ASTM A514 Gr.Q Steel Welding Process

ASTM A514 Gr.Q is a high-yield-strength, quenched and tempered alloy steel characterized by exceptional yield and tensile strengths, as well as good notch toughness and corrosion resistance.
 
While meeting strength requirements without increasing carbon content, ASTM A514 Gr.Q steel can have its hardenability and resistance to temper softening improved through the judicious addition of alloying elements such as Cr, Mo, V, and Cu. However, analyses of its chemical composition and simulated testing have revealed that this steel is prone to cracking or a reduction in toughness during welding.
 
Weldability Testing of A514 Gr.Q Steel:
ASTM A514 Gr.Q steel exhibits significant susceptibility to cold cracking; therefore, to ensure high-quality welds, control measures should be implemented in two key areas:
(1) Controlling the hardness of the Heat-Affected Zone (HAZ);
(2) Controlling the content of residual diffusible hydrogen.
 
When welding ASTM A514 steel, the welding heat input should be controlled at approximately 2.0 kJ/mm, with a t8/5 time of 820 s.
 
ASTM A514 Gr.Q Welding Essentials:
(1) Upon removal from their packaging, welding electrodes must be baked at a temperature of 350–400°C for 2–4 hours. Following baking, these low-hydrogen electrodes must be immediately transferred—while still warm—into a holding oven; the temperature of the holding oven shall be maintained at 120–150°C until the electrodes are issued for use.
(2) Straight beads shall be employed during welding. For horizontal welding positions, the maximum weave width must not exceed 1.5 times the electrode diameter; excessive weaving is strictly prohibited.
(3) Preheating and interpass temperatures must strictly adhere to the specified temperature ranges. During welding, it is essential to ensure proper weld bead formation.