ASME Section VIII div 2 2010. ASME Boiler and Pressure Vessel Code. Alternative Rules

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2010 SECTION VIII, DIVISION 2

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6.2.2.4 when any part of the cladding thickness of the clad base material is included in the design calculations

in accordance with paragraph 4.1.9.

6.5.6.3 When the Integral or Weld Metal Overlay Cladding Thickness Is Not Included in Design

Thickness

When the cladding thickness is not included in the design calculations (see paragraph 6.5.6.2), the procedure

for groove welds shall be qualified as in paragraph 6.5.3. Alternatively, the weld in the base joint or cladding

joint may be qualified by itself with the rules in Section IX.

6.5.6.4 Performance Qualification for Groove Welds in Base Material with Corrosion Resistant Integral or

Weld Metal Overlay Cladding

Welders and welding operators shall be qualified in accordance with the requirements of Section IX.

6.5.7 Examination Requirements

Examination requirements for vessels with clad or weld metal overlay linings are located in paragraphs 7.4.8.1

and 7.4.8.2.

6.5.8 Inspection and Tests

Inspection and testing requirements for vessels with clad or weld metal overlay linings are located in

paragraph 7.4.8.3 and Part 8, respectively.

6.5.9 Stamping and Reports

The provisions for stamping and reports in Part 2 shall apply to vessels that have clad or weld overlay

corrosion resistant linings. The Manufacturer's Data Reports shall include the specification and type of lining

material and the applicable paragraph under which the shell and heads were designed.

6.6 Special Requirements for Tensile Property Enhanced Q and T Ferritic Steels

6.6.1 General

The following supplemental rules are applicable to steels suitable for welded vessel parts where the tensile

properties that have been enhanced by the quenching and tempering heat treatments shown in Table 6.17

and Table 3.A.4. These supplemental rules shall be used in conjunction with the general requirements for

fabrication in Part 6, as applicable. The provisions of paragraph 3.10.5.2.d shall also apply to materials

whose tensile properties are enhanced by quenching and tempering heat treatment.

6.6.2 Marking on Plates and Other Materials

Any steel stamping shall be done with "low stress" stamps, as commercially available. Steel stamping of all

types may be omitted on material below 13 mm (1/2 in.) in thickness. Requirements for the use of other

markings in lieu of stamping are covered in paragraph 6.1.1.2.b.

6.6.3 Requirements for Heat Treating After Forming

a) Pieces that are formed after quenching and tempering at a temperature lower than the final tempering

temperature shall be heat treated in accordance with Table 6.17 when the extreme fiber elongation from

forming exceeds 5% as determined by the lesser of the applicable equations in Table 6.1.

b) Pieces formed at temperatures equal to or higher than the original tempering temperature shall be

re-quenched and tempered in accordance with the applicable material specifications either before or

after welding into the vessel.

6.6.4 Minimum Thickness after Forming

The minimum thickness after forming of any section subject to pressure shall be 1.6 mm (1/16 in.).

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6.6.5 Welding Requirements

6.6.5.1 Qualification of Welding Procedures and Welders

The qualification of the welding procedure and the welders shall conform to the requirements of Section IX

and such qualification tests shall be performed on postweld heat treated specimens when a postweld heat

treatment is used.

6.6.5.2 Additional Welding Requirements

a) Filler metal containing more than 0.06% vanadium shall not be used for weldments subject to postweld

heat treatment.

b) The materials in Table 6.18 are exempt from production impact tests of the weld metal in accordance

with paragraph 3.11 under the conditions given below:

1) One of the high nickel alloy filler metals in Table 6.19 is used.

2) All required impact tests shall be performed as part of the procedure qualification tests as specified

in paragraph 3.11.

3) Production impact tests of the heat affected zone shall be performed in accordance with paragraph

3.11.

4) The welding processes are limited to gas metal arc, shielded metal arc, and gas tungsten arc.

5) The minimum design metal temperature of the vessel shall be not colder than -195°C (-320°F).

c) For SA-508 and SA-543 materials, the following, in addition to the variables in Section IX, QW-250, shall

be considered as essential variables requiring requalification of the welding procedure.

1) A change in filler metal SFA classification or to weld metal not covered by an SFA specification.

