The sensitiveness of material for Hydrogen Cracking is tested by way
of standard corrosion tests. Most common are mentioned below.
1) Hydrogen-Induced Cracking (HIC) Test, NACE TM0284
to evaluate the resistance of pipeline and pressure vessel plate
steels to Hydrogen Inducted Cracking caused by hydrogen absorption
from aqueous sulfide corrosion. An unstressed test specimen is exposed
to a solution at ambient temperature and pressure and after a
specified time.
Number of pieces to be tested upto 88mm thick/dia - set of 3 pieces to
be tested
Number of pieces to be tested more than 88mm thick/dia - 5 pieces to
be tested
Test Solution
NACE TM0284 specifies either Solution A or Solution B. Solution A is
acidified brine. Solution B is simulated seawater prepared in
accordance with ASTM D1141.52. In either case, H2S is bubbled through
the solution constantly throughout the test period. NACE TM0284
specifies test duration of 96 hours.
Report
Each report should includes a description of the test sample that was
received, the test procedure that was used, and the pH values of the
test solution before exposure and after the exposure. The test bars
are cut into sections and examined under a microscope for hydrogen-
induced cracks. The dimensions of any such cracks are recorded and
used to compute the values in percentage for Crack Length Ratio (CLR),
Crack Thickness Ratio (CTR) and Crack Sensitivity Ratio (CSR).
2) Sulfide Stress Corrosion Cracking (SSC), NACE TM 0177
Sulfide stress corrosion cracking (SSC) is a form of hydrogen
embrittlement cracking which occurs when a susceptible material is
exposed to a corrosive environment containing water and H2S at a
critical level of applied or residual tensile stress.
NACE TM0177 Test Details
Method A: Tensile Test (Proof Rings)
Method B: Bent Beam Test (3 or 4 Point Bends)
NACE TM0177 specifies Solution A (acidified), Solution B (acidified
and buffered) and Solution C (for martensitic stainless steel).
Solution A is used in Methods A unless the properties of Solution B or
C are specified. In any case, H2S is bubbled through the solution
constantly throughout the test period.
Testing is performed in NACE solutions A and/or B, saturated with H2S
at 24º and 90º Celsius. Stressed samples are exposed to sour
environment for a pre-determined time, after which they are removed
and analyzed for crack detection. NACE TM0177 specifies test duration
of 30 days (720 hours) for Method A or B test.
Report
Report should include a description of the test sample that was
received and of the test procedure that was used, the pH values of the
test solution before and after the exposure, the results of the
hardness test performed on the test specimen and a statement declaring
the results of each test.
Hope this information is useful for you
On 21 jan, 17:01, ELAMARAN RAJAN <elams.ra...@gmail.com> wrote:
> Hi
> Can any body give me the notes of hydrogen induced cracking test
> how it will be measured
> regards
> --
> maran
--
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