Volume-2 Api510 Exam

~

i.,;l ~

t,;) ~

,;J

-.J ;,;)

VOLUME - II

~ ~

;,:,

.~ ~

STUDY OF CODES AND STANDARDS

~ ~ ~

1. ASME SEC. VIII Drv.1 Pressure Vessel code

~ ~ ~

2. API 510 Pressure Vesse! Inspection code

~ ~

3. API RP 572 Recommended

~

o o

,, ,,

Practice

4. API RP 576 Pressure Reliving Devices 5. ASME Sec. IX Welding Qualification Code

r> ~

,

r> ~

) )

I

I l ,

~ )

,

)

) )

• ~~I

- -.-

_L_ L•. _JI!!!!IIIHI _l

j ,._

•••• ~_~~~_

~ ~ ~

-

'W 'W

-

API -. 510 COURSE NOTES

W ~

VOLUME - I I

~ ~ ~ ~ ~

;;) I

::)\

.;) ~

o

o o o

:)

:>

o

/

~--

o ~

o

:> :> o ~

:> o

o ;:)

:> ~

,

::>

"'

:> ~

;)

:> ')

STUDY OF

ASME See, VIrI

Div, 1

::-----~---==.. ~

_._=__h_ .._

\) \) ~

STUDY OF ASME See. VIII Div. 1

~ ~

-.) ~ ~

CONTENTS

~

D

, :) ,,C ,, , :>

~

:> )

1.

AS~1E BOILER & PRESSURE VESSEL CODES

2.

INTRODUCTION TO ASME SECTION VIII DIV.

3.

MATERIAL OVERVIEW

4.

DESIGN

OF PRESSURE VESSEL

5.

FABRICATION

REQUIREMENTS

>

6.

INSPECTION

• )

7.

NDE OF PRESSURE VESSELS

•

8.

CODE STAMPING AND REPORTS

9.

TOPICS FROM ASME SEe. VIII ON. 1 FOR

)

•

,

& TESTING

NUMERICAL QUESTIONS IN API-SI0

EXAM

-

1.

ASME BOILER & PRESSURE VESSEL CODES

11 INTRODUCTION

ASME Codes give stipulations and guidelines for !he design, materials, manufacture and testing of pressure vessels. These are issued by the American Society of Mechanical Engineers, New York. The codes were first issued in 1915. Since then, many changes have been made and new sections added to the code as need arose. It is a LIVE code and is revised and updated periodically. It keeps pace with time and is responsive to its users.

2) CODE SYSTEM In its present from the ASME Code System is a follows: Section I Section Part Part Part Part

" Power Boilers.

II A B C D

Material specifications. Ferrous materials, Non Ferrous Materials Welding rods, electrodes, filler metals. Material properties.

Section 111 Nuclear Power Plant Components. Section IV

Heating Boilers.

Section V Non destructive

Examinations.

Section V/ Care and operation of Heating Boilers. Section V/I Rules for care of Power Boilers SecUo" VII/

Division 1 - Pressure Vessels Division 2 Alternative Ru!es ( Pr Vessel) Division 3 Rules fer constructive of High Pressure Vessels \fl'e/ding and Brazing Qualifications r--'~)er glass reinforced Plastic Prc:s::;urc \ '.':;sols

, ,':S for in I'

service; IfIspectlon

:iCI ;Jlan( COlflrOllcnts

,,'

r011Cli::21

-

~ ~ ~

,

~

3)

ISSUE

FREQUENCY

~

:

ASME

Issues complelely

new edilion

of all Sections

three years on 1" of .July of the year 01 issue.

-.;

was issued on : 1sl July 2001. Addenda issued on 1sl July every year.

~

Latest

aftor

edition

to the latest edition

are

2001 Edition with 2001 Add. _ 1sl July 2001 . st

. 2002 Addenda

- 1 July2002 .... (A 02)

2003 Addenda

1sl July 2003 ..... (A03)

A fully revised edition incorpOraling issued on 1sl July 2004.

4) APPLICABILl1Y

all above addenda

The editions and addenda become applicable

would

be

after six months

from date of issue. Thus, for 1" Jan. 2004 to 31 Jan,200A,

Ihe

construclion of Pressure Vessels shall be as per 2001 edition 1 and 200 +2002 addenda. However, for old C ;)

;) (

o :>

ii.

Manufacturer's: (a)

Compliance of all requirements (ie. Vendors)

of Code by himself, and by all others

(b) (c) (d)

Providing proper certification of materials and construction. Providing applicable design calculations. Establishing a mandatory Quality System.

Inspector's:

~

(a) (b) (c) (d) (e)

Monitoring quality control. Verification of design calculations. Conducting specified inspections. Code stamping. Certification.

l) :>

Code

Composition:

D

:)

~

)

)

The code content is organised in 3 sub-sections i) Sub-section A - General Requirements

)

ii) Iii) IV) v)

~

General

)(

) ) ) )

i

Sub-section B - Requirements Sub-section C - Requirements Mandatory Appendices Non-Mandatory Appendices

and two Appendices

as follows:-

pertaining to methods of fabrication pertaining toclasses of materials

Requirements:

Desiqn The User shall assure vessel.

will be suitable

penar'mance,

retention

hiniself

that the design.

for Intended of satisfactory

(jetC:'flOratlon during t:le vessel's

service,

matprial

with respect

mechanical

Illtended

and constn.ictioll

properties,

service life

/.1.,

to s8fety,

of the intended

and protected

relatively

from

111gh"factor

of

j-~

•

--.--.'- ..

