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Technical Library > STUD BOLTS > STUD BOLTS MATERIALS > Stud Bolts Materials ASTM A193/A320/A453/A182
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STUD BOLTS MATERIALS


In this article, we have collected useful information about stud bolts materials for flanges, such as available grades, chemical composition, mechanical properties:

In addition, we suggest how to select the correct stud bolts material grade (based on flange material and, process temperature).


 

ASTM A193 (STUD BOLTS MATERIALS FOR HIGH TEMPERATURE)

ASTM A193 / A193M is the Standard Specification for alloy-steel and stainless steel stud bolts materials for high temperature or high-pressure service and other applications. This norm covers several grades, including ferritic steels and austenitic stainless steels which are designed as B5, B8, and so on. The selection of the right stud bolts material depends on design, service conditions (temperature, pressure, fluids), required mechanical and tensile properties, and other specific conditions of the application. Bolts materials according to ASTM A193 B7 are available in national coarse (UNC) thread pitches, generally used in traditional applications, which means that there are 8 threads per inch (“thread per inch”) for rod diameters above 1 inch. The most common stud bolts materials under ASTM A193 are listed below (high-temperature service):

  • ASTM A193 B5
  • ASTM A193 B6
  • ASTM A193 B7: Alloy steel, AISI 4140/4142 quenched and tempered
  • ASTM A193 B7M
  • ASTM A193 B16
  • ASTM A193 B8: Class 1 Stainless steel, AISI 304, carbide solution treated.
  • ASTM A193 B8A
  • ASTM A193 B8M: Class 1 Stainless steel, AISI 316, carbide solution treated.
  • ASTM A193 B8MA
  • ASTM A193 B8cl2: Class 2 Stainless steel, AISI 304, carbide solution treated, strain hardened
  • ASTM A193 B8Tcl2
  • ASTM A193 B8Mcl2: Class 2 Stainless steel, AISI 316, carbide solution treated, strain hardened

ASTM A193 MECHANICAL PROPERTIES

Grade and Class Diameter Tensile Strength Min KSI Yield Strength 0.2% Offset KSI Elongation in 4D, Min, % Reduction of Area Min, % Hardness Max Brinell Hardness Max Rockwell
B5 up to 4″ incl 100 80 16 50
B6 up to 4″ incl 110 85 15 50
B6X up to 4″ incl 90 70 16 50 C26
B7 to 2-1/2″ 125 105 16 50 C35
  over 2-1/2 to 4″ 115 95 16 50 C35
  over 4″ to 7″ 100 75 18 50 C35
B7M up to 4″ incl 100 80 18 50 235 B99
  over 4″ to 7″ 100 75 18 50 235 B99
B16 to 2-1/2″ 125 105 18 50 321 C35
  over 2-1/2″ to 4″ 110 95 17 45 321 C35
  over 4″ to 7″ 100 85 16 45 321 C35
Classes 1 and 1D: B8, B8M, B8P, B8LN, B8ML ALL 75 30 30 50 223 B96
Class 1: B8C, B8T ALL 75 30 30 50 223 B96
Class 1A: B8A, B8CA, B8MA, B8PA, B8TA, B8LNA, B8MLNA, B8NA, B8MNA, B8MLCuNA ALL 75 30 30 50 192 B90
Classes 1B & 1D: B8N, B8MN, B8MLCuN ALL 80 35 30 40 223 B96
Class 1C and 1D: B8R ALL 100 55 35 55 271 C28
Class 1C: B8RA ALL 100 55 35 55 271 C28
Classes 1C and 1D: B8S ALL 95 50 35 55 271 C28
Classes 1C: B8SA ALL 95 50 35 55 271 C28
Class 2: B8, B8C, B8P, B8T, B8N to 3/4″ 125 100 12 35 321 C35
  over 3/4″ to 1″ 115 80 15 35 321 C35
  over 1″ to 1-1/4″ 105 65 20 45 321 C35
  over 1-1/4 to 1-1/2″ incl 100 50 28 45 321 C35
Class 2 B8M, B8MN, B8MLCuN to 3/4″ 110 96 15 45 321 C35
  over 3/4″ to 1″ 100 80 20 45 321 C35
  over 1″ to 1-1/4″ 95 65 25 45 321 C35
  over 1-1/4 to 1-1/2″ incl 90 50 30 45 321 C35
Class 2B: B8, B8M2 to 2″ incl 95 75 25 40 321 C35
  over 2″ to 2-1/2″ incl 90 65 30 40 321 C35
  over 2-1/2 ” to 3″ incl 80 55 30 40 321 C35
Class 2C: B8M3 to 2″ incl. 85 65 30 60 321 C35
  over 2″ 85 60 30 60 321 C35

