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  4. ASTM F879/F879M Specification

ASTM F879/F879M Stainless Steel Screws Specification

Stainless steel metric hexagon socket button (SBHCS) and flat countersunk (SFHCS) head cap screws intended for use in applications requiring general corrosion resistance

ASTM F879/F879M Chemical Requirements

Alloy Group UNS Designation Alloy C Mn P S Si Cr Ni Cu Mo
1 S30400 304 0.08 2.00 0.045 0.030 1.00 18.0 to 20.0 8.0 to 10.5 1.00 . . .
S30403 304L 0.030 2.00 0.045 0.030 1.00 18.0 to 20.0 8.0 to 12.0 1.00 . . .
S30500 305 0.12 2.00 0.045 0.030 1.00 17.0 to 19.0 10.5 to 13.0 1.00 . . .
S38400 384 0.08 2.00 0.045 0.030 1.00 15.0 to 17.0 17.0 to 19.0 . . . . . .
S30430 18-9LW 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 . . .
S30433 302HQ 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 . . .
... 304J3 A 0.08 2.00 0.045 0.030 1.00 17.0 to 19.0 8.0 to 10.5 1.00 to 3.00 . . .
2 S31600 316 0.08 2.00 0.045 0.030 1.00 16.0 to 18.0 10.0 to 14.0 . . . 2.00 to 3.0
S31603 316L 0.03 2.00 0.045 0.030 1.00 16.0 to 18.0 10.0 to 14.0 . . . 2.00 to 3.0
  • (A) 304J3 from JIS G 4309.

ASTM F879/F879M Mechanical Property Requirements

Alloy Group Alloy  Condition Full Size Product Tests A Machined Specimen Tests Core Hardness B
Tensile  Strength ksi Extension C min Tensile  Strength ksi Yield  Strength ksi Elongation  % min Vickers Rockwell
All AF 85 max 0.6D 85 max 55 max 40 210 max 95 HRB max
All CW 80 min 0.4D 80 min 40 min 25 150 min 50 HRA min
All CW1 102 min 0.4D 87 min 65 min 20 220 min 59 HRA min
  • (A) Actual full-size testing of condition CW and CW1 may result in decreased tensile strength because of the head configuration (see Table 3). For fasteners with nominal thread diameters larger than 0.625 in., the mechanical properties shall be agreed upon between the user and manufacturer.
  • (B) Core hardness is only required when full-size product testing cannot be accomplished.
  • (C) D denotes nominal thread size.

ASTM F879/F879M Breaking Strength Values for Full Size Fasteners (Inch)

Nominal Size Tensile Stress Area, in.2 Alloy Condition, lb. min
AF CW CW1
0 0.060-80 0.00180 153 115 147
1 0.073-64 0.00263 223 168 215
2 0.086-56 0.00370 314 237 303
3 0.099-48 0.00487 414 312 399
4 0.112-40 0.00604 513 386 495
5 0.125-40 0.00796 676 509 652
6 0.138-32 0.00909 772 581 745
8 0.164-32 0.0140 1191 897 1149
10 0.190-24 0.0175 1490 1122 1438
1/4 0.250-20 0.0318 2705 2037 2609
5/16 0.312-18 0.0524 4457 3356 4299
3/8 0.375-16 0.0775 6587 4959 6354
1/2 0.500-13 0.1419 12 061 9082 11 636
5/8 0.625-11 0.226 19 210 14 464 18 532

ASTM F879/F879M Breaking Strength Values for Full Size Fasteners (Metric)

Nominal Size and Thread Pitch Stress Area, mm2 Property Class
A1-50 A1-55 A1-70
kN, max kN, min kN, min
M3 × 0.5 5.03 2.94 2.21 2.82
M4 × 0.7 8.78 5.14 3.86 4.92
M5 × 0.8 14.2 8.30 6.24 7.94
M6 × 1.0 20.1 11.8 8.9 11.3
M8 × 1.25 36.6 21.4 16.1 20.5
M10 × 1.5 58.0 33.9 25.5 32.5
M12 × 1.75 84.3 49.3 37.1 47.2
M14 × 2.0 115.0 67.5 50.8 64.6
M16 × 2.0 157.0 91.7 68.9 87.7
M20 × 2.5 245.0 143 108 137

ASTM F879/F879M Mechanical Property Requirements

Alloy conditions Full Sized Product Tests Machined Specimen Tests Hardness
Tensile Strength ksi Yield Strength ksi Tensile Strength ksi Yield Strength ksi Elongation % min Vickers Rockwell
min max min max
CW 90 min 0.4D 85 min 58 min 20 220 330 B80 C33

ASTM F879/F879M Bolting Surface Treatment Specifications

ASTM F879/F879M 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.

ASME Dimensional Standards

ISO 7380 - 1 Hex socket button head cap screws
ISO 10642 - Hexagon socket countersunk head screws

ASTM F879/F879M 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 F879/F879M Testing Standards

A751 Test Methods, Practices, and Terminology for Chemical Analysis of Steel Products
F606/F606M Test Methods for Determining the Mechanical Properties of Externally and Internally Threaded Fasteners, Washers, Direct Tension Indicators, and Rivets
E18 Test Methods for Rockwell Hardness of Metallic Materials
E92 Test Methods for Vickers Hardness and Knoop Hardness of Metallic Materials
A262 Practices for Detecting Susceptibility to Intergranular
A342/A342M Test Methods for Permeability of Weakly
A751 Test Methods, Practices, and Terminology for Chemical Analysis of Steel Products

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 F879/F879M Supplementary Requirements

S1 Shipment Lot Testing
S2 Alloy Control
S3 Permeability
S4 Identification
S5 Corrosion Resistance Tests
S6 Passivation
S7 Mechanical Property Requirements