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ASTM A540 - Standard specification for Alloy Steel Bolting for Special Applications

This specification covers 5 grades of bolting with twelve classes of yield strength ranging from 50 to 120 ksi [345 to 827 Mpa] for used in high temperature service such as fasteners for pressure bessel and valve flanges. The specification is expressed in both inch-pound units and in SI units. BoltPort primarily stocks and supply A453 Grade 660 Boltings for high temperature service. We stock round bar in Grade 660, Grade 651 & Grade 665 for quick manufacturing these bolts. These bolts are solution annealed and age hardened to provide maximum efficiency in their applications. We offer Rupture Test Facility for sufficient quantity order.

ASTM A540 Grades

Grade Tensile Class
Grade B21 Class 5 Class 4 Class 3 Class 2 Class 1
Grade B22 Class 5 Class 4 Class 3 Class 2 Class 1
Grade B23 Class 5 Class 4 Class 3 Class 2 Class 1
Grade B24 Class 5 Class 4 Class 3 Class 2 Class 1
Grade B24V -- -- Class 3 Class 2 Class 1

ASTM A540 Properties

ASTM A540 Chemical CompositionA

Element Grade B21 Grade B22 Grade B23 Grade B24 Grade B24V
Cr-Mo-V 4142-H E-4340-H 4340-Mod. 4340V-Mod.
Chrome Moly Vanadium Chrome Moly Chrome Nickel Vanadium Chrome Nickel Vanadium Chrome Nickel Moly Vanadium
RangeB, %
Carbon 0.35 - 0.44 0.39 - 0.46 0.37 - 0.44 0.37 - 0.44 0.37 - 0.44
Manganese 0.45 - 0.70 0.65 - 1.10 0.60 - 0.95 0.70 - 0.90 0.60 - 0.95
PhosphorusC, max 0.025 0.025 0.025 0.025 0.025
SulfurC, max 0.025 0.025 0.025 0.025 0.025
Silicon 0.15 - 0.35 0.15 - 0.35 0.15 - 0.35 0.15 - 0.35 0.15 - 0.35D
Chromium 0.80 - 1.15 0.75 - 1.20 0.65 - 0.95 0.70 - 0.95 0.60 - 0.95
Nickel -- -- 1.55 - 2.00 1.65 - 2.00 1.55 - 2.00
Molybdenum 0.50 - 0.65 0.15 - 0.25 0.20 - 0.30 0.30 - 0.40 0.40 - 0.60
Vanadium 0.25 - 0.35 --- --- --- 0.04 - 0.10

A The intensional addition of Bi, Se, Te and Pb is not permitted.
B Unless otherwise specified, separate determinations may vary from the specified ranges, except that elements in any heat mush not vary both above and below the specified range.
C Phosphorus and sulfur content is 0.04% max when open hearth steel is specified.
D Silicon content is 0.35& mac if vacuum carbon deoxidized.

