Determining the overstrength factor based on statistical values of European steel grades

2020 ◽  
Vol 2 (1-2) ◽  
pp. 20-28
Author(s):  
Max Gündel
Keyword(s):  
Overstrength Factor ◽  
Steel Grades

Numerical analysis of local heat flux and thin-slab solidification in a CSP funnel-type mold with electromagnetic braking

2020 ◽  
Vol 117 (6) ◽  
pp. 602
Author(s):  
Heping Liu ◽  
Jianjun Zhang ◽  
Hongbiao Tao ◽  
Hui Zhang
Keyword(s):  
Heat Flux ◽  
Casting Speed ◽  
Shell Growth ◽  
Local Heat ◽  
Operating Conditions ◽  
Thin Slab ◽  
Wide Face ◽  
Slab Width ◽  
Steel Grades ◽  
Local Heat Flux

In this article, based on the actual monitored temperature data from mold copper plate with a dense thermocouple layout and the measured magnetic flux density values in a CSP thin-slab mold, the local heat flux and thin-slab solidification features in the funnel-type mold with electromagnetic braking are analyzed. The differences of local heat flux, fluid flow and solidified shell growth features between two steel grades of Q235B with carbon content of 0.19%C and DC01 of 0.03%C under varying operation conditions are discussed. The results show the maximum transverse local heat flux is near the meniscus region of over 0.3 m away from the center of the wide face, which corresponds to the upper flow circulation and the large turbulent kinetic energy in a CSP funnel-type mold. The increased slab width and low casting speed can reduce the fluctuation of the transverse local heat flux near the meniscus. There is a decreased transverse local heat flux in the center of the wide face after the solidified shell is pulled through the transition zone from the funnel-curve to the parallel-cure zone. In order to achieve similar metallurgical effects, the braking strength should increase with the increase of casting speed and slab width. Using the strong EMBr field in a lower casting speed might reverse the desired effects. There exist some differences of solidified shell thinning features for different steel grades in the range of the funnel opening region under the measured operating conditions, which may affect the optimization of the casting process in a CSP caster.

Tendencies of export and import of steel industry products of Russia within 9 months of 2019

2020 ◽  
Vol 76 (2) ◽  
pp. 107-112
Author(s):  
N. G. Zinov’eva
Keyword(s):  
Middle East ◽  
Steel Industry ◽  
Pig Iron ◽  
Finished Steel ◽  
Steel Pipes ◽  
Ferrous Metals ◽  
Steel Grades ◽  
Cis Countries ◽  
Further Development ◽  
Coated Sheet

Structure of the Russian export and import of steel industry products presented by results of 9 months of 2019 operation. It was shown, that the total share of pig iron, ferroalloys and semi-products (40.3%) in the ferrous metals export from Russia is practically the same as the share of rolled products and steel pipes (39.4%), whereas the shares in the import structure were 7.7 and 75% accordingly. The share the far abroad countries in the Russian export and import of finished steel products (in natural terms) accounted for 80.6 and 28.7% accordingly, while the share of CIS countries – 19.4 and 71.3% accordingly. For 9 months of 2019 the Russian export of semi-products declined by 10.9% comparing with the analogue period of 2018 and accounted for 10.9 m tons. 54.6% of the total export shipping of semi-products were directed to Mexico, Turkey, Egypt and Taiwan. Within the nearest years the Russian export of semi-products and billets, in particular, will be effected by the further development of the semi-products production in in the countries of Middle East, Turkey, Vietnam and India. The domestic market remained to be more attractive for many Russian companies. For the 9 months of 2019, export of long and flat products accounted for 3 and 5.7 m tons accordingly, declining comparing with the analogue period of the previous year by 11 and 15.6% accordingly. Import of long and flat products decreased by 12 and 0.5%, accounting for 1.0 and 2.9 m tons accordingly. By the results of 9 months of 2019, import declined and export shipping of coated sheet increased. Taking into account the expansion of steel grades assortment by Russian plants, increase of capacities for production of sheet with different coatings, this tendency is likely to remain.

scholarly journals Post-Fire Susceptibility to Brittle Fracture of Selected Steel Grades Used in Construction Industry—Assessment Based on the Instrumented Impact Test

Materials ◽  
2021 ◽  
Vol 14 (14) ◽  
pp. 3922
Author(s):  
Mariusz Maslak ◽  
Michal Pazdanowski ◽  
Marek Stankiewicz ◽  
Paulina Zajdel
Keyword(s):  
Charpy Impact ◽  
Water Mist ◽  
Heating Regime ◽  
Building Structures ◽  
Initial State ◽  
Slow Cooling ◽  
Natural Fire ◽  
Development Scenarios ◽  
Steel Grades ◽  
Fire Conditions

The change in the value of the breaking energy is discussed here for selected steel grades used in building structures after subjecting the samples made of them to episodes of heating in the steady-state heating regime and then cooling in simulated fire conditions. These changes were recorded based on the instrumented Charpy impact tests, in relation to the material initial state. The S355J2+N, 1H18N9T steels and also X2CrNiMoN22-5-3 duplex steel were selected for detailed analysis. The fire conditions were modelled experimentally by heating the samples and then keeping them for a specified time at a constant temperature of: 600 °C (first series) and 800 °C (second series), respectively. Two alternative cooling variants were investigated in the experiment: slow cooling of the samples in the furnace, simulating the natural fire progress, without any external extinguishing action and cooling in water mist simulating an extinguishing action by a fire brigade. The temperature of the tested samples was set at the level of −20 °C and alternatively at the level of +20 °C. The conducted analysis is aimed at assessing the risk of sudden, catastrophic fracture of load-bearing structure made of steel degraded as a result of a fire that occurred previously with different development scenarios.