2) An increase in the maximum interpass temperature or a decrease in the minimum specified preheat

temperature. The specified range between the preheat temperature and the interpass temperature

shall not exceed 85°C (150°F).

3) A change in the heat treatment (procedure qualification tests shall be subjected to heat treatment

essentially equivalent to that encountered in fabrication of the vessel or vessel parts, including the

maximum total aggregate time at temperature or temperatures and cooling rates).

4) A change in the type of current (AC or DC), polarity, or a change in the specified range for amp,

volt, or travel speed.

5) A change in the thickness,

t , of the welding procedure qualification test plate as follows:

i) For welded joints that are quenched and tempered after welding, any increase in thickness.

The minimum thickness qualified in all cases is 6 mm (1/4 in.).

ii) For welded joints with a thickness,

t , less than 16 mm (5/8 in.) that are not quenched and

tempered after welding, for any decrease in thickness. The maximum thickness qualified is

2t .

iii) For welded joints with a thickness,

t , greater than or equal to 16 mm (5/8 in.) that are not

quenched and tempered after welding, for any departure from the range of 16 mm (5/8 in.) to

2t .

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6) Consumables control, drying, storage, and exposure requirements shall be in accordance with the

following.

i) Due consideration shall be given to protection of electrodes and fluxes for all welding

processes in order to minimize moisture absorption and surface contamination.

ii) Electrodes for shielded metal arc welding shall be low hydrogen type conforming to SFA-5.5

Electrodes shall be purchased or conditioned so as to have a coating moisture content not

greater than 0.2% by weight. Once opened, electrode storage and handling shall be

controlled so as to minimize absorption of moisture from the ambient atmosphere. The

practice used for controlling the moisture content shall be developed by the vessel

Manufacturer or that recommended by the electrode manufacturer.

7) The minimum preheat temperature is a function of the material thickness,

t , as shown below. The

preheat temperature shall be maintained for a minimum of 2 hours after completion of the weld joint.

i) 40°C (100°F) for t ≤ 13 mm (1/2 in.)

ii) 95°C (200°F) for 13 mm ( ½ in.) < t ≤ 38 mm (1-1/2 in.)

iii) 150°C (300°F) for t>38 mm (1-1/2 in.)

iv) For SA-517and SA-592 materials, the requirements of paragraphs 6.6.5.2.c.1 through

6.6.5.2.c.4 and 6.6.5.2.c.6 in addition to the variables in Section IX, QW-250, shall be

considered as essential variables requiring requalification of the welding procedure.

8) The postweld heat treatment temperature as required by Table 6.17 may be waived for SA-517 and

SA-592 materials with a nominal thickness,

t , such that, 15 mm (9/16) < t ≤ 32 mm (1-1/4 in.)

provided all of the following conditions are met:

i) A minimum preheat of 95°C (200°F) and a maximum interpass of 205°C (400°F) are used.

ii) After completion of welding and without allowing the weldment to cool below the minimum

preheat temperature, the temperature of the weldment is raised to a minimum of 205°C (400°F)

and maintained at that temperature for at least 4 hr; and

iii) All welds are examined by nondestructive examination in accordance with the provisions of this

Part.

6.6.5.3 Preparation of Base Metal

The preparation of plate edges, welding bevels, and chamfers and similar operations involving the removal of

metal shall be by machining, chipping, or grinding, by gas cutting or gouging. If metal removal is

accomplished by methods involving melting, such as gas cutting or arc air gouging, the metal removal shall

be done with appropriate precautions to avoid cracking. When thermal cutting is used, the effect on

mechanical properties shall be taken into consideration. The edges to be welded shall be uniform and

smooth.

6.6.5.4 Joint Alignment

a) Longitudinal Joint Alignment – In lieu of paragraph 6.1.6.1, the longitudinal joint misalignment for

quenched and tempered steels shall not exceed 20% of the nominal plate thickness or 2.5 mm (3/32 in.).

b) Circumferential Joint Alignment – In lieu of paragraph 6.1.6.1, the circumferential joint misalignment for

quenched and tempered steels shall not exceed the following values.

1) If t ≤ 24 mm (15/16 in.), then the tolerance is 20% of the plate thickness.

2) If 24 mm (15/16 in.) < t ≤ 38 mm (1-1/2 in.), then the tolerance is 5 mm (3/16 in.).