-.,

--"-

---...-.. ~ ,

)

)

~ ~

safety" (previously 4, prQ~ently 3.:5) is ddQr.:.~(.;

)

;.::' :.a'-l.ecare of the incidental

material abuse: during construction and serviCE:. > )

)

General Principle: .

A vessel may be manufactured by any process which shall not unduly impair the inherent material properties or jeopardize tl1e safe, reliable and optimum performance of the vessel.

Methods of fabrication: requirements are Getailed in subsection B UW for welded vessels UF for forged vessels UB for brazed vessels ULW for layered construction [Alternative Rules] ReqUirements based on materials:

(

Requirements based on materials adopte-J and other specifications are referred to in the following clauses of

subsection C of the ASME Code Section VIII

Divn.1. The stress values have been tabulated in the Part '0' of Section II. UCS UH.~ UNF UCL

-

for for for for

Carbon and low alloy stecis high alloy (stainless) steels non-ferrous materials clad materials

/

UHT for high tensile, heat treated Ferritic Steels (such as Q & T) UCI & UCO - for Cast Iron & Cast Ductile Iron Steels. UL T for low temperature appliC3tion using materiais of higher permissible stress values

(

MATERIAL OVERVIEW

3.

COMMON ASTM SrECS. FOR C.S. PLATES

Sr No

Plate Spec.

Composition % C

')

L

(

3

4

(max)

P (max)

S (max)

A36

0.26

0.04

A283Grc

0.24

A285Grc

A515Gr60 Gr70

5

A516Gr60 Gr70

Remarks:

( l

Si

En~~. properties Mn

T.S.

Y.S.

Elog

(x1000 psi)

(x1000 psi)

0/0

0.05

58 - 80

36

20

0.04

0.05

55 - 65

30

25

0.28

0.035

0.045

0.90' (max)

55 - 75

30

28

0.24

0.035

0.04

0.15 0.30

0.90' (max)

60 - 80

32

25

0.31

0.035

0.04

0.15 0.30

0.90' (max)

70 - 90

38

21

0.21

0.035

0.04

0.15 0.30

0.8 1.25

fiO - 80

32

25

0.27

0.035

0.04

0.15 0.30

0.8 -

70 - 90

38

21

1.25

-

Structural

Quality

Plates

& Shapes.

Structural

Steel for Bending

,.., /

Plates

may be ordered

I Forming

(Low & Med

as rolled or norm

T. S )

(P V plates, Low & Med. T. S)

Plates >= 2" thk Must be normalized for < 2" purchaser's (P V plates, High & Med Temp service)

option

f'lates >= 15" ttlk Must be normailled for < 1 5" purchaser's V plates, Moderate & Low Temp service)

W

. ',)ptlonal

If present,

not to excecc1 spcclflerJ

Illaximum

option

~ ~ ~ ~

.

~

SELECTION OF CARBON & ALLOY STEELS SERVICE TEMPERATURE

~

BASED ON

~ !~

STEEL TYPE ~

SPECIFICA TIONS

i;) MODERATE

0

1.

TEMP.

C - Steels

SA 285 grC (3/4 in. thk max)

0 0

SA 516 All Grades

0

.ELEVATED

:"

2.

(

3.

C - 1/2 Mo

SA 204 gr 8, C

C - 5/4 Mn - 1/2 Mo

4.

1/2 Cr - 1/2 Mo

~

SA 302 gr 8 SA 387 gr 2 1000 (max)

,, , ,

5.

~

1Cr - 1/2 Mo

SA 387 gr 12 1100 (max)

6.

5/4 Cr-

1/2 Mo - Si

SA 387 gr 11 1150 (max)

7.

9/4 Cr - 1 Mo

,,

SA 387 gr 22 1200 (max)

~

LOW TEMP 8.

C - Steel (F. G.)

~ ~

,

9.

, ~ ~

5/4 Ni Steels

10

7/2 Ni Steels

~RYOGENIC 11

SA 516 A.II Grades (Impact tested) SA 203 gr A or 8

(

~ ~

875 (max) 875 (max)

~

~

775 (max)

TEMP

~

~

600 (max)

SA 515 All Grades

~

~

TYPICAL TEMP. LIMIT (DEG. F)

SA 203 gr C or 0

( -50 )

( -90 )

( -150 )

TEMP

9 Nr Steel

SA 353 ( -320 )

p

:'c;s:cnilrc

SS S/\ 240 Type 304.3041,347

( -425 )

~

o

~

.,

ill '"

~

••.,

MA TERIAL REQUIREMENTS:

•• •• ••... 1/

"-

••

•..

GENERAL: 1.

