How to weld astm a572 grade 50

What is ASTM A572 material?

ASTM A572 standard is for high strength low alloy (HSLA) structural steel plate. The ASTM A572 specification is the Standard Specification for High-Strength Low-Alloy Columbium-Vanadium Structural Steel for plates used in general construction and structural applications. ASTM A572 includes five grades with specified minimum yield strengths of 42, 50, 55, 60, and 65 ksi, respectively.

Grades 42, 50, 55 are intended for riveted, bolted or welded structurals, Grade 60 and 65 are for riveted and bolted construction of bridges, welded constructions and more applications.

Chemical properties of ASTM A 572

Chemical properties of Grade 42 are:


Chemical properties of Grade 52 are:


Chemical properties of Grade 55 are:


Chemical properties of Grade 60 are:


Chemical properties of Grade 65 are:


Mechanical properties:

GradeYield Point (ksi)Tensile Strength (ksi)Min. 8″ Elongation %
4242 (290 MPa) 60 (415 MPa)20
5050 (345 MPa) 65 (450 MPa) 18
5555 (380 MPa) 70 (485 MPa) 17
6060 (415 MPa) 75 (520 MPa) 16
6565 (450 MPa) 80 (550 MPa) 15

SMAW, TIG MIG welding of ASTM A 572

Selection of suitable welding electrode is very essential for the welding of this grade. ASTM A 572 grades 42, 50 & 55 can be welding with SMAW or stick welding rod E7018 (SFA 5.1). Welding of ASTM A572 Grade 60 & 65 shall be carried out using E8018-G electrode.

TIG or MIG welding of ASTM A 572 grades 42, 50 & 55 is made with ER70S-6 and for grade 60 & 65, it is welded using ER80S-G. FCAW welding is carried out with E71T-1M to have good mechanical properties. For grade 60 & 65 FCAW welding is carried out using E8XTX-X as per SFA 5.29.

Note: When selecting consumables with G classification, find the one with minimum additional alloying elements. Electrode with G classification are available in various alloying element combinations.

Preheat/ Interpass temperature of ASTM A 572

Preheat temperature must be applied when welding thick parts of ASTM A572. The grade of ASTM A572 also important for determining the preheat temperature. For example, for ASTM A572, Grades 42, 50, 55- Preheat temperature of 110°C (225°F) to be applied for thickness more than 2.5 inch (65 mm), for thickness above 1.5 inch to 2.5 inch preheat temperature of 65°C (150°F) to be applied. Less than 1.5 inch, preheat to ambient temperature is sufficient.

A572, Grades 60 & 65 need higher preheat temperature. For thickness above 0.75 inch (18 mm) minimum preheat of 65°C (150°F) to be applied. Preheat temperature of 150°C (300°F) to be applied for thickness more than 2.5 inch (65 mm), for thickness above 1.5 inch to 2.5 inch preheat temperature of 110°C (225°F) to be applied.

PWHT Temperature and time for ASTM A 572

Post Weld Heat Treatment (PWHT) of ASTM A 572 is 1094 °F-1110°F (590-600°C). The micro-alloyed grades of ASTM A 572 can results in change in mechanical properties so it is recommended to follow plate manufacturer guidelines.

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