Effect of nickel 3

[priyam07]

Hello all, I was wondering if there is a specific reason customers ask foundries for Ni (1-2%) in low alloy steel castings to improve weldability? We know Ni is good for low temperature toughness but not sure what is the effect on weldability.

 

[metengr]

Toughness aside, Ni has little affect on the weldability of various steels based on review of the carbon equivalency formulas. Nickel and even copper have a high denominator in the CE formula's, which means they have little impact on precautions necessary for welding.

http://www.twi-global.com/technical...rmulae-used-in-relation-to-hydrogen-cracking/

 

[priyam07]

Exactly, but adding more Ni would only increase the CE so why want more Ni if you have met the toughness spec?

 

[metengr]

Because Ni does help with increasing hardenability of the casting, which helps for heat treatment (quenching) of thick section castings.

 

[arunmrao]

What grade of castings ASTM 148 ? Some manufacturers maintain 1.5% Ni with 0.3%Mo. I use lower quantities of Ni and increase Mn up to 1.2% with some grain refiners. It is a matter of choice and experience. Apart from this grade, I have no knowledge of Ni being added in low alloy steel castings.

I'm just one step away from being rich, all I need now is money.
( read somewhere on the internet)

 

[priyam07]

That's right, adding Mn, Cr and Mo should be able to take care of the hardenability (better effect than Ni anyways).
Thanks!

 

[metengr]

You can count on arunmrao as our metal foundry expert.

 

[Guest102023]

In terms of steel hardenability, nickel is a pretty benign alloy addition, which is reflected in various carbon equivalent formulae. Its primary effect is grain refinement, a strengthening mechanism that also improves low temperature fracture toughness.
My background is welding, and I consider 1Ni-¼Mo to be the "sweet spot" for a low alloy filler metal composition with all-round good properties.

"If you don't have time to do the job right the first time, when are you going to find time to repair it?"