Mechanical Properties of
Alloy Steel Socket Head Cap Screws - Blue Devil




Nominal Size Tensile Strength
Lbs., Min.
Yeild Strength
Lbs., Min.
Body Section Tightening Torque
Inch Lbs.
UNRC UNRF UNRC UNRF Single Shear
Strength
Lbs., Min.
UNRC UNRF
0 320 290 304 2.6
1 475 500 425 450 450 4.5 4.8
2 665 710 600 635 625 7.5 8.0
3 875 940 790 845 830 11.0 12.0
4 1,090 1,190 975 1,070 1,060 16.0 18.0
5 1,430 1,490 1,290 1,345 1,325 24.0 24.0
6 1,640 1,825 1,470 1,645 1,615 30.0 34.0
8 2,520 2,650 2,270 2,385 2,280 55.0 58.0
10 3,150 3,600 2,835 3,240 3,060 79.0 90.0
1/4 5,725 6,550 5,150 5,900 5,295 200.0 230.0
5/16 9,430 10,440 8,490 9,395 8,285 415.0 460.0
3/8 13,950 15,805 12,555 14,225 11,910 740.0 845.0
7/16 19,135 21,365 17,220 19,230 16,200 1190.0 1305.0
1/2 25,540 28,780 22,990 25,905 21,175 1800.0 2065.0
5/8 38,400 43,500 34,550 39,150 31,300 3,400.0 3,800.0
3/4 56,750 63,400 51,100 57,050 45,050 6,000.0 6,750.0
7/8 78,500 86,500 70,700 77,850 61,350 8,250.0 9,200.0
1 103,000 112,700 92,700 101,450 80,100 12,500.0 13,000.0
1-1/4 164,700 182,400 148,250 164,150 125,100 25,000.0 27,750.0
1-1/2 238,800 268,800 215,950 241,900 180,200 43,500.0 49,000.0



Notes on Cap Screws

  • Applications - Ideal for precision assembly work with close tolerances and applications needing a well tooled appearnace. Supplies greater tensile strength than equivalent sizes of Grade-5 or Grade-8 hex head cap screws while requiring less surface area or counterbore since the fastener is internally wrenched.
  • Material - Cap screws shal be made from an alloy steel which conforms to the following chemical composition requirements (per product analysis) - Carbon: .31% minimum, Phosphorus: .04% maximum, Sulfur: .045% maximum. Also, one or more of the following elements shall be present in sufficient quantity to meet the strength requirements listed below: chromium, nickel, molybdenium, or vanadium.
  • Heat Treatment: Cap screws shall be heat treated by oil quenching from above the transforamtion temperature and then tempered at a temperature not lower than 650°F
  • Hardness: 0 thru 1/2" diameters: Rc39 Minimum, 5/.8" and larger: Rc37 Minimum
  • Cap screws of a length (3 x nominal diameter) are subject to tensile strength, yeild strength, elongation and reduction of area testing.
  • Tensile Strength: 0 thru 1/2" diameters: 180,000 psi minimum, 5/8" and larger: 170,000 psi minimum
  • Yield Strength: 0 thru 1/2" diameters: 162,000 psi minimum, 5/8" and larger: 153,000 psi minimum
  • Elongation: 10% minimum (applies to machined specimens of length of at least 4 x nominal length)
  • Reduction of Area: 33% minimum (applies to machined specimens)


Assembly Instructions



Smith Fastener Company • 3613 East Florence Avenue, Bell, California, 90201
Phone: ( 323 ) 587-0382 • FAX: ( 323 ) 587-8712 • E-mail: sales@smithfast.com
Copyright © 2009 by Smith Fastener Company

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