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B7 Heavy Hex Bolt, Teflon

Selected A193 Grade B7 Heavy Hex Bolt PTFE Teflon BlueB7 Heavy Hex Bolt, Teflon
A193 Grade B7 Heavy Hex Bolt PTFE Teflon BlueB7 Heavy Hex Bolt, Teflon

ASTM A193 Grade B7 heavy hex head bolts are high strength fasteners manufactured from heat treated alloy steel AISI 4140/4142, quenched and tempered. Dimensional specifications are governed by ASME B18.2.1. Grade markings consists of both the grade symbol "B7" and the manufacturer's identification mark. Inch series fasteners meeting ASTM A193 Grade B7 specifications are typically used in flange bolting applications. ASTM A193 covers the requirements for high temperature and high pressure bolting. Heavy hex head bolts have a larger head to increase the bearing surface and distribute the clamping load over a larger area. Bolts listed that are smaller than 1/2" diameter may be finished pattern bolts. A193 B7 hex bolts, as well as all thread stud bolts having diameters above 1" are most common 8UN (8 threads per inch) and are also available UNC (coarse thread). PTFE coating (commonly referred to as Teflon) is formulated with superior characteristics for maximum fastener life. Technical components include a tensile strength of up to 4,000 psi and an operating pressure up to 100,000 psi. The absence of nut locking oxides enable easy and safe removal. PTFE coatings have extreme chemical resistance and are ideal for applications including insulating piping, boiler rooms, water filled piping, water lines and more.

Products

Mechanical Properties

Chromium-Molybdenum, Quenched & Tempered Per ASTM A193/A193M-16
Diameter Tempering
Temperature		 Tensile
Strength		 Yield Strength min,
0.2% offset		 Elongation
in 4D		 Reduction
in Area		 Hardness
Min Min ksi ksi Min % Min % Max
up to 2 1/2" 1100F 125 105 16 50 321 HBW or 35 HRC
over 2 1/2" to 4" 1100F 115 95 16 50 321 HBW or 35 HRC
over 4 to 7" 1100F 100 75 18 50 321 HBW or 35 HRC

Dimensional Specifications

Heavy Hex Bolt dimensions
Per ASME B18.2.1-2012
Nominal Diameter UNC UNF UN8 E F G H
Body Diameter Width Across Flats Width Across Corners Head Height
Max Min Basic Max Min Max Min Basic Max Min
1/4 0.2500 20 28   0.2500 0.2405 7/16 0.4380 0.4280 0.5050 0.4880 5/32 0.1630 0.1500
5/16 0.3125 18 24   0.3125 0.3065 1/2 0.5000 0.4890 0.5770 0.5570 13/64 0.2110 0.1950
3/8 0.3750 16 24   0.3750 0.3690 9/16 0.5620 0.5510 0.6500 0.6280 15/64 0.2430 0.2260
7/16 0.4375 14 20   0.4375 0.4305 5/8 0.6250 0.6120 0.7220 0.6980 9/32 0.2910 0.2720
1/2 0.5000 13 20   0.515 0.482 7/8 0.875 0.850 1.010 0.969 11/32 0.364 0.302
5/8 0.6250 11 18   0.642 0.605 1 1/16 1.062 1.031 1.227 1.175 27/64 0.444 0.378
3/4 0.7500 10 16   0.768 0.729 1 1/4 1.250 1.212 1.443 1.383 1/2 0.524 0.455
7/8 0.8750 9 14   0.895 0.852 1 7/16 1.438 1.394 1.660 1.589 37/64 0.604 0.531
1 1.0000 8 14   1.022 0.976 1 5/8 1.625 1.575 1.876 1.796 43/64 0.700 0.591
1 1/8 1.1250 7 12 8 1.149 1.098 1 13/16 1.812 1.756 2.093 2.002 3/4 0.780 0.658
1 1/4 1.2500 7 12 8 1.277 1.223 2 2.000 1.938 2.309 2.209 27/32 0.876 0.749
1 3/8 1.3750 6 12 8 1.404 1.345 2 3/16 2.188 2.119 2.526 2.416 29/32 0.940 0.810
1 1/2 1.5000 6 12 8 1.531 1.470 2 3/8 2.375 2.300 2.742 2.622 1 1.036 0.902

All dimensions are in inches.

Chemical Properties

Per ASTM A193/A193M-16
Grade Material Carbon Manganese Phosphorus Sulfur Silicon Chromium Molybdenum
% by   weight % by weight % by weight % by weight % by weight % by weight % by weight
B7 Chromium-Molybdenum (1) 0.38-0.48 (2) 0.75-1.00 0.035 max 0.04 max 0.15-0.35 0.80-1.10 0.15-0.25
  1. 1. Typical steel compositions used for this grade include 4140, 4142, 4145, 4140H, 4142H, and 4145H.
  2. 2. For bar sizes over 3 1/2 in. [90 mm], inclusive, the carbon content may be 0.50 % max. For the B7M grade, a minimum carbon of 0.28 % is permitted, provided that the required tensile properties are met in the section sizes involved, the use of AISI 4130 or 4130H is allowed.

Governing Standards

ASTM A193 Covers the mechanical and material requirements for inch series fasteners used in automotive and related industries in diameters through 1-1/2″.
ASME B18.2.1 Covers the complete general and dimensional data for multiple types of inch series square and hex bolts and screws.
ASME B1.1 UNC & UNF Class 2A Specifies the thread form, series, class, allowance, tolerance, and designation for unified screw threads.

Grade B7 Head Marking
Grade B7 Material Marking