scholarly journals Influence of Deep Rolling and Induction Hardening on Microstructure Evolution of Crankshaft Sections made from 38MnSiVS5 and 42CrMo4

2021 ◽  
Vol 76 (3) ◽  
pp. 175-194
Author(s):  
A. Fischer ◽  
B. Scholtes ◽  
T. Niendorf
Keyword(s):  
Process Parameters ◽  
Microstructure Evolution ◽  
Surface Hardening ◽  
Qualitative Evaluation ◽  
Induction Hardening ◽  
Deep Rolling ◽  
Automotive Components ◽  
Hardening Treatment ◽  
Steel Grades ◽  
Definition Of

Abstract In order to improve properties of complex automotive components, such as crankshafts, in an application-oriented way, several surface hardening treatments can be applied. Concerning the material performance the definition of adequate process parameters influences the resulting surface properties and, thus, the effectiveness of surface hardening treatments. To analyze most relevant process-microstructure-property relationships, the present paper reports results obtained by two different well-established surface hardening procedures, i. e. deep rolling as a mechanical treatment and induction hardening as a thermal treatment. For each hardening process widely used crankshaft steel grades, i. e. a medium carbon 38MnSiVS5 microalloyed steel and a quenched and tempered 42CrMo4 were selected and thoroughly characterized upon processing, using equal parameter settings. The results reveal that deep rolling in contrast to induction hardening proves to be a less sensitive surface layer treatment with regard to small differences in the initial microstructure, the chemical composition and the applied process parameters. Differences in microstructure evolution with respect to the applied surface hardening treatment are studied and discussed for the highly stressed fillet region of automotive crankshaft sections for all conditions. In this context, high-resolution SEM-based techniques such as EBSD and ECCI are proven to be very effective for fast qualitative evaluation of induced microstructural changes.

scholarly journals Impact of Solidification on Inclusion Morphology in ESR and PESR Remelted Martensitic Stainless Steel Ingots

Metals ◽  
2021 ◽  
Vol 11 (3) ◽  
pp. 408
Author(s):  
Ewa Sjöqvist Persson ◽  
Sofia Brorson ◽  
Alec Mitchell ◽  
Pär G. Jönsson
Keyword(s):  
Stainless Steel ◽  
Martensitic Stainless Steel ◽  
Dendritic Structure ◽  
Steel Grade ◽  
Solidification Structure ◽  
Production Scale ◽  
Steel Grades ◽  
Steel Ingots ◽  
Columnar Dendritic Structure ◽  
The Impact

This study focuses on the impact of solidification on the inclusion morphologies in different sizes of production-scale electro-slag remelting (ESR) and electro-slag remelting under a protected pressure-controlled atmosphere, (PESR), ingots, in a common martensitic stainless steel grade. The investigation has been carried out to increase the knowledge of the solidification and change in inclusion morphologies during ESR and PESR remelting. In order to optimize process routes for different steel grades, it is important to define the advantages of different processes. A comparison is made between an electrode, ESR, and PESR ingots with different production-scale ingot sizes, from 400 mm square to 1050 mm in diameter. The electrode and two of the smallest ingots are from the same electrode charge. The samples are taken from both the electrode, ingots, and rolled/forged material. The solidification structure, dendrite arm spacing, chemical analyzes, and inclusion number on ingots and/or forged/rolled material are studied. The results show that the larger the ingot and the further towards the center of the ingot, the larger inclusions are found. As long as an ingot solidifies with a columnar dendritic structure (DS), the increase in inclusion number and size with ingot diameter is approximately linear. However, at the ingot size (1050 mm in diameter in this study) when the center of the ingot converts to solidification in the equiaxial mode (EQ), the increase in number and size of the inclusions is much higher. The transition between a dendritic and an equiaxial solidification in the center of the ingots in this steel grade takes place in the region between the ingot diameters of 800 and 1050 mm.

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.

scholarly journals Development of Universal Mould Geometry for the Teeming of Cylindrical Iron-Base Alloy Ingots

Metals ◽  
2021 ◽  
Vol 11 (3) ◽  
pp. 471
Author(s):  
Josef Odehnal ◽  
Pavel Ludvík ◽  
Tomáš Studecký ◽  
Pavel Michálek
Keyword(s):  
Alloy Steel ◽  
Base Alloy ◽  
Cast Steel ◽  
Solidification Process ◽  
High Alloy ◽  
High Alloy Steel ◽  
Iron Base Alloy ◽  
Steel Grades ◽  
Borated Stainless Steel ◽  
Filling And Solidification

The presented work is aimed at developing a mould geometry suitable for casting both low- and high-alloy steel grades into 500 kg experimental ingots. The high Height-to-Diameter (H/D)-ratio mould currently used in COMTES FHT Inc. served as a reference and for finite element method simulations (FEM) of the filling and solidification process. The optimized mould geometry, balancing the porosity and segregations, was determined using MAGMA software. Four different steel grades were defined for the simulation. Case studies were carried out for 34CrNiMo6 (W.Nr. 1.6582), DHQ8, CB2 and borated stainless steel grades ranging from low-alloy steel to high-alloy steel. Extended user-defined criteria and verified boundary conditions were used to predict the formation of A-segregations in cast steel. Both primary (PDAS) and secondary (SDAS) arm spacings were modelled as well. The optimized mould shape and the casting assembly were designed based on the simulation results.

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