API 5L X80 and Higher

By Niekie3 (***)

Date 04-28-2002 06:26

In South Africa, we rarely use API piping. As such, I do not know the designation X80. Can you give more info. Is this a Cr-Mo material, or what?

Regards
Niekie

By NDTIII

Date 04-28-2002 10:47

The X80 indicates the minimum yield strength with a max of 100,000psi. The tensile strength is 90,000 to 120,000 psi. That's about all I know at the moment. I do not have the mill test reports to show the chemical composition.

By G.S.Crisi (****)

Date 04-29-2002 20:18

NDTIII,
if I were you, first of all I'd give a look at the applicable Code, which in this case is the ASME/ANSI B31.8 "Gas Transmission and Distribution".

Niekie,
I don't have the API specification on hand now. I'll give a look at it later and will answer your question.
What type of line pipe do you use in South Africa? Perhaps one made to some BS?

Giovanni S. Crisi
Sao Paulo - Brazil

By Niekie3 (***)

Date 05-01-2002 18:00

Hi Prof Crisi

We mostly use ASTM/ASME materials. API materials are also used, but this is quite seldom. We also use BS and DIN materials, but where I come from, the ASTM/ASME materials predominate.

Regards
Niekie

By Mikeomni1 (*)

Date 05-01-2002 23:21

Chemical analysis requirements for API 5L grade x80 =

C = .24 max seamless, .22 welded.
Mn = 1.4 max seamless, 1.85 welded.
P = .025 max seamless and welded.
S = .015 max seamless and welded.

Cb, V and Ti may be used at the descretion of the manufacturer. The sum of these three elements shall not exceed 0.15%.

Other chemical compositions may be furnished by agreement between purchaser and mfg.

Regards,
Mike M

By Niekie3 (***)

Date 05-02-2002 18:18

It looks to me like this is a HSLA steel that only uses "micro" alloying to achieve its strength. (In addition to some Mn.) Generally this is done by ensuring that the grain structure is very fine. (Refining the grain structure is the only way to improve strength and impact properties at the same time.)

You will need to use welding procedures and fillers that maintain these properties. Typically you will need to minimize grain growth in the HAZ by ensuring you use low heat input techniques. This includes as low a pre-heat and interpass temp as possible for the particular material thickness.

In addition the filler metal needs to exhibit the same strength properties. This can be done by selecting a typical 90ksi filler that uses Ni as a grain refiner. (Typically 1.5% Ni) - Not the 90ksi fillers that use Cr and Mo to get their strength because these typically need a PWHT that could destroy your mechanical properties.

Hope this gives you some idea.

Regards
Niekie Jooste

By bspeirs (*)

Date 05-03-2002 00:46

We have been using an 8010-G for root, hot +1 or t2 passes - , say up to 8-10 mm fill.

Used to use 8010 for the complete fill, but switched to a gas shielded FCAW for fill and cap because of the speed. Wall thickness was up to 24 mm (just shy of an inch)

Combination of 8010 + E71T-1 always gave over 90 ksi tensile, plus very good charpy results.

Just a tad uncomfortable using a 70 class wire for guarenteed 90 ksi results, so for 90 ksi pipe we switched to a higher strength wire for fill and cap - Esab 101-H4M. It does have a bit of nickle in it, and also has a very low hydrogen count - allowed the preheat requirment with 8010 to be reduced quite a bit. It worked very well - not quite as nice to run in the overhead position, but the repair rate did not change, and all the welds passed RT.