Effect of electro-spark deposition process on surface properties for Gas turbine blades

مقدم أطروحة جامعية

Mahdi, Baha Sami

مشرف أطروحة جامعية

Hafiz, Muhammad H.
Thamir, Ayman D.

الجامعة

الجامعة التكنولوجية

الكلية

-

القسم الأكاديمي

قسم هندسة الإنتاج و المعادن

دولة الجامعة

العراق

الدرجة العلمية

دكتوراه

تاريخ الدرجة العلمية

2013

الملخص الإنجليزي

Turbine blades used in Iraqi electrical gas power stations need to expensive maintenance by traditional processes frequently.

These blades are made of nickel superalloys as 1N738LC, where this alloy which used as a substrate material in this research by using electro-spark deposition process (ESD) to repair it's corroded or eroded surfaces.

The work includes information about the ESD process and most variables affecting the deposition mechanism in discharge, surface roughness and the deposition rate for the deposited surface.

1N625 superalloy was selected as a deposition material in the form of rode with diameter of 3.2 mm.

This deposition material was selected due to its high corrosion and creep resistance in addition to many shared elements between it and the.

The experimental work includes applying the input electrical variables for the ESD machine and the electrode rotating speed to see their effects on the output results like the surface properties.

During the ESD process eight electrical frequency values were selected from 50 to 800 Hz and six values of the electrical voltage were selected, from 25 to 125 volt, while the electrical capacitance was fixed for all experiments at value of 50 microfarad.

The best selected electrode rotating speed was around 1000 rpm and the maximum deposition rate achieved was 2.3 gram per hour at applied voltage of 100v and electrical frequency of 700 Hz .

The deposition rate directly proportional to the applied voltage in a second order power equation and linearly proportional with the electrical frequency, and minimum value of the surface roughness was Ra=1.9^m at applied voltage of 25v and 13.9^m at voltage of 125v.

The adhesion of the deposited IN625 on ductile substrate was good without scaling in bending tests where the coating was sustained in extreme environments, and the shared phases between the substrate and the deposition layer was S-(NiCr) alone.

The deposition layer microstructure was a mixture of nano-grains with amorphous structure and diluted interface layer thickness varied from 4 to 10 micrometers.

التخصصات الرئيسية

العلوم الهندسية والتكنولوجية (متداخلة التخصصات)

• APA
• MLA
• AMA

لغة النص

الإنجليزية

نوع البيانات

رسائل جامعية

رقم السجل

BIM-417639