weldedsteel tank

SECTION 2—MATERIALS

2.1 GENERAL

2.1.1

Materials used in the construction of tanks shall conform

to the specifications listed in this section, subject to the

modifications and limitations indicated in this standard.

Material produced to specifications other than those listed in

this section may be employed, provided that the material is

certified to meet all of the requirements of a material specification

listed in this standard and the material’s use is

approved by the purchaser. The manufacturer’s proposal shall

identify the material specifications to be used.

2.1.2

When any new or unused plate and pipe material cannot

be completely identified by records that are satisfactory to

the purchaser as material conforming to a specification listed

in this standard, the material or product may be used in the

construction of tanks covered by this standard only if the

material passes the tests prescribed in Appendix N.

2.1.3

When a tank is designed to the requirements of this

standard using plate material from Group-I through

Group-IIIA steels, the tank manufacturer responsible for

any proposed material substitution to use Group-IV

through Group-VI steels must:

a. Maintain all of the original design criteria for the lower

stress Group-I through Group IIIA steels.

b. Obtain the prior written approval of the purchaser.

c. Ensure that all of the design, fabrication, erection and

inspection requirements for the material being substituted

will meet the lower stress Group-I through Group IIIA specifications

for items including but not limited to:

1. Material properties and production process methods.

2. Allowable stress levels.

3. Notch toughness.

4. Welding procedures and consumables.

5. Thermal stress relief.

6. Temporary and permanent attachment details and

procedures.

7. Nondestructive examinations.

d. Include the pertinent information in the documents provided

to the purchaser, including a certification statement that

the substituted material fully complies with 2.1.3 in all

respects, and provide all other records covered by the work

processes applied to the material such as impact testing, weld

procedures, nondestructive examinations, and heat treatments.

2.1.4

Where materials of construction are used that are certified

to two or more material specifications, the material

specification chosen for the design calculations shall also be

used consistently in the application of all other provisions of

this standard. The purchaser shall be notified of this choice

and receive confirmation that the material fully complies with

the chosen material specification in all respects.

2.2 PLATES

2.2.1 General

2.2.1.1

Except as otherwise provided for in 2.1, plates

shall conform to one of the specifications listed in 2.2.2

through 2.2.5, subject to the modifications and limitations in

this standard.

2.2.1.2

Plate for shells, roofs, and bottoms may be ordered

on an edge-thickness basis or on a weight [kg/m

2

(lb/ft

2

)]

basis, as specified in 2.2.1.2.1 through 2.2.1.2.3.

2.2.1.2.1

The edge thickness ordered shall not be less than

the computed design thickness or the minimum permitted

thickness.

2.2.1.2.2

The weight ordered shall be great enough to provide

an edge thickness not less than the computed design

thickness or the minimum permitted thickness.

2.2.1.2.3

Whether an edge-thickness or a weight basis is

used, an underrun not more than 0.25 mm (0.01 in.) from the

computed design thickness or the minimum permitted thickness

is acceptable.

2.2.1.3

All plates shall be manufactured by the openhearth,

electric-furnace, or basic oxygen process. Steels produced

by the thermo-mechanical control process (TMCP)

may be used, provided that the combination of chemical composition

and integrated controls of the steel manufacturing is

mutually acceptable to the purchaser and the manufacturer,

and provided that the specified mechanical properties in the

required plate thicknesses are achieved. Copper-bearing steel

shall be used if specified by the purchaser.

2.2.1.4

Shell plates are limited to a maximum thickness of

45 mm (1.75 in.) unless a lesser thickness is stated in this

standard or in the plate specification. Plates used as inserts or

flanges may be thicker than 45 mm (1.75 in.). Plates thicker

than 40 mm (1.5 in.) shall be normalized or quench tempered,

killed, made to fine-grain practice, and impact tested.