Material

subject

to stress due to pressure

of ttle specifications

(i.e. pressure

given in ASME Code Section

are permitted

in the applicable

2

Specifications

parts) shall conform

to one

II, ,md shall be limited to those that

Part (such as UCS,UNF,UHT

etc.) of the subsection

C.

rI

•.. rI

••~ ••, ',"I

,

Permitted

Rods

for Plates, Forqinqs,

and Bars are covered

and SB for nonferrous

"

\Nith

~

,(

Manufacturer,

~

material

Certified

complied

3.

ilot

identified

permitted

issued

by

by a suffix SA for ferrous

Materials

Steel

all requirements

material Properties

where

certificate

or not recognized

are to be identified

I Raw

I Product

Material

of the Specification

and grade are

as required by the relevant

markings

specifications.

markings

is not available,

can be ascertained

or is certified

Sect. VIII Div I, may bs accepted

out on representative

allowable

as

to a Specification

sample/s

provide'd

and satisfy

In such cases Vessel or part manufacturer

to the Specification

specifications

identification

by ASME

I tests are carried

The maximum

Code

needs to re-certify

and grade, based on the findings.

stress

and grades

values

for different

are stipulated

service

in ASME

temperatures Code

Section

for these II Part D _

of Materials.

Permitted

Section

respectively.

with identification

materials,

but material

analyses

the material

5.

Fasteners,

specification.

appr'oved

4

Certificates

with, before correlating

authentic,

check

Test

These are designated

materials

and verified whether

"Partially"

being

Mill

Pipes & Tubes,

in the ASME Code Section II Part A (for ferTous materials)

& Part 8 (for non- ferrous materials). materials,

Castinas,

Specifications

II Pari C

These

for Weldinq

specifications

S:::.:\ or SFl3 for sUltat)le classification

G. Preforned

or Prefabricated

ConsumaQles

are give:l

are covered

a designation

by ASME

number

Code

with a suffi\:

and grading

Pressure

Paris when made

by otttcr

litcHI tile=:pressure

:0

Form

U2. with .For welding

containers

or packages,

be accepted

7.

query

or tagging

jf done as per the app.licable Consumable

for pr.vessels

Requirements

(Section

are discussed

one should refer to applicable General Material

a)

(

tht: marking

may

viii

Div.1 stipulations)

here for understanding

purpose

only. For specific

code book and addenda.

Requirements types

Compatible

Product

welding Consumables

( ASME Section

Plates Castings Forgings

d) e)

Pipes & Tubes (SA 106/312) (SA 179/213) I=asteners (SA 193/194/307)

f)

(SA 515/516/240/285) (SA 216/351/217/352) (SA 181/105/182 etc.)

Bars & Shapes (Sections)

Max. Allowable MASVs

at

specification

Stress Values

various

I;:, sed

provlderj Ofl

SA 36/283/479

(MASVs):

service

temperatures

for

each

acceptable

material

are given in ASME Section 11- Part D.

f~or vessels designed Deg F is used

IS

II Part C )

Forms and Typical Specifications

a) b) c)

"lith

Specification,

Steel & Low Alloy Steels with max. 0.35% Camon High alloy steels ( stainless steels and alloys) Non ferrous (AI, Cu, Ni, Cu Ni, Ni Cu etc.)

b) c) d)

TillS

of the materials,

in lieu of Certified Test report.

Materials

General

con~urnabl"f.,

to operate

at low temperature,

over and above tile thicknesses

service experience

V(~ss('1 dimensions

All design

in corroded

generally

calculated

calculations

the MASV at 100

for pressure

are required

vessels,

to be made

condition

,,

, ,

Use of Structural Steels for pre$su,-e parts (Typica!ly. SA 36/ SA 283 ) a)

b)

Limitations: i)

not pennitted for lethal service

ii)

should not be used for unfired steam boilers

iii)

Design temperature only (-) 20 Deg.F. to (+) 650 Deg.F.

iv)

for thicknesses below 5/8" (160101) only

Testinq: Each plate to check test for chemistry and physical properties. ( Tensile strength, Y.S., % Elongation and severe Bend test as per SA-6 requirements ).

a.Check Tests for materials used for pressure parts

( a)

Check test allowed only in the case of partial identification:

b)

Check test requirements :Each piece is tested for chemical properties. Acceptance

composition

& mechanical

criteria as per pemlitted specification

for

which the material is being qualified. Cast, forqed, rolled and die-formed pressure parts: These shall be made from materials of permitted specifications; meeUor be suitable for design conditions of completed vessel.

and should

NOT [RT/PT/MT]

and Heat treatment (Nonn/SR) as applicable must be conducted prior to its release for attachment to the pressure vessel. Partial data report (form U2)

(

needs to be issued for such components.

in ev:dence of code compliance.

f\rUJlundertolerance a)

Plates with 0.01 inch or 6% under tolerance (whichever is smaller) may be used for full desigr. ~ressure, However If material specification

o

allows greater under tolerance

(eg

3mm for a 10mm thick plate), then ordered thickness for the matenal

SllOlilcJ

IlC

suffiCiently 0.006L) t,

==

P x L x M / (2SE - O.2P) or P == SEt / (LM + O.2t)

where L M

==

==

inside spherical crown radius 1/4

x [3 .r

Limitations

+ (L / ==

r ) 1/2

is the inside knuckle radius in inches.