3) If t > 38 mm (1-1/2 in.), then the tolerance is 12.5% of the nominal plate thickness but not more than

6 mm (1/4 in.)

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6.6.5.5 Weld Finish

The requirements of paragraphs 6.2.4.1 and 7.5.2 shall be met, except that the maximum weld reinforcement

shall not exceed 10% of the plate thickness or 3 mm (1/8 in.), whichever is less. The edge of the weld

deposits shall merge smoothly into the base metal without undercuts or abrupt transitions. This requirement

shall apply to fillet and groove welds as well as to butt welds.

6.6.5.6 Attachment and Temporary Welds

a) Material for Structural Attachments and Stiffening Rings – Except as permitted by paragraph 4.2.5.6, all

permanent structural attachments and stiffening rings that are welded directly to pressure parts shall be

made of material whose specified minimum yield strength is within ±20% of that of the material to which

they are attached.

b) Fabrication of Structural and Temporary Welds – Welds for pads, lifting lugs, and other nonpressure

parts, as well as temporary lugs for alignment, shall be made by qualified welders in full compliance with

a qualified welding procedure. The type of welds used shall conform to the requirements of paragraph

4.2.5.6. Examination requirements for these welds are covered in paragraph 6.6.8.

c) Removal of Temporary Welds – Temporary welds shall be removed and the metal surface shall be

restored to a smooth contour. The area shall be examined by a magnetic particle or liquid penetrant

method for the detection and elimination of cracks or crack-like defects. If repair welding is required, it

shall be in accordance with a qualified procedure, and the finished weld surface shall be examined in

accordance with Part 7. Temporary welds and repair welds shall be considered the same as all other

welds insofar as requirements for qualified welders and welding procedures and for heat treatment are

concerned.

6.6.6 Postweld Heat Treatment

6.6.6.1 Vessels or parts of vessels constructed of quenched and tempered steels shall be postweld heat

treated when required in Table 6.17, when welding ferritic materials greater than 3 mm (1/8 in.) thick with the

electron beam welding process, and when welding materials of all thicknesses using the inertia and

continuous drive friction welding processes. The total thickness of the base material shall be used as the

thickness used to determine postweld heat treatment requirements for clad or weld overlayed parts.

6.6.6.2 Requirements for Postweld Heat Treatment

Postweld heat treatment shall be performed in accordance with paragraph 6.4, as modified by the

requirements of Table 6.17 and paragraph 6.6.6. In no case shall the PWHT temperature exceed the

tempering temperature. PWHT and tempering may be accomplished concurrently. The maximum cooling

rate established in paragraph 6.4.4.e need not apply. Where accelerated cooling from the tempering

temperature is required by the material specification, the same minimum cooling rate shall apply to PWHT.

6.6.6.3 Postweld Heat Treatment of Connections and Attachments

All welding of connections and attachments shall be postweld heat treated whenever required by Table 6.17

based on the greatest thickness of material at the point of attachment to the head or shell (see paragraphs

6.4.2.5 and 6.4.2.6).

6.6.6.4 Heat Treatment Procedure

a) Heating Furnace – Furnaces for heating and for quenching and tempering shall be provided with suitable

equipment for the automatic recording of temperatures. The metal temperature of the vessel or vessel

part during the holding period shall be recorded and shall be controlled within ±15°C (±25°F).

b) Liquid Quenching of Flat Plates or Parts – Liquid quenching of flat plates and individual parts shall be

done as required by the applicable material specifications.

c) Quenching of Shell Sections or Heads – Formed plates for shell sections and heads may be quenched

by sprays or immersion.

d) Quenching of Entire Vessels – Entire vessels, after completion of all welding operations, may be

quenched by sprays or immersion.

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6.6.6.5 Design and Operation of Quenching Equipment

The design and operation of spray equipment and the size of tanks and provision for forced circulation shall

be selected to produce a severity of quench in the quenched item sufficient to meet, in representative test

specimens after tempering, the requirements of the material specifications.

6.6.7 Heat Treatment Certification Tests

6.6.7.1 Heat Treatment Verification Tests

Tests shall be made to verify that the quenching and tempering heat treatments and subsequent thermal

treatments, performed by the Manufacturer, have produced the required properties. The requirements of

paragraph 6.6.7.2.b and 6.6.7.2.c shall be taken as minimum steps toward these objectives.

