Chromium on A36 Structural Plate

[napster385]

Hi Everyone,

Just want to ask if what is the effect of Cr on A36 Plate if the percentage content is 0.30%. Generally what is the effect of Cr on carbon steel and will it affect the weldability of A36 plate?

Appreciate your comments and advice.

Thanks

 

[metengr]

This amount of chromium is in the tramp element range for A-36 steel and should have little effect on the overall mechanical properties. You can actually determine the effect on weldability by using the carbon equivalent equation and compare the CE value using 0.30% and 0% for chromium contents.

 

[swall]

I would say that 0.30 Cr is kind of high for an incidental element. Can you post the complete analysis?

 

[napster385]

Hi Swall,

The chemical analysis provided by mill for A36Cr plate are as follows:

C - less than or equal to 0.21%
Si - less than or equal to 0.35%
Mn - less than or equal to 1.20%
P - less than or equal to 0.035%
S - less than or equal to 0.035%
Cr - greater than or equal to 0.30%

Appreciate your response.

 

[mrfailure]

Napster, that chemical analysis sounds more like a spec than a mill cert - certs would not be stating in terms of greater or less than. Even the terminology A36Cr, if it is the mill's, sounds like a custom alloy. As metengr already noted, you should calculate carbon equivalency based on actual cert values to determine if weldability is affected.

 

[swall]

Agree with mrfailure on this. If you are concerned about an issue with chromium, you need to get an analysis that shows the actual amount, not just the stated spec range or stated range on a purchase order. If weldabiility is the basis for your concern, you need to find exact percentage of chromium and other elements that effect carbon equivalent.

 

[napster385]

Thank you for your responses Swall and Mrfailure.

I will be asking for actual content of their previously manufactured steel which should be also indicated in the mill certificates. But what are the other factors I can be concerned for adding an additional alloy aside from weldability?