Evolution of oxide and nitride inclusions during processing of stainless steel

Because of its superior properties, stainless steel has been widely used for many applications. Nonmetallic inclusions can influence the quality of stainless steel products. A set of samples was used to track the response of inclusion composition during processing of a heat of titanium-bearing 18% chromium steel, from deoxidation after decarburization, to the solidified slab. The oxide inclusions responded as expected to additions of deoxidizers and calcium treatment, changing from silica to alumina and spinels, and then to calcium aluminates. The samples confirmed that titanium nitride can nucleate on liquid calcium aluminate during steel solidification.

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Evolution behaviour of nonmetallic inclusions in Ti-bearing 11Cr stainless steel with calcium treatment

Ironmaking & Steelmaking ◽

10.1080/03019233.2019.1568367 ◽

2019 ◽

Vol 47 (1) ◽

pp. 31-39 ◽

Cited By ~ 1

Author(s):

Jingyu Li ◽

Guoguang Cheng ◽

Qiang Ruan ◽

Jixiang Pan ◽

Xingrun Chen

Keyword(s):

Stainless Steel ◽

Nonmetallic Inclusions ◽

Calcium Treatment

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Effect of Calcium Treatment on Inclusions in H08A Welding Rod Steel

Metals ◽

10.3390/met11081227 ◽

2021 ◽

Vol 11 (8) ◽

pp. 1227

Author(s):

Fangjie Lan ◽

Changling Zhuang ◽

Changrong Li ◽

Guangkai Yang ◽

Hanjie Yao

Keyword(s):

Melting Point ◽

Molten Steel ◽

Calcium Aluminate ◽

Large Scale ◽

Energy Dispersive Spectrometer ◽

Calcium Content ◽

Calcium Treatment ◽

Inclusion Composition ◽

Metallic Inclusions ◽

Before And After

The effect of calcium treatment on inclusions in H08A welding rod steel was studied by industrial experiment and using thermodynamics theory. The effects of inclusion composition, morphology, quantity, and size in H08A welding rod steel before and after calcium treatment were studied by metallographic microscope, scanning electron microscope (SEM), and energy dispersive spectrometer (EDS). Thermodynamic studies show that the addition of calcium can form various forms of xCaO·yAl2O3, under the condition that the composition of molten steel remains unchanged, the control of calcium content is the key to generate low melting point calcium-aluminate complex non-metallic inclusions and improve the quality of molten steel. The production practice in steel plant shows that for welding rod steels, the calcium content in a suitable range can meet the requirements of calcium treatment. Effective calcium treatment can not only transform the high melting point Al2O3 inclusions into the low melting point complex non-metallic inclusions between 3CaO·Al2O3 and 12CaO·7Al2O3, but also make the original shape-diversified inclusions into the spherical calcium-aluminate complex non-metallic inclusions. Meanwhile, the total number of inclusions and large-scale inclusions in welding rod steel are reduced, and the inclusions tend to disperse in the steel, which is very conducive to the improvement of steel quality. The results show that the modification path of magnesium aluminate spinel in steel is as follows: Al2O3 → MgO-Al2O3 → MgO-CaO-Al2O3. In addition, calcium treatment can modify MgO-Al2O3 spinel in steel into liquid MgO-CaO-Al2O3 complex non-metallic inclusions with low melting point.

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AISI TYPE 440B

Alloy Digest ◽

10.31399/asm.ad.ss0223 ◽

1969 ◽

Vol 18 (4) ◽

Keyword(s):

Fracture Toughness ◽

Stainless Steel ◽

Corrosion Resistance ◽

Heat Treating ◽

Chromium Steel ◽

Ball Bearings ◽

High Carbon ◽

High Chromium ◽

Steel Mills ◽

Aisi Type

Abstract AISI Type 440B is a hardenable high-carbon high-chromium steel recommended stainless for cutlery, valve parts, ball bearings, pivot pins, etc. This datasheet provides information on composition, physical properties, microstructure, hardness, elasticity, and tensile properties as well as fracture toughness. It also includes information on corrosion resistance as well as forming, heat treating, machining, joining, and surface treatment. Filing Code: SS-223. Producer or source: Stainless steel mills.