 


ASTM A320 (STUD BOLTS MATERIALS FOR LOW TEMPERATURE)

ASTM A320 / A320M is the Standard Specification for alloy-steel and Stainless Steel stud bolts materials for low-temperature service. Each alloy under ASTM A320 shall conform to prescribed chemical requirements. The material, as represented by the tension specimens, shall conform to specific requirements in terms of tensile strength, yield strength, elongation, and hardness. The stud bolt material shall meet the prescribed impact energy absorption requirements and the target test temperature. According to the ASTM A320 norm, manufacturers shall execute at least the following mechanical tests on the material: impact test, tension test, and hardness test. Under the ASTM A320 norm, several stud bolts grades are included, such as ferritic and austenitic steels grades designated as L7, B8, etc. The selection of the correct grade within this norm depends on design, service conditions, mechanical properties, and the specific situations under a low-temperature steel are required. The most common stud bolts materials under ASTM A193 are listed below (low-temperature service):

  • ASTM A320 L7: Alloy steel, AISI 4140/4142 Quenched and tempered 
  • ASTM  A320 L7M
  • ASTM A320 L43: Alloy steel, AISI 4340 Quenched and tempered 
  • ASTM A320 B8 Class 1: Stainless steel, AISI 304, carbide solution treated 
  • ASTM A320 B8A
  • ASTM A320 B8T
  • ASTM A320 B8TA
  • ASTM A320 B8C
  • ASTM A320 B8M: Class 1 Stainless steel, AISI 316, carbide solution treated 
  • ASTM A320 B8MA
  • ASTM A320 B8cl2: Stainless steel, AISI 304, carbide solution treated, strain hardened 
  • ASTM A320 B8Mcl2: Stainless steel, AISI 316, carbide solution treated, strain hardened

ASTM A320 MECHANICAL PROPERTIES

Grade Diameter Tensile, KSI, min Yield, KSI, min Charpy Impact 20-ft-LBF @ temp Elong, %, min RA, %, min
L7 Up to 212 125 105 -150° F 16 50
L43 Up to 4 125 105 -150° F 16 50
B8 Class 1 All 75 30 N/A 30 50
B8M Class 1 All 75 30 N/A 30 50
B8 Class 2 Up to 34 125 100 N/A 12 35
78 – 1 115 80 N/A 15 35
118 – 114 105 65 N/A 20 35
138 – 112 100 50 N/A 28 45
B8M Class 2 Up to 34 110 95 N/A 15 45
78 – 1 100 80 N/A 20 45
118 – 114 95 65 N/A 25 45
138 – 112 90 50 N/A 30 45


 ASTM A453 (ALLOY STUD BOLTS AND NUTS FOR HIGH TEMPERATURE)

The ASTM A453 specification covers standards for Grade 660 (Class A, B, C, and D), Grade 651 (Class A and B), Grade 662 (Class A and B), and Grade 665 (Class A and B) of bolting materials, with ten classes of yield strength ranging from 50 to 120 KSI [345 to 827 MPa], for use in high-temperature service such as fasteners, pressure vessels and flanges. Bolting materials in ASTM A453 are covered rolled, forged, or hot-extruded bars, and also bolts, nuts, screws, washers, studs, and stud bolts. Materials shall adhere to specified contents of carbon, manganese, phosphorus, sulfur, silicon, nickel, chromium, molybdenum, tungsten, titanium, columbium, aluminum, vanadium, boron, and copper.According to ASTM A453 materials shall be subjected to tension, stress-rupture, and hardness tests. Materials shall conform to yield strength, tensile strength, elongation, reduction of area, Brinell hardness, and Rockwell hardness requirements. Hardening and solution treatment requirements for each material class are also given. The most common grades under ASTM A453 are:

