Production method of high-reliability large-specification welded H-shaped steel

The invention discloses a high-reliability large-specification welded H-shaped steel production method which comprises the following steps: casting blank production: smelting by adopting a 210-ton top-bottom combined blown converter and LF and RH vacuum refining, and adopting a low-superheat-degree casting, steady-speed steel drawing and casting blank soft reduction technology to ensure that the macrosegregation of a casting blank is lower than class-C 1.5 level and internal cracks do not exist; the heating temperature of the casting blank ranges from 1100 DEG C to 1180 DEG C, and the heating time ranges from 9 min/cm to 14 min/cm; the tapping temperature is 1090 to 1180 DEG C; t-shaped steel rolling is conducted, specifically, after a casting blank is discharged out of a furnace and descaled, multi-pass rolling is conducted on a multi-pass profile rolling machine, the rolling starting temperature is 1120 DEG C, and the final rolling temperature is 810-850 DEG C; h-shaped steel is combined ...