PIPING MATERIALMODULAR FABRICATION YARD
PIPING MODULE – PART II
INTRODUCTION
Piping Materials can be classified as
Metals (ferrous) : CS, SS, Alloy Steel Metals (non-ferrous) : Cupro Nickel, Al Non-metals : PVC, cement, glass Materials are selected based on their mechanical
and metallurgical properties. Mechanical properties: strength, ductility,
hardness, brittleness, toughness Metallurgical properties: Chemical composition,
weldability
CARBON STEEL
Low Carbon Steel : C < 0.15%
Condenser Tubes : SA 179 Weldability : Excellent
Mild Steel : 0.15% < C < 0.30%
Pipes : SA 106 GR B
Weldability: Good
CARBON STEEL
Medium Carbon Steel : 0.3% < C < 0.5%
Machinery Parts
Weldability: Fair
High Carbon Steel : 0.5% < C < 1%
Dies & punch, Tools
Weldability: Poor Steel : Carbon < 2% Cast Iron : Carbon > 2%
Weldability As Carbon % increases , weldability decreases Effect of carbon & other elements on the weldability of
carbon steels can be estimated by equating them to an equivalent amount of carbon.
Carbon Equivalent:
Ceq = C + Mn/6 + Cr + Mo+ V + Cu + Ni
5 15 Killed Steel
During Steel making process oxygen present is removed by adding Silica (De oxidizing agent).
ALLOY STEEL Addition of elements such as Cromium, Nickel,
Molybdenum, Manganese, Silicon along with heat treatment improves the properties of steels such as mechanical strength, corrosion resistance, toughness
Steel is a ferrous alloy having main constituent Iron and other alloying elements / Impurities like Carbon, Manganese, Phosphorus, Sulfur, Silicon, Chromium, Nickel, Molybdenum
ALLOY STEELSolid solubility in ferrous alloys : Interstitial solid solution : Carbon with Iron forms interstitial solid solution(Carbon steel)Substitutional solid solution :Cromium and Nickel with iron forms Substitutional
solid solution (Stainless steel)
Low alloy steels :
Alloying elements < 5%
High alloy steels :
Alloying elements > 5%.
STAINLESS STEEL Alloy of iron with Cromium content more than
11% and less than 30% and other alloying elements Nickel, Molybdenum etc is called stainless steel.
Stainless steel has excellent resistant to corrosion.
Stainless steel becomes corrosion resistant (passive) because of formation of un-reactive film which adheres tightly to the surface of metal. This can be chromium oxide (Cr2O3) film that acts as a barrier protecting metal against corrosion.
EFFECT OF ALLOYING ELEMENTS
Chromium : Increases resistance to Oxidation.
Nickel : Increases resistance to mineral acid,
produces tightly adhering high temperature oxides.
Molybdenum: Increases resistance to chloride.
Copper : Increases resistance to sulphuric acid.
Titanium : Stabilize carbides to prevent formation of chromium carbide
Niobium: Stabilize carbides to prevent formation of chromium carbide
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S i l i c o n ↑ ↑ ↑ ↑ ↓ ↓ ↑ ↑ ↑ ↑ ↓ ↓ ↓ ↓ ↓ ↓ ↓ ↓M a n g a n e s e i n
p e r l i t . s t e e l s ↑ ↑ ↑ • • ↑ • ↓ • ↓ ↓ ↑ ↓ •M a n g a n e s e i n
a u s t e n i t . s t e e l s . ↓ ↓ ↓ ↑ ↓ ↑ ↑ ↑ – – – ↓ ↓ – – ↓ ↓ ↓ ↓ ↓ ↓ ↓ ↓C h r o m i u m ↑ ↑ ↑ ↑ ↑ ↑ ↓ ↓ ↑ ↑ ↓ ↓ ↓ ↑ ↑ ↑ ↓ – ↓ ↓ ↓
