Abstract: The austenitic stainless steel that does not cause defects such as aging crack or delayed fracture even after the expansion and curling process of 5 steps or more is disclosed. In accordance with an aspect of the present disclosure, an austenitic stainless steel with excellent pipe expanding workability and aging crack resistance includes, in percent (%) by weight of the entire composition, C: 0.01 to 0.04%, Si: 0.1 to 1.0%, Mn: 0.1 to 2.0%, Cr: 16 to 20%, Ni: 6 to 10%, Cu: 0.1 to 2.0%, Mo: 0.2% or less, N: 0.035 to 0.07%, the remainder of iron (Fe) and other inevitable impurities, and the C+N satisfies 0.1% or less, the product of the Md30 (° C.) value and average grain size (?m) satisfies less than ?500.

Abstract: A ferritic stainless steel for an exhaust system heat exchanger having excellent sound absorption properties and a method for manufacturing the same are disclosed. The ferritic stainless steel for an exhaust system heat exchanger having excellent sound absorption properties includes, by weight percent, 0.001 to 0.01% of C, 0.001 to 0.01% of N, 0.2 to 1% of Si, 0.1 to 2% of Mn, 10 to 30% of Cr, 0.001 to 0.1% of Ti, 0.001 to 0.015% of Al, 0.3 to 0.6% of Nb, 0.01 to 2.5% of Mo, and the balance of Fe and other unavoidable impurities, wherein the number of inclusions existing in a ferrite matrix and satisfying the following Formula 1 is 5 ea/mm2 or more.

Abstract: Provided is a ferritic stainless steel for an exhaust system heat exchanger and a method of manufacturing the same. The ferritic stainless steel includes, in percent (%) by weight of the entire composition, 0.003 to 0.1% of carbon (C), 0.01 to 2.0% of silicon (Si), 0.01 to 1.5% of manganese (Mn), 0.05% or less of phosphorus (P), 0.005% or less of sulfur (S), 10 to 30% of chromium (Cr), 0.001 to 0.10% of titanium (Ti), 0.001 to 0.15% of aluminum (Al), 0.003 to 0.03% of nitrogen (N), 0.3 to 0.6% of niobium (Nb), 0.01 to 2.5% of molybdenum (Mo), and the remainder of iron (Fe) and other inevitable impurities, wherein TiN precipitates having a size of 0.1 ?m or more are distributed in a surface layer of a ferrite matrix at a concentration of 2.5*104 ea/mm2 or less.

Abstract: The austenitic stainless steel that does not cause defects such as aging crack or delayed fracture even after the expansion and curling process of 5 steps or more is disclosed. In accordance with an aspect of the present disclosure, an austenitic stainless steel with excellent pipe expanding workability and aging crack resistance includes, in percent (%) by weight of the entire composition, C: 0.01 to 0.04%, Si: 0.1 to 1.0%, Mn: 0.1 to 2.0%, Cr: 16 to 20%, Ni: 6 to 10%, Cu: 0.1 to 2.0%, Mo: 0.2% or less, N: 0.035 to 0.07%, the remainder of iron (Fe) and other inevitable impurities, and the C+N satisfies 0.1% or less, the product of the Md30 (° C.) value and average grain size (?m) satisfies less than ?500.

Abstract: A Ti, Nb-added ferritic stainless steel with excellent low-temperature toughness of weld zone according to an embodiment of present disclosure includes, in percent (%) by weight of the entire composition, C: 0.004 to 0.015%, N: 0.004 to 0.015%, Si: 0.01 to 0.7%, Mn: 0.01 to 0.7%, P: 0.0001 to 0.04%, S: 0.0001 to 0.005%, Cr: 10 to 30%, Al: 0.005 to 0.04%, Ti: 0.1 to 0.5%, Nb: 0.1 to 0.6%, Ca: 0.0001 to 0.003%, the remainder of iron (Fe) and other inevitable impurities, satisfies the following equation (1), and Al—Ca—Ti—Mg—O-based oxide and Ti—Nb—C—N carbonitride containing the oxide have an average diameter of 3 to 10 ?m and a distribution density of 4/mm2 or more. {(Ti+0.5*Nb)*(C+N)}/Al>0.

Abstract: Provided is a ferritic stainless steel for an exhaust system heat exchanger and a method of manufacturing the same. The ferritic stainless steel includes, in percent (%) by weight of the entire composition, 0.003 to 0.1% of carbon (C), 0.01 to 2.0% of silicon (Si), 0.01 to 1.5% of manganese (Mn), 0.05% or less of phosphorus (P), 0.005% or less of sulfur (S), 10 to 30% of chromium (Cr), 0.001 to 0.10% of titanium (Ti), 0.001 to 0.15% of aluminum (Al), 0.003 to 0.03% of nitrogen (N), 0.3 to 0.6% of niobium (Nb), 0.01 to 2.5% of molybdenum (Mo), and the remainder of iron (Fe) and other inevitable impurities, wherein TiN precipitates having a size of 0.1 ?m or more are distributed in a surface layer of a ferrite matrix at a concentration of 2.5*104 ea/mm2 or less.

Abstract: A ferritic stainless steel for automotive exhaust system parts with improved expandability is disclosed. A ferritic stainless steel with improved expandability according to an embodiment of the present disclosure includes, in percent (%) by weight of the entire composition, Cr: 10 to 25%, N: 0.015% or less (excluding 0), Al: 0.005 to 0.04%, Nb: 0.1 to 0.6%, Ti: 0.1 to 0.

Abstract: A ferritic stainless steel for an exhaust system heat exchanger having excellent sound absorption properties and a method for manufacturing the same are disclosed. The ferritic stainless steel for an exhaust system heat exchanger having excellent sound absorption properties includes, by weight percent, 0.001 to 0.01% of C, 0.001 to 0.01% of N, 0.2 to 1% of Si, 0.1 to 2% of Mn, 10 to 30% of Cr, 0.001 to 0.1% of Ti, 0.001 to 0.015% of Al, 0.3 to 0.6% of Nb, 0.01 to 2.5% of Mo, and the balance of Fe and other unavoidable impurities, wherein the number of inclusions existing in a ferrite matrix and satisfying the following Formula 1 is 5 ea/mm2 or more.