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D.C.: 621.771
Vasile
Caţarschi: Manufacturing Engineering of the Forged Mill Rolls for Rolled
Products from S.C.FORTUSS.A.
Iaşi
Metalurgia
(56) 2004, nr.6 p.5
During the
rolling process, the rolls work in a very heavy duty because they take over
high local and total pressures, together with the sliding of the material on
the contact surface. Besides, rather frequently, the rolling process is
developing in conditions of high temperature of the working surface and this
temperature can vary suddenly.
For the above-mentioned reasons, when
operating mill rolls, it is of great importance not only the high mechanical
strength but also their capacity to oppose to various types of wear. The roll
surface is worn out during operation. Turning and grinding can restore this
surface, such operation causing the step-by-step reduction of the working
diameter. For hot milling of plate and profiles steel cast and forged rolls
are largely used as well as hard shell cast iron rolls.
In this paper it is presented manufacturing
engineering of the forged mill rolls for rolled products from S.C.FORTUS S.A. Iassy.
D.C.: 621.785
Alin
Stăncioiu: Research Concerning at the Heat Treatments in the Qualities Tools
from the Cutting Steels (part I)
Metalurgia
(56) 2004, nr.6, p.13
The positive
influence of the heat treating on the wear resistance of tools is
differentiated according to the chemical composition of steel and the type of
the heat treating used.
In this
paper are shown the results of some researches, with different heat
treatments, on the steel OSC 10 compared to the steel 205 Cr 115, from which
few cutting punches were made, each of them being used for 16,000 punching,
in the same technological conditions
The effect
of the heat treatments by durability quantification was appreciated through
the following items strains of the active part, wear, cutting forces, the
aspect of cutting edges, deviations from the geometric shape and the residual
stress.
D.C : 622-78
Valentin
Petrescu, Toderiţa Nemeş: Heat optimization
mathematical model for ISP sintering process
Metalurgia
(56) 2004, nr.6, p.19
The agglomeration process is the precursory
operation to the melting process of selective sulphide concentrates and
collective concentrates of Zn and Pb into the ISP furnace and its purpose is
to transform the sulphide into specific metal oxides.
The quality conditions imposed by the Zn-Pb
agglomeration enforce a good knowledge of the full material base and the
preparing recipes and combinations of different sorts of concentrates and
recycling materials.
Therefore,
it was considered opportune to elaborate a mathematical model which establishes
the dependency of three quality indicators of the agglomerate (Zn/Pb ratio,
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Pb/Cu ratio and S quantity in the
agglomerate, %Sagl) based on the chemical composition of the crude charge.
The
mathematical model obtains three regressive equations, which were solved with
data obtained from the experimental researches for eight types of crude
charges.
The
results shows that the mathematical model verifies the main conditions
enforced by the I.S.P. technology and it can be used for the optimization of
the ingoing charges into the agglomeration process.
D.C.: 669.054.11
Marian
Ionescu: Studies Regarding Steel
Quality after Electrical Remelting under Synthetic Slags of Quaternary System
Metalurgia
(56) 2004, nr.6, p.26
Synthetic
slags have a definite role during the
electrical remelting process under slag which requires the study of
compatibilisation of remelted steel quality with chemical composition of
synthetic slags, as well as aspects of economical efficiency.
Experience
achieved by binary system CaF2 Al2O3
represented the background for development of experiments in which slags
belonging to ternary and quaternary
systems were used. In these experiments, oxidic slags, including CaO,
MgO, SiO2 etc., are also used.
Results of
experimental work put into evidence the efficiency of metallurgical processes
taking place during the melting under synthetic slags, belonging to
quaternary system at the same time with better economical efficiency.
D.C.: 620.178.162
Aurel Ciurea,
Marian Bordei: Considerations Regarding the Analysis of the Aleatory Wear of the
Equipments in the Hot Sections
Metalurgia
(56) 2004, nr.6, p.30
The wear of
the equipments in the hot sections is a problem with implications on the
quality and quantity of the production and also on the costs. In this
respect, the analysies of the aleatory wear of the equipments represents a
necessity, and the resulting data can be used both during the projection and
exploitation stage of the hot sections, effects on the production rhythmicity
and on manufacture costs. This paper presents an analysing method of the
aleatory wear of the equipments and mechanisms from the hot sections.
D.C.: 678.029.5
Key words: superplasticity, cavitation, cavity nucleation, cavity growth, cavity
coalescence
Ana-Luciana
Rus: Cavitation and Fracture in Superplastics Materials
Metalurgia
(56) 2004, nr.6, p.33
Superplastic
alloys generally exhibit very large elongations to failure by virtue of their
high strain rate sensitivities, m. A high value of m provides these alloys
with a considerable resistance towards flow localization. Most superplastic
alloys cavitate during deformation, and in some materials extensive
cavitation may lead to premature failure. The present paper will review
aspects of cavity nucleation, cavity growth and coalescence in superplastic
alloys and procedures to reduce cavitation during superplasticity.
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