F1554 Grade 55

Overview

ASTM F1554 grade 55 anchor bolts are manufactured from a modified mild steel that has a higher minimum yield strength (55 ksi) than traditional A36 mild steel (36 ksi). This specification was widely used in the light pole and traffic signal industry long before the ASTM F1554 specification was introduced in 1994 and was commonly referred to as A36M55. Just as with grade 36, grade 55 covers anchor bolts in diameters ranging from 1/4" through 4".

Galvanizing

F1554 grade 55 anchor bolts can be provided in either a black or galvanized condition.

Welding

Contrary to popular belief, not all grade 55 material is weldable. If weldability is required, supplementary requirement S1 must be specified. A weldable grade 55 may be substituted at the supplier's option when grade 36 is specified. All of the grade 55 round bar that Portland Bolt stocks will meet the S1 weldability requirements.

Supplementary Testing

A supplementary requirement S4 also exists which designates Charpy Impact testing requirements.

Material Substitution

Be skeptical of fastener distributors and manufacturers with limited manufacturing capabilities who attempt to substitute 1045 round bar or even A193 grade B7 material for F1554 grade 55. These materials and other grades of steel may exceed the tensile and yield requirements of the F1554 grade 55 specification, but will usually not meet the elongation and reduction of area requirements. Grade 55 round bar is not commonly available through local warehouses. Portland Bolt buys mill runs of round bar and stocks this material for immediate processing.

Mechanical Requirements

Grade	Identification1	Size, Inches	Tensile, ksi	Yield, ksi min	Yield, MPa min	Elong. % min	Reduction of Area %, min
55		1/4 - 2	75 - 95	55	380	21	30
		2-1/4 - 2-1/2	75 - 95	55	380	21	22
		2-3/4 - 3	75 - 95	55	380	21	20
		3-1/4 - 4	75 - 95	55	380	21	18
1Color coding (yellow) is required while permanent stamping with manufacturer's identification and grade designation are supplementary requirements.

Nuts and Washers

Grade	Identification	Size, Inches	Recommended A563 Nut				Washer
			Plain Finish		Hot-Dip or Mechanical Zinc Coated
			Grade	Style	Grade	Style
55		1/4 - 1-1/2	A	Hex	A	Heavy Hex	F436
		1-5/8 - 4	A	Heavy Hex	A	Heavy Hex
For additional compatible nuts see the Nut Compatibility Chart.