Application of Statistics of Extreme Values for the inclusions in Type 304 Stainless Steel throughout the Steel Making Process

• Application of statistics of extreme values was applied to determine the inclusion sizes in Type 304 stainless steel. The samples taken from a tundish, slab and hot rolled steel in one heat were examined by using a cross sectional observation. In the molten steel sample, the extreme value distribution (EVD) containing two different types of inclusions, which are deoxidation products (SiO2-CaO-MgO-Al2O3) and reoxidation products (SiO2-MnO-Cr2O3), resulted in two different slopes in one EVD. Meanwhile, the inclusions in the slab sample provided a good linearity with respect to the EVD. The correlation coefficients of the regression lines for both the slab and rolled steel samples were found to increase with an increased number of measurements between 40 and 80. Based on the EVD data obtained from the slab and rolled steel samples, it was found that the EVD data for the area of fractured inclusions on a parallel cross section of rolled steel agrees well with that for the initial undeformed inclusions area in a slab sample. According to the geometrical considerations of morphological change of inclusion during the hot rolling, the EVD for the length of fractured inclusions after the rolling is possible to estimate from their initial sizes in the case of the fracture into the equivalent particle size.

Ämnesord

TEKNIK OCH TEKNOLOGIER  -- Materialteknik -- Metallurgi och metalliska material (hsv//swe)

ENGINEERING AND TECHNOLOGY  -- Materials Engineering -- Metallurgy and Metallic Materials (hsv//eng)

Nyckelord

extreme value analysis

largest inclusion

regression line

correlation coefficient

hot rolling

fracture

Metallurgical process and manufacturing engineering

Metallurgisk process- och produktionsteknik

Publikations- och innehållstyp

vet (ämneskategori)

rap (ämneskategori)