2.2.2 ASTM Specifications

Plates that conform to the following ASTM specifications

are acceptable as long as the plates are within the stated

limitations:

a. ASTM A 36M/A 36 for plates to a maximum thickness of

40 mm (1.5 in.). None of the specifications for the appurtenant

materials listed in Table 1 of ASTM A 36M/A 36 are

considered acceptable for tanks constructed under this standard

unless it is expressly stated in this standard that the

specifications are acceptable.

b. ASTM A 131M/A 131, Grade A, for plates to a maximum

thickness of 12.5 mm (0.5 in.); Grade B for plates to a maxi-

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mum thickness of 25 mm (1 in.); Grade CS for plates to a

maximum thickness of 40 mm (1.5 in.) [insert plates and

flanges to a maximum thickness of 50 mm (2 in.)]; and

Grade EH36 for plates to a maximum thickness of 45 mm

(1.75 in.) [insert plates and flanges to a maximum thickness

of 50 mm (2 in.)].

c. ASTM A 283M/A 283, Grade C, for plates to a maximum

thickness of 25 mm (1 in.).

d. ASTM A 285M/A 285, Grade C, for plates to a maximum

thickness of 25 mm (1 in.).

e. ASTM A 516M Grades 380, 415, 450, 485/A 516,

Grades 55, 60, 65, and 70, for plates to a maximum

thickness of 40 mm (1.5 in.) [insert plates and flanges to

a maximum thickness of 100 mm (4 in.)].

f. ASTM A 537M/A 537, Class 1 and Class 2, for plates to a

maximum thickness of 45 mm (1.75 in.) [insert plates to a

maximum thickness of 100 mm (4 inches)].

g. ASTM A 573M Grades 400, 450, 485/A 573, Grades 58,

65, and 70, for plates to a maximum thickness of 40 mm

(1.5 in.).

h. ASTM A 633M/A 633, Grades C and D, for plates to a

maximum thickness of 45 mm (1.75 in.) [insert plates to a

maximum thickness of 100 mm (4.0 in.)].

i. ASTM A 662M/A 662, Grades B and C, for plates to a

maximum thickness of 40 mm (1.5 in.).

j. ASTM A 678M/A 678, Grade A, for plates to a maximum

thickness of 40 mm (1.5 in.) [insert plates to a maximum

thickness of 65 mm (2.5 in.)] and Grade B for plates to a

maximum thickness of 45 mm (1.75 in.) [insert plates to a

maximum thickness of 65 mm (2.5 in.)]. Boron additions are

not permitted.

Figure 2-1—Minimum Permissible Design Metal Temperature for Materials Used in Tank Shells

Without Impact Testing

–60

–50

–40

–30

–20

–10

0

10

20

30

40

50

60

・・

F

–51

–46

–40

–34

–29

–23

–18

–12

–7

–1

4

10

16

・・

C

–51

–46

–40

–34

–29

–23

–18

–12

–7

–1

4

10

16

・・

C

–60

–50

–40

–30

–20

–10

0

10

20

30

40

50

60

・・

F

Design metal temperature

Group VI and Group VIA

Group V

See Note 2

Group I

Group II

Group III

Group IV

Group IIIA

See Note 1

Group IVA

Group IIA

Thickness, including corrosion allowance

mm 6 12.5 19 25 32 38

in. 0.25 0.50 0.75 1.00 1.25 1.50

Notes:

1. The Group II and Group V lines coincide at thicknesses less than 12.5 mm (

1/2 in.).

2. The Group III and Group IIIA lines coincide at thicknesses less than 12.5 mm (

1/2 in.).

3. The materials in each group are listed in Table 2-3.

4. This figure is not applicable to controlled-rolled plates (see 2.2.7.4).

5. Use the Group IIA and Group VIA curves for pipe and flanges (see 2.5.5.2 and 2.5.5.3).

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k. ASTM A 737M/A 737, Grade B, for plates to a maximum

thickness of 40 mm (1.5 in.).

l. ASTM A 841M/A 841, Grade A, Class 1 and Grade B,

Class 2, for plates to a maximum thickness of 40 mm (1.5 in.)

