Normalizing Steel 1

[raqui3]

Where may I find the criteria that specifies that the "Plate shall be Normalized"? I understand the reason for normalizing and looked in ASME B&PVC, but is there a specific requirement? Using A516 GR70.

 

[metengr]

Review ASME SA-516. In part 5) Heat Treatment, plates can be furnished as-rolled below 1.50" and under in thickness. Over 1.50", plates SHALL be normalized.

 

[raqui3]

Thanks,
I've seen nominal t=1" of A516 specified in hyper baric chamber drawing & calculation packages to be specified normalized; is it just a matter of preference to take advantage of better allowable streses? 20ksi as opposed to 17.5ksi at a given temp & test pressure?

 

[metengr]

Yes. The purchaser has the option of specifying N&T for plate thickness at or below 1.50".

 

[raqui3]

THANK YOU. That clarifies the matter for me.

 

[SnTMan]

Another reason, at least for Sec VIII, Div 1 work is to afford a lower MDMT w/o impact test, "Curve D material" per UCS-66.

I don't believe allowables are affected by heat treat.

Regards,

Mike

 

[metengr]

SnTMan;
I agree with your comment above regarding allowable stresses and heat treatment using the following explanation.

Leaving the impact or notch toughness issue aside for steels, heat treatment will affect minimum mechanical properties of steels. In some cases, a normalization heat treatment versus no specific heat treatment is optional because the hardenability of the steel (based on specified chemical composition) would allow the thickness of the plate to still meet minimum tensile and yield strength requirements thru thickness. However, if you increase the plate thickness, a specific heat treatment would be necessary to assure meeting minimum mechanical properties thru thickness.

So, heat treatment can have an effect on achieving minimum mechanical properties, of which the allowable stresses are assigned. Notch toughness is directly related to heat treatment.

 

[deanc]

A Caution:

Study the MTRs. Make sure the test specimens were "attached" and/or received the same treatment. Have also seen some problems with time and temprature.