turbine rotor gland seal system,

[Stephen Booth]

Hi everyone, I had this inquiry come into me from the Philippines. I did not have any business, service or sales to the customer.

Thought it might be interesting for answering by the group.

Hello Sir Stephen,

Good day!

I just want to ask the following:

To restore our turbine rotor gland seal system, we applied Twin Wire Arc Spray using Inconel 625 with Arc Bond 95/5 and HVOF for the surface coating.
The bonding between the rotor and the Twin Wire Arc Spray failed last January 19, 2015. To recall, the thermal spray application was done last September 29,2012.
It happened twice that there is a bonding failure between our gland seal castellation and the rotor of our 2 turbine units which only lasted for 2-3 years.

a. Is the scenario justifies that the life span of a Twin wire arc spray + HVOF repair is good for at least 2 years only?
b. What is the acceptable code to use for Qualification of Thermal Spray Operator or Personnels / Qualification of Procedure or Qualification of Materials involve in this kind of repair?


I'm looking forward to hear feedback from you Sir.
Thanks in advance.

[Johnny_Blaze]

Hi everyone, I had this inquiry come into me from the Philippines. I did not have any business, service or sales to the customer.

Thought it might be interesting for answering by the group.

Hello Sir Stephen,

Good day!

I just want to ask the following:

To restore our turbine rotor gland seal system, we applied Twin Wire Arc Spray using Inconel 625 with Arc Bond 95/5 and HVOF for the surface coating.
The bonding between the rotor and the Twin Wire Arc Spray failed last January 19, 2015. To recall, the thermal spray application was done last September 29,2012.
It happened twice that there is a bonding failure between our gland seal castellation and the rotor of our 2 turbine units which only lasted for 2-3 years.

a. Is the scenario justifies that the life span of a Twin wire arc spray + HVOF repair is good for at least 2 years only?
b. What is the acceptable code to use for Qualification of Thermal Spray Operator or Personnels / Qualification of Procedure or Qualification of Materials involve in this kind of repair?


I'm looking forward to hear feedback from you Sir.
Thanks in advance.

Hi Stephen,
I would like to know more info on tensile tests that were performed between the HVOF top-coat on an arc sprayed coating. Typically you have substantial stress differences between the two coating processes and ultimately that will play a role in the life-cycle.

On Operator training, as a former training technician for operators I typically look for welders and former electro-plators due to their experience with , coated layers, gases, high temperatures and metallurgical knowledge. At the same time I have trained people with absolutely no exposure or experience to industrial trades such as, welding, machining and chemical processing, those with a background in Industrial Automation fair well too.

Sometimes it just comes down to a persons aptitude to learn and put into practice what they have been taught and are fully compliant to application procedures in all aspects.

What is really required, is first and foremost, someone with an excellent background and experience in thermal spray to pass on the knowledge and oversee the training and progress of the operators.

Qualification of materials can vary from company to company so that is typically put together by a team of engineers who put the standards and a procedures in place to define conformance.

Regards,
John