摘要:
There is provided a high-strength steel plate having acicular ferrite and bainite as a main microstructure and an austenite/martensite (M & A) as a second phase under the control of a cooling rate above the austenite transformation temperature. The high-strength steel plate comprises: carbon (C): 0.03 to 0.10 wt %, silicon (Si): 0.1 to 0.4 wt %, manganese (Mn): 1.8 wt % or less, nickel (Ni): 1.0 wt % or less, titanium (Ti): 0.005 to 0.03 wt %, niobium (Nb): 0.02 to 0.10 wt %, aluminum (Al): 0.01 to 0.05 wt %, calcium (Ca): 0.006 wt % or less, nitrogen (N): 0.001 to 0.006 wt %, phosphorus (P): 0.02 wt % or less, sulfur (S): 0.005 wt % or less, and the balance of iron (Fe) and other inevitable impurities. The method for manufacturing a high-strength steel plate may be useful to economically and effectively manufacture a high strength steel, which is able to secure excellent properties such as high strength and high toughness since the acicular ferrite and bainite may be effectively formed without adding expensive elements such as molybdenum (Mo).
摘要:
There is provided a high-strength steel plate having acicular ferrite and bainite as a main microstructure and an austenite/martensite (M & A) as a second phase under the control of a cooling rate above the austenite transformation temperature. The high-strength steel plate comprises: carbon (C): 0.03 to 0.10 wt %, silicon (Si): 0.1 to 0.4 wt %, manganese (Mn): 1.8 wt % or less, nickel (Ni): 1.0 wt % or less, titanium (Ti): 0.005 to 0.03 wt %, niobium (Nb): 0.02 to 0.10 wt %, aluminum (Al): 0.01 to 0.05 wt %, calcium (Ca): 0.006 wt % or less, nitrogen (N): 0.001 to 0.006 wt %, phosphorus (P): 0.02 wt % or less, sulfur (S): 0.005 wt % or less, and the balance of iron (Fe) and other inevitable impurities. The method for manufacturing a high-strength steel plate may be useful to economically and effectively manufacture a high strength steel, which is able to secure excellent properties such as high strength and high toughness since the acicular ferrite and bainite may be effectively formed without adding expensive elements such as molybdenum (Mo).
摘要:
A steel plate for linepipes having ultra-high strength and excellent low temperature toughness, and a method for manufacturing the same are disclosed. The steel plate has a strength of 930 MPa or more and excellent toughness even with much smaller amounts of alloying elements than that of conventional steel plates, and a method for manufacturing the same. The steel includes by weight %: 0.03˜0.10% C; 0˜0.6% Si; 1.6-2.1% Mn; 0˜1.0% Cu; 0-1.0% Ni; 0.02-0.06% Nb; 0-0.1% V; 0.1-0.5% Mo; 0-1.0% Cr; 0.005-0.03% Ti; 0.01-0.06% Al; 0.0005-0.0025% B; 0.001-0.006% N; 0-0.006% Ca; 0.02% or less P; 0.005% or less S; and the balance Fe and unavoidable impurities. The microstructure includes at least about 75 area percent of a mixture of bainitic ferrite and acicular ferrite.