Piping Material Pres

PIPING MATERIAL MODULAR 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 STEEL Solid 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 Nickel

: Increases resistance to Oxidation. : 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

ALLOYING ELEMENT

HARDNESS

STRENGTH

YIELD POINT

ELONGATION

IMPACT VALUE

ELASTICITY

HIGH TEMPERATURE STABLITY

COOLING RATE

CARBIDE FORMATION

RESISTANCE TO WEAR

FORGEABILITY

MACHINABILITY

SCALING

THE EFFECT OF ALLOYING ELEMENTS ON THE PROPERTIES OF STEEL

Silicon Manganese in perlit.steels Manganese in austenit.steels. Chromium Nickel in perlit.steels Nickel in austennit.steels Aluminum Tungsten Vanadium Cobalt Molybdenum Copper Sulphur Phosphorous

↑

↑

↑↑

↓

↓

↑↑↑

↑

↓

↓

↓↓↓

↓

↓

↓

↑

↑

↑

•

•

↑

•

↓

•

↓↓

↑

↓

•

↓↓↓ ↑↑

↑ ↑↑

↓ ↑↑

↑↑↑ ↓

– ↓

– ↑

– ↑

↓↓ ↓↓↓

– ↑↑

– ↑

↓↓↓ ↓

↓↓↓ –

↓↓ ↓↓↓

↑

↑

↑

•

•

–

↑

↓↓

–

↓↓

↓

↓

↓

↓↓ – ↑ ↑ ↑ ↑ ↑ – ↑

↑ – ↑ ↑ ↑ ↑ ↑ – ↑

↓ – ↑ ↑ ↑ ↑ ↑↑ – ↑

↑↑↑ – ↓ • ↓ ↓ • ↓ ↓

↑↑↑ ↓ • ↑ ↓ ↑ • ↓ ↓↓↓

– – – ↑ – – – – –

↑↑↑ – ↑↑↑ ↑↑ ↑↑ ↑↑ ↑ – –

↓↓ – ↓↓ ↓↓ ↑↑ ↓↓ – – –

– – ↑↑ ↑↑↑↑ – ↑↑↑ – – –

– – ↑↑↑ ↑↑ ↑↑↑ ↑↑ – – –

↓↓↓ ↓↓ ↓↓ ↑ ↓ ↓ ↓↓↓ ↓↓↓ ↓

↓↓↓ – ↓↓ – • ↓ • ↑↑↑ ↑↑

↓↓ ↓↓ ↓↓ ↓ ↓ ↑↑ • – –

↑=Increase

↓=Decrease

• = constant

- = not characteristic or unknown

Several arrows =more intensive effect

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, Fe Non Magnetic High Corrosion resistance at temp up to 1500F Hardenable by cold working Crystallographic form-Face centered Cubic lattice (fine grain structure) Possess high impact strength at low temp Ex: Type 304, 304L,316,316L

STAINLESS STEEL Ferritic SS:  Alloy of Cr, Fe  Magnetic  Non 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 cracking  Ex: 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 &347  Grain 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, 316L  Can be stress relieved, welded & cooled slowly without significantly increasing their susceptibility to IGC.

PROPERTIES OF STAINLESS STEEL ALLOYS

ALLOYS

UNS NO

UTS (PSI)

YS ( PSI)