Knuckle radius shall nol be less than 6% of inside crown radius [ Ri ], nor less than three times knuckle thickness.

c) 14)

For Hemispherical Heads:

Ri shall be less than Do.

The formula Hemispherical shell can be adopted

,LQintEfficiencies Joint

Efficiency

'E' referred to above are chaned out in T2ble UW-12 as

:opplicable to weld jOints completed by an arc or' gas welding process. Joint efficiency

depends on Ihe Iype of joint and on Ihe degree of radiography

-2Xamlnatlon of the jOint. Table UV"'~2 of ASME Code See. Viii Div. 1 details !Olnl deSCriPtion, IIOlilations, JOint categories and degree 01 rOdiography ·::examination for each type number [Type 1 to Type 6 ) of the \','eld seam. Fig .':'/V·3

S110\'/S

weld

jOint

locations of Categories A, G, C & D

-----.- ....--_ .. _h __ ._. ._._....~

15)

Formed Heac.s, Pressure on Convex Side, The

required

tori spherical thicknesses a)

thickness

at the thinnest

or hermispherical

heads

point after shall be

forming

greater

of

of ellipsoidal, the

following

The thickness as computed for heads with pressure on the concave side as given in (13) above, and,

b)

16)

Thickness as computed by the procedure given in UG-28 and Mandatory Appendix-5 for Heads.

Minimum Thickness of Unstayed Flat Heads and Covers: t,

,

=

0

x [ CP I SE ]

112

~

= a factor depending upon the method of attachment o = Inside diameter of shell inches.

where C

'( )

The above

)

attachments. incorporated.

) )

formula is applicable

17)

Extra moments

to both welded

applied to the cover

of the flat head

and bolted by bolting,

methods

of

are to be

Openinqs in Pressure Vessels:

)

a)

•

Shape of the openings:

Openings in cylindrical and conical portions of"

vessels, or in formed heads, shall preferably be circular, elliptical or

>

obround. Openings of other shapes shall be provided with a suitable radius at all comers. b)

Size of the openinqs : Properiy reinforced openings, in cylindrical shells of diameter of upto 60 inches, shall not exceed half the vessel diameter, and in any case not over 20 inches. For vessel diameter of over 60 inches, the openings

shall not exceed 1/3rd the vessel diameter and in no case

eXceed 40 inches. For larger openings, supplemental rules apply. 18)

~nforcement a)

of Openirlqs :

Beinfo~ent

required f~in!:]sifls!lell~_§ ~ ~

21 )

b)

for shell side of fixed tube heataxchangers;

c)

other exceptions are detailed in ~G-46 C, 0 & E.

d)

for sizes of mandatory inspection openings: see UG-46F.

Permissible Out-Of Roundness for Shells and Formed Heads:

.;> ;)

a)

~

b)

,,( )

For internal pressure, (Oi Max - Oi Min) divided by Oi Nom = 1% Max. For external pressure, Refer Fig.UG-80.1 : Max. plus/minus deviation' e', from true circular form, shall be between 0.020 t to 1.0 t, as plotted on the

~

:> :>

.

c)

curves with Do / t on Y axis a,nctu Do on X axis, where L = design length. Heads: out of profile + 1 1/40/ _ 5/8 0 for Hemispherical Head, use L=0.50 in the ratio UOo.

Welded Joint Efficiency Values (UW -12)

) ) ) )

Type of joint and radiography

)

Efficiency allowed percent

)

1) Double-welded butt joints (Type 1)

(

Fully radiographed Spot-radiographed No radiograph

100

85 70

2) Single-welded butt joints (backing st;-ip left in place) (Type 2) Fully radiographed Spot-radiographed No radi8gr2ph 3) Slr1gle-welded butt jOints (Type 3)

90 80 65

b .__ ._ ~ ~ ~

5.

~

FABRICATION REQUIREMENTS

~

1. GENERAL (UW - 26)

(a) The rules in the following paragraphs apply specifically to the fabrication of pressure vessels and vessel parts that are fabricated by welding. These shall be used in conjunction with the general requirements for Fabrication

in

Subsection

In

A, and with

the specific

requirements

for

Fabrication

Subsection C that pertain to the class of material used. (b) Each Manufacturer or parts Manufacturer shall be responsible for the quality of the welding done by his organization. He shall conduct tests not only of the welding procedure to determine its sUitability to ensure welds 'Nhich will meet the required

tests, but also of the welders and welding

operators

to

determine their ability to apply the procedure properiy. ~ . (c) No production welding shall be undertaken until after the welding procedures which are to be used ,have been qualified. Only welders and welding operators who are qualified in accordance with Section IX shan be used in Production. (d) Welders not in the employ of the Manufacturer (Certificate of Authorizatr;~ Holders)

may

be used to fabricate

pressure

vessels

constructed

in

accordance with this Division, provided all the following conditions are met.

