3 results listed
Today, parallel to the rapid development of the industry, mechanical and metallurgical properties of the steel profiles
that used as structural elements for constructions need to be improved. The constructions where steel profiles are used scaling
up over time, require higher strength values for the materials or larger cross-sectional areas. Larger cross-sectional area
has significant disadvantages in terms of product cost due to the weight increase, and the addition of strength-enhancing
microalloys has significant disadvantages in terms of raw material cost. In this study, low-carbon and non-microalloyed base
quality steel profiles that neither the hard nor the very soft material structure of undesirable were subjected to quenching of the
profile surface to a certain depth with the quenching method, and then tempered the cooled surface by the region which was
hot in the profile center. The changes in mechanical and metallurgical properties of the materials tested as a result of the
process application designed according to the steel profile quality and cross-section. According to the results obtained, it
was determined that the mechanical properties of the material increased and this increment was observed by the change
in the material microstructure which was caused by the applied process. As a result of the study, it has been determined that
more economical solutions can be revealed with the quenching process instead of using microalloying by using rare elements
in a working environment where competition is gradually increasing.
International Iron & Steel Symposium
UDCS
Mehmet Akkaş
Ezgi SEVGİ
Burak ÖNDER
Aytaç BAŞSÜLLÜ
Osman Çulha
In recent years, analysis of product and production processes with the help of
numerical simulation methods; the effects of production processes on mechanical and
microstructural properties of products, efficiency studies in the processes, material flow,
determination of cooling regime, distortion, folding, etc., provides a significant contribution
to the determination of the relationship between production-structure-propertyperformance in R & D / Design studies. Hot and cold forging, rolling and extrusion can be
solved under finite elements and finite volume method with the help of computer aided analysis.
In this study, the solution of the phase transformations in the material microstructure,
due to the heat transfer coefficient in different cooling environments as a result
of the production with hot forging, is investigated by the numerical simulation method.
Critical phase conversion temperatures of 1.7035 and 1.1191 code steels, nonrecrystallization temperature, critical forging temperatures were calculated
according to alloy composition. Hot forging operation was carried out by finite volume method
and cooling process was solved by finite element method. Simufact.Forming software was used
in numerical simulation supported solutions. As a result of hot forging and cooling process;
phase ratios, strength, distortion in the product, residual stress values were revealed.
International Iron & Steel Symposium
UDCS
Osman Çulha
Fulya Eyçin
Serhat Bardakçı
Chemical composition and steel alloy structure are the most important process inputs
affecting the material properties in production with hot forging. Different mechanical
properties can be obtained in the product due to the cooling regime applied at the end of the
forging operation. Especially, as a result of the cooling process, the alloy phase structure is
transformed into different phases at room temperature. The microstructure of micro alloyed
steels at room temperature, which is obtained by thermomechanical forging at high
temperatures, differs from one another depending on cooling atmosphere. According to the
literature review; microstructure of forged material shows that the finer grain structure has
higher toughness and fatigue strength. In this study, 1.1141 coded cardan shaft fixed forked
flange produced by hot forging at 1200 oC and 5 different operations, used as sample.
Microstructural; grain size, type, distribution and rate of phase and mechanical properties;
hardness and strength variations of hot forged samples under four different cooling media such
as; controlled, air, oil and water cooling, were investigated in simulation. Phase
transformation and distribution were calculated according to the cooling rate and TTT-CCT
diagram of sample.
International Iron & Steel Symposium
UDCS
Osman Çulha
Fulya Eyçin
Serhat Bardakçı