350MPa-level low temperature resistant H-shaped steel and preparation method thereof

The invention belongs to the technical field of steel, and particularly relates to 350MPa-level low temperature resistant H-shaped steel and a preparation method thereof. The 350MPa-level low temperature resistant H-shaped steel comprises the following chemical components in percentage by weight: 0.05-0.09% of carbon, 0.20-0.35% of silicon, 1.35-1.50% of manganese, 0.020-0.035% of niobium, 0.015-0.025% of vanadium, 0.005-0.025% of titanium, smaller than and equal to 0.020% of phosphorus, smaller than and equal to 0.015% of sulfur, and iron and inevitable impurities for balance. According to the 350MPa-level low temperature resistant H-shaped steel and the preparation method thereof, mainly through the low carbon content, and the application of niobium-titanium complex microalloying technology, the production of the 350MPa-level low temperature resistant H-shaped steel is realized; a prepared product has a yielding strength larger than 380 MPa, is good in low temperature resistant steel mechanical property, and has low-temperature (minus 40 DEG C) resistant longitudinal impact power larger than 76 J.