Elongation (%) min

MODULUS OF HARDNESS ELASTICITY

1) Austenitic SS Type 304 Type 304L Type 316 Type 316 L

S S S S

30,400 30,403 31,600 31,603

75,000 70,000 75,000 70,000

30,000 25,000 30,000 25,000

30 35 30 35

29,000,000 29,000,000 28,000,000 28,000,000

80 RB 75 RB 80 RB 75 RB

2) Ferritic SS Type 430 Type 439 Type 409

S 43,000 S 43,035 S 40,900

60,000 60,000 55,000

30,000 30,000 30,000

20 20 20

29,000,000 29,000,000 29,000,000

85 RB 90 RB 85 RB

3) Duplex SS Alloy 2205 70 Mo Plus Alloy 255

S 31,805 S 32,950 S 32,550

90,000 90,000 1,10,000

65,000 70,000 80,000

25 20 15

29,000,000 29,000,000 30,500,000

30 RC 30 RC 32 RC

4) Martensitic SS Type 410 Type 420 Type 440L

S 41,000 S 42,000 S 44,050

1,90,000 1,50,000 2,40,000 2,00,000 2,80,000 2,70,000

15 5 2

29,000,000 29,000,000 29,000,000

41 RC 55 RC 60 RC

5) Precipitatim SS 17.7 PH 17.4 PH Custom 455

S 17,700 S 17,400 S 45,500

2,10,000 1,90,000 1,90,000 1,70,000 2,30,000 2,20,000

5 8 10

32,500,000 28,000,000 29,000,000

48 RC 45 RC 48 RC

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 Material A : Ferrous 312 : Manufacturing Process No. TP : Tubular Product 304 : Grade SA 234 GR WPB S : ASME approved Material A : Ferrous 234 : Manufacturing Process No. GR : Grade. WP : Wrought Product B : 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 corrosion crevice corrosion Stress 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. NACE MR-0175 standard presents metallic material requirements for resistance to sulfide stress cracking(SSC) for petroleum production,drilling,gathering,flowline equipment, and field processing facilities to be used in hydrogen sulfide (H2S)-bearing hydrocarbon services. 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

NACE NACE: 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 Criteria Service 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 SERVICE TEMPERATURE (°F)

C R Y O G E N I C T E M P

PLATE

PIPE

FORGING

SA 240 types 304, 304L, 347

SA 312 types 304,304L, 347

SA 182 grades F304, F304L, F347

SA 240 types 304, 340L, 316, 316L SA 353

SA 312 types 304, 304L, 316, 316L

SA 182 grades F304, F304L, F316

(-425) – (-321)

(-320) – (-151)

PRESSURE BOLTING

Bolts: SA 320 gr. B8 strain. Hardened Nuts: SA 194 gr.8 (S5 SA 20)

Material Selection for Temperature (Continued…) SERVICE TEMPERATURE (°F)

L O W T E M P E R A T U R E

PLATE

PIPE

FORGING

(-150) – (-76)

SA 203 GR.D OR E

SA 333 GR.3

SA 350 GR. LF3

(-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

(-20) – (+4)

SA 516 ALL GRADES OVER 1 IN. THICK IMPACT TESTED

(+5) – (+32)

SA 516 ALL GRADES OVER 1 IN. THICK IMPACT TESTED

SA 53 (SEAMLESS) OR SA 106

SA 350 GR. LF1 OR LF2

PRESSURE BOLTING

BOLTS: SA 320 GR.L7 NUTS: SA 194 GR.4

BOLTS: SA 193 GR.B7 NUTS: SA 194 GR.2H

Material Selection for Temperature (Continued…) SERVICE TEMPERATURE (°F)

I N T E R M E D I A T E T E M P

(+33) – (+60)

(+61) – (+775)

PLATE

PIPE

FORGING

SA 53 (SEAM LESS) OR SA 106

SA 181 GR.I OR II SA 105 GR.I OR 11

PRESSURE BOLTING

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 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

Bolts: SA 193 gr. B7 Nuts: SA 194 gr. 2H

Material Selection for Temperature (Continued…) SERVICE TEMPERATURE (°F) (+776) – (+875) E L E V A T E D T E M P E R A T U R E

PLATE

PIPE

SA 204 GR.B OR C

SA 335 GR.P1

(+876) – (+1000)

SA 387 GR.11 CL1 SA 387 GR.12 CL.1

SA 335 P11 SA 335 P12

(+1000)– (+1100)

SA 387 GR.22 CL1

SA 335 P22

FORGING SA 182 GR.F1

SA 182 GR. F11 SA 182 GR. F12

SA 182 GR.22

(+1100)– (+1500)

ABOVE +1500

SA 240 TYPES 304, 316, 321, 347, 347PREFERED

TYPE STAINLESS INCOLOY

310

SA 312 TYPES 304H, 316H, 312, 347H

PRESSURE BOLTING

SA 182 GRADES 304H, 316H, 321H, 347H

BOLTS: SA 193 GR.L7 NUTS: SA 194 GR.2H

SA 193 GR.B5 SA 194 GR.3

SA 193 GR.B8 SA 194 GR.8

GROUPING OF MATERIALS Base Metal P1 P3, P4,P5 P6, P7 P8 P9 P10, P11

Type : Carbon Steel : Alloy Steel : Ferritic & Martensitic Steel : Austenitic Stainless Steel : Nickel Steel : 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

FORGED FLANGES/ FITTINGS FASTNERS

A 105

A 182 GR F11

A 182 GR F 316

A 182 GR F 51 UNS S 31803

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

A 516 GR 70

A 387 GR 11

A 240 GR 316

A 240 UNS S 31803

PLATES