Casting Sand inclusion/Porosity 1

[HakiNoir]

Hi All,

We faced a problem with a Chinese foundry on a precision casting: They poured the same part from CD4MCuN with no problem before but now they have this sand inclusion problem with A216 WCB (as shown attached)! I am wondering if any body has experienced this kind of defect and know the root cause? This is the critical path for a big project so any recommendations would be much appreciated!

Thanks.

http://files.engineering.com/getfil...9f49-4fce-ab34-b6f8b6c29987&file=IMG_0249.jpg

 

[bobjustbob]

From your picture, it looks to be what we would call burn in sand. The metal is penetrating into the mold and encapsulating the sand. Solving the problem isn't cut and dry. It could be mold compaction, pouring speed, molding material, pouring temperature, etc..

How large is the casting, how large is this protrusion into the part, how large is the section thickness around the hole, is the hole in the cope, drag or made by a core, how is the mold made, if made by a core how is it made, and what kind of sand is used?

 

[arunmrao]

Can you please tell more about the casting, moulding process etc. It will help give better suggestions.
It appears to be case of broken core, leading to metal penetration in the hole.

Was the defective casting shipped to you without your consent?

Since you continue to patronize China foundry, it will help if you keep a copy of " International Atlas of Casting Defects" by AFS.

"Even,if you are a minority of one, truth is the truth."

Mahatma Gandhi.

 

[HakiNoir]

Thanks for your inputs. No, our inspector found it in China.
The sand intrusion is not only around the centre bore. See the attached picture for the moulding. They used what they called it urea! I'll try to get more info for the sand.

http://files.engineering.com/getfil...789e-4979-aae1-be0704a4aa8e&file=IMG_0226.JPG

 

[arunmrao]

These are terrible ones. They do not deserve any merit. Just reject that source .

"Even,if you are a minority of one, truth is the truth."

Mahatma Gandhi.