ASTM A709 Grade 50

General Product Description

The ASTM A709 is the Standard Specification for Structural Steel for Bridges and encompasses carbon, high-strength low-alloy, and quenched and tempered alloy steels used as structural plates in the construction of bridges. SSAB offers the following five grades of A709; 36, 50, 50W, HPS 50W and HPS 70W. The three weather grades of 50W, HPS 50W, and HPS 70W have an ASTM G101 enhanced Atmospheric Corrosion Resistance Index of ≥6.0.

Available Dimensions
Grade Thickness (in) Width (in) Length (in)
50 0.1875 - 3.00 72 - 120 240 - 1200
50T 0.1875 - 3.00 72 - 120 240 - 1200
50F 0.1875 - 2.50 72 - 120 240 - 1200
50F 2.51 - 3.00 (1) 72 - 120 240 - 1200

Width: Please inquire for plate widths less than 72 in. and over 120 in. Inquire for widths greater than 96 in. for thicknesses less than 0.250 in.

Length: Please inquire for plate lengths greater than the listed maxima. Plate length may be limited by maximum individual plate weight of 66,000 lbs.
Plate length maximum of 960 in. for thicknesses less than 7/16 in.

(1) Please inquire for thicknesses greater than 2.50 inches up to 3.0 inches.

Mechanical Properties

Tensile testing is performed in the transverse direction according to ASTM A370 requirements.

Mechanical Properties
Grade Thickness
(in)
Yield strength (1)
(min ksi)
Tensile strength
(ksi)
Elongation in 2" (2)
(min %)
Elongation in 8" (2)
(min %)
50 0.1875 - 3.00 50 65 21 18
50T 0.1875 - 3.00 50 65 21 18
50F 0.1875 - 3.00 50 65 21 18

(1) Yield strength measured as 0.2% offset or 0.5% extension under load.

(2) For plates wider than 24 in, the elongation requirement is reduced by two percentage points. See elongation requirement adjustments in the Tension Test section of Specification ASTM A6.

Impact Properties

Impact Properties
Grade Thickness (in) Min Longitudinal
Average Energy (1)
(ft-lbs)
Min Longitudinal
Individual Value
(ft-lbs)
Zone 1 Test Temp Zone 2 Test Temp Zone 3 Test Temp
50T 0.1875 - 2.00 15 10 70 °F 40 °F 10 °F
50T 2.01 - 3.00 20 15 70 °F 40 °F 10 °F
50F 0.1875 - 2.00 25 20 70 °F 40 °F 10 °F
50F 2.01 - 3.00 30 24 70 °F 40 °F 10 °F

(1) CVN impact testing in accordance with ASTM A673. Please inquire for orders requiring CVN impact testing.

Chemical Composition

(Heat Analysis, wt. %, maximum unless noted)

Chemical Composition
Type C (1) (max wt %) Mn (1) (%) P (max wt %) S (max wt %) Si (wt %) Cu (2) (min wt %) V (wt %) Cb (wt %) V+Nb (wt %)
1 0.23 1.35 0.030 0.030 0.40 0.20 --- 0.005 - 0.05 ---
2 0.23 1.35 0.030 0.030 0.40 0.20 0.01 - 0.15 --- ---
3 0.23 1.35 0.030 0.030 0.15 - 0.40 0.20 0.01 - 0.15 0.005 - 0.05 0.02 - 0.15

(1) Manganese minimum 0.80% for plates over 3/8 inches in thickness; a minimum of 0.50% for plates 3/8 inches and less in thickness. The manganese to carbon ratio shall not be less than 2 to 1. For each reduction of 0.01% below the specified carbon maximum, an increase of 0.06% manganese above the specified maximum is permitted up to a maximum of 1.60%.

(2) For plates greater than 1.50 inches in thickness, silcon range shall be 0.15% to 0.40.

(3) Copper when specfied shall have a minimum content of 0.20%.


All information derived from globally recognized specifications, subject to change, user discretion is advised.