[insert plates to a maximum thickness of 65 mm (2.5 in.)].

2.2.3 CSA Specifications

Plate furnished to CSA G40.21 in Grades 260W/(38W),

300W/(44W), and 350W/(50W) is acceptable within the limitations

stated below. (If impact tests are required, Grades

260W/(38W), 300W/(44W), and 350W/(50W) are designated

as Grades 260W/(38WT), 300W/(44WT), and 350W/

(50WT), respectively.) Imperial unit equivalent grades of

CSA Specification G40.21, shown in parenthesis, are also

acceptable.

a. The W grades may be semikilled or fully killed.

b. Fully killed steel made to fine-grain practice must be specified

when required.

c. Elements added for grain refining or strengthening shall be

restricted in accordance with Table 2-1.

d. Plates shall have tensile strengths that are not more than

140 MPa (20 ksi) above the minimum specified for the grade.

e. Grades 260W/38W and 300W/44W are acceptable for

plate to a maximum thickness of 25 mm (1 in.) if semikilled

and to a maximum thickness of 40 mm (1.5 in.) if fully killed

and made to fine-grain practice.

f. Grade 350W/50W is acceptable for plate to a maximum

thickness of 45 mm (1.75 in.) [insert plates to a maximum

thickness of 50 mm (2 in.)] if fully killed and made to finegrain

practice.

2.2.4 ISO Specifications

Plate furnished to ISO 630 in Grades E 275 and E 355 is

acceptable within the following limitations:

a. Grade E 275 in Qualities C and D for plate to a maximum

thickness of 40 mm (1.5 in.) and with a maximum manganese

content of 1.5% (heat).

b. Grade E 355 in Qualities C and D for plate to a maximum

thickness of 45 mm (1.75 in.) [insert plates to a maximum

thickness of 50 mm (2 in.)].

2.2.5 National Standards

Plates produced and tested in accordance with the requirements

of a recognized national standard and within the

mechanical and chemical limitations of one of the grades

listed in Table 2-2 are acceptable when approved by the purchaser.

The requirements of this group do not apply to the

ASTM, CSA, and ISO specifications listed in 2.2.2, 2.2.3,

and 2.2.4. For the purposes of this standard, a

national standard

is a standard that has been sanctioned by the government

of the country from which the standard originates.

2.2.6 General Requirements for Delivery

2.2.6.1

The material furnished shall conform to the

applicable requirements of the listed specifications but is

not restricted with respect to the location of the place of

manufacture.

2.2.6.2

This material is intended to be suitable for fusion

welding. Welding technique is of fundamental importance,

and welding procedures must provide welds whose strength

and toughness are consistent with the plate material being

joined. All welding performed to repair surface defects

shall be done with low-hydrogen welding electrodes compatible

in chemistry, strength, and quality with the plate

material.

2.2.6.3

When specified by the plate purchaser, the steel

shall be fully killed. When specified by the plate purchaser,

fully killed steel shall be made to fine-grain practice.

2.2.6.4

For plate that is to be made to specifications that

limit the maximum manganese content to less than 1.60%,

the limit of the manganese content may be increased to

1.60% (heat) at the option of the plate producer to maintain

the required strength level, provided that the maximum carbon

content is reduced to 0.20% (heat) and the weldability of

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Table 2-1—Maximum Permissible Alloy Content

Alloy

Heat Analysis

(percent) Notes

Columbium 0.05 1, 2, 3

Vanadium 0.10 1, 2, 4

Columbium (

≤

0.05%) plus

vanadium

0.10 1, 2, 3

Nitrogen 0.015 1, 2, 4

Copper 0.35 1, 2

Nickel 0.50 1, 2

Chromium 0.25 1, 2

Molybdenum 0.08 1, 2

1. When the use of these alloys or combinations of them is not

included in the material specification, their use shall be at the option

of the plate producer, subject to the approval of the purchaser. These

elements shall be reported when requested by the purchaser. When

more restrictive limitations are included in the material specification,

those shall govern.

