Control of Non-metallic Inclusions by Slag-metal Reactions for High Strength Alloying Steels

The combination of high strength and formability of transformation induced plasticity (TRIP) steels is interesting for the automotive industry. However, the poor weldability limits its industrial application. This paper shows the results of six low-alloy TRIP steels with different chemical composition which were studied in order to correlate retained austenite (RA) and non-metallic inclusions (NMI) with their resistance spot welded zones to their joints’ final mechanical properties. RA volume fractions were quantified by X-ray microdiffraction (µSXRD) while the magnetic saturation technique was used to quantify NMI contents. Microstructural characterization and NMI of the base metals and spot welds were assessed using scanning electron microscopy (SEM). Weld nuggets macrostructures were identified using optical microscopy (OM). The lap-shear tensile test was used to determine the final mechanical properties of the welded joints. It was found that NMI content in the fusion zone (FZ) was higher than those in the base metal and heat affected zone (HAZ). Whereas, traces of RA were found in the HAZ of highly alloyed TRIP steels. Lap-shear tensile test results showed that mechanical properties of spot welds were affected by NMI contents, but in a major way by the decomposition of RA in the FZ and HAZ.

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Mould Components Impact on Structure and Quality of Elektron 21 Alloy

Archives of Foundry Engineering ◽

10.2478/afe-2013-0029 ◽

2013 ◽

Vol 13 (2) ◽

pp. 17-23 ◽

Cited By ~ 2

Author(s):

B. Dybowski ◽

A. Kiełbus ◽

R. Jarosz

Keyword(s):

Solid Solution ◽

Magnesium Alloys ◽

Volume Fraction ◽

Weight Ratio ◽

High Strength ◽

Shrinkage Porosity ◽

Sand Cast ◽

Magnesium Casting ◽

Metallic Inclusions

Abstract Magnesium alloys due to their low density and high strength-to-weight ratio are promising material for the automotive and aerospace industries. Many elements made from magnesium alloys are produced by means of sand casting. It is essential to investigate impact of the applied mould components on the microstructure and the quality of the castings. For the research, six identical, 100x50x20mm plates has been sand cast from the Elektron 21 magnesium casting alloy. Each casting was fed and cooled in a different way: one, surrounded by mould sand, two with cast iron chills 20mm and 40mm thick applied, another two with the same chills as well as feeders applied and one with only the feeder applied. Solid solution grain size and eutectics volume fraction were evaluated quantitatively in Met-Ilo program, casting defects were observed on the scanning electron microscope Hitachi S3400N. The finest solid solution grain was observed in the castings with only the chills applied. Non metallic inclusions were observed in each plate. The smallest shrinkage porosity was observed in the castings with the feeders applied.

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Unveiling Interactions of Non-Metallic Inclusions within Advanced Ultra-High Strength Steel: A Spectro-Microscopic Determination and First-Principles Elucidation

SSRN Electronic Journal ◽

10.2139/ssrn.3757898 ◽

2020 ◽

Author(s):

Harishchandra Singh ◽

Tuomas Alatarvas ◽

Andrey Kistanov ◽

Assa SasikalaDevi ◽

Shubo Wang ◽

...

Keyword(s):

First Principles ◽

High Strength Steel ◽

High Strength ◽

Metallic Inclusions ◽

Ultra High Strength Steel

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Quantitative evaluation of effects of non-metallic inclusions on fatigue strength of high strength steels. I: Basic fatigue mechanism and evaluation of correlation between the fatigue fracture stress and the size and location of non-metallic inclusions

International Journal of Fatigue ◽

10.1016/0142-1123(89)90054-6 ◽

1989 ◽

Vol 11 (5) ◽

pp. 291-298 ◽

Cited By ~ 235

Author(s):

Y MURAKAMI ◽

S KODAMA ◽

S KONUMA

Keyword(s):

Fatigue Strength ◽

Fatigue Fracture ◽

Quantitative Evaluation ◽

Fracture Stress ◽

High Strength Steels ◽

High Strength ◽

Metallic Inclusions ◽

Fatigue Mechanism

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The Research and Development of High Strength Spring Steel with Long Service Life

Key Engineering Materials ◽

10.4028/www.scientific.net/kem.575-576.365 ◽

2013 ◽

Vol 575-576 ◽

pp. 365-369

Author(s):

Bo Xiao ◽

Yu Cheng Lei ◽

Xiao Dong Wu

Keyword(s):

Service Life ◽

High Strength ◽

Melting Process ◽

Spring Steel ◽

Quenching Temperature ◽

Tempering Temperature ◽

Metallic Inclusions ◽

Key Points ◽

Strength And Plasticity ◽

And Control

The research centers on the production process of high tensile 60Si2CrVNb spring steel for long service life with reference to the production conditions. Key points of the research lies in: long fatigue life and control techniques of non-metallic inclusions in melting process. Hot treatment process of spring steel also involves with the research, aiming to increase the strength of material by fining grain size by Nb element. The results confirms to the size of non-metallic inclusions can be controlled below 10μm with adoption of technologies of LF slag control and barium microalloy treatment in steelmaking process. The tensile strength can be over 2.0GPa and the elongation can reach up to 10% in the event that the quenching temperature is900°C and the tempering temperature is 410°C resulting obvious increase of strength and plasticity of spring steel.

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Non-Metallic Inclusions and Hot-Working Behaviour of Advanced High-Strength Medium-Mn Steels

Archives of Metallurgy and Materials ◽

10.1515/amm-2016-0137 ◽

2016 ◽

Vol 61 (2) ◽

pp. 811-820 ◽

Cited By ~ 2

Author(s):

A. Grajcar ◽

D. Woźniak ◽

A. Kozłowska

Keyword(s):

Rare Earth ◽

Rare Earth Elements ◽

Hot Rolling ◽

Isothermal Holding ◽

High Strength ◽

Hot Working ◽

Controlled Cooling ◽

Inclusion Type ◽

Metallic Inclusions ◽

Mn Content

AbstractThe work addresses the production of medium-Mn steels with an increased Al content. The special attention is focused on the identification of non-metallic inclusions and their modification using rare earth elements. The conditions of the thermomechanical treatment using the metallurgical Gleeble simulator and the semi-industrial hot rolling line were designed for steels containing 3 and 5% Mn. Hot-working conditions and controlled cooling strategies with the isothermal holding of steel at 400°C were selected. The effect of Mn content on the hot-working behaviour and microstructure of steel was addressed. The force-energetic parameters of hot rolling were determined. The identification of structural constituents was performed using light microscopy and scanning electron microscopy methods. The addition of rare earth elements led to the total modification of non-metallic inclusions, i.e., they replaced Mn and Al forming complex oxysulphides. The Mn content in a range between 3 and 5% does not affect the inclusion type and the hot-working behaviour. In contrast, it was found that Mn has a significant effect on a microstructure.

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