Effect of Steel Grades on Technological Properties of Spot Welds

The paper presents results of combined, conventional and non-conventional, approach for evaluation of mechanical and technological properties of structural steel's welded joints. The selected structural steels are in the range of most common used strength level(s), as well as corresponding various chemical composition concept(s) and processing routes. A short review regarding weldability is presented based on recommendation provided in EN 1011-2, manufacturers recommendation, and own results. However, even it is a well-known fact, mismatching of properties is presented rather to provide sense of its level for particular steel grades. Moreover, the level of under-matching of weakest weld zone (coarse grained heat affected zone), provided by mean of welding thermo-cycle simulation is presented. This is due to the fact that such estimation is not possible with everyday conventional (standardized) testing. The most important design and technological properties of welded joint(s) are considered; e.g. strength, ductility, hardness, microstructure and toughness.

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Chemical transformations at carbothermal reduction of barium and boron from oxides

Izvestiya Ferrous Metallurgy ◽

10.17073/0368-0797-2019-11-846-851 ◽

2019 ◽

Vol 62 (11) ◽

pp. 846-851

Author(s):

A. A. Akberdin ◽

M. M. Karbaev

Keyword(s):

Cast Iron ◽

Chemical Transformations ◽

Technological Properties ◽

New Methods ◽

First Case ◽

Recent Developments ◽

Steel Grades ◽

Inclusions In Steel ◽

Low Solubility

Alloys of boron and barium are applied to improve the quality of cast iron, steel, aluminum and other metals. The first industry produces mainly in the form of ferroboron, containing 6 – 17 % of boron depending on the brand. It is produced by an expensive aluminothermic method due to the use of boric anhydride and aluminum powder. At the same time, presence of aluminum in the metal is inevitable, it degrades the technological properties of cast iron and forms line alumina inclusions in steel. Extra-furnace removal of Al leads to oxidation of boron and its loss with slags. Therefore, the authors have proposed new methods for smelting boron-containing ferroalloys. Recent developments include the production technology of boron-containing ferrosilicon, which has been tested in industrial conditions. But its use may be limited in smelting of low-silicon steel grades. Barium is an eﬀective modifier. Due to its low solubility in iron, it is produced in the form of alloys with silicon or aluminum. In the first case, silicides (BaSi, BaSi2 ) are formed and therefore such alloys are called silicon barium or ferrosilicon with barium. In present work, there has been studied the possibility of producing modifier with boron and barium ferroalloy. It was believed that the simultaneous presence of barium and boron in it can be demand for industry. At the first stage, chemistry of transformations in BaO– B2O3 – C ironless system was considered using the carbothermic method. A complete thermodynamic analysis of chemical interactions in this system was performed in the temperature range of 1400 – 3000 K. Possibility of the formation of a condensed metal phase due to boron carbides (B4C) and barium (BaC2 ), as well as barium hexaboride (BaB6 ) is shown. The obtained data can serve as the basis for creation of a new ferroalloy simultaneously containing boron and barium.

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INFLUENCE OF COLD ROLLING ON THE MECHANICAL AND TECHNOLOGICAL PROPERTIES OF AHSS STEEL GRADES

10.5151/1983-4764-30150 ◽

2017 ◽

Author(s):

Francisco Morganti ◽

Michael Breuer ◽

Michael Degner ◽

Gerald Bader ◽

Wolfgang Bleck

Keyword(s):

Cold Rolling ◽

Technological Properties ◽

Steel Grades ◽

Ahss Steel

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Technological properties and structural change of a fired carbonatic clay from Ourzazat (Morocco)

Journal de Physique IV (Proceedings) ◽

10.1051/jp4:2005123031 ◽

2005 ◽

Vol 123 ◽

pp. 183-187

Author(s):

M. Echajia ◽

M. Hajjaji ◽

S. Kacim

Keyword(s):

Structural Change ◽

Technological Properties

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Numerical analysis of local heat flux and thin-slab solidification in a CSP funnel-type mold with electromagnetic braking

Metallurgical Research & Technology ◽

10.1051/metal/2020044 ◽

2020 ◽

Vol 117 (6) ◽

pp. 602

Author(s):

Heping Liu ◽

Jianjun Zhang ◽

Hongbiao Tao ◽

Hui Zhang

Keyword(s):

Heat Flux ◽

Casting Speed ◽

Shell Growth ◽

Local Heat ◽

Operating Conditions ◽

Thin Slab ◽

Wide Face ◽

Slab Width ◽

Steel Grades ◽

Local Heat Flux

In this article, based on the actual monitored temperature data from mold copper plate with a dense thermocouple layout and the measured magnetic flux density values in a CSP thin-slab mold, the local heat flux and thin-slab solidification features in the funnel-type mold with electromagnetic braking are analyzed. The differences of local heat flux, fluid flow and solidified shell growth features between two steel grades of Q235B with carbon content of 0.19%C and DC01 of 0.03%C under varying operation conditions are discussed. The results show the maximum transverse local heat flux is near the meniscus region of over 0.3 m away from the center of the wide face, which corresponds to the upper flow circulation and the large turbulent kinetic energy in a CSP funnel-type mold. The increased slab width and low casting speed can reduce the fluctuation of the transverse local heat flux near the meniscus. There is a decreased transverse local heat flux in the center of the wide face after the solidified shell is pulled through the transition zone from the funnel-curve to the parallel-cure zone. In order to achieve similar metallurgical effects, the braking strength should increase with the increase of casting speed and slab width. Using the strong EMBr field in a lower casting speed might reverse the desired effects. There exist some differences of solidified shell thinning features for different steel grades in the range of the funnel opening region under the measured operating conditions, which may affect the optimization of the casting process in a CSP caster.

