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ASTM F738M Screws Bolts & Studs Specification

Stainless Steel Metric Bolts Screws & studs for use in engineering applications requiring general corrosion resistance

ASTM F738M Hex Bolts, Heavy Hex Bolts, Studs, Socket Head Cap Screws, Threaded Rods

ASTM F738 / F738M Specification covers the chemical and mechanical requirements for stainless steel metric bolts, screws, and studs with nominal thread diameters M1.6 through M36 and is intended for use in engineering applications requiring general corrosion resistance. Eight groups of stainless steel alloys are covered, including three austenitic (Grades A1, A2, and A4), one ferritic (Grade F1), three martensitic (Grades C1, C3, and C4), and one precipitation hardening (Grade P1). Twenty property classes are covered, including nine austenitic, two ferritic, eight martensitic, and one precipitation hardening. This specification is based in concept and content on ISO 3506. The chemical and mechanical requirements speci- fied for all property classes, except as given in 1.4.1, are essentially identical with classes of the same designation in ISO 3506. his specification includes all of the property classes covered in ISO 3506. Additionally, it includes property classes A1-70, A2-70, A4-70, A1-80, A2-80, and A4-80 for products with nominal thread diameters larger than M20; and four non-ISO property classes, C1-110, C4-110, C3-120; and P1-90. Suitable nuts for use with bolts, screws, and studs included in this specification are covered by Specification F836M. Specifications A276, A493, A564/A564M, and A582/A582M are noted for information only as suitable sources of material for the manufacture of bolts, hex cap screws, and studs to this specification.

Related Specifications of ASTM F738M Bolting

F836 EN 3506-1

ASTM F738M Property Classes of Stainless Steel Bolts, Screws, and Studs

Property Class Permissible Alloys
A1-50 304, 304L, 305A
A1-70 384, 18-9LW, 302HQ
A1-80 ... 
A2-50 ...
A2-70 321, 347
A2-80 ... 
A4-50 ...
A4-70 316, 316L
A4-80 ... 
F1-45 430B
C1-70 410
C1-110 ... 
C3-80 431
C3-120 ... 
C4-70 416, 416Se
C4-110 ... 
P1-90 630
  • (A) When approved by the purchaser, Alloys 303, 303Se, or XM1 may be furnished.
  • (B) When approved by the purchaser, Alloy 430F may be furnished.

ASTM F738M Chemical Requirements

Alloy Group Alloy UNS Designation C Mn P S Si Cr Ni Cu Mo Others
A1 303 S30300 0.15 2.00 0.20 0.15 min 1.00 17.0 to 19.0 8.0 to 10.0 ...  0.60 maxA ... 
A1 303Se S30323 0.15 2.00 0.20 0.060 1.00 17.0 to 19.0 8.0 to 10.0 ...  ...  Se 0.15 min
A1 304 S30400 0.08 2.00 0.045 0.030 1.00 18.0 to 20.0 8.0 to 10.5 1.00 ... 
A1 304L S30403 0.03 2.00 0.045 0.030 1.00 18.0 to 20.0 8.0 to 12.0 1.00 ... 
A1 305 S30500 0.12 2.00 0.045 0.030 1.00 17.0 to 19.0 10.5 to 13.0 1.00 ... 
A1 384 S38400 0.08 2.00 0.045 0.030 1.00 15.0 to 17.0 17.0 to 19.0 ... 
A1 XM1 S20300 0.08 5.0 to 6.5 0.040 0.18 to 0.35 1.00 16.0 to 18.0 5.0 to 6.5 1.75 to 2.25 0.50 maxA ... 
A1 18-9LW S30430 0.10 2.00 0.045 0.030 1.00 17.0 to 19.0 8.0 to 10.0 3.0 to 4.0 ...  ... 
A1 302HQ S30433 0.03 2.00 0.045 0.030 1.00 17.0 to 19.0 8.0 to 10.0 3.0 to 4.0 ...  ... 
A4 316 S31600 0.08 2.00 0.045 0.030 1.00 16.0 to 18.0 10.0 to 14.0 ...  2.00-3.00 ... 
A4 316L S31603 0.03 2.00 0.045 0.030 1.00 16.0 to 18.0 10.0 to 14.0 ...  2.00-3.00 ... 
A2† 321 S32100 0.08 2.00 0.045 0.030 1.00 17.0 to 19.0 9.0 to 12.0 ...  ...  Ti  5 × C min
A2 347 S34700 0.08 2.00 0.045 0.030 1.00 17.0 to 19.0 9.0 to 13.0 ...  ...  Cb + Ta 10 × C min
F1 430 S43000 0.12 1.00 0.040 0.030 1.00 16.0 to 18.0 ...  ...  ... 
F1 430F S43020 0.12 1.25 0.060 0.15 min 1.00 16.0 to 18.0 ...  ...  0.60 maxA ... 
C1 410 S41000 0.15 1.00 0.040 0.030 1.00 11.5 to 13.5 ...  ...  ...  ... 
C4 416 416Se S41600 0.15 1.25 0.060 0.15 min 1.00 12.0 to 14.0 ...  ...  0.60 maxA Se 0.15 min
C4 ...  S41623 0.15 1.25 0.060 0.060 1.00 12.0 to 14.0 ...  ...  ...  ... 
C3 431 S43100 0.20 1.00 0.040 0.030 1.00 15.0 to 17.0 1.25 to 2.50 ...  ...  ... 
P1 630 S17400 0.07 1.00 0.040 0.030 1.00 15.0 to 17.5 3.0 to 5.0 3.0 to 5.0 ...  Cb + Ta 0.15-0.45
  • (A) At manufacturer's option, determined only when intentionally added.

