In a nutshell, yes. Both of these steels are pressure vessel carbon steels with similar chemical compositions. The 516 grades have carbon content maximums that are .02 to .04 % lower than the 515 grades. Carbon also happens to be one of the most potent alloying elements in its effect on toughness. The small .02 to .04 % drop in carbon could double the Charpy V-notch energy depending on the test temperature. Remember that plain carbon steels with low carbon contents in general have very steep transition temperature curves, and a plain carbon steel that has good toughness at 32 F can loose more than 50% of that toughness when the temperature drops to 0 F. Andy
What is the niche for SA-515?? I don't know of one. Was it cheaper to make at one time, much like a wooden tennis racket, but now hardly ever made anymore.
I believe that it preceded SA-516. In my opinion, it has no proper place in low temperature climates since SA-516 is readily available. I believe that it's niche was before SA-516 when SA-285 was the standard material and it offered higher allowable stresses. Since the brittle fracture problems associated with SA-515 have become known, most clients insist on SA-516 and will not allow SA-515.
Sir,
Please find at ASME Boiler & Pressure Vessel Code - Part A (Ferrous Material Spesification) table A1.15 for Minimum test temp. combination meeting charpy V-Notch requirements indicated. You can clearly see that the A-516 group is suiable for low temp. Please note that the A-515 group requires post weld heat treatment in order to avoid cracking.
The primary differances between A515 and A516 is that A515 is produce to coarse grain practices and for use in high temperature applications such steam piping or pressure vessels. The coarse grains help to minimize graphitization. A516 is produced to fine grain practices in order to maximize the fracture toughness. Bob
1) I have Pipe A672 Gr.B60 CLASS 22(stress relieved)with thickness 42.30mm and 48.50mm (ASTM Specification A515 Gr.60).
2) The minimum Design Metal Temperature is 0°C (Design T.427°C Max.)as per our class.
3) According to ASTM A515 para.5 (2in and under in thickness mat be ordered normalized or stress relieved, or both).
4) Following to B31.3 Fig.323.2.2A (curve B) it is necessary to impact tested this material.
My question is: the material must be stress relieved or normalized.
UKCats;
Plate material furnished under the ASME SA 515 specification is for use in components or vessels that operate above ambient temperature service because of the coarse grained structure of the material, resulting in lower impact or notch toughness properies. So yes, SA 515 plate material has poorer impact properties in comparison to SA 516 plate material, which is supplied as fine grained material. I believe the SA 515 pressure vessel plate specification replaced the original SA 285 plate specification that was used in many ASME Section I boiler components like waterwall drums, etc.
For vessels or components that operate above ambient temperature service, SA 515 is acceptable plate material because you would be above the ductile to brittle transition temperature in service. For vessels that operate at or below ambient temperature service, the SA 516 plate material would be specified because of improved impact properties or notch toughness per ASME Section VIII Div 1 or Div 2 mimimum design metal temperature requirements.
metengr,
SA515 did not replace SA285. SA285 is alive and well.
Shmulik,
ASME VIII, UCS-56 covers PWHT for the P1 materials (of which SA515 is included) based primarily on a thickness criteria. P1 materials will require PWHT above 1.25 inches, unless preheated to 200F. PWHT is required for thicknesses above 1.50 inches. But, I do not recall any specific requirement that SA515 was singled out for PWHT as a Code rule. Where in the ASME Code does it say that SA515 is required to be PWHT other that when required based on thickness?
SB;
You are correct, it was SA 212 that I was thinking about not 285. That is what happens when entropy sets in after 40. By the way, I deal with NBIC/ASME issues, and I do not recall a similar requirement for PWHT of SA 515, other than PWHT requirements in accordance with UCS-56 or PW 39.
Other than the previously mention differentiation between SA515 and SA516, we had two cases where laminations were a problems in the SA515 plate in thick sections, above 1 1/2" thick. We found out several years later that this was a known problem to some people, though not widely disseminated information.
SA-515 does not preclude fine grain melting practice. With today's greater uniformity of steel making you will often find that SA-515 will be made to fine grain practice when you check the aluminum, vanadium and niobium residual element analysis. Only if you order Supplementary Requirement S61 will you guarantee that the material will have a coarse grain. Coarse grain is beneficial in improving high temp creep properties (over SA-516) and provides somewhat improved resistance to graphitization.
