Difference between SA 516 Gr. 60 and 70 (w.r.t. vessel service) 1

[strain2]

Hi All,
Just wondering if there is a difference between SA 516 Gr. 60 and 70 from equipment service point of view.

Other than material strength, is there any other deciding factor when chosing these two materials?

Thanks

 

[weldstan]

From a stress corrosion standpoint, lower HAZ hardness should be expected due to the lower carbon equivalenbt; however, this is not always true and, in our one size fits all world where materials are multiple stamped, buyer beware.

 

[Shmulik]

Grade 60 provides higher elongation, and Charpy V-Notch energy absorption at lower temperature.

 

[Guest102023]

They are usually one and the same, being dual certified. Almost everything that meets Gr. 70 will meet Gr. 60.
There are SCC situations in refinery service where you prefer Gr 60 (or Gr 55) with a maximum tensile strength below the allowable max. in ASTM A516.

Shmulik - not automatically. Better ductility does not necessarily bring better low temperature fracture toughness.

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

 

[weldstan]

When SCC is a concern, add further limits on Carbon and Manganese for lowere grades in the P.O.

 

[Shmulik]

brimstoner: indeed, it is not automatically. Higher elongation is required by Section II part A ; SA-516
Temperature / V-Notch energy absorption at SA-20.

 

[Guest102023]

A516 is one of the materials most affected by the curse of dual certification. Grade 60 only can be hard to find.

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