ASTM A738 Grade B

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General Product Description

The ASTM A738 specification is the Standard Specification for Heat-treated, Carbon-Manganese-Silicon Steel used in welded pressure vessels subjected to moderate and lower temperature service. Grade B is supplied in the quenched & tempered condition.

Dimension Range

Grade
Grade
A738 Grade B
Product type
Mill Plate
Thickness
(in)
0.375 - 2.00
Width
(in)
96 - 120
Length
(in)
240 - 588

Thickness: Inquire for plate thicknesses of less than 0.375 inches down to 0.250 inches, or greater than 2.00 inches up to 3.5 inches.

Width: Inquire for widths <96 inches down to 60 inches and for widths >120 inches up to 131.9 inches.

Mechanical Properties

Tensile testing is performed in the transverse direction according to ASTM A20 requirements. The required mechanical properties are tabulated below:

Grade
Grade
A738 Grade B
Thickness
(in)
0.375 - 2.00
UTS
(MPa)
85 - 102
Elongation in 2"
(min %)
22

Mechanical testing

Charpy V-Notch Impact Toughness requirements may be ordered as a supplementary requirement (S5). A minimum Charpy V-notch impact energy value of 30 ft-lbs [41 J] at - 40°F [-40°C] in longitudinal specimens is a typical supplemental impact toughness requirement. Please inquire for applications requiring a specified minimum impact toughness.

Chemical Composition

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

Meets chemical requirements of ASTM A738 Grade B/SA738 Grade B, as shown below. ASTM A20 limits applyto unspecified elements.

C
(max wt %)
C
(max wt %)
0.20
Mn
(max wt %)
1.50
P 1)
(max wt %)
0.020
S 1)
(max wt %)
0.01
Si
(max wt %)
0.55
Cu
(max wt %)
0.35
Ni
(max wt %)
0.60
Cr
(max wt %)
0.30
Mo
(max wt %)
0.20
V
(max wt %)
0.07
Cb
(max wt %)
0.04
V + Cb
(max wt %)
0.08

1) P and S are more restrictive than A537/SA537 requirements. Even lower limits for P and S are available on an inquiry basis.

Carbon Equivalent

Thickness (in)
Thickness (in)
Typical CET (wt %)
0.375 - 2.00
0.34
Thickness (in)
Thickness (in)
Typical CEV (wt %)
0.375 - 2.00
0.47

Available Chemistries: Carbon equivalent (CEV) restrictions for weldability are available as a supplementary requirement (S20). Please inquire for additional chemistry restrictions.

Tolerances

Thickness, width, and length tolerances for A738 Grade B/SA738 Grade B are in accordance with ASTM A20 requirements. The flatness tolerance for as- supplied product is ½ ASTM A20.

Delivery Conditions

ASTM A738 Grade B/SA738 Grade B is supplied in the quench and tempered condition.

Formability properties

A738 Grade B/SA738 Grade B exhibits excellent cold forming characteristics. Shear burrs and heat-affected zones of thermal cut edges on or near the bend axis as well as sharp corners on edges and on gas cut or punched holes located on or adjacent to the bend axis should be removed by grinding prior cold forming. The following recommended minimum inside bend radius, R, and die width opening, W, as a function of bending orientation are provided:

Thickness
(in. [mm])
Thickness
(in. [mm])
0.375 – 1.00 [9.5 – 25.4]
Bend Axis Perpendicular to Rolling Direction Inside Radius, R (min.)
1.5t
Bend Axis Perpendicular to Rolling Direction Die Width, W (min.)
8t
Bend Axis Parallel to Rolling Direction Inside Radius, R (min.)
2.25t
Bend Axis Parallel to Rolling Direction Die Width, W (min.)
10t
Thickness
(in. [mm])
Thickness
(in. [mm])
1.00 – 2.00 [25.4 – 50.1]
Bend Axis Perpendicular to Rolling Direction Inside Radius, R (min.)
2.5t
Bend Axis Perpendicular to Rolling Direction Die Width, W (min.)
8t
Bend Axis Parallel to Rolling Direction Inside Radius, R (min.)
3.75t
Bend Axis Parallel to Rolling Direction Die Width, W (min.)
10t

Weldability

Welding of A738 Grade B/SA738 Grade B shall be performed in accordance with applicable welding code. In the absence of a specified welding code, the following minimum preheat and interpass temperatures and welding consumables are provided. Special welding consumables and welding procedures may be required to avoid detrimental effects on the mechanical properties of the base metal. Low hydrogen practices are strongly recommended.

