Strain-Induced Precipitation of Nb(CN) during Deformation of Undercooled Austenite in Nb-Microalloyed HSLA Steels

2005 ◽  
pp. 105-108 ◽  
Author(s):  
Guoan Chen ◽  
Wang Yue Yang ◽  
Shou Zhen Guo ◽  
Zu Qing Sun
Keyword(s):  
Hsla Steels ◽  
Undercooled Austenite

Strain-Induced Precipitation of Nb(CN) during Deformation of Undercooled Austenite in Nb-Microalloyed HSLA Steels

2005 ◽  
Vol 475-479 ◽  
pp. 105-108 ◽  
Author(s):  
Guoan Chen ◽  
Wang Yue Yang ◽  
Shou Zhen Guo ◽  
Zu Qing Sun
Keyword(s):  
Grain Size ◽  
Incubation Period ◽  
Volume Fraction ◽  
Microalloyed Steel ◽  
Isothermal Transformation ◽  
Dynamic Precipitation ◽  
Hsla Steels ◽  
Nb Microalloyed Steel ◽  
Undercooled Austenite ◽  
Good Agreement

By using TEM strain-induced precipitation of Nb(CN) during deformation of undercooled austenite was investigated in Nb-microalloyed steel. The results showed that at 1200°C all of Nb were dissolved and there were no Nb(CN) precipitates formed during cooling until down to 760°C; During deformation enhanced ferrite transformation Nb(CN) of dynamic precipitation required an incubation period, but compared with isothermal transformation it reduced significantly. Only when the strain increased to 0.69, Nb(CN) began to precipitate on dislocation nodes and grain boundaries. Furthermore the volume fraction of Nb(CN) precipitation increased with increasing strain but their coarsening wasn’t significant. Results showed that the measured grain size is in good agreement with the calculated value.

TEM study on fine carbide precipitates and dislocation cell structure

1990 ◽  
Vol 48 (4) ◽  
pp. 904-905
Author(s):  
Mengzhe Chen ◽  
Siqin Wang ◽  
Jun Ke
Keyword(s):  
Carbide Particle ◽  
Cell Structure ◽  
Ferrite Matrix ◽  
Dislocation Cell ◽  
Isothermal Treatment ◽  
Particle Sizes ◽  
Dislocation Cell Structure ◽  
Thin Foils ◽  
Hsla Steels ◽  
Fine Carbide

A series of investigations have been conducted into the nature and origin of the dislocation cell structure. R.J.Klassen calculated that the dislocation cell limiting size in pure ferrite matrix is about 0.4 μm. M.N.Bassion estimated the size of dislocation cell in deformed ferrite of HSLA steels to be of the same order.In this paper, TEM observation has been concentrated on the interaction of fine carbide precipitates with dislocation cell structure in deformed Fe-C-V (0.05%C, 0.13% and 0.57%V) and Fe-C-Nb (0.07 %C and 0.04%Nb) alloys and compared with that in Fe-C (0.05%). Specimens were austenitized at 1500 “C/20 min and followed by isothermal treatment at 750 °C and 800 “C for 20, 40 and 120 minutes . The carbide particle sizes in these steels are from 9 to 86nm measured from carbon extraction replicas. Specimens for TEM were cut from differently deformed areas of tensile specimens deformed at room temperture. The thin foils were jet electropolished at -20 C in a solution of 10% perchloric acid and 90% ethanol. The TEM observation was carried out in JEM 100CX , EM420 at 100kv and JEM 2000FX at 200kv.

Development of NbTiB Microalloyed HSLA Steels for High-Strength Heavy Plate

2005 ◽  
Vol 500-501 ◽  
pp. 565-572 ◽  
Author(s):  
H. Meuser ◽  
F. Grimpe ◽  
S. Meimeth ◽  
C.J. Heckmann ◽  
C. Träger
Keyword(s):  
High Strength ◽  
Optimum Process ◽  
Low Carbon ◽  
Low Alloy Steel ◽  
Alloying Element ◽  
Heavy Plate ◽  
Hsla Steels ◽  
Bainitic Microstructure ◽  
Bainitic Structure ◽  
Low Temperature Toughness

This paper deals with the development of low carbon NbTiB micro-alloyed high strength low alloy steel for heavy plates with high wall thickness. In the production of heavy plate it is remarkably difficult to achieve a combination of high strength and good low-temperature toughness. Bainitic microstructures have shown the capability to attain such requirements. To achieve a bainitic microstructure even for heavy wall products the formation of bainite can be promoted and supported by the use of small amounts of boron as a micro-alloying element. This industrial research project is based on the addition of small amounts of boron to promote the desired bainitic structure. Mill rolling trials were carried out to determine the optimum process parameters. The results of experimental mill rolling trials on 35 mm plates will be presented in this paper.

