Hardfacing Powder making bubbles in the cord

[attin]

Hi all,

We use powder which is between 18-30 HRC, hardfacing for the glass industry. In our process we use fusewelder torch. But we have some problems about our application. These problems are:

- especially 22 HRC powder, the 1st lay make some bubbles in the deposit.
- the 2nd lay makes some sparkling appear
- the 3rd lay does not make appear anything, finally bubbles in the inner cord.
- light sparkles when we pass on the cord without powder.
- some black dirts appear on higher thicknesses

We are experiencing the same problems in other powders. Are we in trouble with the powder or our process?

[derek]

In order to get perfect fuseweld coating, you need to do some thing before the process:

1, Clean the base material to avoid oil, rust etc.
2, Make sure the base material reach the certain temperature before start the process.
3, 1st lay shouldn't be too thick and make sure the welding joint happen between powder and substrate.

[attin]

Thanks Derek,

Before starting the process, we clean the surface. The temperature of the base material that we think is appropriate for the application. Maybe, we are making thick 1st lay before the 2nd lay. Is the problem likely to be powder?

[derek]

You can order some other vender's powder to see what happens, but usually it is the process problem.

[attin]

Dear Derek,

I've tried other companies powder. These powder bubble problem are less then i used, problem continues occasionally.

[Simon Kim]

Maybe the first layer was treated under low preheating temperature.

If the temperature is over than 100℃, it should be less bubble.

Because weak preheat can not remove the moisture on the surface.


Simon