ASTM F738M Mechanical Requirements

Property Class Condition Alloy Mechanical Property Marking Nominal Thread Diameter Product Length Full Size Product Tests Machined Specimen Tests Hardness
Tensile Strength,MPa C Yield Strength,MPa C,D Exten-sion E Torsional Strength F Tensile Strength,MPa Yield Strength,MPa Elonga-gation,% Vickers Rockwell
min min min min min min min min max min max
A1-50  AF F738A M1.6±M5 all 500 . . . . . . Table 6 . . . . . . . . . . . . 165 . . . B85
A2-50 F738B M6±M36 all 500 210 0.6D . . . 500 210 30 . . . 165 . . . B85
A4-50 F738C . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
A1-70 F738D M1.6±M5 8D 700 . . . . . . Table 6 . . . . . . . . . 220 330 B96 C33
A2-70 CW F738E M6±M20 8D 700 450 0.4D . . . 650 400 20 220 330 B96 C33
A4-70 F 738F over M20±M36 8D 550 300 0.2Dx . . . 520 270 25 160 310 B83 C31
M1.6±M5 8D 800 . . . . . . Table 6 . . . . . . . . . 240 350 C23 C36
A1-80  SH F738G M6±M20 8D 800 600 0.3D . . . 780 600 12 240 350 C23 C36
A2-80 F738H over M20±M24 8D 700 500 0.2D . . . 680 480 15 220 330 B96 C33
A4-80 F 738J over  M24±M30 8D 650 400 0.2D . . . 620 370 20 200 310 B93 C30
over  M30±M36 8D 600 300 0.2D . . . 570 270 28 180 285 B89 C28
F1-45 AF F 738K M1.6±M5 all 450 . . . . . . . . . . . . . . . . . . . . . 165 . . . B85
M6±M36 all 450 250 0.2D . . . 450 250 25 . . . 165 . . . B85
F1-60 CW F 738L M1.6±M5 8D 600 . . . . . . . . . . . . . . . . . . 180 285 B89 C28
M6±M36 8D 600 410 0.2D . . . 550 360 20 180 285 B89 C28
C1-50  A F738M M1.6±M5 all 500 . . . . . . . . . . . . . . . . . . . . . 165 . . . B85
C4-50 F738N M6±M36 all 500 250 0.2D . . . 500 250 20 . . . 165 . . . B85
C1-70  H F738P M1.6±M5 all 700 . . . . . . . . . . . . . . . . . . 220 330 B96 C34
C4-70 F738R M6±M36 all 700 410 0.2D . . . 700 410 18 220 330 B96 C34
C1-110  HT F738S M1.6±M5 all 1100 . . . . . . . . . . . . . . . . . . 350 440 C36 C45
C4-110 F738T M6±M36 all 1100 820 0.2D . . . 1100 820 12 350 440 C36 C45
C3-80 H F 738U M1.6±M5 all 800 . . . . . . . . . . . . . . . . . . 240 340 C23 C35
M6±M36 all 800 640 0.2D . . . 800 640 15 240 340 C23 C35
C3-120 HT F 738V M1.6±M5 all 1200 . . . . . . . . . . . . . . . . . . 380 480 C39 C48
M6±M36 all 1200 950 0.2D . . . 1200 950 10 380 480 C39 C48
P1-90 AH F 738W M1.6±M5 all 900 . . . . . . . . . . . . . . . . . . 285 370 C28 C38
M6±M36 all 900 700 0.2D . . . 900 700 16 285 370 C28 C38
  • (A) Legend of Conditions: 
    •  AF-formed and annealed. 
    • CW-formed from annealed stock, thus acquiring a degree of cold work. 
    • SH-machined from strain hardened stock. 
    • A-machined from annealed or solution annealed stock, thus retaining the properties of the original material, or hot formed and solution annealed. 
    • H-hardened and tempered at 565°C medium. 
    • HT-hardened and tempered at 275°C minimum. 
    • AH-solution annealed and age hardened after forming.
  • (B) For product lengths: ªallº means all lengths ª8D º means 8 times nominal diameter maximum.
  • (C) Tensile strength and yield strength values for full-size products of each property class are given in table on yield and tensile strength.
  • (D) Yield strength is the stress at which an offset of 0.2 % gage lingth occurs.
  • (E) Extension measurement is determined in accordance with the test procedure speci®ed in 10.2.3.
  • (F) Torsional strength requirements apply only to austenitic steel fasteners with nominal thread diameters M5 and smaller. Values are given in table on torsional strength.

