115 year old cast iron 5 ton pieces welded with good results

Date 03-14-2012 18:07

Ladies and Gentlemen,
I am a CWI graduate engineer. My background is petroleum etc. In the British magazine “PROFESSIONAL ENGINNERING MAGAZINE” MARCH 2010 edition there was the article “Technical Application / Good As New". They covered a heavy plus 115 year old cast iron 5 ton pieces welded with good results. Been around cast iron for more than 20 years. Old stuff is guess work and brazing is often done.
It was pieces of Tower Bridge in London Completed in 1894 cast iron fence lamp post supports about meter by meter by meter cubes weighing about five tons were lifted out / brought to a shop / paint removed / heated to 600 degrees Celsius ( 1112 F ) “castings to be preheated at a controlled rate to achieve 600 C. This temperature is maintained throughout the welding process while the prepared area is subjected to intense localized heat with an oxy-acetylene torch that turns the area to be welded into a molten pool. An operator maintains the pool and gradually fills the area with a cast iron filler material of the same chemical composition as the original casting.
The result is undetectable to the eye and will have the same characteristics and strength as the original casting.”
Your comments appreciated.
I hope this is helpful.
Sincerely
Len Andersen weld@spemail.org

By Sourdough (****)

Date 03-15-2012 14:32

I have welded a lot of cast, and it took me a while to figure out that the more heat and the longer the heat on a cast piece, that is the answer. There are cast parts on those rigs I used to work on that are still in service and taking a beating today. There is some cast you just will never get a good weld on, because of it's composition.

By DaveBoyer (*****)

Date 03-16-2012 03:43

The gas welding cast iron with cast iron filler is a viable procedure. The cast rods are available, but may not be stocked by Your LWS.

I have seen cast iron piston rings used as filler on manifold repairs with an oxy acetylene torch. You need a high temperature flux, borax, boric acid or commercially made high temperature flux.