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Tendencies of export and import of steel industry products of Russia within 9 months of 2019

Ferrous Metallurgy Bulletin of Scientific Technical and Economic Information ◽

10.32339/0135-5910-2020-2-107-112 ◽

2020 ◽

Vol 76 (2) ◽

pp. 107-112

Author(s):

N. G. Zinov’eva

Keyword(s):

Middle East ◽

Steel Industry ◽

Pig Iron ◽

Finished Steel ◽

Steel Pipes ◽

Ferrous Metals ◽

Steel Grades ◽

Cis Countries ◽

Further Development ◽

Coated Sheet

Structure of the Russian export and import of steel industry products presented by results of 9 months of 2019 operation. It was shown, that the total share of pig iron, ferroalloys and semi-products (40.3%) in the ferrous metals export from Russia is practically the same as the share of rolled products and steel pipes (39.4%), whereas the shares in the import structure were 7.7 and 75% accordingly. The share the far abroad countries in the Russian export and import of finished steel products (in natural terms) accounted for 80.6 and 28.7% accordingly, while the share of CIS countries – 19.4 and 71.3% accordingly. For 9 months of 2019 the Russian export of semi-products declined by 10.9% comparing with the analogue period of 2018 and accounted for 10.9 m tons. 54.6% of the total export shipping of semi-products were directed to Mexico, Turkey, Egypt and Taiwan. Within the nearest years the Russian export of semi-products and billets, in particular, will be effected by the further development of the semi-products production in in the countries of Middle East, Turkey, Vietnam and India. The domestic market remained to be more attractive for many Russian companies. For the 9 months of 2019, export of long and flat products accounted for 3 and 5.7 m tons accordingly, declining comparing with the analogue period of the previous year by 11 and 15.6% accordingly. Import of long and flat products decreased by 12 and 0.5%, accounting for 1.0 and 2.9 m tons accordingly. By the results of 9 months of 2019, import declined and export shipping of coated sheet increased. Taking into account the expansion of steel grades assortment by Russian plants, increase of capacities for production of sheet with different coatings, this tendency is likely to remain.

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Operation intensification methods of aggressive industrial sewage neutralization facilities

Ferrous Metallurgy Bulletin of Scientific Technical and Economic Information ◽

10.32339/0135-5910-2020-11-1149-1153 ◽

2020 ◽

Vol 76 (11) ◽

pp. 1149-1153

Author(s):

N. S. Tsarev ◽

V. I. Aksenov ◽

I. I. Nichkova

Keyword(s):

Cold Water ◽

Specific Productivity ◽

Technological Properties ◽

Technological Parameters ◽

Preliminary Heating ◽

Sediment Treatment ◽

Circulating Water ◽

Equipment Operation ◽

Sediment Volume ◽

Industrial Sewage

To neutralize the waste pickling solutions and rinsing water, resulting from cleaning metal products s surface of rust by acids solutions, lime is used. Being cheap, this method of sewage neutralization has considerable drawbacks. Forming in the technological pipes strong gypsum depositions and low specific productivity of the equipment for sediment dewatering are most significant of them. Characteristic of aggressive industrial sewage, formed at pickling of ferrous metals presented. Methods of elimination of drawbacks of industrial sewage neutralization by lime considered, including stabilization of neutralized industrial sewage and control of properties of the sediment formed. It was noted, that stability of the circulating water can be provided by accelerating of crystallization of the forming gypsum sediments by introducing in it fine priming powder and heating the neutralized water up to 65-70 °С followed by thermal softening of a part of circulating water, removed out of the circulating system. It was shown, that the heating of the water and the ongoing changes of the composition and properties of the sediment result in decrease of filtration resistance 2-3 folds, increase of deposition speed 3-4 folds and decrease the sediment volume 1.5-2 folds comparing with lime neutralization in cold water. Calculated dozes of lime at the heating were taken the same as at the regular lime neutralization. Elimination of the circulating water oversaturation by bi-water gypsum can be reached also by addition into the water of powder-like gypsum pulp - priming powder for microcrystals of the gypsum, followed by aeration during 30-40 min. This method was tested under industrial conditions. Technological properties of the forming sediment can be improved by sediment treatment by flocculants and preliminary heating of the neutralized water up to 65-70 °С. Control of technological properties of the sediment is done by addition of flocculants and heating of the neutralized water. Recommendations for improving operation of the neutralization facilities presented with indicating particular technological parameters of the equipment operation for sewage and sediment treatment.

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