Graph Model of Steel Distribution on the Ship’s Hull

2000 ◽  
Vol 37 (03) ◽  
pp. 153-161
Author(s):  
Vadim V. Ivannikov
Keyword(s):  
Linear Programming ◽  
Graph Model ◽  
High Strength ◽  
Suggested Method ◽  
Effective Solution ◽  
Shipbuilding Steel ◽  
Linear Programming Methods ◽  
Hull Steel ◽  
Steel Grades

This paper discusses the task of optimizing vessel hull steel distribution by means of a graph model. Optimal and suboptimal options as far as the dimensions and steel grades are concerned are found by means of linear programming methods—the Dejikstra or Ford-Fulkerson flow algorithms. The suggested method has been used for an economically effective solution for utilizing high-strength shipbuilding steel and corrosion-proof steel for train-ferries in operation as well as for those being designed.

scholarly journals Methods of automated control over composition and structure of metalworking equipment

2018 ◽  
Vol 224 ◽  
pp. 01095 ◽  
Author(s):  
Svetlana Lukina ◽  
Elena Korshunova ◽  
Igor Dorozhkin
Keyword(s):  
Mathematical Model ◽  
Linear Programming ◽  
Evaluation Criteria ◽  
Graph Model ◽  
Financial Indicators ◽  
Automated Control ◽  
Alternative Structures ◽  
Linear Programming Methods ◽  
Economic Production ◽  
Composition And Structure

The technique of automated control over the composition and structure of metalworking equipment is examined based on a set of criteria. Multitude of alternative structures and technical and economic solutions to the problem of overhaul or local re-equipment of production is formed on the basis of the developed multi-layer graph model. The generated mathematical model is defined on the set of Boolean variables and implemented using linear programming methods. The choice of an effective composition and structure of technical means for equipping technological operations is based on the results of an analysis of evaluation criteria that determine technical, economic, production and financial indicators of an industrial enterprise, as well as partial indicators of quality and competitiveness of production facilities.

scholarly journals Overview of HSS Steel Grades Development and Study of Reheating Condition Effects on Austenite Grain Size Changes

Materials ◽  
2021 ◽  
Vol 14 (8) ◽  
pp. 1988
Author(s):  
Tibor Kvackaj ◽  
Jana Bidulská ◽  
Róbert Bidulský
Keyword(s):  
Mechanical Properties ◽  
Grain Size ◽  
High Strength Steel ◽  
Single Phase ◽  
Hsla Steel ◽  
High Strength ◽  
Strength Properties ◽  
Austenite Grain Size ◽  
Austenite Grain ◽  
Steel Grades

This review paper concerns the development of the chemical compositions and controlled processes of rolling and cooling steels to increase their mechanical properties and reduce weight and production costs. The paper analyzes the basic differences among high-strength steel (HSS), advanced high-strength steel (AHSS) and ultra-high-strength steel (UHSS) depending on differences in their final microstructural components, chemical composition, alloying elements and strengthening contributions to determine strength and mechanical properties. HSS is characterized by a final single-phase structure with reduced perlite content, while AHSS has a final structure of two-phase to multiphase. UHSS is characterized by a single-phase or multiphase structure. The yield strength of the steels have the following value intervals: HSS, 180–550 MPa; AHSS, 260–900 MPa; UHSS, 600–960 MPa. In addition to strength properties, the ductility of these steel grades is also an important parameter. AHSS steel has the best ductility, followed by HSS and UHSS. Within the HSS steel group, high-strength low-alloy (HSLA) steel represents a special subgroup characterized by the use of microalloying elements for special strength and plastic properties. An important parameter determining the strength properties of these steels is the grain-size diameter of the final structure, which depends on the processing conditions of the previous austenitic structure. The influence of reheating temperatures (TReh) and the holding time at the reheating temperature (tReh) of C–Mn–Nb–V HSLA steel was investigated in detail. Mathematical equations describing changes in the diameter of austenite grain size (dγ), depending on reheating temperature and holding time, were derived by the authors. The coordinates of the point where normal grain growth turned abnormal was determined. These coordinates for testing steel are the reheating conditions TReh = 1060 °C, tReh = 1800 s at the diameter of austenite grain size dγ = 100 μm.

