scholarly journals Transformation of M/A Constituents during Tempering and Its Effects on Impact Toughness of Weld Metals for X80 Hot Bends

2019 ◽  
Vol 2019 ◽  
pp. 1-10 ◽  
Author(s):  
Gui-ying Qiao ◽  
Xiu-lin Han ◽  
Xiao-wei Chen ◽  
Xu Wang ◽  
Bo Liao ◽  
...  
Keyword(s):  
Impact Toughness ◽  
Weld Metal ◽  
Acicular Ferrite ◽  
Tempering Temperature ◽  
Factors Affecting ◽  
Weld Metals ◽  
Gleeble 3500 ◽  
The Impact ◽  
Carbide Particles

Impact toughness of the weld metal is one of the important factors affecting the quality of hot bends, which is strongly dependent on the microstructure transformation during hot bending and tempering. In this study, three kinds of weld metals with different Ni contents were selected, and then the effects of tempering temperature on the microstructure impact toughness of weld metals for hot bends were investigated by simulation conducted on a Gleeble-3500 thermal simulator. The results show that the nonmetallic inclusion particles in weld metals can become the nuclear core of acicular ferrite like in as-welded metal. So, the overlapping acicular ferrite microstructure is obtained in the weld metal after direct cooling from the reheating temperature. During tempering, the overlapping acicular ferrite microstructure is degenerated, and martensite/austenite (M/A) constituents in the acicular ferrite microstructure decompose into ferrites and carbides. The resulting carbide particles mainly distribute along the acicular ferrite grain boundaries. With the increase of the tempering temperature, the carbide particles coarsen, which decreases the impact toughness of the weld metal of hot bends. Addition of Ni to weld metals can refine the acicular ferrite and improve the impact toughness.

scholarly journals The influence of the oxygen equivalent in a gas-mixture on the structure and toughness of microalloyed steel weldments

2006 ◽  
Vol 71 (3) ◽  
pp. 313-321 ◽  
Author(s):  
Radica Prokic-Cvetkovic ◽  
Andjelka Milosavljevic ◽  
Aleksandar Sedmak ◽  
Olivera Popovic
Keyword(s):  
Impact Toughness ◽  
Crack Propagation ◽  
Weld Metal ◽  
Acicular Ferrite ◽  
Microalloyed Steel ◽  
Gas Mixtures ◽  
Gas Mixture ◽  
Weld Metals ◽  
Maximum Crack ◽  
The Impact

Testing were carried out on two steels. The first was microalloyed with Nb and second with Ti, Nb and V. The impact toughness of weld metals of these steels was evaluated using an instrumented Charpy pendulum. Five different gas mixtures (Ar, CO2, O2) were used to determine the optimal gas shielded metal arc process for both steels. The oxygen equivalent was used as a representative parameter of a mixture to follow, in particularly, its effect on the microstructure, toughness and crack propagation energy of the weld metal. For these investigated steels, the optimum gas mixture was established (5%CO2, 0.91%O2, balance Ar), which provided the maximum crack propagation energy, due to the microstructure which consisted dominantly of acicular ferrite.

Effects of oxygen content on microstructure and impact toughness of high heat input flux-cored wire weld metals

2018 ◽  
Vol 115 (4) ◽  
pp. 410
Author(s):  
Fengyu Song ◽  
Yanmei Li ◽  
Ping Wang ◽  
Fuxian Zhu
Keyword(s):  
Grain Size ◽  
Impact Toughness ◽  
Weld Metal ◽  
Oxygen Content ◽  
Heat Input ◽  
High Heat ◽  
Cored Wire ◽  
Weld Metals ◽  
High Heat Input ◽  
The Impact

Three weld metals with different oxygen contents were developed. The influence of oxygen contents on the microstructure and impact toughness of weld metal was investigated through high heat input welding tests. The results showed that a large number of fine inclusions were formed and distributed randomly in the weld metal with oxygen content of 500 ppm under the heat input condition of 341 kJ/cm. Substantial cross interlocked acicular ferritic grains were induced to generate in the vicinity of the inclusions, primarily leading to the high impact toughness at low temperature for the weld metal. With the increase of oxygen content, the number of fine inclusions distributed in the weld metal increased and the grain size of intragranular acicular ferrites decreased, which enhanced the impact toughness of the weld metal. Nevertheless, a further increase of oxygen content would contribute to a great diminution of the austenitic grain size. Following that the fraction of grain boundary and the start temperature of transformation increased, which facilitated the abundant formation of pro-eutectoid ferrites and resulted in a deteriorative impact toughness of the weld metal.

