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Investigations of the relationship between the Brinell hardness and strength parameters of structural steels S235 and S355
Published in Marian A. Giżejowski, Aleksander Kozłowski, Marcin Chybiński, Katarzyna Rzeszut, Robert Studziński, Maciej Szumigała, Modern Trends in Research on Steel, Aluminium and Composite Structures, 2021
P. Organek, B. Gosowski, M. Redecki
The classification of steel grades is based on their chemical composition and mechanical properties. The most important, with regards to designing steel structures, are mechanical properties (yield point, tensile strength, impact strength). In turn, the chemical composition is taken into account during the production of welded structures. This is due to the fact that it determines one of the main parameters of metallurgical weldability - the CEV carbon equivalent.
Milling of intersecting contours on tubular structures to avoid structural changes of the material and meet the requirements for automated welding
Published in Amin Heidarpour, Xiao-Ling Zhao, Tubular Structures XVI, 2018
J. Müglitz, S. Keitel, J. Schuster
Three types of fine grained steel are in practical use: – normalized fine grained steel grades,– thermomechanical rolled steel grades and– heat treated steel grades.
A learning-based solution method for practical slab allocation problem in multiple hot rolling lines
Published in IISE Transactions, 2023
Ying Meng, Qingxin Guo, Qingyang Wang, Haichao Wang
As described early, the mismatching cost relates to steel grade difference, dimension difference, transportation cost, and the original relationship between slabs and orders. Among them, the steel grade difference is usually difficult to evaluate, whereas the others can be easily evaluated by actual costs, such as cut-loss and transportation costs. In practice, steel grade is used to identify the chemical composition and mechanical properties of steel products, designed according to the requirement of customers. Each steel grade usually involves more than 60 types of chemical elements and tens of technical parameters. Hence, it is difficult for planners to evaluate the difference between two steel grades. In addition, although the operations in steelmaking are conducted following the designed ones, it is common that the chemical composition of slabs may be different from their designed ones, due to production deviations. It increases the difficulty in evaluating differences in steel grades.
A robust optimization approach to steel grade design problem subject to uncertain yield and demand
Published in International Journal of Production Research, 2023
Qi Zhang, Shixin Liu, MengChu Zhou
Noting the advantages of the two-stage robust optimisation approach in modeling and solution, we employ it to SGDP to coordinate the production and allocation of steel grades while hedging against any possible realisation in uncertain yield and demand. More specifically, the first-stage decisions refer to determining a production plan for steel grades, which are made before the revelation of uncertainty. The second-stage decisions refer to determining an allocation scheme of steel grades, which are adjustable after the first-stage decisions are made and the uncertainty is revealed. To facilitate the understanding of SGDP, we summarise its characteristics as follows. Contradiction between production mode and customer demand. The monthly production capacity of a real steelmaking shop is about 50 steel grades and 500 charges (about 50,000–150,000 tons). These steel grades are classified into about 10 steel grade series (e.g. high-carbon, medium-carbon, and low-carbon steel), and each steel grade series contains about 2–6 steel grades with similar metallurgical compositions. At an SCC stage, molten steel of the same steel grade is generally produced in batches of about 3,000 tons according to process constraints. However, there are about 1,000 customer orders per month in the HR stage, and the weight of customised orders ranges from 1.2–100 tons.Uncertainty of yield and demand. An SCC stage often involves complex chemical reactions and physical changes. Thus, the yield rate is uncertain (Qiu, Sun, and Sun 2021), which is defined as the ratio of the weight of qualified steel products to the weight of input raw materials. For instance, the weight of one charge is 100 tons, while the weight of the produced slabs may be 95 tons, and the yield rate is 95% (generally within 96% ± 2%).