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AISI TYPE 442

Alloy Digest ◽

10.31399/asm.ad.ss0187 ◽

1966 ◽

Vol 15 (10) ◽

Keyword(s):

Fracture Toughness ◽

Stainless Steel ◽

Corrosion Resistance ◽

High Temperature ◽

Heat Treating ◽

Chromium Steel ◽

General Purpose ◽

Steel Mills ◽

Temperature Performance ◽

Aisi Type

Abstract AISI Type 442 is a non-hardenable ferritic chromium steel recommended for general purpose corrosion and heat resisting applications. It is magnetic in all conditions. This datasheet provides information on composition, physical properties, hardness, elasticity, and tensile properties as well as fracture toughness and creep. It also includes information on high temperature performance and corrosion resistance as well as forming, heat treating, machining, joining, and surface treatment. Filing Code: SS-187. Producer or source: Stainless steel mills.

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Modification of Type B Inclusions by Calcium Treatment in High-Carbon Hard-Wire Steel

Metals ◽

10.3390/met11050676 ◽

2021 ◽

Vol 11 (5) ◽

pp. 676

Author(s):

Linzhu Wang ◽

Zuobing Xi ◽

Changrong Li

Keyword(s):

Inclusion Size ◽

Type B ◽

Calcium Treatment ◽

High Carbon ◽

Fine Size ◽

Dispersed Inclusions ◽

Wire Steel ◽

Classical Thermodynamics ◽

The Relationship

To investigate the modification of type B inclusions in high-carbon hard-wire steel with Ca treatment, Si-Ca alloy was added to high-carbon hard-steel, and the composition, morphology, size, quantity, and distribution of inclusions were observed. The samples were investigated by scanning electron microscopy-energy dispersive spectroscopy (SEM-EDS). The experimental thermal results showed that the modification effect of inclusion was better in high-carbon hard-wire steel with Al of 0.0053% and Ca of 0.0029% than that in steel with Al of 0.011% and Ca of 0.0052%, in which the inclusions were mainly spherical semi-liquid and liquid CA2, CA, and C12A7. The inclusion size decreased from 3.2 μm to 2.1 μm. The degree of inclusions segregation was reduced in high-carbon hard-wire steels after calcium treatment. The results indicate that the modification of inclusions is conducive to obtaining dispersed inclusions with fine size. The ratio of length to width decreased and tended to be 1 with the increase in CaO content in the inclusion. When the content of CaO was higher than 30%, the aspect ratio was in the range of 1 to 1.2. The relationship between the activity of aluminum and calcium and the inclusions type at equilibrium in high-carbon hard-wire steel was estimated using classical thermodynamics. The calculated results were consistent with the experimental results. The thermodynamic software Factsage was used to analyze the effect of aluminum and calcium additions on the type and quality of inclusions in high-carbon hard-wire steels. The modification law and mechanism of type B inclusions in high-carbon hard-wire steels are discussed.

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Metal artefact reduction of different alloys with dual energy computed tomography (DECT)

Scientific Reports ◽

10.1038/s41598-021-81600-1 ◽

2021 ◽

Vol 11 (1) ◽

Author(s):

Anand John Vellarackal ◽

Achim Hermann Kaim

Keyword(s):

