Astm A204

Designation: A 204/A 204M – 93 (Reapproved 1999) An American National Standard

Standard Specification for

Pressure Vessel Plates, Alloy Steel, Molybdenum1

This standard is issued under the fixed designation A 204/A 204M; the number immediately following the designation indicates the year

of original adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval.

A superscript epsilon (e) indicates an editorial change since the last revision or reapproval.

This standard has been approved for use by agencies of the Department of Defense.

1. Scope

1.1 This specification2 covers molybdenum-alloy steel

plates, intended particularly for welded boilers and other

pressure vessels.

1.2 Material under this specification is available in three

grades having different strength levels as follows:

Grade

Tensile Strength,

ksi [MPa]

A 65–85 [450–585]

B 70–90 [485–620]

C 75–95 [515–655]

1.3 The maximum thickness of plates is limited only by the

capacity of the composition to meet the specified mechanical

property requirements; however, current practice normally

limits the maximum thickness of plates furnished under this

specification as follows:

Grade

Maximum Thickness,

in. [mm]

A 6 [150]

B 6 [150]

C 4 [100]

1.4 The values stated in either inch-pound units or SI units

are to be regarded separately as standard. Within the text, the

SI units are shown in brackets. The values stated in each

system are not exact equivalents; therefore, each system must

be used independently of the other. Combining values from the

two systems may result in nonconformance with this specification.

2. Referenced Documents

2.1 ASTM Standards:

A 20/A 20M Specification for General Requirements for

Steel Plates for Pressure Vessels3

A 435/A 435M Specification for Straight-Beam Ultrasonic

Examination of Steel Plates3

A 577/A 577M Specification for Ultrasonic Angle-Beam

Examination of Steel Plates3

A 578/A 578M Specification for Straight-Beam Ultrasonic

Examination of Plain and Clad Steel Plates for Special

Applications3

3. General Requirements and Ordering Information

3.1 Material supplied to this material specification shall

conform to Specification A 20/A 20M. These requirements

outline the testing and retesting methods and procedures,

permissible variations in dimensions and mass, quality and

repair of defects, marking, loading, etc.

3.2 Specification A 20/A 20M also establishes the rules for

the ordering information that should be complied with when

purchasing material to this specification.

3.3 In addition to the basic requirements of this specification,

certain supplementary requirements are available when

additional control, testing, or examination is required to meet

end use requirements. These include:

3.3.1 Vacuum treatment,

3.3.2 Additional or special tension testing,

3.3.3 Impact testing, and

3.3.4 Nondestructive examination.

3.4 The purchaser is referred to the listed supplementary

requirements in this specification and to the detailed requirements

in Specification A 20/A 20M.

3.5 If the requirements of this specification are in conflict

with the requirements of Specification A 20/A 20M, the requirements

of this specification shall prevail.

4. Manufacture

4.1 Steelmaking Practice—The steel shall be killed.

5. Heat Treatment

5.1 Plates 11⁄2in. [40 mm] and under in thickness are

normally supplied in the as-rolled condition. The plates may be

ordered normalized or stress relieved or both.

5.2 Plates over 11⁄2in. [40 mm] in thickness shall be

normalized.

6. Chemical Requirements

6.1 The steel shall conform to the chemical requirements

shown in Table 1 unless otherwise modified in accordance with

Supplementary Requirement S17, Vacuum Carbon-Deoxidized

1 This specification is under the jurisdiction of ASTM Committee A-1 on Steel,

Stainless Steel, and Related Alloys and is the direct

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