ASTM A540 Mechanical Properties

Grades Class Diameter, inch. Tensile Strength, min Yield Strength,
0.2% offset,
min
Elongation
min, %
Reduction
of Area, min, %
Surface
Brinell
Hardness
Charpy V Notch +10 °F [-12.2 °C]
Inch Pound Units
ksi ksi In 2 inch. Min Max
Grade B21 (Cr-Mo-V) 5 to 2, incl. 120 105 15 50 241 285 D
5 over 2 to 6, incl. 115 100 15 50 248 302 D
5 over 6 to 8, incl. 115 100 15 50 255 311 D
4 to 3, incl. 135 120 13 45 269 331 D
4 over 3 to 6, incl. 135 120 13 45 277 352 D
3 to 3, incl. 145 130 12 40 293 352 D
3 over 3 to 6, incl. 145 130 12 40 308 375 D
2 to 4, incl. 155 140 11 40 311 401 D
1 to 4, incl. 165 150 10 35 321 429 D
Grade B22 (4142-H) 5 to 2, incl. 120 105 15 50 248 293 A
5 over 2 to 4, incl. 115 100 15 50 255 302 D
4 to 1, incl. 135 120 13 45 269 341 A
4 over 1 to 4, incl. 135 120 13 45 277 363 D
3 to 2, incl. 145 130 12 40 293 363 D
3 over 2 to 4, incl. 145 130 12 40 302 375 D
2 to 3, incl. 155 140 11 40 311 401 D
1 to 1-1/2, incl. 165 150 10 35 321 401 D
Grade B23 (E-4340-H) 5 to 6, incl. 120 105 15 50 248 311 A
5 over to 8, incl. 115 100 15 50 255 321 A
5 over 8 to 9-1/2, incl. 115 100 15 50 262 321 D
4 to 3, incl. 135 120 13 45 269 341 A
4 over 3 to 6, incl. 135 120 13 45 277 352 A
4 over 6 to 9-1/2, incl. 135 120 13 45 285 363 D
3 to 3, incl. 145 130 12 40 293 363 B
3 over 3 to 6, incl. 145 130 12 40 302 375 B
3 over 6 to 9-1/2, incl. 145 130 12 40 311 388 D
2 to 3, incl. 155 140 11 40 311 388 D
2 over 3 to 6, incl. 155 140 11 40 311 401 D
1 to 3, incl. 165 150 10 35 321 415 D
1 over 3 to 6, incl. 165 150 10 35 331 429 D
1 over 6 to 8, incl. 165 150 10 35 341 444 D
Grade B24 (4340 Mod.) 5 to 6, incl. 120 105 15 50 248 311 A
5 over 6 to 8, incl. 115 100 15 50 255 321 A
5 over 8 to 9-1/2, incl. 115 100 15 50 262 321 A
4 to 3, incl. 135 120 13 45 269 341 A
4 over 3 to 6, incl. 135 120 13 45 277 352 A
4 over 6 to 8, incl. 135 120 13 45 285 363 A
4 over 8 to 9-1/2, incl. 135 120 13 45 293 363 D
3 to 3, incl. 145 130 12 40 293 363 B
3 over 3 to 8, incl. 145 130 12 40 302 388 B
3 over 8 to 9-1/2, incl. 145 130 12 40 311 388 D
2 to 7, incl. 155 140 11 40 311 401 B
2 over 7 to 9-1/2, incl. 155 140 11 40 321 415 D
1 to 6, incl. 165 150 10 35 321 415 C
1 over 6 to 8, incl. 165 150 10 35 331 429 D
Grade B24V (4340 Mod.) 3 to 4, incl. 145 130 12 40 293 363 A
3 over 4 to 8, incl. 145 130 12 40 302 375 B
3 over 8 to 11, incl. 145 130 12 40 311 388 C
2 to 4, incl. 155 140 11 40 311 388 B
2 over 4 to 8, incl. 155 140 11 40 311 401 C
2 over 8 to 11, incl. 155 140 11 40 321 415 D
1 to 4, incl. 165 150 10 35 321 415 C
1 over 4 to 8, incl. 165 150 10 35 331 429 D
1 over 8 to 11, incl. 165 150 10 35 331 444 D

ASTM A540 Heat Treatment

Bolting material ordered in the annealed condition shall have a structure suitable for machining. Such annealed material is not intended to be used without subsequent quenching and tempering. Bolting ordered in the liquid quenched and tempered condition shall be uniformly reheated froma temperature below the cooling transformation range to the proper austenitizing temperature, quenched in a liquid medium under substantially uniform conditions, and then uniformly reheated for tempering. The minimum tempering tempereture shall be 850°F [455°C].
Material that has been straintened after quenching and tempering shall be stress relieved by reheating to a temperature not lower than 100°F [55°C] under the tempering temperature.

Hardness Requirements for ASTM A540 Bolts

The hardness shall be determined on the surface of the material removal of decarburization. The hardness of material in the annealed condition shall not be greater than 235 HB. The hardness of material in the quenched and tempered or quenched, temepred and stress-relieved condition shall be within the limits in hardness column of the mechanical properties table.

ASTM A540 Bolt Marking

Grade and manufacturer's identification symbols shall be applied to one end of studs and to the heads of bolts of all sizes. If the available area is inadequate, the grade symbol may be marked on one end and the manufacturer's identification symbol marked on the other end.