The invention belongs to the technical field of
welding steel materials and discloses a method for
welding high-grade wear-resistant steel under protection of
carbon dioxide. The method comprises the following steps of: utilizing a high-grade wear-resistant steel plate with the
hardness grade of HB500 and the thickness of below 25mm, combining and butt jointing the
steel plates with the same thicknesses; according to different requirements of a structure on
mechanical property, respectively selecting CO2 gas and a
welding wire with the extension strength Rm of larger than or equal to 500MPa or the extension strength Rm of larger than or equal to 690MPa; selecting the welding wire with the extension strength Rm of larger than or equal to 500MPa, pre-heating to 120 DEG C before welding when
butt welding and back welding are performed on a fixed point; continuously welding, wherein the temperature of an interval between filling and cap weld welding beads is not lower than 120 DEG C and is not higher than 200 DEG C, and welding heat input amount is controlled within 8-20KJ / cm in welding; or selecting the extension strength Rm of larger than or equal to 690MPa, pre-heating to 150 DEG C before welding when
butt welding and back welding are performed on a fixed point; and continuously welding, wherein the temperature of an interval between filling and cap weld welding beads is not lower than 150 DEG C and is not higher than 200 DEG C, and welding heat input amount is controlled within 8-20KJ / cm. The method for welding high-grade wear-resistant steel under the protection of the
carbon dioxide, disclosed by the invention, ensures that a
welding joint has higher strength so that a welding bead has excellent anti-
cracking performance, the
welding joint has higher low-temperature
impact toughness storage and
safety margin, the construction condition is modified and the production cost is reduced.