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Blow Holes in Manganese Steel Casting
2

Blow Holes in Manganese Steel Casting

Blow Holes in Manganese Steel Casting

(OP)
Hello


I am having a problem with blow holes on the side and around the neck of all of the feeders attached to a 380 kg steel casting.
It is made of manganese steel (GX120Mn13) and I would like to ask if anybody has encountered such a problem before.

I have strong doubts regarding the feeder material and the temperature witch the item was cast.

I have attached a photo of the feeder and the casting.
 

RE: Blow Holes in Manganese Steel Casting

2
ertefer,I am unable to open the link. Can you please upload once again.

You can expect shrinkage porosity in the feeder region,if not properly selected. Is this a persistent problem with the casting or an intermittent one. It is safe to use a side riser with a notch at the connection. Top risers pose a lot of problem in Manganese steels(though my preference is always to use a top riser). Pouring temperatures can definitely be an issue.

As Manganese steels have high fluidity and their feeding distance is also large,pour at a lower temperature and use fewer number of risers.  

_____________________________________
"It's better to die standing than live your whole life on the knees" by Peter Mayle in his book A Good Year

RE: Blow Holes in Manganese Steel Casting

lower pour temp will help.
You should also be concerned about dissolved gasses, these alloys will soak up lots of hydrogen and nitrogen.

= = = = = = = = = = = = = = = = = = = =
Plymouth Tube

RE: Blow Holes in Manganese Steel Casting

(OP)
I uploaded the photo once more (altered the file name)

The holes seem to expand from the main body of the riser to the neck and around a small area of the casting in close proximity to the neck.
This is a consistent problem.
There is a problem with the credibility of the pyrometer
(unable to calibrate it.)
 
Regarding the risers , I used top risers because I cannot get the necessary data (modules) for side risers from my supplier.

I used the number of risers required to feed the casting (but to be honest I do not know the true yield of these risers for manganese steel and of course it is difficult to determine it without accurate tempereture data)(I only use theoretical data for the geometry of these risers from a Robert Wlodawer's book)
 

RE: Blow Holes in Manganese Steel Casting

It is high temperature related defect. Reduce your pouring temperature,why is the riser having those porosities. You also change over to side risers,you can sleep happily.

 Add some aluminium to the metal,though not suggested commonly to reduce gas in liquid metal.  

_____________________________________
"It's better to die standing than live your whole life on the knees" by Peter Mayle in his book A Good Year

RE: Blow Holes in Manganese Steel Casting

(OP)
I 've seen these blowholes in castings before, but I really needed a second opinion regarding the temperature issue.
(and of course the side risers is an option I have never thought as a solution to this kind of problem)

cannot thank you enough...

 

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