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    ASTM F468/F468M Grade C64200 642 Aluminum Silicon Bronze Fasteners

    High quality ASTM F468 Aluminum Silicon Bronze fasteners manufactured for industrial and corrosion resistant applications.

    ASTM F468/F468M Grade C64200 Aluminum Silicon Bronze fasteners are manufactured in accordance with ASTM specifications for nonferrous bolts, hex cap screws, socket head cap screws, and studs.

    Chemical Requirements

    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
    Grade C64200 642 aluminum silicon bronze 6.3-7.6 88.65 D 0.30 0.10 0.25 . . . 1.5-2.2 E 0.50 0.05 0.20 max 0.15
    • (A) Elements shown as balance shall be arithmetically computed by deducting the sum of the other named elements from 100.
    • (B) Copper plus specified elements = 99.8 min; copper plus silver = 88.5-91.5.
    • (C) Cobalt is to be counted as nickel.
    • (D) Minimum content of copper plus all other elements with specified limits shall be 99.5 %.
    • (E) An alloy containing as high as 2.6 % silicon is acceptable provided the sum of all the elements other than copper, silicon, and iron does not exceed 0.30 %.

    Mechanical Requirements

    Alloy Mechanical Property Marking Nominal Thread Diameter, in. Hardness A Full-Size Tests B Machined Specimen Tests
    Tensile Strength, ksi Yield Strength, min, ksi C Tensile Strength, min, ksi Yield Strength min, ksi C Elongation in 4D, min, % D
    Alloy Cu 642 468J All 75-95 HRB 75-110 35 75 35 10
    • (A) Where both tension and hardness tests are performed, the tension tests shall take precedence for acceptance purposes. For aluminum and titanium alloys, hardness tests are for information only. See 6.5.
    • (B) The yield and tensile strength values for full-size products shall be computed by dividing the yield and maximum tensile load by the stress area for the product diameter and thread pitch as given in table on tensile stress areas.
    • (C) Yield strength is the stress at which an offset of 0.2 % gage length occurs.
    • (D) Elongation is determined using a gage length of 4 diameters of test specimen in accordance with Test Methods E8/E8M.
    • (E) "HF" denotes a hot-formed product.
    • (F) Aluminum alloy temper designations are in accordance with ANSI H35.1.
    • (G) Full-size test mechanical properties apply to fasteners with a maximum diameter of 76 mm. Mechanical properties of larger sections shall be negotiated between the material manufacturer and the fastener producer.
    • (H) Ti 5 Class A requires wedge tensile testing in accordance with Ti 5 Class B requires wedge tensile testing in accordance.

    ASTM F468/F468M Grade C64200 642 Aluminum Silicon Bronze Tensile Stress Areas and Threads(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 / 18 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 F468/F468M Grade C64200 642 Aluminum Silicon Bronze Tensile Stress Areas (Metric)

    Nominal Product Diameter and Thread Pitch Stress Area, A mm 2 Nominal Product Diameter and Thread Pitch Stress Area, A mm 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:
    • A s = 0.7854 (D − 0.9382 P) 2
    • where:
    • As = stress area, mm2,
    • D  = nominal thread diameter, mm, and
    • P  = thread pitch, mm.

    Frequently Asked Questions

    What is Aluminum-Silicon Bronze C64200?

    Aluminum-silicon bronze C64200 is a Cu-Al-Si alloy (~91 Cu, 7 Al, 2 Si) per ASTM F468 - the silicon addition improves machinability while retaining most of the aluminum-bronze corrosion resistance. Tensile 75-100 ksi. Used for screw-machine production of bronze bolting where chip break matters.

    When use C64200 over C61300?

    C64200 machines significantly better than C61300 or C61400 - the silicon addition gives clean chip break on automatic equipment. Choose for high-volume bronze fastener production where mfg cost matters. Corrosion behavior is similar to other aluminum bronzes.

    Marine service performance?

    Acceptable for general marine bolting. For severe service or high-load propeller hardware, step up to nickel-aluminum bronze C63000.

    Available dimensional patterns?

    F468 ASME B18 inch + metric range. Most common in B18.2.1 hex cap screws and B18.3 socket head cap screws.

    References & Standards

    • ASTM F468 / F468M - Standard Specification for Nonferrous Bolts, Hex Cap Screws, and Studs for General Use
    • ASTM F467 / F467M - Companion specification for Nonferrous Nuts (mate with F468 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 B18.2.1 / B18.2.3 series / B18.3 / B18.6.7M / B18.31 / B16.5 - Dimensional standards referenced by F468
    • DIN 912 / 933 / 931 - Metric hex socket head and hex head cap screw dimensional standards