pISSN : 1598-706X / eISSN : 2288-8381
한국주조공학회지 (21권5호 280-285)
Formation Mechanism of Surface Crack and Its Control on Continuously Cast Slabs of Nb-containing Austenitic Stainless Steel
Nb 첨가 오스테나이트계 스테인레스강의 연속주조시 표면크랙 형성기구 및 제어
Sang-Dae Shim, Sun-Koo Kim
POSCO Technical Research Lab.
Nb-containing austenitic stainless steel is widely used as exhaust frame and diffuser assembly in power plant. However, this steel is known to be difficult to produce by the continuous casting process due to the surface cracks. Therefore, the continuous casting technology was developed for the prevention of the surface cracks on CC slabs. Precipitates and the analysis of heat trasfer in a slab were investigated in order to find out the formation mechanism of surface cracks on cc slabs It was found that surface cracks are occurred due to the NbC precipitates, which are formed along the grain boundaries around 800℃. The secondary cooling pattern has been developed to produce the defect free CC slabs of Nb-containing austenitic stainless steel.
Stainless steel, Hot ductility, Precipitation, Continuous casting