  • ASTM A453 660A
  • ASTM A453 660B
  • ASTM A453  660C
  • ASTM A453 660D

ASTM A453 CHEMICAL COMPOSITION

ELEMENT Grade 660 Grade 651 Grade 662 Grade 665 Grade 668
% % % % %
Carbon 0.08 max 0.28-0.35 0.08 max 0.08 max 0.08 max
Manganese 2.00 max 0.75-1.5 0.40-1.00 1.25-2.00 2.00 max
Phosphorus, max 0.040 max 0.040 max 0.040 max 0.040 max 0.040 max
Sulfur, max 0.030 max 0.030 max 0.030 max 0.030 max 0.030 max
Silicon 1.00 max 0.30-0.80 0.40-1.00 0.1-0.80 1.00 max
Nickel 24.0-27.0 8.0-11.0 24.0-28.0 24.0-28.0 17.5-21.5
Chromium 13.5-16.0 18.0-21.0 12.0-15.0 12.0-15.0 13.5-16.0
Molybdenum 1.00-1.50 1.00-1.75 2.0-3.50 1.25-2.25 1.50 max
Tungsten 1.00-1.75
Titanium 1.9-2.35 0.1-0.35 1.80-2.10 2.70-3.30 2.20-2.80
Columbium * 0.25-0.6
Aluminum 0.35 max 0.35 max 0.25 max 0.50 max
Vanadium 0.10-0.50 0.50 max
Boron 0.001-0.010 0.001-0.010 0.01-0.07 0.001-0.010
Copper 0.50 max 0.50 max 0.25 max

ASTM A453 MECHANICAL PROPERTIES

ASTM A453 Grade Class Tensile, Mpa Yield, Mpa Elong. %, min RA %, min
Grade 660 A, B , & C 895 min 585 min 15 18
  D 895 min 725 min 15 18
Grade 651 A 690 min 485 min 18 35
415 min
  B 655 min 415 min 18 35
345 min
Grade 662 A 895 min 585 min 15 18
  B 860 min 550 min 15 18
Grade 665 A 1170 min 830 min 12 15
  B 1070 min 830 min 12 15
Grade 665 A & B 895 min 858 min 15 18

HEAT TREATMENT REQUIREMENTS FOR ASTM A453 STUD BOLTS MATERIALS

Grade Class Solutiona Treatment Hardening Treatment
660 A 1650 +/- 25 °F [900 +/-14 °C], hold 2 h, min and liquid quench 1325 +/- 25 °F [720 +/- 14 °C] 16h, air cool
B 1800 +/- 25 °F [980 +/-14 °C], hold 1 h, min and liquid quench 1325 +/- 25 °F [720 +/- 14 °C] 16h, air cool
C 1800 +/- 25 °F [980 +/-14 °C], hold 1 h, min and oil quench 1425 +/- 25 °F [775 +/- 14 °C] hold 16h, air cool followed by 1200 +/- 25 °F [650 +/- 14 °C], hold 16h, air cool
D 1650 +/- 25 °F [900 +/-14 °C], hold 2 h, min and liquid quench OR

1325 +/- 25 °F [720 +/- 14 °C] hold 16h, air cool followed by 1200 +/- 25 °F [650 +/- 14 °C], hold 16h, air cool

if neccessary to achieve properties, second age : 1200 +/- 25 °F [650 +/- 14 °C] hold 16h, air cool