Development of X90 and X100 Steel Grades for Seamless Linepipe Products

2014 ◽  
Author(s):  
Diana Toma ◽  
Silke Harksen ◽  
Dorothee Niklasch ◽  
Denise Mahn ◽  
Ashraf Koka
Keyword(s):  
Wall Thickness ◽  
Deep Water ◽  
High Strength ◽  
Oil And Gas Industry ◽  
Pipe Material ◽  
Line Pipe ◽  
Materials Development ◽  
Additional Tool ◽  
Technical Requirements ◽  
Steel Grades

The general trend in oil and gas industry gives a clear direction towards the need for high strength grades up to X100. The exploration in extreme regions and under severe conditions, e.g. in ultra deep water regions also considering High Temperature/High Pressure Fields or arctic areas, becomes more and more important with respect to the still growing demand of the world for natural resources. Further, the application of high strength materials enables the possibility of structure weight reduction which benefits to materials and cost reduction and increase of efficiency in the pipe line installation process. To address these topics, the development of such high strength steel grades with optimum combination of high tensile properties, excellent toughness properties and sour service resistivity for seamless quenched and tempered pipes are in the focus of the materials development and improvement of Vallourec. This paper will present the efforts put into the materials development for line pipe applications up to grade X100 for seamless pipes manufactured by Pilger Mill. The steel concept developed by Vallourec over the last years [1,2] was modified and adapted according to the technical requirements of the Pilger rolling process. Pipes with OD≥20″ and wall thickness up to 30 mm were rolled and subsequent quenched and tempered. The supportive application of thermodynamic and kinetic simulation techniques as additional tool for the material development was used. Results of mechanical characterization by tensile and toughness testing, as well as microstructure examination by light-optical microscopy will be shown. Advanced investigation techniques as scanning electron microcopy and electron backscatter diffraction are applied to characterize the pipe material up to the crystallographic level. The presented results will demonstrate not only the effect of a well-balanced alloying concept appointing micro-alloying, but also the high sophisticated and precise thermal treatment of these pipe products. The presented alloying concept enables the production grade X90 to X100 with wall thickness up to 30 mm and is further extending the product portfolio of Vallourec for riser systems for deepwater and ultra-deep water application [1, 3, 4].

scholarly journals Research of the College Enrollment Plan Based on Fuzzy Linear Programming Model

2021 ◽  
Vol 251 ◽  
pp. 01092
Author(s):  
Yuhong Sun ◽  
Guoxing Zhang ◽  
Yueyang Gao ◽  
Mingzhu Chen
Keyword(s):  
Linear Programming ◽  
Mathematical Models ◽  
Hierarchical Structure ◽  
College Enrollment ◽  
Programming Model ◽  
College Admission ◽  
Fuzzy Linear Programming ◽  
Linear Programming Model ◽  
Use Of Resources ◽  
Linear Programming Methods

This paper aims at the problems of professional structure and hierarchical structure in college admission plans, uses linear programming methods to establish mathematical models, maximizes the use of resources on the basis of completing the national enrollment plan, determines the reasonable enrollment structure and enrollment scale, and makes the enrollment plan more scientific and reasonable. In actual situations, the number of students enrolled in the school, the consumption of students, and the number of teachers are constantly changing. Therefore, the concept of fuzzy linear programming is introduced, and the constraints of the linear programming model are fuzzy optimized to obtain more reasonable results, which inspires some reasonable suggestions for colleges in formulating enrollment plans.

Numerical and Experimental Studies of Residual Stresses in Multipass Welding of High Strength Shipbuilding Steel

2015 ◽  
Vol 59 (3) ◽  
pp. 133-144 ◽  
Author(s):  
Guangming Fu ◽  
Tetyana Gurova ◽  
Marcelo I. Lourenco ◽  
Segen F. Estefen
Keyword(s):  
Residual Stresses ◽  
Experimental Studies ◽  
High Strength ◽  
Shipbuilding Steel ◽  
Multipass Welding
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