Stainless Steel ◽

Image Quality ◽

Femoral Stem ◽

Dual Energy ◽

Dual Energy Ct ◽

Bony Tissue ◽

Stem Image ◽

Metal Artefact ◽

Artefact Reduction

AbstractTo evaluate the influence of dual-energy CT (DECT) and Virtual monochromatic spectral (VMS) imaging on: (1) the artefact size of geometrically identical orthopaedic implants consisting of three different compositions and (2) the image quality of the surrounding bone, three similar phantoms—each featuring one femoral stem composed of either titanium, chrome-cobalt or stainless steel surrounded by five calcium pellets (200 mg hydroxyapatite/calcium carbonate) to simulate bony tissue and one reference pellet located away from the femoral stem—were built. DECT with two sequential scans (80 kVp and 140 kVp; scan-to-scan technique) was performed, and VMS images were calculated between 40 and 190 keV. The artefact sizes were measured volumetrically by semiautomatic selection of regions of interest (ROIs), considering the VMS energies and the polychromatic spectres. Moreover, density and image noise within the pellets were measured. All three phantoms exhibit artefact size reduction as energy increases from 40 to 190 keV. Titanium exhibited a stronger reduction than chrome-cobalt and stainless steel. The artefacts were dependent on the diameter of the stem. Image quality increases with higher energies on VMS with a better depiction of surrounding structures. Monoenergetic energies 70 keV and 140 keV demonstrate superior image quality to those produced by spectral energies 80 kVp and 140 kVp.

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Experimental Investigation on Micro Deep Drawing of Stainless Steel Foils with Different Microstructural Characteristics

Chinese Journal of Mechanical Engineering ◽

10.1186/s10033-021-00556-5 ◽

2021 ◽

Vol 34 (1) ◽

Author(s):

Jingwei Zhao ◽

Tao Wang ◽

Fanghui Jia ◽

Zhou Li ◽

Cunlong Zhou ◽

...

Keyword(s):

Stainless Steel ◽

Deep Drawing ◽

Annealing Temperature ◽

Localized Deformation ◽

Microstructural Characteristics ◽

Height Profile ◽

Annealing Temperatures ◽

Micro Deep Drawing ◽

Profile Distribution

AbstractIn the present work, austenitic stainless steel (ASS) 304 foils with a thickness of 50 µm were first annealed at temperatures ranging from 700 to 1100 ℃ for 1 h to obtain different microstructural characteristics. Then the effects of microstructural characteristics on the formability of ASS 304 foils and the quality of drawn cups using micro deep drawing (MDD) were studied, and the mechanism involved was discussed. The results show that the as-received ASS 304 foil has a poor formability and cannot be used to form a cup using MDD. Serious wrinkling problem occurs on the drawn cup, and the height profile distribution on the mouth and the symmetry of the drawn cup is quite non-uniform when the annealing temperature is 700 ℃. At annealing temperatures of 900 and 950 ℃, the drawn cups are both characterized with very few wrinkles, and the distribution of height profile, symmetry and mouth thickness are uniform on the mouths of the drawn cups. The wrinkling becomes increasingly significant with a further increase of annealing temperature from 950 to 1100 ℃. The optimal annealing temperatures obtained in this study are 900 and 950 ℃ for reducing the generation of wrinkling, and therefore improving the quality of drawn cups. With non-optimized microstructure, the distribution of the compressive stress in the circumferential direction of the drawn foils becomes inhomogeneous, which is thought to be the cause of the occurrence of localized deformation till wrinkling during MDD.

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High-quality percussion drilling with ultrashort laser pulses

Applied Physics A ◽

10.1007/s00339-021-04818-w ◽

2021 ◽

Vol 127 (9) ◽

Author(s):

A. Feuer ◽

R. Weber ◽

R. Feuer ◽

D. Brinkmeier ◽

T. Graf

Keyword(s):

Stainless Steel ◽

Laser Fluence ◽

Ablation Threshold ◽

Laser Pulses ◽

Ultrashort Laser Pulses ◽

High Quality ◽

Edge Quality ◽

Ultrashort Laser ◽

Percussion Drilling

AbstractThe influence of the laser fluence on the quality of percussion-drilled holes was investigated both experimentally and by an analytical model. The study reveals that the edge quality of the drilled microholes depends on the laser fluence reaching the rear exit of the hole and changes with the number of pulses applied after breakthrough. The minimum fluence that must reach the hole’s exit in order to obtain high-quality microholes in stainless steel was experimentally found to be 2.8 times the ablation threshold.

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