Steels Bhadeshia, Harshad; Honeycombe, Robert
2017.
eBook
By examining the properties of steels in conjunction with structure, this book provides a valuable description of the development and behavior of these materialsthe very foundation of their ...widespread use. --
It is difficult to observe the nucleation mechanism of inclusions in real-time. In this study, the nucleation process of zirconium oxide inclusions was systematically studied by classical nucleation ...theory and first principles. Zr deoxidized steel with 100 ppm Zr addition was processed into metallographic samples for scanning electron microscopy energy-dispersive spectroscopy observation. The electrolytic sample was analyzed by micro X-ray diffraction and transmission electron microscopy, and the zirconium oxide in the sample was determined to be ZrOsub.2. The nucleation rate and radius of the ZrOsub.2 inclusions were calculated by classical nucleation theory, and they were compared with the experimental values. There was a considerable difference between the experimental and theoretical values of the nucleation rate. The effect of the nucleation size was analyzed by first-principles calculation, and the thermodynamic properties of ZrOsub.2 clusters and nanoparticles were analyzed by constructing (ZrOsub.2)n (n = 1-6) clusters. The thermodynamic properties of ZrOsub.2 calculated by first principles were consistent with the values in the literature. Based on two-step nucleation theory, the nucleation pathway of ZrOsub.2 is as follows: Zrsub.atom + Osub.atom → (ZrOsub.2)n → (ZrOsub.2)sub.2 → core (ZrOsub.2 particle)-shell ((ZrOsub.2)sub.2 cluster) nanoparticle → (ZrOsub.2)sub.bulk.
Steels represent the most widely-used metallic alloy, possessing a wide range of microstructures and mechanical properties. By examining the mechanical properties of steels in conjunction with ...microstructure this book provides a valuable description of the development and behavior of these materials, the very foundation of their widespread use. Updated throughout and including new chapters on nanostructured steels, and new alloys and technologies for the energy and automobile industries, the book is clearly written and illustrated, with extensive bibliographies and real-life examples. This is an essential reference, both compact and readily comprehensive, for metallurgists and engineers, as well as senior undergraduate students and postgraduates in materials science, physical metallurgy and mechanical engineering.
In the present work, three different scratch tests are compared on their ability to rank the abrasion resistance of low alloy steels for industrial applications where the abrasion play a key role, ...e.g., in earthmoving, agricultural and mining equipment. The first test involves single pass scratching of pristine surfaces with a relatively large rigid indenter. The second test involves multi-pass scratching along a fixed track using the same large indenter. The third test involves the creation of a multi-pass scratch track using the same large indenter followed by final scratching of the abrasion track with a sharp indenter, i.e., Multi-Pass Dual Indenter (MPDI) scratch test. The three test protocols activate different abrasion mechanisms. Five low alloy construction steel grades with different strain hardening capabilities, i.e., Interstitial-free Ferritic steel (IF steel), Fully Martensitic steel (FM steel), Dual Phase steel (DP steel), Quench Partitioning steel (Q&P steel) and TWining Induced Plasticity steel (TWIP steel), are used. The results show that for both single (large) indenter scratch test protocols, the scratch depths always increase with indenter load and the failure mechanism is pure ploughing except for the IF steel due to the nature of softness. While for the dual-indenter scratch test, the scratch depth is a more complex function of the load applied during creation of the work hardened surface layer. The conventional scratch test protocols cannot well reveal micro-cracks and defect in (sub) surface and cannot well reflect the real response of strain hardening of steels. However, the MPDI test can distinguish between different steels with different initial hardness and different strain hardening behaviour and reveal the damage and, equally important, can indicate how average loading conditions may affect the relative abrasion resistance of construction steels during steady state conditions.
•For SPSI and MPSI scratch mode the scratch depths increase linearly with the loads.•For MPDI mode the scratch depth is a more complex function of the load.•The SPSI and MPSI mode only reveal the ploughing mechanism but MPDI mode can reveal ploughing accompanying with cracking.•The SPSI and MPSI mode cannot well reveal micro-cracks/defect but MPDI mode can work.•MPDI mode can indicate how loading conditions may affect the abrasion resistance.
Krupp James, Harold
2012., 20120226, 2012, 2012-02-26, 20120101
eBook
The history of Krupp is the history of modern Germany. No company symbolized the best and worst of that history more than the famous steel and arms maker. In this book, Harold James tells the story ...of the Krupp family and its industrial empire between the early nineteenth century and the present, and analyzes its transition from a family business to one owned by a nonprofit foundation.
Krupp founded a small steel mill in 1811, which established the basis for one of the largest and most important companies in the world by the end of the century. Famously loyal to its highly paid workers, it rejected an exclusive focus on profit, but the company also played a central role in the armament of Nazi Germany and the firm's head was convicted as a war criminal at Nuremberg. Yet after the war Krupp managed to rebuild itself and become a symbol of Germany once again--this time open, economically successful, and socially responsible.
Books on Krupp tend to either denounce it as a diabolical enterprise or celebrate its technical ingenuity. In contrast, James presents a balanced account, showing that the owners felt ambivalent about the company's military connection even while becoming more and more entangled in Germany's aggressive politics during the imperial era and the Third Reich.
By placing the story of Krupp and its owners in a wide context, James also provides new insights into the political, social, and economic history of modern Germany.
Automated computer-vision-based defect detection has received much attention with the increasing surface quality assurance demands for the industrial manufacturing of flat steels. This article ...attempts to present a comprehensive survey on surface defect detection technologies by reviewing about 120 publications over the last two decades for three typical flat steel products of con-casting slabs and hot- and cold-rolled steel strips. According to the nature of algorithms as well as image features, the existing methodologies are categorized into four groups: statistical, spectral, model-based, and machine learning. These works are summarized in this review to enable easy referral to suitable methods for diverse application scenarios in steel mills. Realization recommendations and future research trends are also addressed at an abstract level.
•A 3-D damage plasticity based FE model is developed for SCS sandwich shells.•Geometry and material nonlinearities were considered in the FE model.•The influence of the curvature on the resistance of ...SCS sandwich shells was studied.•The accuracy of analytical models on the resistance of sandwich shells was checked.
This paper develops a three-dimensional damage plasticity based finite element model (FEM) to study the ultimate strength of the steel–concrete–steel (SCS) sandwich shell structure under patch loading. The FEM considers complex geometric nonlinearities of hundreds of stud connectors in the structure, complex interaction between the connectors and concrete, and material nonlinearities of steel and concrete used in the structure. In the developed FEM, the concrete core material adopts the concrete damage plasticity model to predict the post-peak softening and residual strength; the stud connectors and steel shells adopt a continuum damage model to phenomenologically describe the damage evolution in the steel material. The reasonable agreement between FE analysis and the quasi-static tests on the SCS sandwich shell structure confirms the accuracy of the FEM in predicting the ultimate shear resistance, load–deflection relationship, cracks in the concrete core, and punching shear failure of the top steel shell. A subsequence parametric study based on the validated FEM investigates the influence of the curvature on the first peak resistance of the SCS sandwich structure. Finally, the paper validates accuracy of an analytical model on the punching shear resistance of the concrete core of the SCS sandwich shell.
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