ASTM F738M Yield and Tensile Strength Values for Full-Size Fasteners, kN

Nominal Size and Thread Pitch Stress Area,A mm2 Yield or Tensile Stress, MPa
210 250 300 400 410 450 500 550 600 640 650 700 800 820 900 950 1100 1200
M1.6 3 0.35 1.27 ... ... ... ... ... 0.57 0.64 ... 0.76 ... ... 0.89 1.02 ... ... ... 1.4 1.52
M2 3 0.4 2.07 ... ... ... ... ... 0.93 1.04 ... 1.24 ... ... 1.45 1.66 ... ... ... 2.28 2.48
M2.5 3 0.45 3.39 ... ... ... ... ... 1.52 1.7 ... 2.03 ... ... 2.37 2.71 ... ... ... 3.73 4.07
M3 3 0.5 5.03 ... ... ... ... ... 2.26 2.52 ... 3.02 ... ... 3.52 4.02 ... ... ... 5.53 6.04
M4 3 0.7 8.78 ... ... ... ... ... 3.95 4.39 ... 5.27 ... ... 6.15 7.02 ... ... ... 9.66 10.5
M5 3 0.8 14.2 ... ... ... ... ... 6.39 7.1 ... 8.52 ... ... 9.94 11.4 ... ... ... 15.6 17
M6 3 1 20.1 4.22 5.03 6.03 8.04 8.24 9.05 10.1 11.1 12.1 12.9 13.1 14.1 16.1 16.5 18.1 19.1 22.1 24.1
M8 3 1.25 36.6 7.69 9.15 11 14.6 15 16.5 18.3 20.1 22 23.4 23.8 25.6 29.3 30 32.9 34.8 40.3 43.9
M10 3 1.5 58 12.2 14.5 17.4 23.2 23.8 26.1 29 31.9 34.8 37.1 37.7 40.6 46.4 47.6 52.2 55.1 63.8 69.6
M12 3 1.75 84.3 17.7 21.1 25.3 33.7 34.6 37.9 42.2 46.4 50.6 54 54.8 59 67.4 69.1 75.9 80.1 92.7 101
M16 3 2 157 33 39.3 47.1 62.8 64.4 70.7 78.5 86.4 94.2 100 102 110 126 129 141 149 173 188
M20 3 2.5 245 51.5 61.3 73.5 98 100 110 123 135 147 157 159 172 196 201 221 233 270 294
M24 3 3 353 74.1 88.3 106 141 145 159 177 194 212 226 229 247 282 289 318 335 388 424
M30 3 3.5 561 118 140 168 224 230 252 281 309 337 359 365 393 449 460 505 533 617 673
M36 3 4 817 172 204 245 327 335 368 409 449 490 523 531 572 654 670 735 776 899 980
  • A Stress area = 0.7854 ( D − 0.9382 P)2
    • where:
    • D = nominal size, mm, and
    • P = thread pitch, mm

ASTM F738M Values for Length x A

Nominal Thread Diameter x, mm
M1.6 4
M2 5
M2.5 6
M3 8
M4 10
M5 12
M6 14
M8 20
M10 25
M12 30
M16 40
M20 45
M24 and larger 3D
  • (A) x equals the minimum length of product subject to tension testing.

ASTM F738M Torsional StrengthA of Screws

0.63 Nominal Size and Thread Pitch Torsional Strength, min − Grades A1, A2, A4
Class 50 Class 70 Class 80
N´m N´m N´m
M1.6 3 0.35 0.15 0.20 0.27
M2 3 0.4 0.30 0.40 0.56
M2.5 3 0.45 0.60 0.90 1.20
M3 3 0.5 1.10 1.60 2.10
M3.5 3 0.6 1.80 2.50 3.20
M4 3 0.7 2.70 3.80 4.90
M5 3 0.8 5.50 7.80 10.00
  • (A) Torsional strength requirements apply only to austenitic steel screws and studs with nominal thread diameters M5 and smaller.