scholarly journals Effect of Nickel on the Microstructure, Hardness and Impact Toughness of SM570-TMC Weld Metals

2019 ◽  
Vol 269 ◽  
pp. 02007 ◽  
Author(s):  
Nova Arief Setiyanto ◽  
Herry Oktadinata ◽  
Winarto Winarto
Keyword(s):  
Impact Toughness ◽  
Weld Metal ◽  
Nickel Content ◽  
Optical Microscope ◽  
Fusion Welding ◽  
Welding Wire ◽  
Butt Weld ◽  
Weld Metals ◽  
Flux Cored Arc Welding ◽  
The Impact

SM570-TMC steel was applied in the various fields of steel construction where higher strength is required than conventional mild steel. This steel is commonly fabricated by fusion welding where flux-cored arc welding (FCAW) is preferred due to efficiency consideration. In this study, 14 mm thickness of SM570-TMC steel was butt weld by FCAW using three electrode wires with different nickel content (0% Ni, 1% Ni, 1.5% Ni). The microstructure of weldments was studied using an optical microscope. The hardness distribution tests were performed in the heat affected zone, parent metal and weld metal. And impact toughness of weld metals were measured at temperatures of 25 °C, 0 °C and -20 °C. The results show the steel plate welded using welding wire containing 1% Ni provides more superior impact toughness in the weld metal than welding wire 0% Ni, while the impact toughness of the sample which welded using welding wire containing 1.5% tend to decrease. Nickel element which deposited to weld metal by using welding wires containing 1% Ni has improved the impact toughness, but 1.5% Ni may too high which deteriorate impact toughness.

scholarly journals Effect of Welding Heat Input on Microstructure and Impact Toughness in the Simulated CGHAZ of Low Carbon Mo-V-Ti-N-B Steel

Metals ◽  
2021 ◽  
Vol 11 (12) ◽  
pp. 1997
Author(s):  
Mingliang Qiao ◽  
Huibing Fan ◽  
Genhao Shi ◽  
Leping Wang ◽  
Qiuming Wang ◽  
...  
Keyword(s):  
Impact Toughness ◽  
Heat Input ◽  
Acicular Ferrite ◽  
Granular Bainite ◽  
Equivalent Diameter ◽  
Low Carbon ◽  
Welding Heat Input ◽  
Lath Bainite ◽  
Gleeble 3500 ◽  
The Impact

Welding thermal cycles with heat inputs ranging from 25 to 75 kJ/cm were performed on a Gleeble 3500. The impact energy improved significantly (from 10 to 112 J), whereas the simulated coarse-grain heat-affected zone (CGHAZ) microstructure changed from lath bainite ferrite (LBF) and granular bainite ferrite (GBF) + martensite/austenite (M/A) to acicular ferrite (AF) + polygonal ferrite (PF) + M/A as the heat input increased. Simultaneously, the mean coarse precipitate sizes and the degree of V(C,N) enrichment on the precipitate surface increased, which provided favorable conditions for intragranular ferrite nucleation. The Ar3 of CGHAZ increased from 593 °C to 793 °C with increasing heat inputs; the longer high-temperature residence time inhibited the bainite transformation and promoted the ferrite transformation. As a result, acicular ferrite increased and bainite decreased in the CGHAZ. The CGHAZ microstructure was refined for the acicular ferrite segmentation of the prior austenite, and the microstructure mean equivalent diameter (MED) in the CGHAZ decreased from 7.6 µm to 4.2 µm; the densities of grain boundaries higher than 15° increased from 20.3% to 45.5% and significantly increased the impact toughness. The correlation of heat input, microstructure, and impact toughness was investigated in detail. These results may provide new ideas for the development of high welding heat input multiphase steels.

scholarly journals The Impact of Post-Manufacture Treatments on the Surface Characteristics Important for Finishing of OSB and Particleboard

Forests ◽  
2021 ◽  
Vol 12 (8) ◽  
pp. 975
Author(s):  
Antonio Copak ◽  
Vlatka Jirouš-Rajković ◽  
Nikola Španić ◽  
Josip Miklečić
Keyword(s):  
Water Vapour ◽  
Oriented Strand Board ◽  
Construction Material ◽  
Surface Characteristics ◽  
Surface Treatments ◽  
Factors Affecting ◽  
Treatment Conditions ◽  
Water Vapour Absorption ◽  
The Impact

