BS3100 A1 2

[andysf]

I am currently making castings in BS3100 A1 material, more often than not the castings I have made previously are full of gas holes. Can anyone suggest why this may be? Where can I find typical melting temperatures for this material grade?

 

[jwhit]

Melting point would typically be 2500-2550f, pouring temperature should be a bit higher, more on the order of 2800-2900f. There are a lot of possibilities for gassing up a heat. In 316 or similar alloys, I would look more towards the other processes such as molding for an answer. Also, what is your actual composition? I won't claim to be an expert on this end of it, but will keep an eye on this topic as I might be able to track down someone who is.

 

[arunmrao]

BS3100 A1 is equivalent to ASTM A27 Gr 60-30. This is a general purpose carbon steel casting grade material. If the castings are gassy, you need to use clean charge (oil and rust free), melt fast and pour . Use of proper deoxidises is important to avoid any gassy metal. Finally use preheated ladles and dry molds for casting. The pouring temperature will depend on the time to transfer the metal to the molds ,number of molds to be poured and section thickness of the castings,.Hope it helps.

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

 

[jwhit]

My mistake in cross referencing materials(fat finger syndrome probably), carbon steel is a different animal than stainless when it comes to castings. Arunmrao gives good advice above.
You definitely want to use clean charge material, too much revert into the charge is asking for trouble, especially material that has been cycled several times. It reaches a point where it is "dead" metal and remelting it without AOD or vacuum degas is pointless. A charge of carbon steel plate and 30% revert shouldn't be a problem, deoxidize with Al, keep it <0.07% or use Ti, can be done in the ladle. Use a fixed amount of Al or Ti per ladle and fill the ladle to the same level every time if pouring multiple ladles from a heat. Make up any additions of C, Mn & Si that you need before deox. Mn and Si will also help with deox. If you are induction melting keep in mind that there is very little refining going on in the furnace, so garbage in, worse garbage out. Pouring temp should probably be around 2900f.

 

[arunmrao]

@jwhit,

I realized the error,regarding temperatures. 1625 C is a good temperature in my experience. But then I assumed maybe you were referencing some high carbon alloys

Rest all other comments, I agree with you.

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

 

[andysf]

Thanks for the advice guys, very helpfu[tt][/tt]l indeed.