6.6.7.2 Certification Test Procedure

a) One or more test coupons representative of the material and the welding in each vessel or vessel

component shall be heat treated with the vessel or vessel component.

b) One or more test coupons from each lot of material in each vessel (see paragraph 6.6.7.2.e) shall be

quenched with the vessel or vessel component. A lot is defined as material from the same heat,

quenched or normalized simultaneously and whose thicknesses are within ±20% or 13 mm (1/2 in.) of

nominal thickness, whichever is smaller. The test coupons shall be so proportioned that tensile and

impact tests may be taken from the same locations relative to thickness as are required by the applicable

material specifications. Weld metal and heat affected zone impact test specimens shall be taken from

locations relative to coupon thickness in accordance with paragraph 3.11.8.2. The gage length of

tensile specimens and the middle third of the length of impact specimens must be located at a minimum

distance of

t from the quenched edge and/or end of the test coupon, where t is the thickness of the

material that the test coupon represents. If desired, the effect of this distance may be achieved by

temporary attachment of suitable thermal buffers. The effectiveness of such buffers shall be

demonstrated by tests.

c) In cases where the test coupon is not attached to the part being treated, it shall be quenched from the

same heat treatment charge and under the same conditions as the part which it represents (see

paragraph 3.10.5). It shall be so proportioned that test specimens may be taken from the locations

prescribed in paragraph 6.6.7.2.b.

d) Tempering Requirements

1) Attached Test Coupons – The test coupons shall remain attached to the vessel or vessel

component during tempering, except that any thermal buffers may be removed after quenching.

After the tempering operation and after removal from the component, the coupon shall be subjected

to the same thermal treatment(s), if any, to which the vessel or vessel component will be later

subjected. The holding time at temperature shall not be less than that applied to the vessel or

vessel component (except that the total time at each temperature may be applied in one heating

cycle) and the cooling rate shall be no faster.

2) Separate Test Coupons – Test coupons that are quenched separately, as described in paragraph

6.6.7.2.c, shall be tempered similarly and simultaneously with the vessel or component that they

represent. The conditions for subjecting the test coupons to subsequent thermal treatment(s) shall

be as described in paragraph 6.6.7.2.b.

e) Number of Tests – For base materials, one tensile and one impact test shall be made on material from

coupons representing each heat-treated lot of material in each vessel or vessel component. A lot is

defined as material from the same heat quenched simultaneously and whose thicknesses are within

±20% or 13 mm (1/2 in.) of nominal thickness, whichever is smaller.

1) Coupons not containing welds shall meet the complete tensile requirements of the material

specification and impact requirements of this Part.

2) Coupons containing weld metal shall be tested across the weld and shall meet the ultimate tensile

strength requirements of the material specifications; in addition, the minimum impact requirements

shall be met by samples with notches in the weld metal. The form and dimension of the tensile test

2010 SECTION VIII, DIVISION 2

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specimen shall conform to QW-462.1(a) or QW-462.1(d) of Section IX. The yield strength and

elongation are not a requirement of this test. Charpy impact testing shall be in accordance with the

requirements of paragraph 3.11.

6.6.8 Examination Requirements

Examination requirements for vessels and vessel parts constructed of quenched and tempered steels are

located in paragraphs 7.4.9.

6.6.9 Inspection and Tests

The provisions for inspection and testing in Part 7 and Part 8, respectively, shall apply to vessels and vessel

parts constructed of quenched and tempered steels.

6.6.10 Stamping and Reports

The provisions for stamping and reports in Part 2 shall apply to pressure vessels constructed in whole or in

part of quenched and tempered steels, except that the use of nameplates is mandatory for shell thicknesses

below 13 mm (1/2 in.). Nameplates are preferred on vessels of quenched and tempered steels in

thicknesses above 13 mm (1/2 in.) instead of stamping. In addition to the required marking, the letters QT

shall be applied below the symbol.

6.7 Special Requirements for Forged Fabrication

6.7.1 General

The rules in the following paragraphs apply specifically to vessels, main sections of vessels and other vessel

parts, and to liquid quenched and tempered, integrally forged vessels without welded joints, and shall be used

to supplement the applicable requirements for fabrication given in paragraph 6.1. For high alloy steel forged

vessels, the applicable paragraphs of Part 3 shall also apply.

