Destructive and Non-destructive Material Testing
Presented by
Santosh Punaskar
Mumbai Refinery
April 2020
Contents
• Chemical Analysis
• Destructive Material Testing
Tensile test, Hardness test, Impact test, Flattening test, Flaring test, IGC, SSC, HIC,
Microstructure
• Non-destructive Material Testing
DPT, MPI, UT, ECT, RT
2
Chemical Analysis
Significance
• Determine chemical elements in the sample -
conformance to ASTM, NACE and other standards
• Resistance to corrosion, high temperature resistance,
toughness, resistance to SSC / HIC, IGC, etc.
• Failure investigations to establish whether the correct
alloy was used
Standards – ASTM / IS / ISO / API
Methods of Chemical Analysis
• XRF spectroscopy (X-Ray Fluorescence Spectroscopy)
• OES (optical emission spectroscopy)
3
Tensile Test
Standards : ASTM A370, B557, ASTM E8, ISO 6892-1, IS 1608
Significance
• Determine strength, ductility, elasticity, yield stress
• Confirm whether material meets design requirements
Testing: Universal Testing Machine (UTM)
Interpretation of tensile test results:
• Cup and cone fracture signifies ductile material
• Shear fracture indicates brittle material
4
5
Stress Strain Curve
6
Hardness Test
Hardness is resistance to scratch / indentation
Types of hardness
• Brinell
• Rockwell
• Vickers
• Shore – Rubber / Polymers
Significance
• Checking susceptibility to HIC / SSC
• Avoid brittle failure / cracking
• Evaluate effect of hot or cold working and heat
treatment
• Estimate other mechanical properties such as
tensile strength
Standards :
• Brinell – ASTM E10, Rockwell – ASTM E18
• Vickers – ASTM E384, Shore – ASTM E2240
7
Hardness Test
8
9
Impact test
It measures toughness.
Toughness is the ability of a material to absorb energy and
plastically deform without fracturing.
Measures the energy absorbed by material before
fracture.
Standards: ASTM A370, ASTM E23, EN10045-1, ISO 148
Significance:
• Resistance to low temperature environment
• Determine whether the material is brittle or
ductile in nature
• Study temperature-dependent brittle-ductile
transition
Types:
• Charpy V-Notch Impact test
• Izod Impact test 10
11
Creep Test
Creep: Elongation of material due to constant high load at constant high
temperature.
Creep can cause materials to fail at a stress below there tensile strength.
During creep testing, the tensile specimen is subjected to sufficiently high
load and temperature, to produce a time-dependent inelastic strain.
The strain in the specimen varies with time. For an appropriate constant
stress and elevated temperature, a strain time plot (creep curve) is drawn
Standards: ASTM E139, IS 3407-2, ISO 148
Significance:
• Determine resistance to stress at elevated temperature
• Failure analysis - study temperature and stress dependent
behavior of metals
12
Flattening test
• A section of tubing is flattened under a specific load using the
tensile machine.
• Then, a visual inspection is performed to see the damage
evident in the surface of the tube.
• If the observation consists of damage such as cracking or
orange-pealing, the specimen fails the test. If there is no
visible damage to the surface of the tube then, the specimen
passes.
Standards : ASTM A370
Significance
• Check the ultimate plastic deformation ability
of seamless steel pipes under the given compressed load
without crack defects.
• Check strength and ductility of welded tubes
13
Flaring Test
Method : A tapered mandrel is inserted into the sample to
expand by a 60°angle the mouth of the flare.
The samples must not have any visible cracks.
Standard: ASTM A370
Significance
• Determine the ductility of metal – useful for tube
expansion during installation
• Ductility of welded tubes
14
IGC Test
Definition:
Metals like stainless steels, DSS, SDSS contain elements such as
niobium and chromium, often integrated because of their natural
corrosion resistance. However, when a material is exposed to high
temperatures (550 to 850 deg cel) for long periods of time, a
process called sensitization may occur. Sensitization causes the
grain boundaries of a material to precipitate, creating carbide
deposits and causing the material to be susceptible to intergranular
attack.
Intergranular corrosion (IGC) is a selective attack in the vicinity of
the grain boundaries of a stainless steel. It is as a result of
chromium depletion, mainly due to the precipitation of chromium
carbides in the grain boundaries.
Standards: ASTM A262 Practice A/B/C/E/F
Significance
• Susceptibility to IGC cracking
• Check carbide precipitation at grain boundaries
15
SSC and HIC Test
• Sulfide Stress Cracking (SSC) is defined as cracking of metal under
the combined action of tensile stress and corrosion in the presence
of water and H2S.
• SSC is a form of hydrogen stress cracking resulting from absorption
of atomic hydrogen that is produced by the sulfide corrosion
process on the metal surface. Presence of H2S in aqueous solution
or hydrogen environment
• Hydrogen Induced Cracking (HIC) is a common form of wet H2S
cracking caused by the blistering of a metal due to a high
concentration of hydrogen.
Applicability: CS and alloy steel
Standards:
• NACE TM 0177 – SSC Test
• NACE TM 0284 – HIC Test
Significance
• Check susceptibility to SSC and HIC
• Conformance to NACE standards for sour service applications 16
NDT
DPT ECT MPI UT RT
Die Eddy
Ma gne tic Ultrasonic
Pe ne tra nt Curre nt Radiography
P article Insp Te sting
Te st te st
Conductive Magnetic
Appl i cabl e s ubs trate Al l metals Al l materi al Al l materi al
ma terial s materi al
Eddy current X-ray a bsorpti on
Utrasonic
Principle of opera ti on ca pillary effect and magneti c Magneti c flux due to variati on
wa ves
flux in densiti es
Defect/Issue
Cracks/Chips/Voids
Misse d Ope ra tions
Structural Inte grity
Product Lot Variation
Defect Location
Surface (Exte rna l)
Inte rna l
Brazing/Bo nding/W e lding
Speed/Training/Cost
Throughput
Training/Ce rtifica tion
Tota l Inspe ction Costs
Automation Capacity
Quantitative Re sults
Ea se of Automa tion
Cost of Automation
Legend - Excellent Fair Poor Animation Link 17
Thank you
18
