Metal finishing Q&As since 1989

-----

Controlling Zinc Granules on edges of galvanized coils

January 14, 2010

Dear all

For a period of time I am making a research to control the appearance Zinc Granules on the coil edge in the process of galvanization.

I need to know what is the efficient way to control this matter.

thank you

Ayman Hassouneh
galvanizing plant - Q.A - Amman, Jordan

---

January 15, 2010

Sir:

I have several means to solve the problem you describe.

If you post a few photos it would be informative.

Regards,

Dr. Thomas H. Cook
Galvanizing Consultant - Hot Springs, South Dakota, USA

---

Dear Mr. Cook;

Thank you for your response.

I'll upload some photos for the case I asked about.

Best Regards.

  

Ayman Hassouneh
- Amman, Jordan
January 19, 2010

---

January 19, 2010

Sir:

I am having some difficulty orienting to the photos. What there seems to be are granules; and grooves and ridges. What type kettle do you have? Ceramic or iron? How long has it been in operation? Do you use a flux solution or (more likely) nitrogen/hydrogen? Could you describe the problem further? What is your usual aluminum? Could you section the granules and etch them and do SEM/EDX of the composition of these granules?

Regards,

Dr. Thomas H. Cook
Galvanizing Consultant - Hot Springs, South Dakota, USA

---

January 21, 2010

Dear Sir;

Thank you for your response.

well, we are using a ceramic/glass kettle, operated in 2008. we use the nitrogen/hydrogen in our line.

The AL is 10% - 15%.

regarding the tests required I'll post the results within 2 days once they are ready.

hereby another photo, which it may clarify the case.

Best Regards.

Ayman Hassouneh, Q.A
- Amman, Jordan

---

January 22, 2010

Sir:

If it is true that you use 10% to 15% aluminum in your molten zinc bath, then I am not qualified to help you further. If however you are using 10% or 15% Aluminum; Balance Zinc as the means to maintain around 0.2% aluminum in your molten zinc then I may be able to help you.

Even Galfan has only 5% aluminum in the zinc (This is a low melting eutectic). I still wonder if your aluminum additions are uniform.

Regards,

Dr. Thomas H. Cook
Galvanizing Consultant - Hot Springs, South Dakota, USA