Oriented strand board (OSB) is a commonly used structural wood-based panel for walls and roof siding, but recently the industry has become interested in OSB as a substrate for indoor and outdoor furniture. Particleboard is mainly used in furniture productions and has become popular as a construction material due to its numerous usage possibilities and inexpensive cost. Moisture is one of the most important factors affecting wood-based panel performance and the post-treatment conditions affected their affinity to water. When OSB and particleboard are used as substrates for coatings, their surface characteristics play an important role in determining the quality of the final product. Furthermore, roughness can significantly affect the interfacial phenomena such as adsorption, wetting, and adhesion which may have an impact on the coating performance. In this research particleboard and OSB panels were sanded, re-pressed and IR heated and the influence of surface treatments on hardness, roughness, wetting, water, and water vapour absorption was studied. Results showed that sanding improved the wetting of particleboard and OSB with water. Moreover, studied surface treatments increased water absorption and water penetration depth of OSB panels, and re-pressing had a positive effect on reducing the water vapour absorption of particleboard and OSB panels.

THE PROBLEMS OF THE INVESTIGATOR’S FORENSIC THINKING FORMATION

2021 ◽  
pp. 68-73
Author(s):  
Руслан Юрьевич Павлов
Keyword(s):  
Cognitive Abilities ◽  
Educational Process ◽  
Criminal Cases ◽  
Factors Affecting ◽  
Factors Associated ◽  
Personal Qualities ◽  
Definition Of ◽  
The Impact ◽  
Objective Investigation

Актуальность статьи связана с поиском новых способов и методов повышения эффективности борьбы с преступностью, оперативного раскрытия преступлений, а также с набирающим популярность среди криминалистов направлением «криминалистического мышления», овладение навыками которого будет способствовать наиболее полноценному и объективному расследованию уголовных дел. Проблемным в настоящее время является недостаточное качество следствия и необходимость повышения когнитивных способностей следователей (дознавателей). Задачей исследования являлось выявление факторов, влияющих на развитие и формирование криминалистического мышления следователей. Цель работы - провести анализ составных частей процесса становления следователя и особенностей его практической деятельности, влияющих на когнитивные способности с точки зрения криминалистики, путем изучения и сравнения имеющихся материалов по данной тематике. Анализу подвергнуты личностные качества следователя, особенности образовательного процесса и влияние опыта на результаты работы, а также факторы, сопутствующие следственной деятельности (организация труда, уровень стресса, нагрузки и т. д.). Результат проведенного исследования выражен в определении проблемных факторов, влияющих на формирование криминалистического мышления следователя (дознавателя) и возможных путей их преодоления, важности такого мышления, которое остается знанием, постоянно сориентированным в сторону практики. The relevance of the article is related to the search for new ways and methods to improve the effectiveness of the fight against crime, the prompt detection of crimes, as well as the trend of «forensic thinking», which is gaining popularity among criminalists, mastering the skills of which will contribute to the most complete and objective investigation of criminal cases. Problems at present are insufficient quality of investigation and the need to improve the cognitive abilities of investigators (inquirers). The task of the study was to identify factors that influence the development and formation of forensic thinking of investigators. The purpose of the work is- to analyze the components of the process of formation of an investigator and features of his practical activities affecting the cognitive abilities in terms of forensics by studying and comparing existing materials on this topic. The analysis is subjected to the personal qualities of an investigator, the peculiarities of the educational process and the impact of experience on the results of work, as well as factors associated with the investigative activity (organization of work, stress and stress levels, etc.). The result of the study is expressed in the definition of problematic factors affecting the formation of forensic thinking of an investigator (inquirer) and possible ways to overcome them, the importance of such thinking, which remains knowledge, constantly oriented towards practice

scholarly journals The Microstructure and Property of the Heat Affected zone in C-Mn Steel Treated by Rare Earth

2019 ◽  
Vol 38 (2019) ◽  
pp. 362-369 ◽  
Author(s):  
Ming-ming Song ◽  
Yu-min Xie ◽  
Bo Song ◽  
Zheng-liang Xue ◽  
Nan Nie ◽  
...  
Keyword(s):  
Rare Earth ◽  
Impact Toughness ◽  
Heat Affected Zone ◽  
Acicular Ferrite ◽  
Steel Matrix ◽  
Impact Properties ◽  
Treated Steel ◽  
The Impact ◽  
Welding Processes ◽  
Mn Steel

AbstractThe microstructures and impact properties of the heat affected zone (HAZ) in steel treated by rare earth (RE) under different welding processes were discussed. The effect of Al on the impact properties of the HAZ in RE treated steel was analyzed. It finds that when the welding t8/5 is smaller than 111 s, the main microstructure in steels is bainite/widmanstatten. The impact toughness of the HAZ is lower than that of the steel matrix. When t8/5 is more than 250 s, the microstructure is mainly acicular ferrite (AF) in the steel treated by RE, and the impact toughness of HAZ is obviously improved. Even under the welding processing with t8/5 about 600 s in RE treated steel can still obtain a lot of AF. While in the steel killed by Al and treated by RE, the main microstructure is parallel cluster of bainite/widmanstatten, and the impact toughness of HAZ is significantly lower than that of low-Al RE treated steel. Al can deteriorate the optimizing of RE treatment on HAZ.