6.7.2 Ultrasonic Examination

Ultrasonic examination requirements for vessels and vessel parts constructed from forged fabrication are

located in paragraph 7.4.10.1.

6.7.3 Toughness Requirements

a) For vessels constructed of SA-372 Grade J, Class 110 material, transverse impact tests shall be made at

the minimum allowable temperature in accordance with paragraph 3.11, except that in no case shall the

test temperature be warmer than -30°C (-20°F). Paragraph 3.11.2.1.b and paragraph 3.11.3.3 are not

applicable. Certification is required.

b) For vessels constructed of SA-723 Class 1, Grades 1, 2, and 3, or SA-723 Class 2, Grades 1, 2, and 3

materials, the impact requirements of paragraph 3.11.3 shall be met when tested at 4°C (40°F)

maximum.

6.7.4 Tolerances on Cylindrical Forgings

6.7.4.1 Localized Thin Areas

Forgings are permitted to have small areas thinner than required if the adjacent areas surrounding each has

sufficient thickness to satisfy the provisions of Part 5.

6.7.4.2 Tolerances on Body Forgings

a) Correction of Surface Irregularities to Meet Tolerances

Irregularities in the surface under consideration may be corrected by welding or other means to meet

these tolerances. If welding is done, then it shall meet the requirements of paragraph 6.7.7.

b) Use of Out-of-Round Forgings for Lower Pressure

If out-of-roundness exceeds the limit in paragraph 6.1.2.7 and the condition cannot be corrected, then

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the forging shall be rejected, except that if the out-of-roundness does not exceed 3%, the forging may be

certified for a reduced pressure,

P , calculated using Equations (6.1) and (6.2). The measurements

used in this equation shall be corrected for the specified corrosion allowance.

1.25

0.25

PP whenS S

⎛⎞

=≥

⎜⎟

⎝⎠

(6.1)

0.25

PP whenS S=< (6.2)

()

11 2

1.5

PR t D D

tRR

−

⎛⎞

⎜⎟

⎝⎠

(6.3)

(6.4)

RR=+

(6.5)

6.7.5 Methods of Forming Forged Heads

6.7.5.1 Heads shall be made as separate forgings or by closing the extremities of a hollow forged body to

such shape and dimensions as may be required to produce the final form desired.

6.7.5.2 Tolerances on Head Forgings

Tolerances shall meet the requirements of paragraph 6.1.2.7.

6.7.5.3 Correction of Surface Irregularities to Meet Tolerances

Irregularities may be corrected in accordance with paragraph 6.7.4.2.a.

6.7.6 Heat Treatment Requirements for Forged Fabrication

6.7.6.1 Heat Treatment When Vessels Are Fabricated by Welding

Vessels fabricated by welding of forged parts requiring heat treatment shall be heat treated in accordance

with the applicable material specification:

a) after all welding is completed, or

b) prior to welding, followed by postweld heat treatment of the finished weld in accordance with paragraph

6.4.2.

6.7.6.2 Heat Treatment When Material Is to Be Normalized or Annealed

After all forging is completed, each vessel or forged part fabricated without welding shall be heat treated in

accordance with the applicable material specification. When irregularities are corrected by welding,

subsequent heat treatment shall be in accordance with paragraph 6.7.8.3.b.

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6.7.6.3 Heat Treatment of Quenched and Tempered Ferritic Material

Vessels fabricated of SA-372 forging material to be liquid quenched and tempered shall be subjected to this

heat treatment in accordance with the applicable material specifications after all forging and welding is

completed, except for seal welding of threaded openings, which may be performed either before or after final

heat treatment.

a) Examination of Quenched and Tempered Vessels – After the final heat treatment, quenched and

tempered vessels shall be examined for the presence of cracks on the outside surface of the shell and

heads and on the inside surface where practicable. This examination shall be made by the liquid

penetrant or a magnetic particle method in accordance with Part 7.

b) Check of Heat Treatment by Hardness Testing – After the final heat treatment, liquid quenched and

tempered forgings, except those made of austenitic steels, shall be subjected to Brinnell hardness tests

at 1.5 m (5 ft.) intervals with a minimum of four readings at each of not less than three different locations

representing approximately the center and each end of the heat treated forgings. The average of the

individual Brinnell hardness numbers at each location shall be not more than 10% below or more than

25% above the number corresponding to the specified minimum tensile strength of the material. The

highest average hardness number shall not exceed the lowest average value on an individual vessel by

more than 40. Other hardness testing methods may be used and converted to Brinnell numbers by

means of the table in ASTM E 140.

