Diffusional and displacive transformation behaviour in low carbon-low alloy steels studied by a hybrid in situ observation system

2011 ◽  
Vol 64 (1) ◽  
pp. 29-32 ◽  
Author(s):  
Hidenori Terasaki ◽  
Yu-ichi Komizo
Keyword(s):  
Observation System ◽  
In Situ Observation ◽  
Low Alloy Steels ◽  
Low Carbon ◽  
Transformation Behaviour ◽  
Displacive Transformation ◽  
Alloy Steels

scholarly journals Comparative Study of the Tempering Behavior of Different Martensitic Steels by Means of In-Situ Diffractometry and Dilatometry

Materials ◽  
2020 ◽  
Vol 13 (22) ◽  
pp. 5058
Author(s):  
Martin Hunkel ◽  
Juan Dong ◽  
Jeremy Epp ◽  
Daniel Kaiser ◽  
Stefan Dietrich ◽  
...  
Keyword(s):  
Comparative Study ◽  
Length Change ◽  
Low Alloy Steels ◽  
Low Carbon ◽  
Martensitic Steels ◽  
High Alloy ◽  
Microstructural Effects ◽  
Alloy Steels ◽  
The Individual

Martensitic steels are tempered to increase the toughness of the metastable martensite, which is brittle in the as-quenched state, and to achieve a more stable microstructure. During the tempering of steels, several particular overlapping effects can arise. Classical dilatometric investigations can only detect effects by monitoring the integral length change of the sample. Additional in-situ diffractometry allowed a differentiation of the individual effects such as transformation of retained austenite and formation of cementite during tempering. Additionally, the lattice parameters of martensite and therefrom the tetragonality was analyzed. Two low-alloy steels with carbon contents of 0.4 and 1.0 wt.% and a high-alloy 5Cr-1Mo-steel with 0.4 wt.% carbon were investigated by dilatometry and in-situ diffractometry. In this paper, microstructural effects during tempering of the investigated steels are discussed by a comparative study of dilatometric and diffractometric experiments. The influence of the chemical composition on the tempering behavior is illustrated by comparing the determined effects of the three steels. The kinetics of tempering is similar for the low-alloy steels and shifted to much higher temperatures for the high-alloy steel. During tempering, the tetragonality of martensite in the steel with 1.0 wt% carbon shifts towards a low carbon behavior, as in the steels with 0.4 wt.% carbon.

scholarly journals Pelagic deep-sea fauna observed on video transects in the southern Norwegian Sea

Polar Biology ◽  
2021 ◽  
Author(s):  
Philipp Neitzel ◽  
Aino Hosia ◽  
Uwe Piatkowski ◽  
Henk-Jan Hoving
Keyword(s):  
First Record ◽  
Observation System ◽  
In Situ Observation ◽  
Norwegian Sea ◽  
Video Recordings ◽  
In Situ Observations ◽  
Abundance And Distribution ◽  
Oceanic Food Webs ◽  
Deep Sea Fauna

AbstractObservations of the diversity, distribution and abundance of pelagic fauna are absent for many ocean regions in the Atlantic, but baseline data are required to detect changes in communities as a result of climate change. Gelatinous fauna are increasingly recognized as vital players in oceanic food webs, but sampling these delicate organisms in nets is challenging. Underwater (in situ) observations have provided unprecedented insights into mesopelagic communities in particular for abundance and distribution of gelatinous fauna. In September 2018, we performed horizontal video transects (50–1200 m) using the pelagic in situ observation system during a research cruise in the southern Norwegian Sea. Annotation of the video recordings resulted in 12 abundant and 7 rare taxa. Chaetognaths, the trachymedusaAglantha digitaleand appendicularians were the three most abundant taxa. The high numbers of fishes and crustaceans in the upper 100 m was likely the result of vertical migration. Gelatinous zooplankton included ctenophores (lobate ctenophores,Beroespp.,Euplokamissp., and an undescribed cydippid) as well as calycophoran and physonect siphonophores. We discuss the distributions of these fauna, some of which represent the first record for the Norwegian Sea.

Recent Aspects on the Effect of Inclusion Characteristics on the Intragranular Ferrite Formation in Low Alloy Steels: A Review

2017 ◽  
Vol 36 (4) ◽  
pp. 309-325 ◽  
Author(s):  
Wangzhong Mu ◽  
Pär Göran Jönsson ◽  
Keiji Nakajima
Keyword(s):  
Heat Affected Zone ◽  
Low Alloy Steels ◽  
Low Carbon ◽  
Intragranular Ferrite ◽  
Metallic Inclusions ◽  
Theoretical Investigations ◽  
Alloy Steels ◽  
Institute Of Technology ◽  
Future Work

