The invention relates to
rare earth containing H profile steel with high strength and high
toughness and a production method thereof, and belongs to the technical field of
metallurgy and moulding. The
raw material comprises 90wt% of
blast furnace molten iron and 10wt% of high quality steel
scrap. The
casting blank comprises the following components in percentage by weight: 0.07-0.12% of C, 0.10-0.30% of Si, 1.40-1.70% of Mn, less than or equal to 0.020% of P, less than or equal to 0.010% of S, 0.30-0.60% of Cr, 0.20-0.50% of Ni, 0.06-0.20% of V, 0.01-0.03% of Ti, 0.01-0.01% of Al, 0.0005-0.010% of
rare earth element RE, less than 0.10% of Cu and the balance of Fe and microelements which cannot be detected. The process flow is as follows: molten iron pre-treatment;
smelting by a top-bottom combined blowing converter; refining by an LF (
Ladle Furnace); VD (Vapor
Distillation) vacuum treatment;
continuous casting of square billets;
cutting; heating the
casting blank; dephosphorization by
high pressure water; BD1 cogging; BD2 central rolling; dephosphorization by
high pressure water; CCS (Cold Crushing Strength) universal rolling; straightening; cooling; flaw detection; and saw
cutting. The mechanical properties of the steel are as follows: the yield strength is 490-570MPa, the strength of extension is 660-750Mpa, the
yield ratio is greater than or equal to 0.80, the
ductility is greater than or equal to 25%, and the horizontal
impact value: aKV is greater than or equal to 100J / cm<2> (minus 40 DEG C). The product provided by the invention has the characteristics of low content of
impurity elements, high strength, good
toughness and excellent
welding performance.