N i c k e l i n p e r l i t . s t e e l s ↑ ↑ ↑ • • – ↑ ↓ ↓ – ↓ ↓ ↓ ↓ ↓
N i c k e l i n a u s t e n n i t . s t e e l s ↓ ↓ ↑ ↓ ↑ ↑ ↑ ↑ ↑ ↑ – ↑ ↑ ↑ ↓ ↓ – – ↓ ↓ ↓ ↓ ↓ ↓ ↓ ↓
A l u m i n u m – – – – ↓ – – – – – ↓ ↓ – ↓ ↓ T u n g s t e n ↑ ↑ ↑ ↓ • – ↑ ↑ ↑ ↓ ↓ ↑ ↑ ↑ ↑ ↑ ↓ ↓ ↓ ↓ ↓ ↓V a n a d i u m ↑ ↑ ↑ • ↑ ↑ ↑ ↑ ↓ ↓ ↑ ↑ ↑ ↑ ↑ ↑ ↑ – ↓
C o b a l t ↑ ↑ ↑ ↓ ↓ – ↑ ↑ ↑ ↑ – ↑ ↑ ↑ ↓ • ↓M o l y b d e n u m ↑ ↑ ↑ ↓ ↑ – ↑ ↑ ↓ ↓ ↑ ↑ ↑ ↑ ↑ ↓ ↓ ↑ ↑
C o p p e r ↑ ↑ ↑ ↑ • • – ↑ – – – ↓ ↓ ↓ • •S u l p h u r – – – ↓ ↓ – – – – – ↓ ↓ ↓ ↑ ↑ ↑ –
P h o s p h o r o u s ↑ ↑ ↑ ↓ ↓ ↓ ↓ – – – – – ↓ ↑ ↑ –
T H E E F F E C T O F A L L O Y I N G E L E M E N T S O N T H E P R O P E R T I E S O F S T E E L
↑ = In c r e a s e ↓ = D e c r e a s e • = c o n s t a n t - = n o t c h a r a c t e r i s t i c o r u n k n o w n S e ve r a l a r r o w s = m o r e i n t e n s i ve e ffe c t
STAINLESS STEEL
Classification based on
1. Alloying Constituents
2. Metallurgical Microstructure
3. Degree of sensitization
STAINLESS STEEL
Alloying constituents
200 Series : Cr. Ni - Mn group
( Mn replaces a portion of Ni)
300 Series : Cr - Ni group
400 Series : Straight Chromium Group
( Cr < 30%)
STAINLESS STEEL
Metallurgical microstructure.
Austenitic SS: Alloy of Cr, Ni, FeNon MagneticHigh Corrosion resistance at temp up to 1500FHardenable by cold workingCrystallographic form-Face centered Cubic lattice
(fine grain structure)Possess high impact strength at low tempEx: Type 304, 304L,316,316L
STAINLESS STEEL
Ferritic SS:Alloy of Cr, Fe MagneticNon Hardenable by heat treatment Crystallographic form- Body centered cubic lattice
(coarse grain structure)For marine application. (10.5% Cr alloy with no nickel)Contains high carbon, therefore brittle & relatively poor
corrosion resistance Has resistance to chlorides stress corrosion crackingEx: Type 409, 430, 439
STAINLESS STEEL
Martensitic SS. High hardness (carbon added to the alloy) Corrosion resistant Heat treatable to high hardness level Crystallographic form-distorted lattice Type 410,420.
STAINLESS STEEL
Precipitation Hardened SS Magnetic Heat treatable to high strength. Weldable and corrosion resistant similar to type
304 Ex:-17-7PH, 17-4PH
STAINLESS STEEL
Duplex SS Contain both Austenite & Ferrite in microstructure. Ni (4 to
7%). When ferrite- Resistant to chloride stress corrosion cracking. When Austenite-Sensation to chloride stress corrosion
cracking. High strength, Good corrosion resistance Ex: Alloy 2205, Alloy 255
STAINLESS STEEL
3. Degree of sensitization of grain boundaries
GROUP 1
SS grade 304,316,309,310.They are susceptible to sensitization.
(During welding, flame cutting)
STAINLESS STEEL
GROUP 2
Stabilized stainless steel type 321 &347Grain boundaries sensitization eliminated by alloying
elements like Titanium or Columbium. (Because Titanium or Columbium forms carbides first).
Columbium (Type 347) is stronger stabilizing agent than Ti (Type 321), Hence Type 347 is superior to 321
STAINLESS STEEL
GROUP 3
Extra low carbon stainless steel Type 304L, 316LCan be stress relieved, welded & cooled slowly without
significantly increasing their susceptibility to IGC.