1800 +/- 25 °F [980 +/-14 °C], hold 1 h, min and liquid quench
651 A hot-cold worked at 1200 °F[650] min with 15% min reduction in cross sectional area, stress-relief anneal at 1200 °F [650 °C] min or 4h, min
B hot-cold worked at 1200 °F[650] min with 15% min reduction in cross sectional area, stress-relief anneal at 1350 °F [730 °C] min or 4h, min
662 A 1800 +/- 25 °F [980 +/-14 °C], hold 1 h, min and liquid quench 1350 to 1400 °F [730 to 760 °C], hold 20h, furnace cool to 1200 +/- 25 °F [650 +/- 14 °C], hold 20h, air cool
B 1950 +/- 25 °F [1065 +/-14 °C], hold 2 h, min and liquid quench 1350 to 1400 °F [730 to 760 °C], hold 20h, furnace cool to 1200 +/- 25 °F [650 +/- 14 °C], hold 20h, air cool
665 A 1800 +/- 25 °F [980 +/-14 °C], hold 3 h, min and liquid quench 1350 to 1400 °F [730 to 760 °C], hold 20h, furnace cool to 1200 +/- 25 °F [650 +/- 14 °C], hold 20h, air cool
B 2000 +/- 25 °F [1095 +/-14 °C], hold 3 h, min and liquid quench 1350 to 1400 °F [730 to 760 °C], hold 20h, furnace cool to 1200 +/- 25 °F [650 +/- 14 °C], hold 20h, air cool
668 A 1650 +/- 25 °F [900 +/-14 °C], hold 2 h, min and liquid quench 1325 +/- 25 °F [720 +/- 14 °C] 16h, air cool
B 1800 +/- 25 °F [980 +/-14 °C], hold 1 h, min and liquid quench 1325 +/- 25 °F [720 +/- 14 °C] 16h, air cool

TIME TO RUPTURE AND ELONGATION OF ASTM A453 ALLOY STUD BOLTS

Grade Class Test Temperature Stress, Min Time to Rupture Elongation
Deg F [ Deg C ] Ksi Mpa Min, h* Min %
660 A, B & C 1200 [650] 56 385 100 5
651 A & B 1200 [650] 40 275 100 5
662 A & B 1200 [650] 55 380 100 5
665 A 1200 [650] 75 515 100 3
B 1200 [650] 70 485 100 5

 


ASTM A182 (DUPLEX STEEL STUD BOLTS AND NUTS)

ASTM A182 / A182M  Standard Specification for Forged or Rolled Alloy and Stainless Steel Pipe Flanges, Forged Fittings, and Valves and Parts for High-Temperature Service.  Included are similar parts to specified dimensions or to dimensional standards, such as the ASME specifications that are referenced in Section Several grades of low alloy steels and ferritic, martensitic, austenitic, and ferritic-austenitic stainless steels are included in this specification. Selection will depend upon design and service requirements.
In ASTM A182 the values stated in either inch-pound units or SI units are to be regarded separately as the 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 the specification. The most common grades under ASTM A182 for bolting are:

  • ASTM A182  F51 (duplex)
  • ASTM A182  F44 (6Mo)
  • ASTM A182  F53 (super-duplex)
  • ASTM A182 F55 (super-duplex)

CHEMICAL PROPERTIES OF DUPLEX STUD BOLTS MATERIALS (UNS S31803/32205)

C Mn Si P S Cr Mo Ni N
2205
(S31803)
0.03
max
2.0
max
1.0
max
0.03
max
0.02
max
min: 21.0
max: 23.0
min: 2.5
max: 3.5
min: 4.5
max: 6.5
min: 0.08
max: 0.20
2205
(S32205)
0.03
max
2.0
max
1.0
max
0.03
max
0.02
max
min: 22.0
max: 23.0
min: 3.0
max: 3.5
min: 4.5
max: 6.5
min: 0.14
max: 0.20

MECHANICAL PROPERTIES OF DUPLEX STUD BOLTS (UNS S31803/32205)

Grade Tensile Strength
ksi (min)
Yield Strength
0.2% ksi (min)
Elongation % Hardness (HB) MAX
2205 90 65 25 217

PHYSICAL PROPERTIES OF DUPLEX STUD BOLTS (UNS S31803/32205)

