Grade 55

ASTM F1544 Grade 55 is a standard material specification for straight, bent, headed, headless anchor bolts and all-thread anchor rods, made of low yield carbon steel. ASTM F1554 Grade 55 anchors bolts are designated with minimum yield strength value of 55 ksi or 380 MPa. These Grade 55 anchors bolts or anchor rods are intended for anchoring structural supports to concrete foundations. Such structural supports include building columns, column supports for highway signs, street lighting and traffic signals, steel bearing plates, and similar applications.

Supplementary requirements are included to provide for grade 55 weldable steel, permanent manufacturers and grade identification marking, and impact properties for grade 55.

Grade Classification

Type	Descriptions	Tensile Strength, ksi (MPa)	Yield Strength, min, ksi (MPa)	Diameter, Range, Inch.
Grade 55	High strength, low alloy, 55 ksi yield steel anchor bolts	75 - 95 (517 - 665)	55 (380)	1/2 - 4

(For other grades, please visit ASTM F1554)

Chemical Composition

Element		Composition, %
		Grades 55
		All Diameters
Carbon, max	Heat	-
	Product	-
Manganese	Heat	-
	Product	-
Phosphorus, max	Heat	0.04
	Product	0.048
Sulfur, max	Heat	0.05
	Product	0.058
Copper, min (when specified)	Heat	0.20
	Product	0.18

Mechanical Properties [Bar & Machined Specimen]

Property	Grade 55
Tensile Strength, ksi	75 - 95
Yield Strength, min, ksi (0.2% Offset)	55
Elongation in 8 inch, min, % [Note A]	18
Elongation in 2 inch, min, % [Note A]	21
Reduction of Area, min, %	30

Note A:

Elongation in 8 Inch applies to bars. Elongation in 2 inch applies to machined specimens.

Protective Coatings

• Zinc, Hot Dip or Mechanically Deposited:
• When zinc-coated anchor bolts are required, the purchaser shall specify the coating process, for example, hot dip, mechanically deposited, or no preference. When no preference is specified, the supplier may furnish bolts coated with either process. The supplier’s option is limited to one process per item, with no mixed processes in a lot.
• When hot-dip zinc coated anchor bolts are specified, the anchor bolts and nuts shall be zinc-coated in accordance with the requirements of Specification F2329/F2329M.
• When mechanically deposited zinc coated anchor bolts are provided, the anchor bolts and nuts shall be zinccoated in accordance with the requirements of Specification B695, Class 55.
• Unless otherwise specified, when zinc-coated washers are required, the washers shall be hot-dip zinc-coated in accordance with Specification F2329/F2329M, or mechanically deposited zinc coated in accordance with Specification B695, Class 55. The coating process for the washers need not be the same as that for the anchor bolts and nuts.
• Other Coatings:
• When indicated on the inquiry and purchase order, coatings other than those in 7.1 shall be as agreed upon by the purchaser and supplier.

Recommended Nuts & Washers

Anchor Bolts		Recommended A563 Nuts
		Plain Finish		Hot-Dip or Mechanical Zinc Coated
Bolt Grade	Diameter, Inch	Grade	Style	Grade	Style
Grade 55	1/2 - 1 1/2	A	Hex	A	Heavy Hex
	Over 1-1/2 - 4	A	Heavy Hex	A	Heavy Hex