Ductile-brittle transition temperature 1

[metaloga]

Who knows the ductile-brittle transition temperature for steel SA516-70?

Thanks

 

[SJones]

The steelmaker who creates a transition curve for the original manufactured material. Or, the fabricator who does the same after forming it. There is no standard DBTT because there are so many specific variables that contribute to the toughness characteristics.

Steve Jones
Materials & Corrosion Engineer

http://www.linkedin.com/pub/8/83b/b04

 

[unclesyd]

Some on may correct me as to these values recognized by ASME.

30 for non normalized material ASME 516-70

-30 for normalized material. ASME 516-70N

As stated above these values will vary depending on several factors. The material still has to impact tested above 1" thick.

 

[metengr]

Maybe the more relevant question is , what is the minimum design temperature that the above steels can be used without the need for impact testing to establish a DBTT?

Reply; Go to ASME B&PV Code, Section VIII, Div 1 and what you will find are impact exemption curves that have been developed over the years for a group of steels, which the above are included, to ensure a minimum impact energy value for a given service temperature and material thickness.

-20 deg F if not normalized, and less than 0.5" in thickness
-55 deg F if normalized and less than 0.5" in thickness



If the thickness or use of the steel is below a minimum service temperature based on the exemption curves above, impact testing will be required to that heat of material.

 

[blacksmith37]

What do you want the answer to be ?

 

[stanweld]

One can readily obtain SA-516 70 plate materials with Code mandated absorbed energy at -50 F.

 

[rmw]

Wow,

Doing some research for a project and got googled right to this thread.

A question to stanweld. Following up on the pervious post, if impact tested to zone 3 of table 9 of ASTM A709, wouldn't it be good to -60F per Table 7?

rmw

 

[stanweld]

rmw,
I'm not sure what question you are asking. SA-516 70 is not referenced under A-709. A709, S84 does not apply to ASME B & PV Codes. Impact test temperatures and absorbed energy are based on other (ASHTO) design criteria.