Density
lbm/in3
Electrical
Resistivity
mW•in
Thermal
Conductivity
(BTU/hr•ft•°F)
Heat
Capacity
BTU/lbm•°F
Electrical
Resistivity
(in x 10-6)
at 68°F 0.278 27.6 8.7 0.112 33.5
at 212°F 26.1 9.2 0.119 35.4
at 392°F 25.4 9.8 0.127 37.4
at 572°F 24.9 10.4 0.134 39.4

CHEMICAL PROPERTIES OF SUPER-DUPLEX STUD BOLTS (UNS S32750)

C Cr Ni Mo N Others
0.020 25 7 4.0 .27 S=0.001

MECHANICAL PROPERTIES OF SUPER-DUPLEX STUD BOLTS (UNS S32750)

Ultimate Tensile Strength, ksi 116 min.
0.2% Offset Yield Strength 0.2%, ksi 80 min.
0.1% Offset Yield Strength 0.2%, ksi 91 min.
Elongation in 2 inches, % 15 min.
Hardness Rockwell C 32 max.
Impact Energy, ft.-lbs. 74 min.

PHYSICAL PROPERTIES OF SUPER-DUPLEX STUD BOLTS MATERIALS (UNS S32750)

Density lb/in3 0.28
Modulus of Elasticity psi x 106 29
The coefficient of Thermal Expansion
68-212°F/°F
x10-6/°F 7.2
Thermal Conductivity Btu/h ft °F 8.7
Heat Capacity Btu/lb/°F 0.12
Electrical Resistivity W-in x 10-6 31.5

 


STUD BOLTS COATING MATERIALS

Stud bolts can be coated to increase the resistance to corrosion. The most common types of coatings for stud bolts are listed below:

  • Electro zinc plating
  • Electro cadmium plating
  • Hot dip galvanizing
  • PTFE Coating
  • Phosphate coating
  • Electroless nickel plating
  • Zinc-nickel coating
  • Aluminum coating
  • Silver coating
  • Zinc/Nickel by electrodeposition
  • Dacromet
  • Geomet

In addition, also XYLAN and XYLAR coatings are available:

  • XYLAN 1070
  • XYLAN 1024
  • XYLAR 1

Xylan and Xylar coatings for stud bolts have multiple advantages:

  • Lower frictions vs. uncoated bolts (CoF is as low as 0.02)
  • Increased wear resistance for the bolt even under extreme pressures.
  • Strong corrosion and chemical resistance in most demanding environments
  • Increased resistance to adverse weather conditions (such as extreme sunlight, salt-water exposure to chemicals)
  • Wider operating range in terms of temperature (from -420° to +550°F, i.e. -250° to 285°C).
  • Color coding for easier traceability
  • Pliability: Xylan coatings bend easily and repeatedly and do not break
  • Machinability: multiple Xylan coatings can be applied to the stud bolt
  • Strong adhesion to bolting materials 

SELECTION OF STUD BOLTS MATERIALS

The material to use for stud bolts depends on multiple factors, the main ones are the material of the flanges and the pipeline design temperature:

DESIGN
TEMPERATURE
FLANGE MATERIAL SUGGESTED BOLT GRADE SUGGESTED NUTS GRADE
-195° to 102°C ASTM A 182 Gr. F304, F304L, F316, F316L, F321, F347 A320 Gr. B8 Class 2 A194 Gr. 8A
-101° to -47°C ASTM A 350 Gr. LF3 A 320 Gr. L7 A 194 Gr. 7
-46° to -30°C ASTM A 350 Gr. LF2 A 320 Gr. L7 A 194 Gr. 7
-29° to 427°C ASTM A 105 A 193 Gr. B7 A 194 Gr. 2H
428° to 537°C ASTM A 182 Gr. F11, F22 A 193 Gr. B16 A 194 Gr. 2H
538° to 648°C ASTM A182 Gr. F11, F22 A 193 Gr. B8 Class 1 A 194 Gr. 8A
649° to 815°C ASTM A182 Gr. F304 H, F316 H A 193 Gr. B8M Class 1 A 194 Gr. 8A

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ASTM materials for stud bolts and nuts.pdf

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