Influences of Vanadium and Thermo-mechanical Treatment on Microstructures of Medium Carbon Microalloyed Steels

Modification of Non-Metallic Inclusions by Rare-Earth Elements in Microalloyed Steels The modification of the chemical composition of non-metallic inclusions by rare-earth elements in the new-developed microalloyed steels was discussed in the paper. The investigated steels are assigned to production of forged elements by thermo-mechanical treatment. The steels were melted in a vaccum induction furnace and modification of non-metallic inclusions was carried out by the michmetal in the amount of 2.0 g per 1 kg of steel. It was found that using material charge of high purity and a realization of metallurgical process in vacuous conditions result in a low concentration of sulfur (0.004%), phosphorus (from 0.006 to 0.008%) and oxygen (6 ppm). The high metallurgical purity is confirmed by a small fraction of non-metallic inclusions averaging 0.075%. A large majority of non-metallic inclusions are fine, globular oxide-sulfide or sulfide particles with a mean size 17 μm2. The chemical composition and morphology of non-metallic inclusions was modified by Ce, La and Nd, what results a small deformability of non-metallic inclusions during hot-working.

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New post forging treatment of medium carbon microalloyed steels

Steel Research ◽

10.1002/srin.199701788 ◽

1997 ◽

Vol 68 (6) ◽

pp. 266-271 ◽

Cited By ~ 3

Author(s):

Radko Kaspar ◽

Ignacio Gonzälez-Baquet ◽

Johannes Richter ◽

Georg Nußbaum ◽

Alfred Köthe

Keyword(s):

Microalloyed Steels ◽

Medium Carbon ◽

Carbon Microalloyed

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Microstructural Evolution of Two Medium Carbon Microalloyed Steels during Hot Forging Process

Materials Science Forum ◽

10.4028/www.scientific.net/msf.500-501.155 ◽

2005 ◽

Vol 500-501 ◽

pp. 155-162 ◽

Cited By ~ 1

Author(s):

A. Al Omar ◽

A. Chenaoui ◽

Rachid Dkiouak ◽

Jose María Cabrera ◽

Jose Manuel Prado

Keyword(s):

Microstructural Evolution ◽

Hot Forging ◽

Microalloyed Steels ◽

Hollomon Parameter ◽

Medium Carbon ◽

Grain Sizes ◽

Recrystallized Grain Size ◽

Carbon Microalloyed ◽

Hot Forging Process ◽

Cyclic Dynamic

The main aim of the present investigation was to study the flow behaviour of two medium carbon microalloyed steels under hot forming conditions, and to analyse its microstructural evolution. The dependence of recrystallized grain size (Drec) on the Zener-Hollomon parameter Z shows a bimodal behaviour with transition from single to cyclic dynamic recrystallization. Also we observed that the variation of Drec normalized by Burgers vector (b) with sss normalized by shear modulus ( µ) shows the same bimodal behaviour cited above. The Derby’s universal equation cited in literature for recrystallized grain sizes was not followed; it seems that the presence of fine precipitated particles has a clear effect on this disagreement.

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Application of thermomechanical treatment on medium-carbon microalloyed steels continuously cooled from forging temperature

Steel Research ◽

10.1002/srin.199701773 ◽

1997 ◽

Vol 68 (1) ◽

pp. 27-31 ◽

Cited By ~ 11

Author(s):

Radko Kaspar ◽

Ignacio González-Baquet ◽

Nadja Schreiber ◽

Johannes Richter ◽

Georg Nußbaum ◽

...

Keyword(s):

Thermomechanical Treatment ◽

Microalloyed Steels ◽

Medium Carbon ◽

Carbon Microalloyed

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Metallographic techniques for the determination of the austenite grain size in medium-carbon microalloyed steels

Materials Characterization ◽

10.1016/s1044-5803(01)00142-5 ◽

2001 ◽

Vol 46 (5) ◽

pp. 389-398 ◽

Cited By ~ 69

Author(s):

C Garcı́a de Andrés ◽

M.J Bartolomé ◽

C Capdevila ◽

D San Martı́n ◽

F.G Caballero ◽

...

Keyword(s):

Grain Size ◽

Microalloyed Steels ◽

Austenite Grain Size ◽

Medium Carbon ◽

Austenite Grain ◽

Carbon Microalloyed

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Effect of Forging Parameters on the Microstructure and Properties of Medium Carbon Microalloyed Steels

10.4271/930960 ◽

1993 ◽

Cited By ~ 1

Author(s):

Arun Vedhanayagam ◽

Rajiv Shivpuri

Keyword(s):

Microalloyed Steels ◽

Medium Carbon ◽

Microstructure And Properties ◽

Carbon Microalloyed

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INFLUENCE OF NITROGEN ON HOT DUCTILITY BEHAVIOR OF MEDIUM CARBON MICROALLOYED STEEL

International Journal of Modern Physics B ◽

10.1142/s0217979209060567 ◽

2009 ◽

Vol 23 (06n07) ◽

pp. 1122-1128 ◽

Cited By ~ 1

Author(s):

SUJUAN ZHAO ◽

QINGFENG WANG ◽

ZESHENG YAN

Keyword(s):

Microalloyed Steel ◽

True Strain ◽

Tensile Tests ◽

Microalloyed Steels ◽

Hot Ductility ◽

True Strain Rate ◽

Medium Carbon ◽

Ductility Trough ◽

Carbon Microalloyed

The current study aims to estimate the influence of enhanced nitrogen on the hot ductility of medium carbon microalloyed steel. For this purpose, hot tensile tests were carried out at temperatures rangeing from 700°C-1000°C at a true strain rate of 0.001s-1. The fracture surfaces and their neighboring precipitates and matrix microstructures "frozen" in tensile temperatures were observed. The dependence of hot ductility on the fracture mode and in situ microstructural changes were discussed. The results indicate that raising the nitrogen content from 0.003% to 0.014% and 0.021% was found to deteriorate the ductility as the obtained ductility trough became deeper and wider. The trough deepening caused by the addition of nitrogen was due to the formation of film-like ferrite and fine VN precipitation along the austenite grain boundaries promoting low ductility intergranular failure. On the other hand, the retarded dynamic recrystallization, the promoted deformation induced ferrite formation and precipitation at higher temperatures by enhanced nitrogen were regarded as the possible reasons for a wider trough. In summary, the above results indicate the hot ductility of medium carbon microalloyed steels is weakened to some extent by enhanced nitrogen and their windows suitable for continuous casting should be schemed very carefully.

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