Local Notch Toughness of Slab Surface Zone in ULC/IF and HSLA Steels

2015 ◽  
Vol 662 ◽  
pp. 209-212
Author(s):  
Margita Longauerová ◽  
Maria Hurakova ◽  
Pavel Bekeč ◽  
Svätoboj Longauer ◽  
Mária Fedorová ◽  
...  

The aim of this work was to analyze changes in local toughness KCV using Charpy V-notch impact tests in the slab surface zone in relation to the microstructure in ULC/ IF steel and TiNb HSLA steel. Marked heterogeneity in KCV values was confirmed in the surface zone across the width of transitional slabs. Distinct local differences in notch toughness across the slab width were found to be linked primarily with changes in ferrite grain size. Low KCV values in the analyzed steels were linked with coarse grain structure, while much finer ferrite structure was identified in tough samples. The heterogeneity of KCV vales in the analyzed steels may be influenced by differences in thickness of the fine-grain slab surface zone, and by the presence of tertial cementite and (in HSLA steel) of pearlite as well.

Author(s):  
Mehdi Soltan Ali Nezhad ◽  
Sadegh Ghazvinian ◽  
Mahmoud Amirsalehi ◽  
Amir Momeni

Abstract Three steels were designed based on HSLA-100 with additional levels of Mn, Ni, Cr and Cu. The steels were prepared by controlled rolling and tempered at temperatures in range of 550–700°C. The continuous cooling time curves were shifted to longer times and lower temperatures with the increased tendency for the formation of martensite at lower cooling rates. The microstructures revealed that controlled rolling results in austenite with uniform fine grain structure. The steel with the highest amount of Mn showed the greatest strength after tempering at 750 °C. The top strength was attributed to the formation of Cu-rich particles. The steel with 1.03 wt.% Mn, tempered at 650 °C exhibited the best Charpy impact toughness at –85°C. On the other hand, the steel that contained 2.11 wt.% Mn and tempered at 700 °C showed the highest yield strength of 1 097.5 MPa (∼159 ksi) and an impact toughness of 41.6 J at –85°C.


2015 ◽  
Vol 647 ◽  
pp. 47-55 ◽  
Author(s):  
Margita Longauerová ◽  
Mária Fedorová ◽  
Pavel Bekeč ◽  
Jaroslav Duška ◽  
Maria Hurakova ◽  
...  

The aim of this work was to analyze the effect of sample thickness on toughness of the slab surface zone at ambient temperature in IF and microalloy steels. Transitional slabs with different pulling rates at the start and the end of the slab were used as well as slabs with standard pulling rates. Samples of standard size 10x10x55 mm and also non-standard size 5x10x55 mm were used for Charpy impact testing. It was confirmed that higher toughness values were found in thin non-standard size samples (5x10x55 mm), or more precisely for a larger portion of non-standard samples with toughness values higher than 50 J.cm-2. Using non-standard size samples confirmed the distinct stability of toughness values, as well as their smaller spread between minimum and maximum values. The transitional slabs had very distinct and non-uniform spread of toughness values across the slab width. This suggests greatly deteriorated quality of these slabs. During stable casting of TiNb microalloyed steel at the standard conventional higher slab pulling rate, uniform toughness was confirmed across the whole slab width in both sample types.


Alloy Digest ◽  
2008 ◽  
Vol 57 (7) ◽  

Abstract Domex 315 MC is a hot-rolled, high-strength low-alloy (HSLA) steel with a fine grain structure produced through thermomechanical rolling. It is used for cold-forming operations. The alloy meets or exceeds the requirements of S315MC in EN 10149-2. This datasheet provides information on composition, physical properties, tensile properties, and bend strength as well as fracture toughness. It also includes information on forming, heat treating, and joining. Filing Code: SA-581. Producer or source: SSAB Swedish Steel Inc.


