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    ASTM F467/F467M Grade C65500 Alloy 655 Nuts Specification

    Corrosion-resistant silicon bronze alloy nuts for marine industries.

    ASTM F467/F467M Grade C65500 Alloy 655 Nuts offer superior mechanical strength, excellent corrosion resistance, and long-lasting industrial performance.

    ASTM F467/F467M Chemical Composition

    ASTM F467/F467M Copper and Copper-Base Alloys

    UNS Designation Number Alloy General Name Al Cu, min Fe, max Mn, max Ni, max P Si Zn, max A Pb, max Tin As, max
    ASTM F467/F467M Grade C65500 655 silicon bronze . . . 94.8 D 0.8 1.5 0.6 . . . 2.8-3.8 1.5 0.05 . . . . . .
    • (A) Elements shown as balance shall be arithmetically computed by deducting the sum of the other named elements from 100.
    • (D) Minimum content of copper plus all other elements with specified limits shall be 99.5 %.

    ASTM F467/F467M Mechanical Requirements

    ASTM F467/F467M Mechanical Requirements (Inch)

    Alloy Mechanical Property Marking Hardness, min A Proof Stress, Hex Nut min, ksi Proof Stress, Heavy Hex Nut min, ksi B
    ASTM F467 Alloy Cu 655 F 467L 75 HRB 50 54
    • (B) Proof stress values for heavy hex nuts are based on 1.08 times the value for corresponding regular hex nuts.

    ASTM F467M Mechanical Requirements (Metric)

    Alloy Mechanical Property Marking Hardness, min A Proof Stress, Mpa
    ASTM F467M Cu 655 F467ML 75 HRB 345

    ASTM F467/F467M Tensile Stress Areas and Threads per Inch

    Nominal Size, in. Coarse Threads-UNC Fine Threads-UNF 8 Thread Series-8UN
    Threads/in. Stress Area A, in 2 Threads/in. Stress Area A, in 2 Threads/in. Stress Area A, in 2
    1/ 4 20 0.0318 28 0.0364 . . . . . .
    5/ 16 18 0.0524 24 0.0580 . . . . . .
    3/ 8 16 0.0775 24 0.0878 . . . . . .
    7/ 16 14 0.1063 20 0.1187 . . . . . .
    1/ 2 13 0.1419 20 0.1599 . . . . . .
    9/ 16 12 0.1820 18 0.2030 . . . . . .
    5/ 8 11 0.2260 18 0.2560 . . . . . .
    3/ 4 10 0.3340 16 0.3730 . . . . . .
    7/ 8 9 0.4620 14 0.5090 . . . . . .
    1 8 0.6060 12 0.6630 . . . . . .
    1 1/ 8 7 0.7630 12 0.8560 8 0.790
    1 1/ 4 7 0.9690 12 1.0730 8 1.000
    1 3/ 8 6 1.1550 12 1.3150 8 1.233
    1 1/ 2 6 1.4050 12 1.5810 8 1.492
    • (A) Tensile stress areas are computed using the following formula:
    • A s = 0.7854 [ D - 0.9743/n ]
      • where:
      • As = tensile stress area, in. 2 ,
      • D = nominal size (basic major diameter), in., and
      • n = number of threads per inch.

    ASTM F467/F467M Tensile Stress Areas and Threads per Metric

    Nominal Nut Diameter and Thread Pitch Stress Area, Amm 2 Nominal Nut Diameter and Thread Pitch Stress Area, Amm 2
    M6 × 1 20.1 M16 × 2 157
    M8 × 1.25 36.6 M20 × 2.5 245
    M10 × 1.5 58.0 M24 × 3 353
    M12 × 1.75 84.3 M30 × 3.5 561
    M14 × 2 115 M36 × 4 817
    • (A) Tensile stress areas are computed using the following formula:
    • As = 0.7854 (D − 0.9382P) 2
      • where:
      • As = tensile stress area, mm. 2 ,
      • D = nominal size (basic major diameter), mm., and
      • n = number of threads per mm.

    ASTM F467/F467M Heat Treatment

    Alloy Condition
    Copper (all alloys) As formed or stress relieved at manufacturer's option
    Nickel alloys 400 and 405 As formed or stress relieved at manufacturer's option
    Nickel alloy 500 Solution annealed and aged
    Aluminum alloy 2024-T4 Solution treated and naturally aged
    Aluminum alloy 6061-T6 Solution treated and artificially aged
    Aluminum alloy 6262-T9 Solution treated, artificially aged, and cold worked
    Titanium 625 Annealed

    Frequently Asked Questions

    What is Silicon Bronze C65500?

    Silicon bronze C65500 is a Cu-Si-Mn alloy (~96 Cu, 3 Si, 1 Mn) per ASTM F467 - the workhorse silicon bronze for nut + marine + architectural applications. Tensile 55-100 ksi depending on temper. Excellent strength + corrosion resistance + weldability + non-sparking behavior.

    Why is C65500 used in architectural bolting?

    C65500 weathers to a stable brown patina (similar to traditional bronze) without dezincification. Used for exterior architectural fasteners on bronze cladding, statuary mounting bolts, and high-end marine yacht hardware where appearance + corrosion resistance both matter.

    Non-sparking applications?

    C65500 is non-ferrous and does not produce sparks on impact - making it acceptable for nut in flammable-atmosphere applications (refineries, gas plants, grain elevators) where ferrous bolts would be a safety hazard.

    Available dimensional patterns?

    Full F467 ASME B18 inch + metric range. Highest-volume silicon bronze fastener spec - generally well-stocked.

    References & Standards

    • ASTM F467 / F467M - Standard Specification for Nonferrous Nuts for General Use
    • ASTM F468 / F468M - Companion specification for Nonferrous Bolts, Hex Cap Screws, and Studs (mate with F467 nuts for matched-alloy assemblies)
    • ASTM F436 / F436M - Hardened steel washers (ferrous washer companion when nonferrous washers are not specified)
    • NACE MR0175 / ISO 15156 - Sour-service hardness limits for petroleum and natural gas industries
    • ASME B18.2.2 / B18.2.4.1M / B18.2.4.6M and ISO 4032 / 4033 / 4035 - Dimensional standards referenced by F467
    • DIN 934 / 439 / 6330 - Metric hex nut dimensional standards