(1)

All COde construction shall be the responsibility of the Manufacturer.

(2)

All welciing shall be performed in accordance with the Manufacturer's welding

procedure

specifications

vvhich have been qualified

by the

Manufacturer in accordance with the requirements of Section IX. (3)

4 ( )

All welders shall be qualified by the Manufacturer in aCQxdance with the requirements of Section IX. The Manuf8cturer's Quality Controi Sysiern shall include as a minimum: (0)

a reqlcirement for complete and exclusive administrative and technical supervision of all welders by the Manufacturer;

(I))

evidence of the Manufacturer's authority to assign and remove welders at his discretio:l without involvc:rnr:nt of

211y

other or!C3ni?3!i n,: r

73

. ~

'-> ')..l ~

'->

(c)

a requirement for Assignment of Welder Identification sy1!111bQts:

(d)

evidence that this pro~ram has been accepted by the Manufacturer's

,.~

Authorized Inspection Agency which provides the inspection service. (5)

"~

.

The Manufacturer shall be responsible for Code compliance of the vessel

..,)

or part, including Code Symbol stamping and providing Data Report

~

Forms propeny executed and countersigned by the Inspector.

;;.)

;;,

2. QUALIFICATION OF WELDING PROCEDURE (UW-28)

~

::;

(a)

;;J

;:,

Each procedure of welding that is to be followed in construction shall be recorded in detail by the manufacturer.

(b)

The procedure used in welding pressure parts and in joining load-carrying

~

nonpressure parts, such as all permanent or temporary clips and lugs, to

~

pressure palis shall be qualified in accordance with Section IX.

,r

,,

~

,

(c)

have essentially no load~carrying function (such as extended heat transfer surfaces, insulation support pins, etc.), to pressure parts shall meet the

:>

following requirements. (1) When the welding process is manual, machine, or semiautomatic, procedufE~/

:> )

The 'procedure used in welding non pressure-bearing attachments which

qualification is required in accordance with Section IX. (2) When

)

the

accordance

• I

is any

automatic

(d)

welding

process

with a Welding Procedure Specification

Section IX as far as applicable), required .

•

l(

welding

performed

in

(in compliance with

procedure qualification

testing is not

Welding of all tes~ coupons shall be conducted by the Manufacturer. Testing of all test coupons shall be the responsibility of the Manufacturer. Qualification of

2

welding procedure by one Manufacturer shall not qualify

that procedure by one Manufacturer except as provided in QW - 201 of Section IX

IC"

3. FORMING SHELL SECTIONS AND HEADS: Thr: following

~

•

Carbon

C)

Vessel

provisions

shall apply in addition

to the general

rules for fanning

UG-79,-

and low alloy steel plates shall not be formed cold by blows.

~ ~

shell sections,

heads, and other pressure

:')

alloy steel plates fabricated

~

the resulting

~

and any of the following

extreme

boundary

parts of carbon

and low

by cold forming shall be heat treated subsquently

fiber elongation conditions

is more than 5% fonn the as-rolled

when

condition

exist.

~ ~ ~

~C

(1) The vessel

will contain

(2) The material

requires

(3) The thickness , (4) The reduction

~

either liquid or gaseous

(see UW-2).

impact testing.

of the part before cold fonning exceeds by cold forming from the as-rolled

(5) The temperature

~

lethal substances

of the material

5/8 in. (16 mm).

thickness

is more than 10%.

during forming is in the range of 2500F to 9000F (

121°C to 482°C).

'~

~ The extreme

~

fiber elongation

shall be detennined

by the following fonnulas

:

~ For double curvature

~

(for example,

heads),

=

% extreme fiber elongation

~

(75t1R) (1 - Rtr)

~ for single curvature

~

(for example,

cylinders),

% extreme fiber elongation

.~

= 50

tlR) ( 1 - Rtr)

Wtiere.

'~ T = plate thickness,

i~

Rr = final center line radius in.

i~

.,

J~

.

in.

R = original VVhen 'lesser

center line radius (equals infinity for flat plate), in

shell sections,

heads, or other pressure

boundary

alloj' steel plate are cold formed by other than the Manufacturer

'~

,"'

rCOurr8d cerLlfication

for tll8 pari sllalllndlcate

paris of canJon or low of the vessel,

wllCther or not the pari

tldS

the

been heat

J"

,

"j

'3 ') '.

;~

~

(~

J

4. GENERAL PRECAUTiUj\lS IN FABRICATION I.

Structural discontinuities

should be avoided. Square comers

of pads

should be fOunded off before fitment and welding . Unweldeci faces offlame cut edges should be ground smooth and sharp edges ground round. ii.

Welding of minor items direct to structural and pressure parts should be avoided. Use of intermediate I doubling pad is preferred.

III. IV.

Toes and brackets and ends of stiffeners should land on stiffened plating Fillet welds should be carried around attachments to avoid points of stress concentration.

v.

Weld sequence

should

be planned

before

hand. Welding

should

progress towards free edges all the time to avoid shrinkage stresses. VI.

