Method for welding specially-thick high-strength bridge steel plate

[0024] Example 1:

[0025] Base material: 100mm thick Q370qE bridge steel plate produced by hot-rolled + normalizing process, yield strength 380MPa, tensile strength 530MPa, elongation 32%, impact energy at -40°C at 1/4 plate thickness, 263J, plate thickness 1/2 The impact energy is 233J at -40℃, the thickness of the welded steel plate is 100mm+100mm, the size of the test plate is 600mm×220mm×100mm, and the groove form is shown in the attachment figure 1 Shown

[0026] Welding material: gas shielded welding wire diameter Φ1.2mm, cladding metal mechanical properties: yield strength 525MPa, tensile strength 595MPa, elongation 27%, -40℃ impact energy 76J; submerged arc welding wire diameter Φ5mm, cladding metal mechanical properties It is: the yield strength is 450MPa, the tensile strength is 560MPa, the elongation is 30%, and the impact energy is 125J at -40°C.

[0027] Welding process: Use mechanical treatment to clean the groove surface before welding to remove oil and rust; preheat 150℃ before welding, and control the interlayer temperature at 150~200℃; gas shielded welding welding process parameters: welding current 230~ 240A, welding voltage 29~31V, welding speed 3.5~4mm/s, welding heat input 20~23kJ/cm; welding process parameters of double wire submerged arc welding: 1 wire, 2 wires spacing 35mm, 2 wires 10° to the vertical , 1 wire welding current 690~710A, 1 wire welding voltage 28~30V, 2 wire welding current 550~600A, 2 wire voltage 34~36V, welding speed 13~14mm/s, total welding heat input 33~35kJ/cm; First, the welding surface is filled with gas shielded welding to 20mm in the center, then the other side is cleaned, and the back welding surface is filled with gas shielded welding + double-wire submerged arc welding, and then the first welding surface is filled with double-wire submerged arc welding ; After welding, use aluminum silicate plate to cover the welded joint for slow cooling.

[0028] 100mm thick bridge steel welded by the above process, the mechanical properties of the welded joint: yield strength 385MPa, tensile strength 537MPa, broken at the base metal; 1/2 thickness of the plate: welding seam -40℃ impact energy 74J, heat affected zone -40 ℃ impact energy 108J; 1/4 plate thickness: welding seam -40℃ impact energy 98J, heat affected zone -40℃ impact energy 189J.

[0029] Example 2:

[0030] Base material: 150mm thick Q370qE bridge steel plate produced by hot-rolled + normalizing process, yield strength 375MPa, tensile strength 520MPa, elongation 30%, impact energy at -40°C at 1/4 thickness, 227J, thickness 1/2 The impact energy is 207J at -40℃, the thickness of the welded steel plate is 150mm+150mm, the size of the test plate is 600mm×220mm×100mm, and the groove form is shown in the attachment figure 2 Shown

[0031] Welding material: gas shielded welding wire diameter Φ1.2mm, cladding metal mechanical properties: yield strength 525MPa, tensile strength 595MPa, elongation 27%, -40℃ impact energy 76J; submerged arc welding wire diameter Φ5mm, cladding metal mechanical properties It is: the yield strength is 450MPa, the tensile strength is 560MPa, the elongation is 30%, and the impact energy is 125J at -40°C.

[0032] Welding process: Before welding, mechanical treatment is used to clean the groove surface to remove oil stains and rust; preheat 150℃ before welding, and the temperature between layers is controlled at 150~200℃; gas shielded welding welding process parameters: welding current 260~ 270A, welding voltage 30~32V, welding speed 4~4.5mm/s, welding heat input 25~27kJ/cm; double wire submerged arc welding process parameters: 1 wire, 2 wires spacing 35mm, 2 wires and the vertical direction is 10 °, 1 wire welding current 700~720A, 1 wire welding voltage 29~31V, 2 wire welding current 580~620A, 2 wire voltage 34~36V, welding speed 12~13mm/s, total welding heat input 35~40kJ/cm ; First, the welding surface is filled with gas shielded welding to the center 30mm, then the other side is cleaned, and the back welding surface is filled with gas shielded welding + double-wire submerged arc welding, and then the first welding surface is filled with double-wire submerged arc welding Full; After welding, use aluminum silicate plate to cover the welded joint for slow cooling.

[0033] The 150mm thick bridge steel welded by the above process, the mechanical properties of the welded joint: yield strength 380MPa, tensile strength 515MPa, broken at the base metal; 1/2 thickness of the plate: welding seam -40℃ impact energy 65J, heat affected zone -40 ℃ impact energy 92J; 1/4 plate thickness: welding seam -40℃ impact energy 83J, heat-affected zone -40℃ impact energy 127J.