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Fastener Identification Markings

Grade Marking Specification Material and Treatment Nominal Size (In.) Mechanical Properties Hardness Rockwell
Proof
Load
Min
(ksi)		 Yield
Strength
Min
(ksi)		 Tensile
Strength
Min
(ksi)		 Elong % Min [9] RA % Min [10] Min Max
SAE J429 Grade 2 SAE J429
Grade 1		 Low or Medium Carbon Steel 1⁄4” – 11⁄2“ 33 36 60 18 35 B70 B100
ASTM A307 Grade A A307
Grade A		 Low or Medium Carbon Steel 1⁄4” – 4″ – – 60 18 – B69 B100
ASTM A307 Grade B A307
Grade B		 Low or Medium Carbon Steel 1⁄4” – 4″ – – 60 min
100 max		 18 – B69 B95
ASTM A307 Grade C One End Green A307
Grade C [7]		 Low or Medium Carbon Steel 1⁄4” – 4″ – 36 58 min
80 max		 23 – – –
ASTM F1554 Grade 36One End Blue F1554
Grade 36		 Low or Medium Carbon Steel 1⁄2” – 4″ – 36 58 min
80 max		 23 40 – –
ASTM F1554 Grade 55 One End Yellow F1554
Grade 55		 Low or Medium Carbon Steel 1⁄2” – 2″ – 55 75 min
95 max		 21 30 – –
21⁄4“- 21⁄2“ 21 30
23⁄4” – 3″ 21 30
31⁄4” – 4″ 21 30
SAE J429 Grade 2 SAE J429
Grade 2 [8]		 Low or Medium Carbon Steel 1⁄4” – 3⁄4“ 55 57 74 18 35 B80 B100
7⁄8” – 11⁄2“ 33 36 60 18 B70 B100
ASTM A193/A320 Grade B8 A193/A320
Grade B8
Class 1		 AISI SS304 Stainless No Restrictions – 30 75 30 50 – B96
ASTM A193/A320 Grade B8 Class 2 A193/A320
Grade B8
Class 2		 AISI SS304 Stainless Up to 3/4 – 100 125 12 35 – C35
7/8 – 1 80 115 15 35
1-1/8 – 1-1/4 65 105 20 35
1-3/8 – 1-1/2 50 100 28 45
ASTM A193/A320 Grade B8M A193/A320
Grade B8M		 AISI SS316 Stainless No Restrictions – 30 75 30 50 – B96
ASTM A193/A320 Grade B8M Class 2 A193/A320
Grade B8M
Class 2		 AISI SS316 Stainless Up to 3/4 – 95 110 15 45 – C35
7/8 – 1 80 100 20 45
1-1/8 – 1-1/4 65 95 25 45
1-3/8 – 1-1/2 50 90 30 45
ASTM A325 Type 1 F3125 Grade A325 Type 1 Medium Carbon Steel, Q & T 1⁄2” – 11⁄2“ 85 92 120 14 35 C24 C35
ASTM A325 Type 3 F3125 Grade A325 Type 3 Atmospheric Corrosion Resistant Steel,
Q & T		 1⁄2” – 11⁄2“ 85 92 120 14 35 C24 C35
SAE J429 Grade 5 SAE J429
Grade 5		 Medium Carbon Steel, Q & T 1⁄4” – 1″ 85 92 120 14 35 C25 C34
11⁄8” – 11⁄2“ 74 81 105 C19 C30
ASTM A449 Type 1 A449
Type 1		 Medium Carbon Steel, Q & T 1⁄4” – 1″ 85 92 120 14 35 C25 C34
11⁄8” – 11⁄2“ 74 81 105 C19 C30
15⁄8” – 3″ 55 58 90 B91 B100
ASTM A449 Type 3 A449
Type 3		 Weathering Steel, Q & T 1⁄4” – 1″ 85 92 120 14 35 C25 C34
11⁄8” – 11⁄2“ 74 81 105 C19 C30
15⁄8” – 3″ 55 58 90 B91 B100
ASTM A193 Grade B7 A193
Grade B7		 Medium Carbon Alloy Steel,
Q & T		 1⁄4” – 21⁄2“ – 105 125 16 50 – C35
25⁄8” – 4″ 95 115 16 50 C35
41⁄8” – 7″ 75 100 18 50 C35
ASTM A354 Grade BC A354
Grade BC		 Medium Carbon Alloy Steel,
Q & T		 1⁄4” – 21⁄2“ 105 109 125 16 50 C26 C36
Over 21⁄2“ 95 99 115 16 45 C22 C33
ASTM F1554 Grade 105 One End Red F1554
Grade 105		 Medium Carbon Alloy Steel,
Q & T		 1⁄2” – 3″ – 105 125 min
150 max		 15 45 – –
ASTM A320 Grade L7 A320
Grade L7		 AISI 4140, 4142, or 4145 1⁄4” – 21⁄2“ – 105 125 16 50 – –
ASTM A320 Grade L43 A320
Grade L43		 AISI 4340 1⁄4” – 4″ – 105 125 16 50 – –
ASTM A490 Type 1 F3125 Grade A490 Type 1 Medium Carbon Alloy Steel,
Q & T		 1⁄2” – 11⁄2“ 120 130 150 min
173 max		 14 40 C33 C38
ASTM A490 Type 3 F3125 Grade A490 Type 3 Atmospheric Corrosion Resistant Steel,
Q & T		 1⁄2” – 11⁄2“ 120 130 150 min
173 max		 14 40 C33 C38
SAE J429 Grade 8 SAE J429 Grade 8 Medium Carbon Alloy Steel,
Q & T		 1⁄4” – 11⁄2“ 120 130 150 12 35 C33 C39
ASTM A354 Grade BD A354
Grade BD [6]		 Medium Carbon Alloy Steel,
Q & T		 1⁄4” – 4″ – 130 150 min
173 max		 14 40 C33 C38
  1. All specifications are ASTM unless otherwise noted.
  2. All specifications shall be marked by the manufacturer with a unique identifier to identify the manufacturer or private label distributor, as appropriate.
  3. Q & T – Quenched and Tempered.
  4. Although markings are shown on hex heads, stamping is a requirement on one end of rods and studs. The exception is F1554 and A307 grade C in which stamping is a supplemental requirement while color coding is required.
  5. Although markings are shown on hex heads, grade markings apply equally to products with other head configurations.
  6. All Grade BD products shall be marked “BD”. In addition to the “BD” marking, the product may be marked with 6 radial lines 60° apart.
  7. ASTM A307 grade C has been replaced by ASTM F1554 grade 36.
  8. Grade 2 requirements for diameters ranging from 1/4″ through 3/4″ only apply to headed fasteners up to and including 6″ in length, and to studs of all lengths. For headed fasteners longer than 6″, see SAE J429 grade 1.
  9. Percent Elongation
  10. Percent Reduction of Area
  11. In 2016, ASTM specifications A325 and A490 were officially withdrawn and replaced by F3125.

“-” = no requirement.