DUPLEX STAINLESS STEEL AND METHOD FOR MANUFACTURING THEREOF

• Main Authors: PARK MINAM, KWON YOUNGJIN
• Format: Patent
• Language: English; Korean
• Published: 21.06.2023
• Subjects: ALLOYS; CHEMISTRY; FERROUS OR NON-FERROUS ALLOYS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUSMETALS OR ALLOYS; MAKING METAL MALLEABLE BY DECARBURISATION, TEMPERING OR OTHERTREATMENTS; METALLURGY; METALLURGY OF IRON; MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; TREATMENT OF ALLOYS OR NON-FERROUS METALS

The present invention relates to a duplex stainless steel and a manufacturing method thereof, which provide improved hole expandability. To this end, the present invention comprises, based on wt%: 0.01%-0.03% of C; 0.3%-0.5% of Si; 0.3%-1.0% of Mn; 23.0%-25.0% of Cr; 5.0%-8.0% of Ni; 3.0%-4.0% of Mo; 0.1%-1.0% of Cu; 0.01%-0.3% of W; 0.01%-0.3% of N; and the balance being Fe and other inevitable impurities. The present invention satisfies the following formula (1) and formula (2). Formula (1): -0.072 × Cr + 0.133 × Ni - 0.100 × Mo - 0.047 × W - 0.335 × N +1.320 > 0.1 Formula (2): -3 < 0.006 × Cr - 1.241 × Ni + 0.305 × Mo - 0.968 × W + 133.295 × N - 13.348 < 4 Here, C, Si, Mn, Cr, Ni, Mo, Cu, W, and N signify the content of each element (wt%). 본 발명은 홀확관성을 향상시킨 듀플렉스계 스테인리스강 및 그 제조방법에 관한 것으로, 중량 %로 C: 0.01% 내지 0.03%, Si: 0.3% 내지 0.5%, Mn: 0.3% 내지 1.0%, Cr: 23.0% 내지 25.0%, Ni: 5.0% 내지 8.0%, Mo: 3.0% 내지 4.0%, Cu: 0.1% 내지 1.0%, W: 0.01% 내지 0.3%, N: 0.01% 내지 0.3%를 포함하고, 나머지는 Fe 및 불가피한 불순물을 포함하고, 하기 식 (1) 및 식 (2)를 만족한다: 식 (1): -0.072×Cr + 0.133×Ni - 0.100×Mo - 0.047×W - 0.335×N +1.320 > 0.1 식 (2): -3 < 0.006×Cr - 1.241×Ni + 0.305×Mo - 0.968×W + 133.295×N - 13.348 < 4 여기서, C, Si, Mn, Cr, Ni, Mo, Cu, W, N 은 각 원소의 함량(중량%)을 의미한다.