6.7.6.4 Heat Treatment of Austenitic Material

In the case of austenitic steels, the heat treatment procedures followed shall be in accordance with paragraph

6.4.

6.7.6.5 Ferrous Material Not Requiring PWHT

Postweld heat treatment of vessels fabricated by welding of forged parts not requiring heat treatment shall

meet the requirements of paragraph 6.4.

6.7.7 Welding For Fabrication

6.7.7.1 All welding used in connection with the fabrication of forged vessels or components shall comply

with the applicable requirements of paragraph 6.2 except as modified in paragraph 6.7.7.2.

6.7.7.2 Restrictions on Ferrous Materials with Carbon Content Exceeding 0.35%

When the carbon content of the material exceeds 0.35% by heat analysis, the vessel shall be fabricated

without welding, except for repairs in accordance with paragraph 6.7.8.2, for minor nonpressure attachments,

for seal welding of threaded openings limited to fillet welds of not over 6 mm (1/4 in.) throat dimension, and for

adding reinforcement to threaded, flanged, or studded openings. Such welding shall be allowed under the

following conditions.

a) The suitability of the electrode and procedure, including preheat and post-heat, shall be established by

making a groove weld specimen as shown in QW-461.2 and QW-461.3 of Section IX in material of the

same analysis and of thickness in conformance with QW-451.1 and QW-451.2 of Section IX. The

specimen before welding shall be in the same condition of heat treatment as the work it represents, and

after welding the specimen shall be subjected to heat treatment equivalent to that contemplated for the

work. Tension and bend specimens, as shown in QW-462.1, QW-462.2, and QW-462.3a of Section IX,

shall be made. These tests shall meet the requirements of QW-150 and QW-160 of Section IX. The

radius of the mandrel used in the guided bend test shall be as shown in Table 6.20.

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b) Welders shall be qualified for minor nonpressure attachments, seal welds, and for fillet welds specified

by making and testing a specimen in accordance with QW-462.4(b) and QW-180 of Section IX.

Welders shall be qualified for adding weld reinforcement for openings and for repair welding by making a

test plate in accordance with QW-461, from which the bend tests outlined in QW-452.1 and QW-452.2 of

Section IX shall be made. The electrode used in making these tests shall be of the same AWS

classification as that specified in the procedure. The material for these tests can be carbon steel plate

or pipe, provided the test specimens are preheated, welded, and postweld heat treated in accordance

with the procedure specification for the type of electrode involved.

c) The finished welds shall be postweld heat treated or given a further heat treatment as required by the

applicable material specification. The welding permitted in paragraph 6.7.7.2 shall be performed prior to

final heat treatment except for seal welding of threaded openings, which may be performed either before

or after final heat treatment.

d) The finished welds shall be examined after postweld heat treatment by the liquid penetrant method or

magnetic particle method in accordance with Part 7.

6.7.8 Repair of Defects in Material

6.7.8.1 Removal of Surface Defects

Surface imperfections such as chip marks, blemishes, or other irregularities may be removed by grinding or

machining, and the surface exposed shall be blended smoothly into the adjacent surface when sufficient wall

thickness permits thin areas in compliance with the requirements of paragraph 6.7.4.1.

6.7.8.2 Repair of Defects by Welding

Thinning to remove defects may be repaired by welding only after approval by the Inspector. Defects shall

be removed to sound metal and verified using an acid etch or any other suitable method of examination.

The welding shall meet the requirements of paragraphs 6.7.8.3 and 6.7.8.4.

6.7.8.3 Weld Repairs of Material Containing 0.35% Carbon or Less

Material having carbon content of 0.35% or less (by heat analysis) may be repaired by welding provided the

requirements of paragraph 6.7 are met.

a) Qualification of Welding Procedure and Welders – The welding procedure and welders shall be qualified

in accordance with Section IX.

b) Postweld Heat Treatment – Postweld heat treatment after welding shall be governed as follows.

1) All welding shall be postweld heat treated if required by paragraph 6.4.2.

