scholarly journals Features of quality indicators of metal of boiler tubes rolled from continuously cast billets produced by Dniprostal metallurgical works LLC

2019 ◽  
pp. 46-53 ◽  
Author(s):  
L. V. Opryshko ◽  
T. V. Golovniak ◽  
I. I. Poltava
Keyword(s):  
Quality Indicators ◽  
Service Reliability ◽  
Structure And Properties ◽  
Tube Surface ◽  
Boiler Tube ◽  
Tube Rolling ◽  
Boiler Tubes ◽  
Continuously Cast ◽  
Technical Specifications

Purpose. Study of patterns of formation of structure and properties as well as the surface quality of boiler tubes in the process of tube rolling at TPA 30-102 tube rolling unit from non-worked continuously cast billets (CCB) of steel 20 produced by Dniprostal Metallurgical Works LLC. Methodology. Metallographic examination (macrostructure, microstructure, contamination by non-metallic inclusions); tensile and impact bend tests at room and elevated temperatures, determination of susceptibility to mechanical aging, long-term strength tests, visual inspection of the billet and the tube surface. Findings. Quality indicators of metal of the CCB produced by Dniprostal Metallurgical Works LLC and hot-rolled tubes produced at TPA 30-102 tube rolling unit from the CCB including service properties were investigated. Regularities of influence of quality of the initial CCB metal, technology of tube processing (hot rolling and heat treatment) on the formation of structure and properties as well as on the state of the boiler tube surface were established. Draft Technical Specifications were developed for the CCB produced by Dniprostal Metallurgical Works LLC intended for production of boiler tubes. Originality. For the first time, based on the revealed regularities of influence of the initial CCB on the formation of quality indicators of tube metal, Technical Specifications for high-duty continuously cast billets produced by Dniprostal Metallurgical Works LLC have been developed which make it possible to produce boiler tubes of high service reliability. Practical value. The research results will allow enterprises of Interpipe Ukraine JSC to produce boiler tubes of high service reliability from continuously cast billets produced by Dniprostal Metallurgical Works LLC. The use of billets of home production will reduce the cost of boiler tubes and eliminate the shortage of boiler tube billets in Ukraine. Keywords: continuously cast billet, hot rolling, elongation ratios, boiler tubes, heat treatment, macrostructure and microstructure, cast structure residues, mechanical properties, heat resistance, defects.

scholarly journals Study of surface defects in tubes made from nondeformed continuously cast billets

2021 ◽  
Vol 98 (2) ◽  
pp. 54-62
Author(s):  
L.V. Opryshko ◽  
◽  
T.V. Golovnyak ◽  
Keyword(s):  
Outer Surface ◽  
Surface Defects ◽  
Gas Bubbles ◽  
Chemical Inhomogeneity ◽  
Tube Surface ◽  
Steel Smelting ◽  
Study Results ◽  
Inner Surface ◽  
Continuously Cast

Defects of outer and inner surfaces of hot-rolled tubes of various steel grades and sizes manufactured on tube-rolling unit with a continuous mill (TPA 30-102) at Interpipe Nikotube LLC from a nondeformed continuously cast billets produced by MZ Dniprostal LLC have been studied. Characteristic genetic and morphological signs of defects were revealed which makes it possible to reliably classify them, identify cause of defect formation and recommend measures to eliminate them. Defects on the outer and inner surfaces of tubes are of metallurgical origin and associated with quality of initial continuously cast billets (a consequence of violation of the smelting and continuous casting technology). Defects on the inner surface of tubes were caused on defects in the axial zone of original billets (unacceptable porosity, looseness, chemical inhomogeneity, liquation stripes and cracks, etc.) and are classified as steel-smelting films and bulges. It was found that displacement of the thermal center of crystallization (a feature of the machines for continuous steel casting of curvilinear type) had an additional negative effect on quality of the inner surface of the studied tubes. Defects on the outer surface of tubes are tears of burning in places of accumulation of low-melting inclusions and their eutectics, as well as steel-smelting scabs on rolled dirt and gas bubbles. Likelihood of formation of scabs on outer surface of the studied tubes over rolled crust introversions is not excluded. The study results will allow manufacturers to reliably classify defects, promptly reject tubes with unacceptable defects of metallurgical origin and minimize supply of low-quality products to consumers. These results will later be included in the classifier of defects in tubes manufactured on the TPA 30-102 unit from nondeformed continuously cast billets. The results of the study of natural signs of defects of metallurgical origin in the tube surface will be useful for elaboration of measures aimed at improvement of the technology of manufacturing initial tube billets. Keywords: tube surface defects, continuously cast billets, microstructure, rolled contamination, low-melting inclusions, eutectic, gas bubbles, decarburization, liquation.

