Investigating the Effects of Conventional and Non-Conventional Welding Techniques on Microstructure and Residual Stress in Creep-Resistant Steels

2018-12-31
The use of creep-resistant steels for the fabrication of components in boiler tubes and fittings in power plants due to their high temperature strength properties has increased in recent years. However, experience with the welded creep resistant steel components currently in service as well as the results of creep tests indicate reduced creep rupture strength of weldments compared to the base material. Besides, it is known that the magnitude and distribution of a residual stress play a vital role in the integrity and reliability of a welded structure. For instance, a tensile residual stress combined with the stresses due to service loads can induce catastrophic effects on a fatigue behavior, corrosion properties and a brittle fracture. Also, the initiation and growth of defects are both influenced considerably by the presence of residual stresses. The aim of this research is to optimize the welding procedure for better service performance of creep-resistant steels in power plants by comparing the effects of conventional (gas metal arc welding) and non-conventional (hybrid plasma arc welding) techniques on the microstructure and residual stress state.

Suggestions

The effects of Cr addition on the atomic ordering properties of Ni based superalloys
Eriş, Rasim; Mehrabov, Amdulla; Akdeniz, Mahmut Vedat (null; 2016-10-01)
Nickel-based superalloys are used in turbine blades, nuclear reactors and power plants due to their excellent mechanical properties and oxidation-corrosion resistance at high temperatures. The superior properties of Nickelbased superalloys are further improved by alloying element additions which lead to formation of coherently GLVWULEXWHG RUGHUHG Ȗ¶ SUHFLSLWDWHV 1L3$O ZLWKLQ Ȗ 1L matrix. Enhancement of mechanical properties has been attributed to Al-sublattice site occupancy of tertiary DOOR\LQJHOHPHQWV...
Modeling the effect of dose rate and time on crosslinking and scission in irradiated polyethylene
Sargın, Irmak; Beckman, S. P. (2020-06-01)
The insulation around the electrical cabling in nuclear power plants is frequently made of ethylene-propylene rubber and crosslinked polyethylene that is subjected to low levels of environmental stressors and radiation over the duration of their decades long service life. For the purpose of maintenance and reactor recertification, it is necessary to develop a non-destructive approach to determine the degree of damage the insulation has sustained. Accelerated aging experiments are used to develop these metho...
Analysis of velocity profiles in concentrated solid-liquid mixtures using ultrasound doppler velocimetry
Taşkın, Ahmet Fırat; Ayrancı Tansık, İnci; Uludağ, Yusuf; Department of Chemical Engineering (2021-7)
Stirred tanks are widely used for a variety of processes in industry such as solid dispersion, crystallization and dissolution processes. Several parameters are used to optimize these stirred tank processes such as impeller type, tank geometry and impeller speed. The flow field in the stirred tank is complex and varies depending on these parameters. In these processes diffusion and chemical reaction rate depend on the flow field and velocity fluctuations; therefore, information about the flow field is valua...
The Effects of High Frequency RF Capacitively Coupled Plasma on Tensile Strain and Functional Groups of PAN based Carbon Fiber
Erözbek Güngör, Ümmügül (2014-04-25)
In this study, high frequency (40.68 MHz) RF capacitively coupled discharge was used to modify tensile strain and chemical structure of unsized PAN-based carbon fiber under different RF powers, pure nitrogen gas pressures and exposure times. The plasma parameters were diagnosed by using single and double Impedans Langmuir probe techniques to understand physics of high frequency RF-CCP treatment processes. The power range was P = 50-200 Watt and the pressure range was p ≈ 0.1-0.8 Torr. The measured plasma pa...
Investigation of Combustion Kinetics of Five Waste Wood Samples with Thermogravimetric Analysis
Yorulmaz, Sema Yurdakul; Atımtay, Aysel (2007-02-24)
In the present study, combustion mechanisms, thermal kinetics, and phases of combustion were investigated for untreated pine and treated MDF, plywood and particleboard samples. Waste wood samples were combusted in air at 10, 20 and 30 degrees C/min heating rates in TGA. As a result of TG analysis, thermal decomposition of treated samples was observed at lower temperatures as compared to the untreated pine sample because of the catalyzing effects of the chemicals in the samples. Therefore, there were less fl...
Citation Formats
C. H. Gür and S. Tirkeş, “Investigating the Effects of Conventional and Non-Conventional Welding Techniques on Microstructure and Residual Stress in Creep-Resistant Steels,” 2018. Accessed: 00, 2020. [Online]. Available: https://hdl.handle.net/11511/59295.