1 ) A u s t e n i t i c S ST y p e 3 0 4 S 3 0 , 4 0 0 7 5 , 0 0 0 3 0 , 0 0 0 3 0 2 9 , 0 0 0 , 0 0 0 8 0 R B
T y p e 3 0 4 L S 3 0 , 4 0 3 7 0 , 0 0 0 2 5 , 0 0 0 3 5 2 9 , 0 0 0 , 0 0 0 7 5 R BT y p e 3 1 6 S 3 1 , 6 0 0 7 5 , 0 0 0 3 0 , 0 0 0 3 0 2 8 , 0 0 0 , 0 0 0 8 0 R B
T y p e 3 1 6 L S 3 1 , 6 0 3 7 0 , 0 0 0 2 5 , 0 0 0 3 5 2 8 , 0 0 0 , 0 0 0 7 5 R B
2 ) F e r r i t i c S S T y p e 4 3 0 S 4 3 , 0 0 0 6 0 , 0 0 0 3 0 , 0 0 0 2 0 2 9 , 0 0 0 , 0 0 0 8 5 R B
T y p e 4 3 9 S 4 3 , 0 3 5 6 0 , 0 0 0 3 0 , 0 0 0 2 0 2 9 , 0 0 0 , 0 0 0 9 0 R BT y p e 4 0 9 S 4 0 , 9 0 0 5 5 , 0 0 0 3 0 , 0 0 0 2 0 2 9 , 0 0 0 , 0 0 0 8 5 R B
3 ) D u p l e x S S A l l o y 2 2 0 5 S 3 1 , 8 0 5 9 0 , 0 0 0 6 5 , 0 0 0 2 5 2 9 , 0 0 0 , 0 0 0 3 0 R C 7 0 M o P l u s S 3 2 , 9 5 0 9 0 , 0 0 0 7 0 , 0 0 0 2 0 2 9 , 0 0 0 , 0 0 0 3 0 R C
A l l o y 2 5 5 S 3 2 , 5 5 0 1 , 1 0 , 0 0 0 8 0 , 0 0 0 1 5 3 0 , 5 0 0 , 0 0 0 3 2 R C
4 ) M a r t e n s i t i c S ST y p e 4 1 0 S 4 1 , 0 0 0 1 , 9 0 , 0 0 0 1 , 5 0 , 0 0 0 1 5 2 9 , 0 0 0 , 0 0 0 4 1 R CT y p e 4 2 0 S 4 2 , 0 0 0 2 , 4 0 , 0 0 0 2 , 0 0 , 0 0 0 5 2 9 , 0 0 0 , 0 0 0 5 5 R C
T y p e 4 4 0 L S 4 4 , 0 5 0 2 , 8 0 , 0 0 0 2 , 7 0 , 0 0 0 2 2 9 , 0 0 0 , 0 0 0 6 0 R C
5 ) P r e c i p i t a t i m S S1 7 . 7 P H S 1 7 , 7 0 0 2 , 1 0 , 0 0 0 1 , 9 0 , 0 0 0 5 3 2 , 5 0 0 , 0 0 0 4 8 R C1 7 . 4 P H S 1 7 , 4 0 0 1 , 9 0 , 0 0 0 1 , 7 0 , 0 0 0 8 2 8 , 0 0 0 , 0 0 0 4 5 R C
C u s t o m 4 5 5 S 4 5 , 5 0 0 2 , 3 0 , 0 0 0 2 , 2 0 , 0 0 0 1 0 2 9 , 0 0 0 , 0 0 0 4 8 R C
A L L O Y S U N S N O H A R D N E S S
P R O P E R T IE S O F S T A IN L E S S S T E E L A L L O Y S
E l o n g a t i o n ( % ) m i n
Y S ( P S I )
U T S ( P S I )
M O D U L U S O F
E L A S T I C I T Y
ASTM / ASME Nomenclature
Materials are listed based on their known chemical composition, manufacturing processes, mechanical strength etc, in different codes i.e,ASTM, ASME, DIN, MSS etc, and common UNS number
ASTM Standard gives various details of materials like manufacturing process, Grades, Chemical Composition, and Mechanical Properties.
