Clad thickness is 3mm and base metal is 10mm thk.
Regards
Subrata Das
-----Original Message-----
From: materials-welding@googlegroups.com
[mailto:materials-welding@googlegroups.com] On Behalf Of hpi001
Sent: Saturday, August 07, 2010 3:41 PM
To: Materials & Welding
Subject: [MW:6359] Re: Quarry on an Inspection requirement
Dear Mr. Das,
I'm not familiar with API 938-C but worked at a laboratory for 12
years where we executed such corrosion tests and I must say that we
often faced problems with testing duplex clad steel welds.
What is the thickness of your duplex clad? This because when you need
to execute a corrosion test according to ASTM A 923 practice C you
need to be sure that no carbon steel is included in the specimen
because this will increase your corrosion rate above the max. allowed
during the test . Also dilution from the carbon steel weld metal in
the duplex clad weld need to be minimized and/or excluded from the
test specimen.
See below for the aim of this corrosion test and test parameters.
Part of ASTM A923 - Method C:
14.1 This test method describes the procedure for conducting
the ferric chloride corrosion test for detecting the presence
of detrimental intermetallic phases in duplex stainless steels.
The presence or absence of corrosion attack in this test is not
necessarily a measure of the performance of the material in
other corrosive environments; in particular, it does not provide
a basis for predicting resistance to forms of corrosion not
associated with the precipitation of intermetallic phases.
19.4 Unless otherwise specified, the test temperature for
S32750 products shall be 40°C (104°F), maintained within an
accuracy of 61°C (2°F) during the test.
Regarding ferrite measurements the following: I assume that API
prescribes the method for determining the ferrite content, this can be
done by way of ferrite counting on the cross-section micro structure
or measuring the content by way of Magne Gauge or Ferritscope.
Normally for duplex stainless steels you need to determine the content
at the weld metal as well as the heat affected zone at both side of
the v-groove.
When a specification mentioned "All weld location shall be checked for
% ferrite measurement" in my opinion they meant that all production
welds need to be tested afterwards by methods like Ferritescope.
Hope this will help you a little bit further.
Best Regards,
Herman pieper
On 7 aug, 11:08, "subrata das" <s...@pkgroup.org> wrote:
> Dear Sir
>
> Can you guide about
>
> 1. Ferric chloride corrosion test as per ASTM A 923 Method C.
>
> 2. What are the additional tests applicable as per API 938-C for
> qualifying PQR.
>
> 3. Reference document for Cross section macro examination and
ferrite
> measurement.
>
> 4. What is the meaning of "All weld location shall be checked for %
> ferrite measurement"
>
> My Job description : Single 'V' Groove weld joint to be done between
Cladded
> plates. Cladded plates are Duplex SS UNS S32750 to SA516 Gr.70 ).
>
> Regards
>
> Subrata Das
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