Shaping mechanism of ultrafine metastable austenite in HSLA steels through a cumulative process of hot rolling, partitioning and tempering

2021 ◽  
Vol 811 ◽  
pp. 141060
Author(s):  
Shilong Liu ◽  
Bin Hu ◽  
Yishuang Yu ◽  
Chengjia Shang ◽  
R.D.K. Misra ◽  
...  
Keyword(s):  
Hot Rolling ◽  
Metastable Austenite ◽  
Hsla Steels ◽  
Cumulative Process

MODELLING TMCP OF HSLA STEELS BY PETRI NEURAL NETWORK TECHNIQUE

2006 ◽  
Vol 45 (3) ◽  
pp. 303-310 ◽  
Author(s):  
S. DATTA ◽  
M.K. BANERJEE
Keyword(s):  
Neural Network ◽  
Hsla Steels

Effect of rare-earth metals on the hot strength of HSLA steels

2002 ◽  
Vol 93 (11) ◽  
pp. 1132-1139 ◽  
Author(s):  
José María Cabrera ◽  
Ignacio Mejía ◽  
José Manuel Prado
Keyword(s):  
Rare Earth ◽  
Rare Earth Metals ◽  
Hot Strength ◽  
Hsla Steels

Microstructure Evolution of Undercooled Austenite during Deformation for Medium-Carbon Si-Mn Steel

2011 ◽  
Vol 704-705 ◽  
pp. 903-906
Author(s):  
Yun Li Feng ◽  
Shao Qiang Yuan ◽  
Meng Song
Keyword(s):  
Microstructure Evolution ◽  
Ferrite Matrix ◽  
Eutectoid Reaction ◽  
Deformation Bands ◽  
Degree Of Deformation ◽  
Medium Carbon ◽  
Transmission Electron ◽  
Mn Steel ◽  
Carbide Particles ◽  
Undercooled Austenite

The microstructure evolution of a medium-carbon Si-Mn steel during deformation of undercooled austenite at different degree of deformation, temperatures and strain rates has been investigated by means of a hot compression simulation test, metallographic microscope, scanning electron microscope and transmission electron microscopy. Also, the mechanism of carbide spheroidized during deformed process has been discussed. The experiment results demonstrate that the process of evolution experienced three stages: that is, strain-induced transformation, austenite eutectoid decomposed to carbides and ferrite matrix, and spheroidization of pearlite at the range of A3-Ar3. The austenitic grains would be refined for the extra-product of ferrite above the Ar3. The eutectoid reaction was induced on the grain boundaries of ferrite and non-transformed austenite and deformation bands with the increasing volume of deformation. An optimum combination of deformation temperature and strain rate is important to obtian the dulplex microstructure consisting of ultrafine ferrites and dispersed carbide particles. The fine spheroidized microstructures are obtained while the deformed temperature reaches 650°C with ≥1.0, meanwhile, The carbides precipate in globular and shot-rod shapes. Keywords: Medium-carbon Si-Mn steel, Undercooled austentite, Microstructure evolution, Deformation induced transformation, Carbide spheroidization

New X70–X80 HSLA steels for structural and line pipe use

JOM ◽  
1977 ◽  
Vol 29 (8) ◽  
pp. 12-18 ◽  
Author(s):  
G. J. Goetz
Keyword(s):  
Line Pipe ◽  
Hsla Steels

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 ◽  
...  
Keyword(s):  
Hsla Steel ◽  
Notch Toughness ◽  
Grain Structure ◽  
Surface Zone ◽  
Slab Surface ◽  
Slab Width ◽  
Fine Grain ◽  
Hsla Steels ◽  
Ferrite Structure ◽  
Ferrite Grain Size

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.

Sign in / Sign up

Export Citation Format

Share Document