Author(s):  
P. J. Lee ◽  
D. C. Larbalestier

Several features of the metallurgy of superconducting composites of Nb-Ti in a Cu matrix are of interest. The cold drawing strains are generally of order 8-10, producing a very fine grain structure of diameter 30-50 nm. Heat treatments of as little as 3 hours at 300 C (∼ 0.27 TM) produce a thin (1-3 nm) Ti-rich grain boundary film, the precipitate later growing out at triple points to 50-100 nm dia. Further plastic deformation of these larger a-Ti precipitates by strains of 3-4 produces an elongated ribbon morphology (of order 3 x 50 nm in transverse section) and it is the thickness and separation of these precipitates which are believed to control the superconducting properties. The present paper describes initial attempts to put our understanding of the metallurgy of these heavily cold-worked composites on a quantitative basis. The composite studied was fabricated in our own laboratory, using six intermediate heat treatments. This process enabled very high critical current density (Jc) values to be obtained. Samples were cut from the composite at many processing stages and a report of the structure of a number of these samples is made here.


Alloy Digest ◽  
1989 ◽  
Vol 38 (4) ◽  

Abstract Ductile Iron grade 45-12 produced by continuous casting has consistent density and fine grain structure. It is the softest of the regular grades of ductile iron and it machines at high speeds with good surface finish. This datasheet provides information on composition, physical properties, microstructure, hardness, elasticity, and tensile properties. It also includes information on heat treating, machining, and joining. Filing Code: CI-58. Producer or source: Federal Bronze Products Inc..


Alloy Digest ◽  
1960 ◽  
Vol 9 (8) ◽  

Abstract KETOS is an oil-hardening non-deforming tool steel having deep hardening qualities with a fine grain structure. This datasheet provides information on composition, physical properties, hardness, elasticity, and tensile properties as well as deformation. It also includes information on forming, heat treating, and machining. Filing Code: TS-96. Producer or source: Crucible Steel Company of America.


1995 ◽  
Vol 411 ◽  
Author(s):  
Chunyan Tian ◽  
Siu-Wai Chan

ABSTRACTThin films of 4% Y2O3 doped CeO2/Pd film/(001)LaA103 with a very low pinhole density were successfully prepared using electron-beam deposition technique. The microstructure of the films was characterized by x-ray diffraction and the electrical properties were studied as a function of temperature with AC impedance spectroscopy. A brick layer model was adopted to correlate the electrical properties to the microstructure of the films, which can be simplified as either a series or a parallel equivalent circuit associated with either a fine grain or a columnar grain structure, respectively. The conductivities of the films fell between the conductivities derived from the two circuit models, suggesting that the films are of a mixed fine grain and columnar grain structure. The measured dielectric constants of the films were found smaller than that of the bulk.


2003 ◽  
Vol 254-255 ◽  
pp. 538-540 ◽  
Author(s):  
J Moulin ◽  
Y Champion ◽  
J.M Grenèche ◽  
F Mazaleyrat

2016 ◽  
Vol 685 ◽  
pp. 487-491 ◽  
Author(s):  
Mikhail Chukin ◽  
Marina Polyakova ◽  
Alexandr Gulin ◽  
Olga Nikitenko

It is shown that combination of strain effects leads to possessing the ultra-fine grain structure in carbon wire. The continuous method of wire deformation nanostructuring was developed on the basis of simultaneous applying of tension deformation by drawing, bending deformation when going through the system of rolls and torsional deformation on a continuously moving wire. One of the main advantages of the developed method is that various hardware devices and tools already applied for steel wire production can be used to implement this method thus simplifying its introduction to the current industrial equipment. The efficiency estimation of the developed continuous method of deformation nanostructuring was carried out using carbon wire with different carbon content. It is shown that the mechanical properties of the wire after combination of different kinds of strain can vary over a wide range. This method makes it possible to choose such modes of strain effect, which can provide the necessary combination of strength and ductile properties of carbon wire depending on its further processing modes and application.


1994 ◽  
Vol 367 ◽  
Author(s):  
Yao Hua Zhu

AbstractExtruded eutectoid Zn-Al alloy was welded by a melt of the same eutectoid alloy. Two different microstructures were observed in the joint part and the bulk of the welded alloy. Typical dendritic structure of as cast Zn-Al alloy was observed in the joint part of the welded alloy. The bulk ofthe welded Zn-Al alloy appeared as fine grain structure. Two different metastable phases η'T decomposed from η's of chilled as cast state and η'E of extruded state were found to be unstable during early stage of ageing. A four phase transformation occurred after the decompositions of these two metastable phases of η'T. Microstructures of both joint part and bulk of the welded alloy were investigated parallely during ageing processes.


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