ASME Code accepts the ASTM materials with some additional specified properties.
ASTM / ASME Nomenclature
SA 312 TP 304 S : ASME approved MaterialA : Ferrous312 : Manufacturing Process No.TP : Tubular Product304 : GradeSA 234 GR WPB S : ASME approved MaterialA : Ferrous 234 : Manufacturing Process No.GR : Grade.WP : Wrought ProductB : Grade
ASTM / ASME Nomenclature SA 350 LF 2 : Low Temperature Forging Grade 2
SA 216 WCB : Weldable Casting Grade B
SA 335 P 11 : Pipe Grade 11
SA 182 Gr F11 : Forging Grade 11
SA 351 Gr CF 8: Centrifugal Cast, Carbon % - 0.08%
SA 351 Gr CF 3 : Centrifugal Cast, Carbon % - 0.03%
SA 351 Gr CF 8M : Centrifugal Cast, Carbon % - 0.08%, Mo
SA 351 Gr CF 3M : Centrifugal Cast, Carbon % - 0.03%, Mo
CORROSION
Corrosion is the tendency of any metal to return to its most stable thermodynamic state i.e. state with most negative free energy formation. . More simply stated, it is a chemical reaction of metal with environment to form an oxide, carbonate, sulphate or other stable compound.
Corrosion is broadly classified into two categories: Low temperature corrosion (corrosion at room
temperature and below)High temperature corrosion (corrosion at elevated
temperature including molten metal.)
CORROSION
Classification :
General or uniform corrosion. Localized Corrosion
Inter granular corrosion (IGC)Pitting corrosioncrevice corrosionStress corrosion cracking
Micro biological influenced corrosion.
INTER GRANULAR CORROSION During Welding:- ( at Temp. 800-1600 F ), Carbon
molecules diffuse to grain boundary & precipitate out of solid solution as chromium carbide at the grain boundaries. This result in the depletion of chromium content in the thin envelope surrounding each grain, Hence Stainless Steel becomes susceptible to Inter Granular Corrosion & is said to be sensitized.
Corrosion property of sensitized steel can be restored by desensitization i.e. heat above 1600 F, & rapid cooling.
Testing Standard: IGC Practice A/B/C/D/E
SULPHIDE STRESS CORROSION CRACKING
A cracking process that requires simultaneous action of corrodant and sustained tensile stress.
Testing Standard: NACE TM- 01/77 Reporting of test result: Curve shall be reported as
per NACE-TM-01-77 for various stress level between 72%and 90% of SMYS.
Acceptance Criteria: At 72 % SMYS, time of failure shall not be less than 720 hrs.
HYDROGEN INDUCED CRACKING
Hydrogen induced cracking (HIC) is also known as cold cracking, delayed cracking or under bead cracking
HIC occurs in piping or vessel as a result of hydrogen pick up in service
It occurs in steels during steel manufacturing, during fabrication, and in service. It occurs as a result of welding, the cracks are sited either in HAZ of parent material or in the weld metal it self.
