High-heat-input combined welding method for thick-walled high-strength steel

A high-heat-input combined welding method for thick-walled high-strength steel, comprising:

• machining a steel plate to be welded into an asymmetric double-sided V-groove, wherein a depth of a front groove is 30 mm to 40 mm;
• then filling and welding the front groove using electrogas welding while controlling a single-pass heat input below 300 kJ/cm;
• and finally filling and welding a back groove while ensuring that the single-pass heat input of the back groove does not exceed that of the front groove,
• wherein, when a back groove depth satisfies H2≤25 mm, flux-cored arc welding is configured for filling welding;
• when the back groove depth satisfies 25 mm<H2≤50 mm, flux-cored arc welding is first configured for filling welding;
• when a remaining groove depth h satisfies following formula, electrogas welding is then configured for filling welding,
• h
• ≤
• H
• 2
• -
• H
• 2
• 2
• ⁢
• tan
• 2
• ⁢
• α
• 2
• 2
• -
• H
• 1
• 2
• ⁢
• tan
• ⁢
• α
• 2
• 2
• ⁢
• tan
• ⁢
• α
• 1
• 2
• tan
• ⁢
• α
• 2
• 2
• in the formula, h represents the remaining groove depth, H2 represents the back groove depth, H1 represents a front groove depth, α1 represents a front groove angle, and α2 represents a back groove angle;
• when the back groove depth satisfies H2>50 mm, triple-wire submerged arc welding is first configured for filling welding;
• when the remaining groove depth h satisfies the formula, electrogas welding is then configured for filling welding,
• h
• ≤
• H
• 2
• -
• H
• 2
• 2
• ⁢
• tan
• 2
• ⁢
• α
• 2
• 2
• -
• H
• 1
• 2
• ⁢
• tan
• ⁢
• α
• 2
• 2
• ⁢
• tan
• ⁢
• α
• 1
• 2
• tan
• ⁢
• α
• 2
• 2
• in the formula, h represents the remaining groove depth, H2 represents the back groove depth, H1 represents the front groove depth, α1 represents the front groove angle, and α2 represents the back groove angle,
• wherein when adopting flux-cored arc welding for filling passes, welding current is within 160A-220A, arc voltage is within 20V-23V, welding speed is 10 cm/min-16 cm/min with heat input of 10 kJ/cm-20 kJ/cm, the electrode extension is within 12 mm-15 mm, and the gas current is at 15 L/min-25 L/min,
• wherein when performing filling welding using triple-wire submerged arc welding, leading wire welding current is 1160A-1380A with welding voltage of 32V-35V;
• middle wire welding current is 1100A-1280A with welding voltage of 40V-42V;
• trailing wire welding current is 950A-1200A with welding voltage of 42V-46V;
• triple-wire submerged arc welding speed is 35 cm/min-81 cm/min with heat input of 90KJ/cm-260KJ/cm.