Cast iron / Steel problems

[Greg A]

Im welding cast iron to steel in a heat exchanger in a Terex rock truck . Using Silicon Bronze got started no problems moved to the other side again no problems . But then the first side got a big old crack down the middle . wanting ideas

 

[hotponyshoes]

Can you use a bigger bit of tube and reduce that weld gap?

 

[leadpig]

try nickel perhaps

 

[addjunkie]

The two metals expand and contract at different rates due to different metrology.

 

[Erie Fred]

I can't see the crack.
Is it in the bronze, the cast, or the steel ?

As above, need a tighter fit, you've got allot of cooling strains/shrinkage going on.
The "starved horse" weld bead is not helping if I am seeing things right.

 

[MattF]

The two metals expand and contract at different rates due to different metrology.

Metallurgy?

 

[not done it yet]

Metallurgy?

A measured response?

 

[Seadog]

No, that's metrology

 

[Erie Fred]

No metal is involved, the parts are steel, Iron & brass......

 

[Brad93]

Sounds like a component that a design engineer should have been consulted on.

As said joint gap is large, forces of contraction as the silicon bronze cools and contracts will be massive.

Different rates of thermal expansion between the steel and the cast iron are another factor.

Lucky the crack didnt migrate into the cast iron - tig brazing cast iron causes hard areas in the heat affected zone.