2. On product analysis, the material shall conform to these requirements,

subject to the product analysis tolerances of the specification.

3. When columbium is added either singly or in combination with

vanadium, it shall be restricted to plates of 12.5 mm (0.50 in.) maximum

thickness unless combined with 0.15% minimum silicon.

4. When nitrogen (

≤

0.015%) is added as a supplement to vanadium,

it shall be reported, and the minimum ratio of vanadium to nitrogen

shall be 4:1.

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the plate is given consideration. The material shall be marked

“Mod” following the specification listing. The material shall

conform to the product analysis tolerances of Table B in

ASTM A 6M/A 6.

2.2.6.5

The use or presence of columbium, vanadium,

nitrogen, copper, nickel, chromium, or molybdenum shall not

exceed the limitations of Table 2-1 for all Group VI materials

(see Table 2-3) and ISO 630, Grade E 355.

2.2.7 Heat Treatment of Plates

2.2.7.1

When specified by the plate purchaser, fully killed

plates shall be heat treated to produce grain refinement by

either normalizing or heating uniformly for hot forming. If

the required treatment is to be obtained in conjunction with

hot forming, the temperature to which the plates are heated

for hot forming shall be equivalent to and shall not significantly

exceed the normalizing temperature. If the treatment of

the plates is not specified to be done at the plate producer’s

plant, testing shall be carried out in accordance with 2.2.7.2.

2.2.7.2

When a plate purchaser elects to perform the

required normalizing or fabricates by hot forming (see

2.2.7.1), the plates shall be accepted on the basis of mill tests

made on full-thickness specimens heat treated in accordance

with the plate purchaser’s order. If the heat-treatment temperatures

are not indicated on the purchase order, the specimens

shall be heat treated under conditions considered appropriate

for grain refinement and for meeting the test requirements.

The plate producer shall inform the plate purchaser of the

procedure followed in treating the specimens at the steel mill.

2.2.7.3

On the purchase order, the plate purchaser shall

indicate to the plate producer whether the producer shall perform

the heat treatment of the plates.

2.2.7.4

Subject to the purchaser’s approval, controlledrolled

or thermo-mechanical-control-process (TMCP) plates

(plates produced by a mechanical-thermal rolling process

designed to enhance notch toughness) may be used where

normalized plates are required. Each plate-as-rolled shall

receive Charpy V-notch impact energy testing in accordance

with 2.2.8, 2.2.9, and 2.2.10. When controlled-rolled or

TMCP steels are used, consideration should be given to the

service conditions outlined in 3.3.3.

2.2.7.5

The tensile tests shall be performed on each plate

as heat treated.

2.2.8 Impact Testing of Plates

2.2.8.1

When required by the purchaser or by 2.2.7.4 and

2.2.9, a set of Charpy V-notch impact specimens shall be

taken from plates after heat treatment (if the plates have been

heat treated), and the specimens shall fulfill the stated energy

requirements. Test coupons shall be obtained adjacent to a

tension-test coupon. Each full-size impact specimen shall

have its central axis as close to the plane of one-quarter plate

thickness as the plate thickness will permit.

2.2.8.2

When it is necessary to prepare test specimens

from separate coupons or when plates are furnished by the

plate producer in a hot-rolled condition with subsequent heat

treatment by the fabricator, the procedure shall conform to

ASTM A 20.

