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Technical Info

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Bolt Strength Requirements by Grade

This chart detailed bolt strength requirements by grade. All specifications below are per ASTM. For more information on fasteners, visit our Fastener Learning Hub.

Bolt Strength Requirement by Grade Chart

Specification	Material	Nominal Size (Inches)	Proof Load Min (ksi)	Strength Min (ksi)	Hardness Min	Hardness Max
A307 Grade A	Low or Medium Carbon Steel	1/4″ to 4″	-	60	B69	B100
A307 Grade B	Low or Medium Carbon Steel	1/4″ to 4″	-	60 Min, 100 Max	B69	B95
F1554 Grade 36	Low or Medium Carbon Steel	1/4″ to 4″	-	58 Min, 80 Max	-	-
F1554 Grade 55	Low or Medium Carbon Steel	1/4″ to 2″, 2-1/4″ to 2-1/2″, 2-3/4″ to 3″, 3-3/4″ to 4″	-	75 Min, 95 Max	-	-
F1554 Grade 105	Medium Carbon Alloy Steel, Q & T	1/4″ to 3″	-	125 Min, 150 Max	-	-
A193/A320, Grade B8	AISI SS304, Stainless	All Included No Restrictions	-	75	-	B96
A193/A320, Grade B8M	AISI SS316, Stainless	All Included No Restrictions	-	75	-	B96
F3125 Grade A325 Type 1	Medium Carbon Steel Q & T	1/2″ to 1″	85	120	C25	C34
F3125 Grade A325 Type 3	Atmospheric Corrosion Resistant Steel, Q & T	1-1/8″ to 1-1/2″	74	105	C19	C30
A449 Type 1 or 3	Medium Carbon Steel Q & T	1-1/4″ to 1″, 1-1/8″ to 1-1/2″, 1-5/8″ to 3″	85, 74, 55	120, 105, 90	C25, C19, B91	C34, C30, B100
A193 Grade B7	Medium Carbon Alloy Steel, Q & T	1/4″ to 2-1/2″, 2-5/8″ to 4″, 4-1/8″ to 7″	-	125, 115, 100	-	C35, C35, C35
A193 Grade B7M	ANSI 4140, 4142, or 4145	1/4″ to 2-1/2″	-	125	-	-
A354 Grade BC	Medium Carbon Alloy Steel, Q & T	1/4″ to 2-1/2″, 2-5/8″ to 4″	105, 95	125, 115	C26, C22	C36, C33
F3125 Grade A490 Type 1	Medium Carbon Alloy Steel, Q & T	1/2″ to 1″	120	150 Min, 173 Max	C33	C38
F3125 Grade A490 Type 3	Atmospheric Corrosion Resistant Steel, Q & T	1/2″ to 1-1/2″	120	150 Min, 173 Max	C33	C38
A354 Grade BD	Medium Carbon Alloy Steel, Q & T	1/4″ to 2-1/2″, 2-5/8″ to 4″	120, 105	150, 140	C3, C313	C39, C39