AbstractIntragranular ferrite (IGF), which nucleates from specific inclusion surfaces in low alloy steels, is the desired microstructure to improve mechanical properties of steel such as the toughness. This microstructure is especially important in the coarse grain heat affected zone (CGHAZ) of weldments. The latest review paper focusing on the role of non-metallic inclusions in the IGF formation in steels has been reported by Sarma et al. in 2009 (ISIJ int., 49(2009), 1063–1074). In recent years, large amount of papers have been presented to investigate different issues of this topic. This paper mainly highlights the frontiers of experimental and theoretical investigations on the effects of inclusion characteristics, such as the composition, size distribution and number density, on the IGF formation in low carbon low-alloyed steels, undertaken by the group of Applied Process Metallurgy, KTH Royal Institute of Technology. Related results reported in previous studies are also introduced. Also, plausible future work regarding various items of IGF formation is mentioned in each section. This work aims to give a better control of improving the steel quality during casting and in the heat affected zone (HAZ) of weldment, according to the concept of oxide metallurgy.

In situ observation of growth behaviour of acicular ferrite in low-carbon steel containing 13 ppm magnesium

2017 ◽  
Vol 46 (2) ◽  
pp. 176-183 ◽  
Author(s):  
Chi-Kang Lin ◽  
Yan-Chi Pan ◽  
Weng-Sing Hwang ◽  
Ying-Chien Fang ◽  
Yen-Hao Su ◽  
...  
Keyword(s):  
Carbon Steel ◽  
Acicular Ferrite ◽  
Low Carbon Steel ◽  
In Situ Observation ◽  
Low Carbon ◽  
Growth Behaviour

scholarly journals Development of "In-situ" Observation System for Oxide Films Formed during Thermal Oxidation Using Raman Spectroscopy

1995 ◽  
Vol 81 (6) ◽  
pp. 607-612 ◽  
Author(s):  
Takayuki NARUSHIMA ◽  
Naoki KIKUCHI ◽  
Makoto MARUYAMA ◽  
Haruo ARASHI ◽  
Yuichiro NISHINA ◽  
...  
Keyword(s):  
Raman Spectroscopy ◽  
Thermal Oxidation ◽  
Oxide Films ◽  
Observation System ◽  
In Situ Observation

The Copernicus global 1/12° oceanic and sea ice reanalysis

2021 ◽  
Author(s):  
Jean-Michel Lellouche ◽  
Romain Bourdalle-Badie ◽  
Eric Greiner ◽  
Gilles Garric ◽  
Angelique Melet ◽  
...  
Keyword(s):  
Sea Ice ◽  
Real Time ◽  
Sea Level ◽  
Observation System ◽  
Small Scale ◽  
Free Access ◽  
In Situ Observation ◽  
Seasonal Forecasts ◽  
Concentration Data

<p>The GLORYS12V1 system is a global eddy-resolving physical ocean and sea ice reanalysis at 1/12° resolution covering the 1993-present altimetry period, designed and implemented in the framework of the Copernicus Marine Environment Monitoring Service (CMEMS). All the essential ocean physical variables from this reanalysis are available with free access through the CMEMS data portal.</p><p>The GLORYS12V1 reanalysis is based on the current CMEMS global real-time forecasting system, apart from a few specificities that are detailed in this manuscript. The model component is the NEMO platform driven at the surface by atmospheric conditions from the ECMWF ERA-Interim reanalysis. Ocean observations are assimilated by means of a reduced-order Kalman filter. Along track altimeter sea level anomaly, satellite sea surface temperature and sea ice concentration data and in situ temperature and salinity (T/S) vertical profiles are jointly assimilated. A 3D-VAR scheme provides an additional correction for the slowly-evolving large-scale biases in temperature and salinity.</p><p>The performance of the reanalysis is first addressed in the space of the assimilated observations and shows a clear dependency on the time-dependent in situ observation system, which is intrinsic to most reanalyses. The general assessment of GLORYS12V1 highlights a level of performance at the state-of-the-art and the reliability of the system to correctly capture the main expected climatic interannual variability signals for ocean and sea ice, the general circulation and the inter-basins exchanges. In terms of trends, GLORYS12V1 shows a higher than observed  warming trend together with a lower than observed global mean sea level rise.</p><p>Comparisons made with an experiment carried out on the same platform without assimilation show the benefit of data assimilation in controlling water masses properties and their low frequency variability. Examination of the deep signals below 2000 m depth shows that the reanalysis does not suffer from artificial signals even in the pre-Argo period.</p><p>Moreover, GLORYS12V1 represents particularly well the small-scale variability of surface dynamics and compares well with independent (non-assimilated) data. Comparisons made with a twin experiment carried out at ¼° resolution allows characterizing and quantifying the strengthened contribution of the 1/12° resolution onto the downscaled dynamics.</p><p>In conclusion, GLORYS12V1 provides a reliable physical ocean state for climate variability and supports applications such as seasonal forecasts. In addition, this reanalysis has strong assets to serve regional applications and should provide relevant physical conditions for applications such as marine biogeochemistry. In a near future, GLORYS12V1 will be maintained to be as close as possible to real time and could therefore provide a relevant reference statistical framework for many operational applications.</p>

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