2.2.8.3

An impact test shall be performed on three specimens

taken from a single test coupon or test location. The

average value of the specimens (with no more than one specimen

value being less than the specified minimum value)

shall comply with the specified minimum value. If more than

one value is less than the specified minimum value, or if one

Table 2-2—Acceptable Grades of Plate Material Produced to National Standards (See 2.2.5)

Mechanical Properties Chemical Composition

Tensile Strength

a

Minimum

Yield

Strength

c

Maximum

Thickness

Maximum

Percent

Carbon

Maximum

Percent

Phosphorus and

Minimum Sulfur

c

Maximum

Grade

b

MPa ksi MPa ksi MPa ksi mm in. Heat Product Heat Product

235

d

360 52 510 74 235 34 20 0.75 0.20 0.24 0.04 0.05

250 400 58 530 77 250 36 40 1.5 0.23 0.27 0.04 0.05

275 430 62 560 81 275 40 40 1.5 0.25 0.29 0.04 0.05

a

The location and number of test specimens, elongation and bend tests, and acceptance criteria are to be in accordance with the

appropriate national standard, ISO standard, or ASTM specification.

b

Semikilled or fully killed quality; as rolled, controlled-rolled or TMCP [20 mm (0.75 in.) maximum when controlled-rolled steel

or TMCP is used in place of normalized steel], or normalized.

c

Yield strength ÷ tensile strength

≤

0.75, based on the minimum specified yield and tensile strength unless actual test values are

required by the purchaser.

d

Nonrimming only.

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value is less than two-thirds the specified minimum value,

three additional specimens shall be tested, and each of these

must have a value greater than or equal to the specified minimum

value.

2.2.8.4

The test specimens shall be Charpy V-notch Type A

specimens (see ASTM A 370), with the notch perpendicular

to the surface of the plate being tested.

2.2.8.5

For a plate whose thickness is insufficient to permit

preparation of full-size specimens (10 mm

・~

10 mm), tests

shall be made on the largest subsize specimens that can be

prepared from the plate. Subsize specimens shall have a width

along the notch of at least 80% of the material thickness.

2.2.8.6

The impact energy values obtained from subsize

specimens shall not be less than values that are proportional

to the energy values required for full-size specimens of the

same material.

2.2.8.7

The testing apparatus, including the calibration of

impact machines and the permissible variations in the temperature

of specimens, shall conform to ASTM A 370 or an

equivalent testing apparatus conforming to national standards

or ISO standards.

2.2.9 Toughness Requirements

2.2.9.1

The thickness and design metal temperature of all

shell plates, shell reinforcing plates, shell insert plates, bottom

plates welded to the shell, plates used for manhole and nozzle

necks, plate-ring shell-nozzle flanges, blind flanges, and manhole

cover plates shall be in accordance with Figure 2-1. Notch

toughness evaluation of plate-ring flanges, blind flanges, and

manhole cover plates shall be based on “governing thickness”

as defined in 2.5.5.3. In addition, plates more than 40 mm (1.5

in.) thick shall be of killed steel made to fine-grain practice and

heat treated by normalizing, normalizing and tempering, or

quenching and tempering, and each plate as heat treated shall

be impact tested according to 2.2.10.2. Each TMCP A 841

plate-as-rolled shall be impact tested. Impact test temperature

and required energy shall be in accordance with 2.2.10.2 in

lieu of the default temperature and energy given in A 841.

2.2.9.2

Plates less than or equal to 40 mm (1.5 in.) thick,

except controlled-rolled plates (see 2.2.7.4), may be used at or

above the design metal temperatures indicated in Figure 2-1

without being impact tested. To be used at a design metal temperatures

lower than the temperatures indicated in Figure 2-1,

plates shall demonstrate adequate notch toughness in accordance

with 2.2.10.3 unless 2.2.10.2 or 2.2.10.4 has been specified

by the purchaser. For heat-treated material, notch

toughness shall be demonstrated on each plate as heat treated

when 2.2.10.2 requirements are specified.

2.2.9.3

Plate used to reinforce shell openings and insert

plates shall be of the same material as the shell plate to which

they are attached or shall be of any appropriate material listed

in Table 2-3 and Figure 2-1. Except for nozzle and manway

necks, the material shall be of equal or greater yield and tensile

strength and shall be compatible with the adjacent shell

material (see 2.2.9.1 and 3.7.2.2, item e).

2.2.9.4

The requirements in 2.2.9.3 apply only to shell

nozzles and manholes. Materials for roof nozzles and manholes

do not require special toughness.