Testing Standard: NACE TM- 02/84
NACENACE: National Association of Corrosion Engineers NACE Standard gives chemical composition, Manufacture,
Fabrication & testing Requirements for Steels intended to be used for Sour Service environment
Sour service Requirements Steel shall be manufactured by Basic Oxygen Process or Electric arc
furnace Steel to be Killed & fine grained Materials shall be in Normalized Condition Nickel % limited to < 1% Carbon content< 0 .23% Carbon Equivalent < 0.43% Hardness < 22 HRC Sulpher content< 0.002%
Material Selection CriteriaService media
Corrosive-sea water, H2S, Ammonia Non Corrosive
Temperature Cryogenic Low temperature Medium temperature High temperature
Pressure Low pressure High pressure
Standard Material specification Additional requirements
Economy Cost Availability Weldability Manufacturability
Material Selection for Temperature
SERVICETEMPERATURE (°F)
PLATE PIPE FORGINGPRESSURE BOLTING
CRYOGENIC
TEMP
(-425) – (-321)
SA 240 types304, 304L, 347
SA 312 types304,304L, 347
SA 182 grades F304, F304L, F347
Bolts: SA 320 gr. B8 strain. HardenedNuts: SA 194 gr.8 (S5 SA 20)
(-320) – (-151)
SA 240 types 304, 340L, 316, 316L SA 353
SA 312 types 304, 304L, 316, 316L
SA 182 grades F304, F304L, F316
Material Selection for Temperature (Continued…)
SERVICETEMPERATURE (°F)
PLATE PIPE FORGINGPRESSURE BOLTING
LOW
TEMPERATURE
(-150) – (-76) SA 203 GR.D OR E SA 333 GR.3 SA 350 GR. LF3
BOLTS: SA 320 GR.L7
NUTS: SA 194 GR.4
(-75) – (-51) SA 203 GR.A OR B SA 333 GR.3 SA 350 GR. LF3
(-50) – (-21) SA 516 ALL GRADES IMPACT TESTED
SA 333 GR.1
SA 350 GR. LF1 OR LF2
(-20) – (+4) SA 516 ALL GRADES OVER 1 IN. THICK IMPACT TESTED
SA 53 (SEAMLESS) OR
SA 106
BOLTS: SA 193 GR.B7
NUTS: SA 194 GR.2H(+5) – (+32) SA 516 ALL
GRADES OVER 1 IN. THICK IMPACT TESTED
Material Selection for Temperature (Continued…)
SERVICETEMPERATURE (°F)
PLATE PIPE FORGINGPRESSURE BOLTING
INTERMEDIATE
TEMP
(+33) – (+60)
SA 285 GR.C, ¾ IN. THK. MAX.SA 515 GR.55, 60, 65, 1.5IN. THK. MAX.SA 516 ALL GRADES, ALL THK.
SA 53 (SEAM LESS) OR SA
106
SA 181 GR.I OR II
SA 105 GR.I OR 11
Bolts: SA 193 gr.
B7Nuts: SA 194 gr.
2H
(+61) – (+775)
SA 285 GR.C, ¾ IN. THK. MAX.SA 515 GR.55, 60, 65, 1.5IN. THK. MAX.SA 516 ALL GRADES, ALL THK.SA 204 GR.B ALL
Material Selection for Temperature (Continued…)
SERVICETEMPERATURE (°F)
PLATE PIPE FORGINGPRESSURE BOLTING
ELEVATED
TEMPERATURE
(+776) – (+875) SA 204 GR.B OR C SA 335 GR.P1 SA 182 GR.F1
BOLTS: SA 193 GR.L7
NUTS: SA 194 GR.2H
(+876) – (+1000) SA 387 GR.11 CL1SA 387 GR.12 CL.1
SA 335 P11SA 335 P12
SA 182 GR. F11SA 182 GR. F12
(+1000)– (+1100) SA 387 GR.22 CL1 SA 335 P22
SA 182 GR.22
SA 193 GR.B5SA 194 GR.3
(+1100)– (+1500) SA 240 TYPES 304, 316, 321, 347, 347PREFERED
SA 312 TYPES 304H, 316H, 312,
347H
SA 182 GRADES
304H, 316H, 321H, 347H
SA 193 GR.B8SA 194 GR.8
ABOVE +1500 TYPE 310 STAINLESS INCOLOY
GROUPING OF MATERIALS
Base Metal Type
P1 : Carbon Steel
P3, P4,P5 : Alloy Steel
P6, P7 : Ferritic & Martensitic Steel
P8 : Austenitic Stainless Steel
P9 : Nickel Steel
P10, P11 : Quenched & Tempered Steel
MATERIAL AND ITS SPECIFICATIONS
DESCRIPTION CS AS SS DSS
PIPE A 106 GR B A 335 GR P11 A 312 TP 316 A 790 UNS S31803
BW FITTINGS A 234 GR WPB A 234 GR WP 11 A 403 WP 316 A 815 UNS S 31803
FORGEDFLANGES/FITTINGS
A 105 A 182 GR F11 A 182 GR F 316 A 182 GR F 51UNS S 31803
FASTNERS A 193 GR B7/A 194 GR 2H
A 193 GR B16/A 194 GR 2H
A 193 GR B7M/A 194 GR 2HM
A 453 GR 660 CL A
PLATES A 516 GR 70 A 387 GR 11 A 240 GR 316 A 240 UNS S 31803
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