(

Back step welding, s~ )

) )

•

~ )

f~Oi tilIC-,S

',0,:1)' llsed

materials given beIIJ'.'.',PWIIT !lccomcs 111211-::::,01\ above nominal

flW/l(:O!1ceJ

below

For carbon steels, nominal t~ickness above 31.i'5mm

For low alloy steels ot grades 1 Cr 1/2 Mo, 2 1/2 (.r.-1 Mo etc., at nomin~l_ thickness above 16mm, and for grades such as 5 Cr. 1/2 Mo and 9 Cr. 1 Mo. PWHT is required for all thicknesses.

For austenitic stainless nor prohibited.

For non-ferrous

steels [Type 304,316, etc.] PWHT is neither required

materials,

PWHT is normally not necessary nor desirable,

except for alloys like CDA-954, Zirconium grace R60705 alloy N08800, etc. For UHT materials (territic steels with enhanced tensile properties], PWHT is required tor all thicknesses.

TABLE UCS - 56 POSTI'JELD HEAT TREA Trv,ENT REQUIREMENTS FOR CARBON AND LOW ALLOY STEERLS

I Normal I

I

Material

Minimum Holding Time at Normal Temperature For Nominal Thickness [See UW - 40(f)]

Holding Temperature, OF, Minimum

Up to 2 in Over 2 in to 5 ir 1 hrlin., 15. 2 hr plus 15 min minimum mln for each additional inch lover 2 in None None

P - No. 1 11100 Gr. Nos. 1, 2, 3 Gr. NO.4

NA

'"

Over 5 in 2 hr plus 15 min for each additional inch over 2 in -~~one

NOTES:

(1)

When it is impractical to postv.'eld heat treat at the temperature specifi~d in this Table,

it

IS

permissible

to carry out the postv,teld heat treatment

temperature for longer periOds of time in accordance (.

Post\'/eld ilcat treatmcnt (e')

for welcjed Joints over

IS

Wltll

at lowe,

T;Jble UCS _ 5G 1

rnanciatory under the following condltlollS .

1 1/)

III

flOrninal tllickness

- I

(b) for welded joints over 1 1/4 in nominal thickness through 1 1/2 in nominal. thickness unless preheat is applied at a minimum temperature of 2000 F during welding.

(c) for welded joints of all thickness if required by UW _ 2, except postweld heat treatment is not mandatory under the conditions specified below:

for groove welds not over 1/2 in size and fillet welds with a throat not over 1/2 in that attach nozzle connections that have a finished inside diameter not greater than 2 in.

(

Nominal

thickness

is defined in clause No. UW-40(f) of ASME Code Section Viii

Div.1. For pressure vessels or parts thereof, it is the greatest weld thickness of the equipment or part of the equipment which has not been previously post weld heat treated.

Thus, the nominal thicknesses in the following cases are: 1.

In a full penetration weld joining materials of same thickness, it is a total depth of the weld, exclusive of any permitted weld reinforcement.

2.

In groove welds, norn;nal thickness is the depth of the groove

3.

In a groove and fillet type of weldment, nominal thickness is the depth of the groove, or the throat thickness of the fillet, whichever is greater.

(

4

In a fillet weld, nominal thickness is Its throat dimension.

S

!n stud welds, nom. thickness is the diameter of the stud.

6.

When parts of unequal thicknesses thickness is,

are Joined together,

then the nomin2!

· thinner of the adjacent parts butt welded. · the thickness of the shell in a corner joint · th~ de~th of actual \,/cldment acros~ the nozz:e neck, includlrlg througll the r"ernforcement pa(j " tl18 thickness of tile n~nl.le fleck

butt welded to a Weld Neck FIClnge

:

/

Q-..--.~ ~

\)

\) lW

W ~

Operation

Of PWHT

The PWHT can be r:-presented as a time and temperature cycle, recordf'd on a chart. The heating and cooling rates as well as the soaking temperature and its holding time are important, and are specified in the Tables above.

-..) ~

=»

PWHT

should be performed preferably by heating the equipment as a whole in an

enclosed

furnace. The equipment may be heated in more than one heat in a furnace,

;)

with an ovenap of atlas 5 feet of the heated sections of the vessel shall be provided. At

:)

the same time, the portion outside the furnace shall be shielded in such a manner that

~

temperature gradients are not harmful.

:)

Local postweld heat treatment , for example, of a heavy section, or a circumferential

)

seam individually, may also be done in more than two or three heats, provided the

,

from likely harmful temperature gradients. In such cases, the heated band on either

)

side of the locally heat treated area shall be atleast twice the thickness of the shell.

r>

For carbon

'J(

~ )

heating is done uniformly and the portion outside the heated band is suitably protected

Deg.C.per

and low alloy st-2-2!s, the maximum heating rate is specified

as 200

hour per inch ~~:·:·~-~ss. ·...~i!e the maximum cooling rate allowed, after the

soaking period, is 278 Deg.C

C-2~

hour per inch thickness.

/

)

)

The maximum loading and unloading temperatures should preferably be 300 Deg.C., to

)

avoid thermal shock, though a temperature upto 400 Deg.C. is allowed by the Code.