2.2.9.5

The design metal temperature is defined as the lowest

emperature considered in the design, which, ulesss experience

or special local conditions justify another assumption,

shall be assumed to be 8ºC (15ºF) above the lowest one-day

mean ambient temperature of the locality where the tank is to

be installed. Isothermal lines of lowest one-day mean temperature

are shown in Figure 2-2. The temperatures are not

related to refrigerated-tank temperatures (see 1.1.1).

2.2.9.6

The maxiumum design temperature is defined as

the highest temperature considered in the design, equal to or

greater than the highest expected operating temperature during

the service life of the tank.

2.2.10 Toughness Procedure

2.2.10.1

When a material’s toughness must be determined,

it shall be done by one of the procedures described in 2.2.10.2

through 2.2.10.4, as specified in 2.2.9.

2.2.10.2

Each plate as rolled or heat treated shall be impact

tested in accordance with 2.2.8 at or below the design metal

temperature to show Charpy V-notch longitudinal (or transverse)

values that fulfill the minimum requirements of Table

2-4 (see 2.2.8 for the minimum values for one specimen and

for subsize specimens). As used here, the term

plate-as-rolled

refers to the unit plate rolled from a slab or directly from an

ingot in its relation to the location and number of specimens,

not to the condition of the plate.

2.2.10.3

The thickest plate from each heat shall be impact

tested in accordance with 2.2.8 and shall fulfill the impact

requirements of 2.2.10.2 at the design metal temperature.

2.2.10.4

The manufacturer shall submit to the purchaser

test data for plates of the material demonstrating that based on

past production from the same mill, the material has provided

the required toughness at the design metal temperature.

2.3 SHEETS

Sheets for fixed and floating roofs shall conform to ASTM

A 1011M/A 1011, Grade 33. They shall be made by the openhearth

or basic oxygen process. Copper-bearing steel shall be

used if specified on the purchase order. Sheets may be

ordered on either a weight or a thickness basis, at the option

of the tank manufacturer.

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Table 2-3a—Material Groups, SI Units (See Figure 2-1 and Note 1 Below)

Group I

As Rolled,

Semikilled

Group II

As Rolled,

Killed or Semikilled

Group III

As Rolled, Killed

Fine-Grain Practice

Group IIIA

Normalized, Killed

Fine-Grain Practice

Material Notes Material Notes Material Notes Material Notes

A 283M C 2 A 131M B 7 A 573M-400 A 131M CS

A 285M C 2 A 36M 2, 6 A 516M-380 A 573M-400 10

A 131M A 2 G40.21-260W A 516M-415 A 516M-380 10

A 36M 2, 3 Grade 250 5, 8 G40.21-260W 9 A 516M-415 10

Grade 235 3, 5 Grade 250 5, 9 G40.21-260W 9, 10

Grade 250 6 Grade 250 5, 9, 10

Group IV

As Rolled, Killed

Fine-Grain Practice

Group IVA

As Rolled, Killed

Fine-Grain Practice

Group V

Normalized, Killed

Fine-Grain Practice

Group VI

Normalized or

Quenched and Tempered,

Killed Fine-Grain Practice

Reduced Carbon

Material Notes Material Notes Material Notes Material Notes

A 573M-450 A 662M C A 573M-485 10 A 131M EH 36

A 573M-485 A 573M-485 11 A 516M-450 10 A 633M C

A 516M-450 G40.21-300W 9, 11 A 516M-485 10 A 633M D

A 516M-485 G40.21-350W 9, 11 G40.21-300W 9, 10 A 537M Class 1

A 662M B G40.21-350W 9, 10 A 537M Class 2 13

G40.21-300W 9 A 678M A

G40.21-350W 9 A 678M B 13

E 275

4, 9 A 737M B

E 355 9

A 841 M, Grade A,

Class 1

A 841 M, Grade B,

Class 2

12, 13, 14

12, 13, 14

Grade 275 5, 9

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2.4 STRUCTURAL SHAPES

2.4.1

Structural steel shall conform to one of the following:

a. ASTM A 36M/A 36.

