Print ISSN: 1681-6900

Online ISSN: 2412-0758

Keywords : Steel


Wear Performance of a Laser Surface Hardened ASTM 4118 Steel

Assifa M. Mohamad

Engineering and Technology Journal, 2013, Volume 31, Issue 17, Pages 3235-3244

In this investigation ASTM 4118 steel was treated by using pulse Nd: YAG
laser with wave length 1064nm and pulse duration 100ns. In order to assess the
new tribological properties of laser surface hardened ASTM 4118 steel, the wear
resistance between specimens treated with laser and those of conventionally
hardened under dry sliding conditions was compared. The change of wear
mechanisms in laser hardened 4118 steel resulted in distinct difference in wear
rates.
The results showed that quenched zones not only had sufficient depth of
hardening and higher hardness, but had more retained austenite and finer carbides
because of a higher degree of carbide dissolution. Laser surface hardened ASTM
4118 steel specimens exhibited superior wear resistance to their conventionally
hardened specimens due to the change in the microstructure hardening, high
hardness. The wear mechanism for both the laser quenched layer and
conventionally hardened layer was highly similar, generally involving adhesive
wear mechanism , material transfer, wear induced oxidation and plowing. Also the
results of hardness show that increases with increasing of laser energy by 70%.

Experimental Behavior of Circular Steel Tubular Columns Filled with Self-Compacting Concrete under Concentric Load

Saad N. Sadik; Wael S. Abdul-Sahib; Ammar A. Ali

Engineering and Technology Journal, 2013, Volume 31, Issue 14, Pages 2760-2772

This paper presents an experimental study on the behavior of circular, concretefilled,
steel tube (CFT) columns concentrically loaded in compression to failure. Selfcompacting
concrete (SCC) is used here as a filler in order to increase homogeneity of
the core and reduce segregation problems. Total six column specimens with different
lengths (0.4 m – 1.5 m) of constant diameter of 160 mm and wall thickness of 2.8 mm
were tested. The purpose here is to investigate the ultimate capacity and the
deformation behavior of different slenderness ratio columns. The behavior of these
columns in confinement was discussed.
Experimental results indicate that the compression force capacity is affected by
slenderness ratio of the column. For slender column the overall buckling was observed
while for the short columns the crushing and the local buckling is the dominant failure
shape.

Effect of Laser Surface Treatment on Mechanical Properties of CK45 Steel

Sabah N. mahmood; Khansaa Dawood Selman

Engineering and Technology Journal, 2011, Volume 29, Issue 8, Pages 1610-1618

The research aims to study the effect of laser surface treatment on mechanical properties of CK45 steel which is widely used in Bolts, Axles Various,Connecting Rods and Hydraulic clamps. Trails of laser hardening were carried out by using CW Nd: YAG laser with different powers 2.7, 3.3, and 4.3 Watt. Mechanical tests were done for the specimens who were used in the research before and after treated by laser such as: Tensile test, Micro hardness. Also grain size measurement and microstructural evaluation were done by using
computerized optical microscope. The results show that improvement in
mechanical properties at laser power 4.3 watt obviously when compared with other laser powers. From tensile test we show that increasing in yield strength, ultimate tensile strength Poisson's ratio and plasticity constant (k). Also decreasing in Young modulus, Rigidity of modulus and strain hardening coefficient (n). While microhardness results show that the highest value was obtained at laser with 4.3
watt power and decreased far from the surface. Metallographic of the specimen show that refining in grains size after the treatment with laser.

One Parameter Composite Semigroups of Linear Bounded Operators in Strong Operator Topology of Schatten Class Cp

Samir Kasim Hassan; Al-Taie M; Al-Malki Anam; Al-Attar Abeer; Mustafa Khaleel Ismael; Fatema Ahmed Sadeq; Radhi A .Zboon; Jehad R.Kider; Samir K .Hassan; Hussain J. M. Alalkawi; Raad H. Majid; Rawaa A. Alomairy; Luma Abdul Ghani Zghair; Hadia Kadhim J.Al-Ogili; Assifa M. Mohamad; Abbas Sheyaa Alwan; Haider L. Aneed; Assim H Yousif; Salema Sultan Salman; Abbas Hussien Miry; Abduladhem A.Ali; Mohammed Zeki Al-Faiz; Sabah N. mahmood; Khansaa Dawood Selman; Shaymaa Tareq Kadhim

Engineering and Technology Journal, 2011, Volume 29, Issue 8, Pages 1463-1470

For semigroups of linear bounded operators on Hilbert spaces, the problem of
being in Cp , 0 Keywords