Оксана Сергеевна Руденко ◽  
Егор Валерьевич Казанцев ◽  
Ирина Александровна Белова

Целью исследования являлось изучение влияния свойств орехового сырья на направление и скорость процессов миграции жиров в глазированных конфетах с пралиновыми корпусами. Исследование процессов миграции жиров между корпусом и глазурью в процессе хранения необходимо для прогнозирования сохранности и предотвращения органо-лептической порчи в результате осветления или умягчения глазури, а также «поседения» поверхности изделий. Предложен подход прогнозирования скорости процессов миграции жиров при хранении конфет с корпусами, изготовленными на основе орехового сырья, с использованием удельной скорости миграции жиров. Исследованы процессы миграции жиров в модельных образцах конфет с пралиновыми корпусами на основе арахиса, фундука, кешью, миндаля, покрытых глазурью с использованием заменителя масла какао лауринового типа при температуре хранения 18 °С. Показано, что удельная скорость миграции олеиновой кислоты на поверхность модельных образцов глазированных конфет с корпусами на основе арахиса превышает скорость миграции в конфетах с корпусами на основе кешью приблизительно в 20 раз. Полученные закономерности позволяют установить дополнительные требования к качеству используемого жирового сырья для уменьшения скорости миграции жиров. The aim of the work - the investigation of the influence of nut raw material properties on the direction and speed of fat migration processes in glazed sweets with praline cases. The study of fat migration processes between the body and the glaze during storage is necessary to predict the safety and prevent organoleptic spoilage as a result of lightening or softening of the glaze, as well as «graying» of the surface of the products. An approach to predicting the rate of fat migration processes during the storage of sweets with cases made on the basis of nut raw materials using the specific rate of fat migration is proposed. The processes of fat migration in model samples of sweets with praline cases based on peanuts, hazelnuts, cashews, almonds, glazed with glaze, with the use of a lauric-type cocoa butter substitute were investigated at a storage temperature of 18 °C. It is shown that the specific rate of migration of oleic acid to the surface of model samples of glazed sweets with peanut-based cases exceeds the migration rate in sweets with cashew-based cases by approximately 20 times. The obtained regularities allow us to establish additional requirements for the quality of the fat raw materials used to reduce the rate of fat migration.


2011 ◽  
Vol 409 ◽  
pp. 569-574
Author(s):  
Matthieu Dubois ◽  
Marie Hélène Mathon ◽  
Vincent Klosek ◽  
Gilles Andre ◽  
Alain Lodini

This work was devoted to the study of a copper based shape memory alloy using the neutron diffraction method. We present the crystallographic texture evolution of the austenite phase of the Cu-11%Al-0.62%Be (wt. %) alloy which was subjected to cold and hot rolling processes. The texture of the cold rolled samples at reduction rates of 5%, 10% and 15% respectively was measured and compared to the raw material. A <001> partial fiber is observed for the raw material and for cold rolled samples whereas the texture of the hot rolled sample is mainly characterized by a <111> fiber. On the second part, we have studied the influence of the rolling treatment on the transition temperatures by following the integrated intensity of the {220} austenite reflection. The increase of the rolling rate seems to shift the characteristic temperatures towards low temperatures.


Alloy Digest ◽  
1977 ◽  
Vol 26 (4) ◽  

Abstract YS-T 50 to YS-T 140 Steels comprise a series of high-strength, cold-rolled steels designed to meet performance and weight-saving objectives. They are an extension of Youngstown's series of hot-rolled high-strength steels (see Youngstown YS-T Steel, Alloy Digest SA-261, March 1971). The YS-T 50 to YS-T 140 steels have minimum yield strengths ranging from 50,000 psi to 140,000 psi. This datasheet provides information on composition, physical properties, hardness, elasticity, tensile properties, and bend strength. It also includes information on heat treating, machining, and joining. Filing Code: SA-331. Producer or source: Youngstown Sheet and Tube Company.


2014 ◽  
Vol 29 (2) ◽  
pp. 201-210
Author(s):  
Ari Isokangas ◽  
Kari Ala-Kaila ◽  
Markku Ohenoja ◽  
Aki Sorsa ◽  
Kauko Leiviskä

Abstract The purpose of this paper is to analyse the log loading process of wood room, which is typically the first processing unit in pulp and paper mills. The aim is to improve the log loading process to obtain production with a constant log flow of well de-iced logs to the debarking drum. This way it is possible to reduce costs and enhance product quality. The research was carried out utilising a log loading simulator. The parameters of the simulation model were selected on the basis of process observations on a mill. The results indicate that it is essential to adjust the process and equipment parameters, raw material properties and truck loader operation together in order to reach the target capacity with minimum costs. Especially the speed of the infeed conveyor affects all performance criteria and should be selected carefully. In addition, wood yard logistics and raw material properties have a remarkable effect on the wood room performance. The results can be utilised in mills to allow the upper level control perform in a planned way so that small wood loss and good product quality can be obtained.


Author(s):  
Siraj Salman Mohammad ◽  
Renata Oliveira Santos ◽  
Maria Ivone Barbosa ◽  
José Lucena Barbosa Junior

: Anthocyanins are widely spread in different kinds of food, especially fruits and floral tissues, there is an extensive range of anthocyanin compounds reach more than 600 exist in nature. Anthocyanins can be used as antioxidants and raw material for several applications in food and pharmaceutical industry. Consequently, a plenty of studies about anthocyanins sources and extraction methods were reported. Furthermore, many studies about their stability, bioactive and therapeutic properties have been done. According to the body of work, we firstly worked to shed light on anthocyanin properties including chemical, antioxidant and extraction properties. Secondly, we reported the applications and health benefits of anthocyanin including the applications in food processes and anthocyanin characteristics as therapeutic and prophylactic compounds. We reviewed anticancer, anti-diabetic, anti-fatness, oxidative Stress and lipid decreasing and vasoprotective effects of anthocyanins. In conclusion, because the importance of phytochemicals and bioactive compounds the research is still continuing to find new anthocyanins from natural sources and invest them as raw materials in the pharmaceutical and nutrition applications.


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