Gordon,

I have a question pertianing the matter above, as you know the electrode that we use in for the air plasma e.g: for 9MB contains Thrioated Tungsten.

I have got a few paper produced by The National Radiological Protection Board in England that talk in detail about the material. But I do not know how to attach them to you. (Let me know if you are interested).

This paper appears to be addressed primarily to the welding industry, which I know little about but it suggests that grinding of thoriated tungsten is practiced. The paper makes clear that thoria is radioactive and states that internal exposure is likely to exist during grinding. In addition to the risk of inhalation, it further states that dust arising from grinding can settle on surfaces and contaminate body and clothing. As you know, the electrodes that we use contain thoriated tungsten and this can be hazardous to the health of workers (You may also note that, without any grinding, there exists a very low exposure to external radiation from our electrodes but this amount is considered negligible).

The reason for the regrinding which I have tested is an initiative of lean event to reduce hardware cost. We manage to salvage atleast >50% consumption of electrodes in an annual basis without affecting any quality of the spraying and coating integrity which I have verified. An electrode can be salvaged max 2 times before it is scrapped.

This is more on sharing and to seek your advice on this practice if this is advisable to continue by putting all the safety measurement in place to eliminate the risk? and if the safty measure is verified by a professional team of EH&S personnel after their have reviewed them.

What 's your opinion on this?

Regards,
Alex

Gordon,

I have a question on the tolerance capability level for thermal spray processes
.
I would like to know, what is the best tolerance (i.e. +/- 0.00x) that can be achieved with HVOF or Air Plasma?

For my process
1. APS - I could achieve a deposition rate in the range of 0.001"~0.003" per pass.

2. HVOF - I could achieve a deposition rate in the range of 0.00025 ~0.0005

Any information would be appreciated!

Thanks.

Regards,
Alex

From where can I buy small quantities of powdered carbon steel in the uk?

Dear Members
We have to sell 200 kgs AlCro, dia. 1.6 mm arc-spray wire.
Please contacts us.
Regards Kalmar

Hi friends


i got a problem in removing the plasma sprayed coating

the powder is METCO-58NS

coating thickness is aprox. 38 microns.

pls suggest any mechanical removing procedures

if any standard process is there to remove these kind of coatings

pls let me know

thanks

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Dear SEF Members

I'm flattered that some of you post your messages addressed to me personally, but we do have a community of members here and are exposed to the WWW. There will always be people more qualified or will have better knowledge or experience on certain subjects. I suggest, that we take care when addressing posts, so we do not put these people off from posting replies.

Dear SEF Members

I'm flattered that some of you post your messages addressed to me personally, but we do have a community of members here and are exposed to the WWW. There will always be people more qualified or will have better knowledge or experience on certain subjects. I suggest, that we take care when addressing posts, so we do not put these people off from posting replies.

hi everybody

My name is Semih, i am a new member and thanks for the giving access.

I am from turkey and i am a student in Sakarya University. My department is Metallurgical and Material Engieering. I am currently 3. class. Surface Engineering is realy a new field for me.

Our department has a project about thermal spray coating. We will build a thermal spray laboratary.
I have taken an engineering design assignment from my teacher who interest in surface engineering. So that my assignment is about location of equipments in a simple thermal spray laboratary and which equipments should be needeed. It's just a simple bird view plan.

Could you give me please information about this issue? or any information source that i can get knowledge about thermal spray laboratary?

Thank you and success at your surface engineering works.


(sorry for grammar mistakes)

Dear Gordon,

The temp.in the internal of an exhaust stack is 50-60 degree C as the heat of flue gas is extracted in the economiser. Due to low temp. sulphuric acid formation takes place inside the chimeny, which corrodes and punctures the exhaust stack within 2 -3 years.

In case of economizer not being used the temp. of flue gas can sometimes go up to 400 degree centigrade.

4% furnace oil is being used.

Would a coating of aluminum thickness 175-200 microns withstand in the above atmosphere or which other coating would you suggest ? What could be the life expectation of the coating ?

Thanks in advance,

Raghav