Ultralow-carbon heat-resistant steel welding wire for high-temperature environment and application and welding method thereof

The invention discloses an ultralow-carbon heat-resistant steel welding wire for a high-temperature environment and application of the ultralow-carbon heat-resistant steel welding wire, and belongs to the technical field of welding materials. The welding wire comprises the following chemical components in percentage by weight: less than or equal to 0.01% of C, 7.5-10.5% of Cr, 0.2-0.6% of Si, 0.4-1.0% of Ni, less than or equal to 0.1% of Mo, 0.06-0.15% of N, less than or equal to 0.01% of Nb, 0.10-0.30% of V, 0.80-1.80% of Mn, 1.40-2.60% of W, less than or equal to 0.08% of Cu, less than or equal to 0.06% of Co, less than or equal to 0.02% of P, less than or equal to 0.02% of S and the balance of iron and inevitable impurities. The welding wire is suitable for welding heat-resistant steel parts used in high-temperature environments such as nuclear power or thermal power, the welding process is stable, splashing is small, and the processing property is good. After the ultralow-carbon heat-resistant steel weldi