Pengaruh Variasi Tekanan Gesek Terhadap Distribusi Temperatur, Sifat Tarik, Struktur Mikro, dan Kekerasan Sambungan Las CDFW Bahan AISI 304-ST 41 untuk Poros Turbin Air

The shaft is one of the important components in a water turbine. The shaft
works in a corrosive environment, so the material used is stainless steel. However,
this material is still relatively expensive. This can be overcome by joining two
different materials, using the CDFW welding method. The continuous drive friction
welding method is a method of joining two solid cylindrical materials, which still
needs to be researched and developed. In particular, dissimilar splicing (Unlike
materials). The purpose of this study was to determine the distribution of
temperature, tensile properties, microstructure and hardness of CDFW welded
joints of stainless steel 304 and St 41 steel.
The welding process, variation is the most important thing that can affect
the results of welded joints. The variations used in this study are frictional pressures
of 30, 40, 50, and 60 MPa. The method in this research is descriptive analysis, while
the research design uses an experimental method which was carried out in the
laboratory of the mechanical engineering study program at the Muhammadiyah
University of Yogyakarta. Tensile testing is carried out using JIS (Japanese
Industrial Standards) Z 2201 standards. The test results data were analyzed using
descriptive analysis method, by describing the comparison of the test specimens
given variations in frictional pressure. This analysis method uses the help of the
Microsoft Excel application.
The results of this study prove that the highest tensile strength value is found
in variations in frictional pressure of 50 MPa. This is directly proportional to the
results of the hardness test. The higher the value of the hardness of the material,
the greater the value of its tensile strength. This is also supported by the data from
the microstructure test results, at a frictional pressure variation of 50 MPa which
shows the smaller the grain size, the higher the hardness of the joint. Variations in
frictional pressure also affect the temperature distribution of welded joints, the
temperature continues to increase from the lowest to highest frictional pressure
variations. However, the results of the tensile strength decreased at a frictional
pressure variation of 60 MPa, this was due to the formation of a eutectoid system,
so that an intermetallic layer was formed which reduced the tensile strength value.