Influence of technology parameters of free-cutting steel continuous casting on the billet internal structure

2020 ◽  
Vol 76 (2) ◽  
pp. 139-142
Author(s):  
A. T. Kunakbaeva ◽  
A. M. Stolyarov ◽  
M. V. Potapova
Keyword(s):  
Regression Analysis ◽  
Continuous Casting ◽  
Internal Structure ◽  
Sulfur Content ◽  
Manganese Content ◽  
High Quality ◽  
Correlation And Regression Analysis ◽  
Cutting Steel ◽  
Continuously Cast

Free-cutting steel gains specific working properties thanks to the high content of sulfur and phosphorus. These elements, especially sulfur, have a rather high tendency to segregation. Therefore, segregation defects in free-cutting steel continuously cast billets can be significantly developed. The aim of the work was to study the influence of the chemical composition of freecutting steel and casting technological parameters on the quality of the macrostructure of continuously cast billets. A metallographic assessment of the internal structure of cast metal made of free-cutting steel and data processing by application of correlation and regression analysis were the research methods. The array of production data of 43 heats of free-cutting steel of grade A12 was studied. Steel casting on a five-strand radial type continuous casting machine was carried out by various methods of metal pouring from tundish into the molds. Metal of 19 heats was poured with an open stream, and 24 heats – by a closed stream through submerged nozzles with a vertical hole. High-quality billets had a cross-sectional size of 150×150 mm. The macrostructure of high-quality square billets made of free-cutting steel of A12 grade is characterized by the presence of central porosity, axial segregation and peripheral point contamination, the degree of development of which was in the range from 1.5 to 2.0 points, segregation cracks and strips – about 1.0 points. In the course of casting with an open stream, almost all of these defects are more developed comparing with the casting by a closed stream. As a result of correlation and regression analysis, linear dependences of the development degree of segregation cracks and strips both axial and angular on the sulfur content in steel and on the ratio of manganese content to sulfur content were established. The degree of these defects development increases with growing of sulfur content in steel of A12 grade. These defects had especially strong development when sulfur content in steel was of more than 0.10%. To improve the quality of cast metal, it is necessary to have the ratio of the manganese content to the sulfur content in the metal more than eight.

Criteria for evaluation of the coordinate measurements quality of parts geometric parameters at pilot-experimental production

2019 ◽  
pp. 3-8
Author(s):  
N.Yu. Bobrovskaya ◽  
M.F. Danilov
Keyword(s):  
Quality Indicators ◽  
Quality Management System ◽  
Technical Specification ◽  
Experimental Production ◽  
Technological Heredity ◽  
Coordinate Measurements ◽  
Reasonable Choice ◽  
The Stability ◽  
Geometric Elements

The criteria of the coordinate measurements quality at pilot-experimental production based on contemporary methods of quality management system and traditional methods of the measurements quality in Metrology are considered. As an additional criterion for quality of measurements, their duration is proposed. Analyzing the problem of assessing the quality of measurements, the authors pay particular attention to the role of technological heredity in the analysis of the sources of uncertainty of coordinate measurements, including not only the process of manufacturing the part, but all stages of the development of design and technological documentation. Along with such criteria as the degree of confidence in the results of measurements; the accuracy, convergence, reproducibility and speed of the results must take into account the correctness of technical specification, and such characteristics of the shape of the geometric elements to be controlled, such as flatness, roundness, cylindrical. It is noted that one of the main methods to reduce the uncertainty of coordinate measurements is to reduce the uncertainty in the initial data and measurement conditions, as well as to increase the stability of the tasks due to the reasonable choice of the basic geometric elements (measuring bases) of the part. A prerequisite for obtaining reliable quality indicators is a quantitative assessment of the conditions and organization of the measurement process. To plan and normalize the time of measurements, the authors propose to use analytical formulas, on the basis of which it is possible to perform quantitative analysis and optimization of quality indicators, including the speed of measurements.