b. ASTM A 131M/A 131.

c. ASTM A 992M/A 992.

d. Structural Steels listed in AISC

Specification for Structural

Steel Buildings, Allowable Stress Design

.

e. CSA G40.21, Grades 260W/(38W), 300W/(44W), 350W/

(50W), 260WT/(38WT), 300WT/(44WT), and 350WT/

(50WT). Imperial unit equivalent grades of CSA Specification

G40.21 are also acceptable.

f. ISO 630, Grade E 275, Qualities B, C, and D.

g. Recognized national standards. Structural steel that is produced

in accordance with a recognized national standard and

that meets the requirements of Table 2-2 is acceptable when

approved by the purchaser.

2.4.2

All steel for structural shapes shall be made by the

open-hearth, electric-furnace, or basic oxygen process.

Copper-bearing steel is acceptable when approved by the

purchaser.

2.4.3

Not all of the structural steel shapes listed in AISC

[2.4.1 (d)] and other national standards [2.4.1 (g)] are well

suited for welding. Material selection for structural shapes

requiring welded connections shall include confirmation of

the materials’ weldability from the structural shape manufacturer,

other reputable sources, or by weld testing. Structural

steel shapes having poor weldability shall only be

used for bolted connection designs.

2.5 PIPING AND FORGINGS

2.5.1

Unless otherwise specified in this standard, pipe and

pipe couplings and forgings shall conform to the specifications

listed in 2.5.1.1 and 2.5.1.2 or to national standards

equivalent to the specifications listed.

2.5.1.1

The following specifications are acceptable for

pipe and pipe couplings:

a. API Spec 5L, Grades A, B, and X42.

b. ASTM A 53, Grades A and B.

c. ASTM A 106, Grades A and B.

d. ASTM A 234M/A 234, Grade WPB.

e. ASTM A 333M/A 333, Grades 1 and 6.

f. ASTM A 334M/A 334, Grades 1 and 6.

g. ASTM A 420M/A 420, Grade WPL6.

h. ASTM A 524, Grades I and II.

i. ASTM A 671 (see 2.5.3).

Notes:

1. Most of the listed material specification numbers refer to ASTM specifications (including Grade or Class); there are, however,

some exceptions: G40.21 (including Grade) is a CSA specification; Grades E 275 and E 355 (including Quality) are

contained in ISO 630; and Grade 235, Grade 250, and Grade 275 are related to national standards (see 2.2.5).

2. Must be semikilled or killed.

3. Thickness

≤ 20 mm.

4. Maximum manganese content of 1.5%.

5. Thickness 20 mm maximum when controlled-rolled steel is used in place of normalized steel.

6. Manganese content shall be 0.80–1.2% by heat analysis for thicknesses greater than 20 mm, except that for each reduction

of 0.01% below the specified carbon maximum, an increase of 0.06% manganese above the specified maximum will be permitted

up to the maximum of 1.35%. Thicknesses

≤ 20 mm shall have a manganese content of 0.8–1.2% by heat analysis.

7. Thickness

≤ 25 mm.

8. Must be killed.

9. Must be killed and made to fine-grain practice.

10.Must be normalized.

11.Must have chemistry (heat) modified to a maximum carbon content of 0.20% and a maximum manganese content of 1.60%

(see 2.2.6.4).

12.Produced by the thermo-mechanical control process (TMCP).

13. See 3.7.4.6 for tests on simulated test coupons for material used in stress-relieved assemblies.

14. See 2.2.9 for impact test requirements (each plate-as-rolled tested).

Table 2-3a—Material Groups, SI Units (See Figure 2-1 and Note 1 Below)

Group I

As Rolled,

Semikilled

Group II

As Rolled,

Killed or Semikilled

Group III

As Rolled, Killed

Fine-Grain Practice

Group IIIA

Normalized, Killed