2) Fillet welds need not be postweld heat treated unless required by paragraph 6.7.8.3.b.1 or unless

the fillet welds exceed the limits given in paragraph 6.4.2, in which case they shall be heat treated in

accordance with the requirements of this paragraph.

3) Repair welding shall be postweld heat treated when required by paragraph 6.7.8.3.b.1, if it exceeds

3780 mm

(6 in.

) at any spot, or if the maximum depth exceeds 6 mm (1/4 in.).

c) Examination of Weld Repairs – See paragraph 7.4.10.2.a.

6.7.8.4 Weld Repairs of Material Containing More Than 0.35% Carbon

Material having carbon content over 0.35% (by heat analysis) may be repaired by welding when the

requirements of this paragraph are met.

a) Qualification of Welding Procedure and Welders – The welding procedure and welders shall be qualified

in accordance with Section IX and the additional requirements of paragraph 6.7.7.2.a and 6.7.7.2.b.

b) Postweld Heat Treatment – The finished repair welds shall be postweld heat treated or given a further

heat treatment as required by the applicable material specification.

c) Examination of Weld Repairs – see paragraph 7.4.10.2.b.

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6.7.8.5 Repair of Weld Defects

a) The repair of welds in forgings having carbon content not exceeding 0.35% by heat analysis shall follow

the requirements of paragraph 6.2.7.

b) The repair of welds in forgings having a carbon content exceeding 0.35% by heat analysis shall follow

the requirements of 6.7.8.4.

6.7.9 Threaded Connections to Vessel Walls, Forged Necks, and Heads

6.7.9.1 Requirements for Straight Threaded Openings

Straight threaded openings shall meet the rules governing openings and reinforcements in paragraph 4.5,

except as limited in paragraph 6.7.9.2. The length of thread shall be calculated for the opening design.

6.7.9.2 Location and Maximum Size of Straight Threaded Openings

Straight threaded center openings in integrally forged heads with nozzle extensions shall not exceed the

smaller of one-half the vessel diameter or DN 200 (NPS 8) as shown in Figure 6.3.

6.7.9.3 Requirements for Tapered Threaded Openings

Tapered threaded openings shall meet the limitations and requirements of paragraph 4.5.

6.7.9.4 Seal Welding of Threaded Openings

When piping or fittings are installed in threaded openings and seal welding is employed, the work shall be

performed and examined at the vessel Manufacturer's plant and included in the certification. Seal welding

shall comply with paragraph 6.7.7.

6.7.10 Inspection, Examination, and Testing

6.7.10.1 The rules in the following paragraphs apply specifically to the inspection, examination, and testing

of forged vessels and their component parts. These rules shall be used to supplement the applicable

requirements and examination in Part 7.

a) All forged vessels shall be examined as manufacturing proceeds to ensure freedom from loose scale,

gouges or grooves, and cracks or seams. After fabrication has passed the machining stage, the vessel

body shall be measured at suitable intervals along its length to get a record of variations in wall

thickness, and the nozzles for connecting piping and other important details shall be checked for

conformity to the design dimensions.

b) Surfaces that are not to be machined shall be carefully examined for visible defects such as seams, laps,

or folds. On surfaces to be machined, the examination shall be made after machining. Regions from

which defective material has been removed shall be examined after removal and again after any

necessary repair.

6.7.10.2 Forged Parts

a) Partial Data Reports Required – When welding is used in the fabrication of forged parts completed

elsewhere, the manufacturer of the forged parts shall furnish a Partial Data Report, Form A-2.

b) Identification and Certification – All parts forgings completed elsewhere shall be marked with the forging

manufacturer's name and the forging identification, including material designation. Should identifying

marks be obliterated in the fabrication process, and for small parts, other means of identification shall be

used. The forging manufacturer shall furnish reports of chemical and mechanical properties of the

material and certification that each forging conforms to all requirements of Part 3.

c) Welded Repairs and Their Certification – Welded repairs to parts forgings need not be inspected by an

Authorized Inspector at the plant of the forging manufacturer, but the forging manufacturer shall obtain

the approval of the vessel Manufacturer and furnish a report of the extent and location of such repairs,

together with certification that they were made in accordance with all other requirements of paragraph

6.7.8.4, as applicable. If desired, welding repairs of forgings made elsewhere may be made, examined,

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