)

The minimum holding temperature,

or what is known as the soaking temperature,

~

varies for different types of materials, designated by ~p Numbers in ASME Code. For

~(

carbon steels the minimum soaking temperature is 593 Deg C. For low alloy steels the

•

soaking temperatures ranges from 630 to 720 Deg C, depending upon the content of Cr & Mo

The spatial variation in holding temperature

during soaking period in a furnace or

heating chamber, should not be more than 30 degrees betwepn the highest and lowest temperature, throughout the portion of the equipment being heated. The Code however allo\\'s a difference of upto 83 Deg C

p----. -..'-'--"-

P

b \

~

-

~

During

~

controlled,

.)

~:'~atl"lg ::;nd ho:r!in~; periods

t~18

as to avoid

reducing

~

prevent

~

Benefits

atmospheres

excessive

the

oxidation

are recommended.

direct flame impingement

fumace

atmosphere

of the vessel Bumer

~hOLiid bE: ~~)

ski'n surface.

locations

should

Neutral

or

be designed

to

on vessel surface.

of PWHT

i) ~

1.

;)

Stress Relief:

Relieving of locked

up stresses in weldments, dispersal of peaks &

valleys of stress levels homogeneously in a welded structure, and affording dimensional stability.

it a

) ) ) )

2.

Tempering: Softening hard zones, such as at HAl and in cold formed components

3.

Providing

escape route 10 nascent Hvdroaen entrapped

in welds, thus preclUding

possibility of underbead cracking. All of the above assure a safe and reliable welded equipment.

~ ~

Summary

~

All carbon-and

• •

Ihickness

of Postweld

Heat Treatment

lOW-alloy steel seams

eXceeds

Some materials

Requirement

must be postweld

1 1/4 in or 1 1/2 in if preheated

must be postwe!d heat-treated

•

Vessels

I

Unfired steam bailers

containing

lethal substances

at lower thickness.

must be postweld

High-alloy

heat-treated:

(oP more than 50 psig)

For welder vessels the details of PWHT describe in fOllOWing table of the code. and low-alloy

if nominal

to 200' F before welding.

Carbon-steel vessels for service at lowered temperature treated unless exempted from impact test.

earbon-

heat-treated

steel vessels

must be posrNeid

temperature

ueS-56,

and hOlding

UCS-66,

UeS-67,

Al;oWdble

working

time

heat'

are

UeS-79,

UeS··85

steel vessels

UHA-32 3. PRESSURE

TESTING

A) HYdrostatic Tesl

mUsl

OF VESSELS:

Test

be al leasl

1 3 limes

Ihe maximum

multiplied by the lov;est ratio of the stress value for the test temperature for the design ternperature

pressure to that

rw' ~

t"

-

[\)

If the allowable sircs$ at design lerr.i)erature is less than the allowable stress at

\i \)

test temperature the hydros;tatic test pressure must be increased proportionally.

\)

Test pro = 1.3 x MAWPX

'"

Allow.stress at test temp. AlIow.stress at design temp.

~

\)

Inspection must be made at a pressure not less than Test pr.divided by 1.3.

\)

Corrosion

~

allowance

may be considered

in calculating

test pressure.

The

maximum allowable working pressure may be assumed to be the same as the

~.

-3 ~

.> :»

design pressure when calculations are not made to determine the maximum allowable working pressure. Max.lnspection temp. = 120 dec F,.

Test gauge range limit = 1.5X Test Pr: = 4X Test Pro

3( ~

:)

:) :) )

)

Min. Test temp.= MDMT+30 deg.F

B) Pneumatic

,.

(Minimum) ( Maximum)

Tests

Pneumatic test may be used instead of hydrostatic test when: Vessels are so designed dndsupported

thai they cannot safely by filled with

water.and Vessels for service in which traces of testing liquid cannot be tolerated Prior to Pneumatic test, Testing of attachment wells asper WU-50 must be performed

) )

Test pressure

must not be less Ihan 1.1 limes maxImum allowable working

pressure multiple by the ratio of stress value S for test temperature oi vessel to ~ ) )

"

the stress value S for design temperature.

Min. Test temp.= MDMT +30 deg.F

-

The pressure in the vessel shall be gradually increased to not more than onehalf of the test pressure. Thereafter, the test pressure shall be increased in steps of approximately one-tenth of the test pressure until the required test pressure has been reached Then the pi€Ssure shall be reduced to a value equ21t09/1 0 of the test pressure and held for a sufficient time to permit inspection of the vessel. Leakage is not allowed at the time 0; the required visual inspectioil. Test

gaug9 range limil = 1 5X Test Pr. = 4X Test Pr

(MillimUill) ( Maximum)

,r ),)

L

I

• L)

D

•

6. INSPECTION & TESlH~G

b ~

From Inspector's Viewpoint, following are the major areas of concern during

~

manufacture of pr. Vessels.