Welding process
Welding process
Shielded Metal Arc (SMAW)
Thickness
(in. [mm])
≤3/4 [≤19]
Minimum Preheat and Interpass Temperature
(°F [°C])
50 [10]
Consumables
AWS E7015-X, E7016-X, E7018-X
Welding process
Welding process
Shielded Metal Arc (SMAW)
Thickness
(in. [mm])
>3/4 – 1.5 [19 – 38]
Minimum Preheat and Interpass Temperature
(°F [°C])
50 [10]
Consumables
AWS E7015-X, E7016-X, E7018-X
Welding process
Welding process
Shielded Metal Arc (SMAW)
Thickness
(in. [mm])
>1.50 – 2.00 [>38 – 50]
Minimum Preheat and Interpass Temperature
(°F [°C])
150 [65]
Consumables
AWS E7015-X, E7016-X, E7018-X
Welding process
Welding process
Gas Metal Arc (GMAW)
Thickness
(in. [mm])
≤3/4 [≤19]
Minimum Preheat and Interpass Temperature
(°F [°C])
50 [10]
Consumables
AWS ER70S-X
Welding process
Welding process
Gas Metal Arc (GMAW)
Thickness
(in. [mm])
>3/4 – 1.5 [19 – 38]
Minimum Preheat and Interpass Temperature
(°F [°C])
50 [10]
Consumables
AWS ER70S-X
Welding process
Welding process
Gas Metal Arc (GMAW)
Thickness
(in. [mm])
>1.50 – 2.00 [>38 – 50]
Minimum Preheat and Interpass Temperature
(°F [°C])
150 [65]
Consumables
AWS ER70S-X
Welding process
Welding process
Submerged Arc (SAW)
Thickness
(in. [mm])
≤3/4 [≤19]
Minimum Preheat and Interpass Temperature
(°F [°C])
50 [10]
Consumables
AWS F7XX-EXXX-XX
Welding process
Welding process
Submerged Arc (SAW)
Thickness
(in. [mm])
>3/4 – 1.5 [19 – 38]
Minimum Preheat and Interpass Temperature
(°F [°C])
50 [10]
Consumables
AWS F7XX-EXXX-XX
Welding process
Welding process
Submerged Arc (SAW)
Thickness
(in. [mm])
>1.50 – 2.00 [>38 – 50]
Minimum Preheat and Interpass Temperature
(°F [°C])
150 [65]
Consumables
AWS F7XX-EXXX-XX
Welding process
Welding process
Flux Cored Arc (FCAW)
Thickness
(in. [mm])
≤3/4 [≤19]
Minimum Preheat and Interpass Temperature
(°F [°C])
50 [10]
Consumables
AWS E7XTX-X
Welding process
Welding process
Flux Cored Arc (FCAW)
Thickness
(in. [mm])
>3/4 – 1.5 [19 – 38]
Minimum Preheat and Interpass Temperature
(°F [°C])
50 [10]
Consumables
AWS E7XTX-X
Welding process
Welding process
Flux Cored Arc (FCAW)
Thickness
(in. [mm])
>1.50 – 2.00 [>38 – 50]
Minimum Preheat and Interpass Temperature
(°F [°C])
150 [65]
Consumables
AWS E7XTX-X

Supplementary Requirements

By agreement between the purchaser and the plate manufacturer, the following Supplementary Agreements may be specified on the purchase order: S1. Vacuum Treatment; S2. Product Analysis; S3. Simulated Post-Weld Heat Treatment of Mechanical Test Coupons; and S12. Ultrasonic Examination in accordance with ASTM A578