scholarly journals Effect of Pre-Slaughter Practises and Early Post-Mortem Interventions on Sheep Meat Tenderness and Its Impact on Microbial Status

Foods ◽  
2022 ◽  
Vol 11 (2) ◽  
pp. 181
Author(s):  
Carlos Álvarez ◽  
Leonard Koolman ◽  
Michael Whelan ◽  
Aidan Moloney
Keyword(s):  
Quality Trait ◽  
Meat Tenderness ◽  
Post Mortem ◽  
Subsequent Aging ◽  
Factors Affecting ◽  
Aging Period ◽  
Sheep Meat ◽  
The Impact ◽  
Microbial Status

Tenderness, together with flavour, is the main quality trait that defines consumer acceptance of sheep meat. The factors affecting tenderness can be grouped as those influenced before slaughter, in the early post-mortem intervention and, finally, during the aging period. These factors have been extensively studied with respect to tenderness, but the impact of early post-mortem interventions and subsequent aging on the microbial quality of the final products has not been broadly reviewed to date. In this review, the authors summarize the most recent knowledge on lamb meat tenderness management and how such practices may impact the final meat quality, especially its microbial status. The impacts of pre-slaughter factors (age, sex, diet, genotype and transport) and post-mortem interventions (chilling regime, electrical stimulation, or hanging method), are described and comprehensively discussed.

scholarly journals Exploration of Factors Affecting Learners' Motivation in E-learning

2019 ◽  
pp. 1269-1275
Author(s):  
Shubham Dubey ◽  
Biro Piroska ◽  
Manjulata Gautam
Keyword(s):  
Dropping Out ◽  
Individual Factor ◽  
Factors Affecting ◽  
E Learning ◽  
Learning Platforms ◽  
The Common ◽  
Khan Academy ◽  
Future Work ◽  
The Impact

The world is changing rapidly, so is academics. E-learning has altered the area of academics and education. ICT enabled learning has given ideal services to students by providing any type of content on demand which is proportional to the performance of students. The concentration of learner has been found instinctive; thus there is a need of engaging mind towards course progress with its entirety till the objectives of the course will be achieved. There are several e-learning platforms available as EdX, Udacity, Khan Academy, Alison those have a number of learners registered for various courses. Studies suggest that these platforms suffer from the common problem of learners’ dropping out. Investigations also claim early leaving rate is increasing due to lack of quality of content, distraction factors, learners’ mind change, outdated and succinct information, and some more detraction factors. These issues have been observed on the basis of early leaving rates in various MOOCs. Thus there is a mammoth scope for minimizing the impact of these reasons on the learners’ mind. It can be achieved by identifying these factors affecting learners’ motivation during the course. This study is aiming on identifying these factors. The approach is to explore some certain keywords on previous literature (total 41) and then calculating their frequencies and co-factors associated with them. Both grouped factors contribution and individual factor contribution have been taken care. The study gives a direction for future work towards overcoming these actor and engaging learners in ICT enabled learning.

scholarly journals Market Responsiveness to Corporate Social Responsibility

2019 ◽  
Vol 8 (4) ◽  
pp. 114
Author(s):  
Zev Fried
Keyword(s):  
Corporate Social Responsibility ◽  
Social Responsibility ◽  
Financial Reporting ◽  
Perceived Quality ◽  
Financial Information ◽  
Factors Affecting ◽  
Earnings Response Coefficients ◽  
Corporate Social ◽  
The Impact

Market reaction to surprises in earnings announcements has long been used to measure the quality of the information content of the announcement, and studies have explored various factors affecting the response. This study adds to this body of research by factoring in the level of corporate social responsibility (CSR) exhibited by the firm and employs a relatively new measure of a company’s level of CSR, rankings published by JUST Capital. I hypothesize that financial information reported by higher ranked companies is weighed more heavily by investors than those reported by non-ranked or lower-ranked companies. Using earnings response coefficients as a measure of the perceived quality of the financial information reported by the firms, my results provide direct support of the hypothesis, indicating that the market reacts more strongly to earnings surprises for firms with high JUST rankings than for unranked firms or firms with lower rankings. This result contributes new insights into the impact of a firm’s CSR in terms of the perceived quality of a firm’s financial reporting.

Sign in / Sign up

Export Citation Format

Share Document