~ ~

A. MATERIAL INSPECTION:

~ ~

> ~ ~

»

»( t

1. Materials for Pressure .parts and Non.pressure .parts ... ( UG-4 a,b ) 2. Scrutiny of Mill-Certificates-compliance

with specification,

co-relate material with certificate

Identification marks,

( UG-93 a)

3. Additional requirements: Impact test results, PWHT etc ..... ( UG-84,85 ) 4. Mill Under-tolerance for plates

( UG-16. c)

5. Tolerances on bought-out heads

(UG-81. a,d)

B. FABRICATION

INSPECTION:

• 1. Tracability of plate maripection. ,

Pressure

vessel

THis dpressure

: A container qesigned to'withstand internal or external pressure. may be imposed by an external source, by the application of heat

from a direct or indirect source, or by any combination thereof.

Pressure

vessel

acceptable

:

to the owner-user

engineering

disciplines

characteristics

(

engineer

Shall be one or more persons or organizations who are knowledgeable

associated

with

evaluating

and experienced mechanical

and

in the material

which affect the integrity and reliability of pressure vessels.

pressure

vessel

engineer,

regarded

as a composite

by consulting

with appmpriate

The

specialists, should

be

of all entities needed to properly assess the technical

requirements.

Quality

assurance

determine

All planned, systematic, and preventative actions required to

if materials,

equipment, or services will meet specified requirements

so

that equipment will perform satisfactorily in service.

Repair

: The work necessary to restore a vessel to a condition suitable for safe

operation

at the design conditions.

pressure,

the requirements

addition

(

or replacement

If any repair changes the design temperature or

for re-rating

shall be satisfied.

A repair can be the

of pressure or non-pressure -parts that do not change the

rating of the vessel.

Repair organization a.

: Anyone

of the following

:

The holder of a valid ASME Certificate of Authorization that authorizes the use of an appropriate ASf\~r::Code symbol stamp.

b

0n ovmer WI

or user of pressure vessels who repairs his or her own equipment

2cco;dance

with this inspection code

'-j

t

/

c.

A contractor whose qualificatiofl.s are- acceptab!.~ io the prE:::sure-vessel owner or user and who makes repairs in accordance with this inspection \

code ..

d.

\ An individual or organization that is authorized by the legal jurisdiction.

Re-rating

: A change in either the temperature ratings or the maximum allowable

working pressure rating of a vessel, or a change in both. The maximum allowable working temperature and pressure of a vessel may be increased or deceased because of a re-rating, and sometimes a re-rating requires a combination of changes. Re-rating below original design conditions is a permissible way to provide for corrosion. (

When a re-rating is conducted in whi~h the maximum allowable

working pressure or temperature is increased or the minimum temperature is decreased so that additional mechanical tests are required, it shall be considered an alteration.

Examiner

: A person who assists the API authorized pressure vessel inspector by

performing specific NDE on pressure vessels but does not evaluate the results of / those examinations in accordance with API 510.

( *********

/

CHAPTER 4 Owner - User Inspection Organization 4.1

GENERAL

An owner or user of pressure vessels who controls the frequency inspectiol}s

of the

of the pressure vessels or the maintenance of them is responsible

for the functions of an authorized inspection agency.

4.3

OWNER - USER ORGANIZATION

(

An owner - user organization implementing,

RESPONS~81L1T1ES

is responsible for developing

documenting,

executing, and assessing pressure vessel inspection systems

and inspection procedures that will meet the requirements of this inspection code.

These

systems

and procedures

will

be contained

In a quality

assurance inspection manual and shall include the following.

a.

Organization

and reports of structure for inspection personnel.

b.

Documentation

and maintenance of inspectioll_and quality assurance

procedures.

( c.

Documentation

d.

Corrective action for inspection and test results.

c.

Intemal audits for compliance with the quality assurance inspection manual.

--~-~-"-----_

_-------

..

and reports of inspection and test results.

/

~ ~

-"--'---'-"'-'--'-'

~

_A,

.._._

... _

._

••. _

.•.. _

/

b

f.

~eview and approval of drawings, dE7si::~tn :..:.a~·";L:lation$, and sjjecifications repairs, ?lterations

~

for

and ratings.

~

)

g.

b

Assurance

that all jurisdictional

repairs, alterations,

requirements

for pressure vessel inspection,

and rerating are continuously

met.

~ ~

h.

)

Reports to the authorized pressure vessel inspector any process changes that could affect pressure vessel integrity.

~

; I.

)

Training

requirements

techniques,

)

for inspection

and technical knowledge

personnel

regarding

inspection

tools,

base.

)

, ,

J

(

J.

Controls

necessary

so that only qualified

welders

and procedures

are used

for all repairs and alterations.

,

k.

Controls personnel

J

•t

I.

Controls

necessary

so that. only qualified

nondestructive

examination

(NOE)

and procedures are utilized.

necessary

so that only materials

conforming

to the applicable

section of the ASME Code are utilized for repairs and alternations.

t

•

m.

Controls necessary so that all inspection measurement are properly maintained

{ I..

n.

Controls

necessary

organizations

and test equipment

and calibrated.

so that

the work

of contract

meet the same inspection

requirements

inspection

or

repair

as the owner - user

organization.

o.

Internal

auditing

relieving

devices.

requirements

for the quality

control

system

,or pressure

p

D

I

~

/

D

•.~.4

API AUHOr-