Welding method for CO2 gas shielded welding of ultra-high strength thick steel plates

Abstract

The invention relates to a welding method for CO2 gas shielded welding for a super-strength thick steel plate. According to the technical scheme of the welding method, a groove is machined in the blanked to-be-welded super-strength thick steel plate and is in an asymmetric X shape; and bottoming layer welding and filling layer welding are sequentially conducted through a CO2 gas shielded welding method, nondestructive testing is conducted on a welding line through ultrasonic waves, and mechanical performance testing is conducted on a welding connector. According to bottoming layer welding, a welding stick of the 500-600 MPa level is used for performing welding, and the thickness of a bottoming layer ranges from 2 mm to 8 mm; and according to filling layer welding, a welding stick with the strength equal to the strength of base metal is adopted for welding. The strength of the to-be-welded super-strength thick steel plate is larger than or equal to 890 MPa, and the thickness of the to-be-welded super-strength thick steel plate ranges from 25 mm to 30 mm. The welding method has the beneficial effects of being simple in technology, low in manual strength, low in welding cost and high in welding efficiency. The welding connector formed through the welding method obtains the good comprehensive mechanical performance and is suitable for super-strength large thick plate structural steel with strength being larger than or equal to 890 MPa.

Description

technical field [0001] The invention belongs to CO 2 Gas shielded welding technology field. Specifically relates to a CO for ultra-high strength thick steel plate 2 Welding method of gas shielded welding. Background technique [0002] In recent years, structural steel has continuously developed towards the direction of ultra-high strength and large structures. Requirements for large components such as construction machinery. [0003] Such high-performance steel materials usually add higher alloy content, such as C, Mn, Cr, Mo and Ni, etc., to ensure the strength, toughness, fatigue and corrosion resistance, and the high alloy content also directly improves the carbon content of the material. The equivalent (Ceq) and cold crack sensitivity coefficient (Pcm) bring difficulties to the subsequent welding process. Therefore, when welding such ultra-high-strength thick plates, it is necessary to preheat before welding, control interlayer temperature and slow cooling after wel...

AI Technical Summary

Problems solved by technology

These processes require heating or slow cooling equipment and devices, and the time of heating and cooling needs to be controlled, which increases the complexity of the process, increases the labor intensity of welding, and also increases labor costs. cost

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