API Standard 650

We will be going through:-

General Discussion Plates Materials Sheets Materials Material with Structural Shapes Piping Materials and Forgings Materials

Flange Materials Bolting Materials Welding Electrode Material

GENERAL

This standard covers

Internal pressures not exceeding the weight of the roof plates

Higher internal pressure is permitted when additional requirements are met Appendix F

Tanks whose entire bottom is uniformly supported

Tanks in nonrefrigerated service

Maximum design temperature of 93C (200F) . For more than 93C temperature see APPENDIX M

API Standard 650

PLATES MATERIALS

All plates shall be manufactured by the open hearth electric-furnace, or basic oxygen process.

TMCP may be used

Copper-Bearing Steel shall be used

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.

Under run not more than 0.25 mm (0.01 in.) from the computed design thickness or the minimum

permitted thickness is acceptable

ASTM Specifications

ASTM Spec Grade Maximum Thickness

ASTM A 36M/A 36 ** 40 mm (1.5 in.).

ASTM

A 131M

/

A 131

Grade A

Grade B

Grade CS

Grade EH36

12.5 mm (0.5 in.)

25 mm (1 in.)

40 mm (1.5 in.)

[insert plates and flanges to a maximum thickness of 50 mm

(2 in.)]

45 mm(1.75 in.)

[insert plates and flanges to a maximum thickness of 50 mm

(2 in.)].

ASTM A 283M/A 283 Grade C 25 mm (1 in.).

ASTM A 285M/A 285 Grade C 25 mm (1 in.)

ASTM

A 516M

Grades 380, 415, 450,

485/A 516,

Grades 55, 60, 65, and 70

40 mm (1.5 in.)

[insert plates and flanges to a maximum thickness of 100 mm

(4 in.)].

ASTM

A 537M/A 537, Class 1 and Class 2,

45 mm (1.75 in.)

[insert plates to a maximum thickness of 100 mm (4 inches)].

ASTM

A 573M

Grades 400, 450, 485/A

573, Grades 58,65, and 70,

40 mm

(1.5 in.).

ASTM

A 633M/A 633 Grades C and D

45 mm (1.75 in.)

[insert plates to a maximum thickness of 100 mm (4.0 in.)].

ASTM A 662M/A 662 Grades B and C 40 mm (1.5 in.).

ASTM

A 678M

/

A 678

Grade A,

Grade B

40 mm (1.5 in.)

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

45 mm (1.75 in.)

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

ASTM A 737M/A 737 Grade B, 40 mm (1.5 in.).

ASTM

A 841M/A 841

Grade A, Class 1 and

Grade B,Class 2,

40 mm (1.5 in.)

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

API Standard 650

Figure 2-1 Permissible MDMT for Materials Used in Tank Shells Without Impact Testing

Table 2-1 Maximum Permissible Alloy Content

General Requirements for Delivery of Plates:

This material is intended to be suitable for fusion welding.

Strength and toughness of welds should be consistent with the plate material All welding performed to repair surface defects shall be done with low-hydrogen welding electrodes Fully killed steel shall be made to fine-grain practice.

Maximum manganese content to less than 1.60%

Maximum carbon content is reduced to 0.20%

The use or presence of columbium, vanadium, nitrogen, copper, nickel, chromium, or molybdenum

shall not exceed the limitations of Table 2-1 Heat Treatment of Plates:

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

(TMCP) plates may be used where normalized plates are required.

The tensile tests shall be performed on each plate as heat treated.

Heat treatment should be mentioned

Impact Testing of Plates:

Table 2-4 Minimum Impact Test Requirements for Plates

Toughness Requirements:

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

Plates more than 40 mm (1.5 in.) thick shall be of killed steel

Each TMCP A 841 plate-as-rolled shall be impact tested.

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

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 2-3a, Table 2-3b and

Figure 2-1 (apply only to shell nozzles and manholes.)

Except for nozzle and man-way necks, the material shall be of equal or greater yield and tensile

strength and shall be compatible with the adjacent shell material.

Materials for roof nozzles and manholes do not require special toughness.

API Standard 650

SHEETS MATERIALS

Sheets for fixed and floating roofs shall conform to ASTM A 1011M/A 1011, Grade 33

They shall be made by the open-hearth or basic oxygen process.

Copper-bearing steel shall be used

MATERIALS WITH STRUCTURAL SHAPES

Structural steel shall conform to one of the following:

ASTM A 36M/A 36. ASTM A 131M/A 131. ASTM A 992M/A 992. Structural Steels listed in AISC Specification for Structural Steel Buildings, Allowable Stress

Design

All steel for structural shapes shall be made by the open-hearth, electric-furnace, or basic oxygen process.

Like all other cases Copper-bearing steel is acceptable when approved by the purchaser.

PIPING MATERIALS AND FORGINGS MATERIALS

The following specifications are acceptable for pipe and pipe couplings:

API Spec 5L, Grades A, B, and X42. ASTM A 53, Grades A and B. ASTM A 106, Grades A and B. ASTM A 234M/A 234, Grade WPB. ASTM A 333M/A 333, Grades 1 and 6. ASTM A 334M/A 334, Grades 1 and 6. ASTM A 420M/A 420, Grade WPL6. ASTM A 524, Grades I and II. ASTM A 671

The following specifications are acceptable for forgings:

ASTM A 105M/A 105.

ASTM A 181M/A 181.

ASTM A 350M/A 350, Grades LF1 and LF2.

(Unless ASTM A 671 pipe is used with electric fusion welding) material for shell nozzles and shell manhole necks shall be seamless pipe, seamless forging, or plate material as specified

When shell materials are Group IV, IVA, V, or VI, seamless pipe shall comply with ASTM A

106, Grade B; ASTM A 524; ASTM A 333M/ A 333, Grade 6; or ASTM A 334M/A 334,

Grade 6.

When ASTM A 671 pipe is used for shell nozzles and shell manhole necks, it shall comply with the

Grades CA 55, CC 60, CC 65, CC 70, CD 70, CD 80, CE 55, and CE 60.

API Standard 650

FLANGES

Hub, slip-on, welding, and welding-neck flange shall conform to the material requirements of ASME

B16.5for forged carbon steel flanges

BOLTING

Bolting shall conform to ASTM A 307 or A 193M/A 193.A 325M/A 325 may be used for structural purposes.

WELDING ELECTRODES

Welding of materials with a minimum tensile strength less than 550 MPa (80 ksi), the manual

arc-welding electrodes shall conform to the E60 and E70 classification series (suitable for the

electric current characteristics, the position of welding, and other conditions of intended use)

in AWS A5.1

For the welding of materials with a minimum tensile strength of 550 through 585 MPa (80 through 85 ksi), the manual arc-welding electrodes shall conform to the E80XX-CX

classification series in AWS A5.5.

Figure 2-3 Governing Thickness for Impact Test Determination of Shell Nozzle and Manhole Materials.