Using the alveograph in developing requirements for the quality of flour for wafer sheet production

2020 ◽  
Vol 29 (12) ◽  
pp. 52-58
Author(s):  
E.P. Meleshkina ◽  
◽  
S.N. Kolomiets ◽  
A.S. Cheskidova ◽  
◽  
...  
Keyword(s):  
Rheological Properties ◽  
Quality Indicators ◽  
Wheat Flour ◽  
Mathematical Statistics ◽  
Intended Purpose ◽  
The Future ◽  
Relationship Of ◽  
The Relationship

Objectively and reliably determined indicators of rheological properties of the dough were identified using the alveograph device to create a system of classifications of wheat and flour from it for the intended purpose in the future. The analysis of the relationship of standardized quality indicators, as well as newly developed indicators for identifying them, differentiating the quality of wheat flour for the intended purpose, i.e. for finished products. To do this, we use mathematical statistics methods.

The impact of sex, gender and healthcare system on quality of care among young adults with acute myocardial infarction

2020 ◽  
Vol 41 (Supplement_2) ◽  
Author(s):  
V Raparelli ◽  
L Pilote ◽  
H Behlouli ◽  
J Dziura ◽  
H Bueno ◽  
...  
Keyword(s):  
Myocardial Infarction ◽  
Acute Myocardial Infarction ◽  
Young Adults ◽  
Quality Of Care ◽  
Healthcare System ◽  
Quality Indicators ◽  
Funding Source ◽  
Post Discharge ◽  
Single Payer

Abstract Background The quality of care among young adults with acute myocardial infarction (AMI) may be related to biological sex, psycho-socio-cultural (gender) determinants or healthcare system-level factors. Purpose To examine whether sex, gender, and the type of healthcare system influence the quality of AMI care among young adults. Methods A total of 4,564 AMI young adults (<55 years) (59% women, 47 years, 66% US) were analyzed from the VIRGO and GENESIS-PRAXY studies consisting of single-payer (Canada, Spain) versus multipayer (US) systems. For each patient treated in each system we calculated a quality of care score (QCS) for pre-AMI (1-year pre admission), in-hospital, and post-AMI (1-year post discharge) phases of care (number of quality indicators received divided by the total number [range=0–100%], with higher scores indicating better quality). Ordinal logistic or linear regression models, and 2-way interactions between sex, gender and healthcare system were tested. Results Women in the multipayer system had the highest risk factor burden. Across the phases of care for AMI, 20% of quality indicators were missed in both sexes. High stress, earner status, and social support were associated with a higher QCS in the pre-AMI phase, whereas only employment and earner status were associated with QCS in all other phases. In the pre-AMI phase, women had higher QCS than men, mainly in the single-payer system (adjusted-OR=1.85, 95% CI 1.46,2.35 vs. 1.07, 95% CI 0.84,1.36, P-interaction= 0.002). Regardless of sex, only employment status had a greater effect in the multipayer system (adjusted-OR=0.59, 95% CI 0.44,0.78 vs 1.13, 95% CI 0.89,1.44, P-interaction <0.001). In the in-hospital phase, women had a lower QCS than men, especially in the multipayer system (adjusted-mean-difference: −2.48, 95% CI-3.87, −1.08). Employment was associated with a higher QCS (2.0, 95% CI 0.9–3.17, P-interaction >0.05). Finally, in the post-AMI phase, men and women had a lower QCS, predominantly in the multipayer system. However, primary earners had higher QCS regardless of system. Conclusion Sex, gender, and healthcare system affected the quality of care after AMI. Women had a poorer in-hospital than men and both women and men had suboptimal post-discharge care. Being unemployed lowered the quality of care, more so in the multipayer system. Funding Acknowledgement Type of funding source: Public grant(s) – National budget only. Main funding source(s): Canadian Institutes of Health and Research (CIHR)

scholarly journals Quality in Assisted Living: Does It Lie in the Eyes of the Beholder?

