516-70 vs 516-70N 2

[KentCaudill]

Who among you can give me a short course on the differences between SA516-70 as rolled and SA516-70 normalized? Under what applications does one callout have advantages over the other?

Thanks for your help, Kent.

 

[unclesyd]

Normalizing is a heat treatment applied to steel which heating involves heating above the critical range followed by cooling in still air. It is performed to refine the crystal structure and eliminate internal stress.
This is normally used to keep movement down during any heating. It has to applied to certain steels that don’t not air harden appreciably.

There is lot more technical explanation but I think this will cover you question.

Don’t call out normalizing unless the material is amendable to normalizing and there is a need for it by design.

 

[Metalguy]

516-70 is one of the many grades of steel where norm. is frequently used. You can expect better mech. props. from it.

 

[WBH]

Norm. better notch toughness values. Allows impact testing to be conducted at lower temps than straight grade. Useful when qualify welding procedures for lower temps.

WBH

 

[stanweld]

As rolled is cheaper and if low temperature toughness testing is not required for the design, as rolled should be purchased. Low temperature toughness can also be met in the as-rolled condition provided the thickness is not too great.

 

[Alengfo]

the most common use of 516-70N is in pressure vessels. In this application all the reasons described below make the normalised version the superior choice. In fact when purchased from a reputable source you would always be provided with 516-70 Normalised. You would have to hunt very hard to find it in a not normalised condition.

 

[priyasachin]

PRIYASACHIN

DEAR FRIEND,

A 516 steels are for pressure vessels. depending upon thickness and the facilities available, the shells may be cold formed or hot rolled. The hot rolling would alter the properties. When it is known that hot rolling would be necessary, we specify to the manufacturer, to conduct the simulated heat treatment, including the PWHT and report the properties. When it is plain cold rolling only with or without subsequent PWHT, it is safe to order in normalised condition. The normalised material will not suffer any loss of properties in working or PWHT. When we buy the material in as rolled condition, the manufacturer would conduct the required normalising on the samples used for testing and provide the TC in that condition.

With regards,
MRCN

 

[deanc]

If you need PVQ steel review ASME SecII PartA SA-20 and SA-516.

In ASME SecVIII Div1 anything of SA-516 Gr70 over 1 1/2" must be normalized.

 

[TomEun]

Normalized SA-516-70 has some advantages as below;

1. Good ductility at low temperature due to the re-crystallized and grain refinement structure and removed internal residual stress;

For example,
ASME Section VIII. Division 1, Fig. UCS-66
Impact test exemption temperature for 1” thickness, SA-516-70
31 deg. F for non-normalized condition
-30 deg. F for normalized condition

As a result, the DBTT (ductile-brittle transition temperature) can be reduced 61 deg .F.

2. Anti-corrosion property

For example,
Good corrosion resistance properties in Caustic, SCC (stress corrosion cracking), SSC (sulfide stress corrosion cracking), Hydrogen Attack, and HIC (hydrogen induced cracking) environment, etc.


However, some properties (e.g., strength and ductility) will be reduced because of the grain growth during rolling, forming, or spinning for the normalized base metal over than normalizing temperature. Hot working below than normalizing temperature is recommended or re-normalizing after hot working over than normalized temperature is recommended.

Thomas Eun