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B7 Heavy Hex Bolt

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).

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Governing Standards
Mechanical Properties
Chemical Properties
Dimensional Specifications

Dimensional Specifications

Dimensional SpecificationsGrade B7

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.

B7 Heavy Hex Bolt

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Diameter Length Threading Item # Availability Price Quantity UOM

1/4

Partial

HHB70250200-I

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$0.86305/EA

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1/4-20 X 2 A193 B7 HEX BOLT

$0.86305/EA

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Quantity	Price
Quantity	Price
1	$0.86305/EA
310	$0.8141/EA
1240	$0.71773/EA
5560	$0.50554/EA

1/2

2 1/2

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HHB70500250-I

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$1.53159/EA

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1/2-13 X 2 1/2 A193 B7 HEAVY HEX BOLT

$1.53159/EA

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Quantity	Price
Quantity	Price
1	$1.53159/EA
60	$1.44473/EA
220	$1.2737/EA
990	$0.89714/EA

5/8

2 3/4

Partial

HHB70620275-I

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$1.97767/EA

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5/8-11 X 2 3/4 A193 B7 HEAVY HEX BOLT

$1.97767/EA

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Quantity	Price
Quantity	Price
1	$1.97767/EA
40	$1.86551/EA
130	$1.64468/EA
570	$1.15844/EA

3/4

Partial

HHB70750300-I

In Stock

$3.60179/EA

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3/4-10 X 3 A193 B7 HEAVY HEX BOLT

$3.60179/EA

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Quantity	Price
Quantity	Price
1	$3.60179/EA
25	$3.39752/EA
80	$2.99532/EA
500	$2.10978/EA

3 1/2

Partial

HHB71000350-I

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$8.94615/EA

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1-8 X 3 1/2 A193 B7 HEAVY HEX BOLT

$8.94615/EA

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Quantity	Price
1	$8.94615/EA
40	$8.43878/EA
80	$7.43981/EA
170	$5.2403/EA

1 1/4

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HHB71250400-I

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$19.19399/EA

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1 1/4-8 X 4 A193 B7 HEAVY HEX BOLT

$19.19399/EA

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Quantity	Price
Quantity	Price
1	$19.19399/EA
20	$18.10543/EA
40	$15.96214/EA
90	$11.24308/EA

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.

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
Diameter	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

Per ASTM A193/A193M-16
Grade	Material	Carbon	Manganese	Phosphorus	Sulfur	Silicon	Chromium	Molybdenum
Grade	Material	% 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

B7 Heavy Hex Bolt

Technical Data

Governing Standards

Governing StandardsGrade B7

Mechanical Properties

Mechanical PropertiesGrade B7

Chemical Properties

Chemical PropertiesGrade B7

Dimensional Specifications

Dimensional SpecificationsGrade B7

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1/4-20 X 2 A193 B7 HEX BOLT

1/2-13 X 2 1/2 A193 B7 HEAVY HEX BOLT

5/8-11 X 2 3/4 A193 B7 HEAVY HEX BOLT

3/4-10 X 3 A193 B7 HEAVY HEX BOLT

1-8 X 3 1/2 A193 B7 HEAVY HEX BOLT

1 1/4-8 X 4 A193 B7 HEAVY HEX BOLT