2020 ◽  
Vol 4 (Supplement_1) ◽  
pp. 726-727
Author(s):  
Diana White ◽  
Tunalilar Ozcan ◽  
Serena Hasworth ◽  
Jaclyn Winfree
Keyword(s):  
Quality Indicators ◽  
Residential Care ◽  
Assisted Living ◽  
Physical Environment ◽  
Sampling Strategy ◽  
Perceived Quality ◽  
Two Stage ◽  
Regulatory Perspective ◽  
To Receive

Abstract Quality is defined in multiple ways and by different stakeholders (e.g., residents, regulators, informed observers). Using a two-stage stratified sampling strategy, we collected data from N=241 residents living in 31 assisted living and residential care communities (AL/RC) in Oregon. Residents rated their overall satisfaction and satisfaction with the AL/RC as a place to live and to receive care. Each interviewer completed a facility profile summarizing their observations about the setting, including quality of staff-resident interactions and physical environment. Residents and interviewers were also asked whether they would recommend the community to others. Finally, we used deficiency citations given during regular inspections by the licensing agency to proxy regulatory perspective. Results show that perceived quality varied by stakeholder (e.g., residents’ assessments differed from deficiency citations). Given this variation, findings suggest that efforts to make quality indicators publicly available should include multiple measures and perspectives, especially residents.

P5599Prognostic impact of quality indicators on outcomes of acute aortic dissection in Japan

2019 ◽  
Vol 40 (Supplement_1) ◽  
Author(s):  
T Yamaguchi ◽  
M Nakai ◽  
Y Sumita ◽  
Y Miyamoto ◽  
H Matsuda ◽  
...  
Keyword(s):  
Aortic Dissection ◽  
Hospital Mortality ◽  
Quality Indicators ◽  
Acute Aortic Dissection ◽  
Vascular Diseases ◽  
Type A ◽  
Administrative Database ◽  
Type B ◽  
Practice Gaps

Abstract Background Despite recent advances in diagnosis and management, the mortality of acute aortic dissection (AAD) remains high. Purpose This study aims to develop quality indicators (QIs) for the management of AAD, and to evaluate the associations between QIs and outcomes of AAD in a Japanese nationwide administrative database. Methods A total of 18,348 patients suffered from AAD (Type A: 10,131, Type B: 8,217) in the Japanese Registry of All Cardiac and Vascular Diseases database between 2012 and 2015 were studied. A systematic review was performed to establish initial index items for QIs. Evaluation was performed through the expert consensus meeting using a Delphi method. Associations between developed QIs and the mortality were determined by multivariate mixed logistic regression analyses. Results A total of nine QIs (five structural and four processatic) were developed. Achievements of developed QIs (High: 7–9, Middle: 4–6, Low: 0–3) were significantly associated with lower in-hospital mortality even after adjustment for covariates in both type A (Middle: odds ratio [OR], 0.257; 95% confidence interval [CI], 0.211–0.312; P<0.001; High: OR, 0.064; 95% CI, 0.047–0.086; P<0.001 vs. Low) and type B (Middle: OR, 0.447; 95% CI, 0.338–0.590; P<0.001; High: OR, 0.128; 95% CI, 0.077–0.215; P<0.001 vs. Low). Additionally, achievements of structural and processatic QIs were consistently associated with reduced in-hospital mortality. QIs and in-hospital mortality Conclusions Developed QIs for AAD management were significantly associated with lower in-hospital mortality. Evaluation of each hospital's management with QIs could be helpful to equalize quality of treatment and to fill the evidence-to-practice gaps in the real-world treatment.

Using Assessing Care of Vulnerable Elders Quality Indicators to Measure Quality of Hospital Care for Vulnerable Elders

2007 ◽  
Vol 55 (11) ◽  
pp. 1705-1711 ◽  
Author(s):  
Vineet M. Arora ◽  
Martha Johnson ◽  
Jared Olson ◽  
Paula M. Podrazik ◽  
Stacie Levine ◽  
...  
Keyword(s):  
Quality Indicators ◽  
Hospital Care
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