ASTM F738M Bolting Surface Treatment Specifications

ASTM F738M Bolting Components Marking

Product Shall be Marked with our manufacturing trade mark "TorqBolt" or "TB" along with the designated Grade.
Grade and manufacturer’s identification symbols shall be applied to one end of studs and to the heads of bolts and screws 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.) For bolts and screws smaller than 1⁄4 in. [6 mm] in diameter and studs smaller than 3⁄8 in. [10 mm] in diameter and for 1⁄4 in. [6 mm] in diameter studs requiring more than a total of three symbols, the marking shall be a matter of agreement between the purchaser and the manufacturer.

Property Class Alloy Mechanical Property Marking
ASTM F738M A1-50 TB F738A
ASTM F738M A2-50 TB F738B
ASTM F738M A4-50 TB F738C
ASTM F738M A1-70 TB F738D
ASTM F738M A2-70 TB F738E
ASTM F738M A4-70 TB F738F
ASTM F738M A1-80 TB F738G
ASTM F738M A2-80 TB F738H
ASTM F738M A4-80 TB F738J
ASTM F738M F1-45 TB F738K
ASTM F738M F1-60 TB F738L
ASTM F738M C1-50 TB F738M
ASTM F738M C4-50 TB F738N
ASTM F738M C1-70 TB F738P
ASTM F738M C4-70 TB F738R
ASTM F738M C1-110 TB F738S
ASTM F738M C4-110 TB F738T
ASTM F738M C3-80 TB F738U
ASTM F738M C3-120 TB F738V
ASTM F738M P1-90 TB F738W
ASTM F738M P1-90 TB F738W

ASME Dimensional Standards

B18.31.2 Imperial Continious Thread, Double End Reduced & Full Body Studs
B18.31.1M Metric Continious Thread, Double End Reduced & Full Body Studs
B16.5 Imperial & Metric Full Thread Stud Bolts
B16.5 Imperial & Metric Full Thread Stud Bolts
B18.2.1 Imperial Square and Hex Bolts and Screws
B18.2.3.1M Metric Hex Cap Screws
B18.2.3.3M Metric Heavy Hex Screws
B18.2.3.5M Metric Hex Bolts
B18.3 Imperial Hexagon Socket and Spline Socket Screws
B18.3.1M Metric Socket Head Cap Screws
B18.6.7M Metric Machine Screws

ASTM F738M Bolting Certifications

  • EN 10204 3.1
  • EN 10204 3.2
  • PED 2014/68/EC
  • MERKBLATT AD 2000 W2/W7/W10
  • API 20 E BSL 1/ BSL 2
  • NACE MR 0175
  • NACE MR 0103

ASTM F738M Testing Standards

E18 Test Methods for Rockwell Hardness of Metallic Materials
E21 Test Methods for Elevated Temperature Tension Tests of Metallic Materials
E112 Test Methods for Determining Average Grain Size
E139 Test Methods for Conducting Creep, Creep-Rupture,and Stress-Rupture Tests of Metallic Materials
E150 Recommended Practice for Conducting Creep and Creep-Rupture Tension Tests of Metallic Materials Under Conditions of Rapid Heating and Short Times
E151 Recommended Practice for Tension Tests of Metallic Materials at Elevated Temperatures with Rapid Heating and Conventional or Rapid Strain Rates
E292 Test Methods for Conducting Time-for-Rupture Notch Tension Tests of Materials
E328 Test Methods for Stress Relaxation for Materials and Structures
E566 Practice for Electromagnetic (Eddy Current) Sorting of Ferrous Metals
E709 Guide for Magnetic Particle Testing
F606/F606M Test Methods for Determining the Mechanical Properties of Externally and Internally Threaded Fasteners, Washers, Direct Tension Indicators, and Rivets
F1940 Test Method for Process Control Verification to Prevent Hydrogen Embrittlement in Plated or Coated Fasteners
A962/A962M Specification for Common Requirements for Bolting Intended for Use at Any Temperature from Cryogenic to the Creep Range
A788/A788M for Steel Forgings, General Requirements

ASME Threading Specifications

ASME B1.1 Unified Inch Screw Threads (UN and UNR Thread Form)
ASME B1.3 Screw Thread Gaging System for Dimensional Acceptability - Inch Screw Threads (IN, UNR, and UNJ)
ASME B1.13M Metric Screw Threads - M Profile
ASME B1.21M Metric Screw Threads - MJ Profile
ASME B1.2 Gauges & gauging for Unified Screw Threads(Imperial)

ASTM F738M Supplementary Requirements

S1 Additional Tests
S2 Alloy Control
S3 Permeability
S4 Passivation
S5 Shipment Lot Testing
S6 Heat Control