A Statistical Analysis of the Mechanical Properties of the Beam 14 in Lines 630 and 650 of Iran National Steel Industrial Group

Structural steel sections are mainly used in beams and columns of building frames. Iran National Steel Industrial Group is among the oldest and largest producers of beams in Iran. It has two beam production lines, namely Line 630 and Line 650. In this study, the mechanical properties of manufactured beams in these production lines were compared. Based on the t-test results, the elongation is significantly higher in Line 650 products while tensile strength is higher in Line 630. However, the two lines do not show any significant differences in the yield stress. Mann-Whitney test was also used to determine if one of the mechanical properties significantly differs in the two lines products. Based on the test, the tensile strength, elongation and yield stress were significantly different in the two production lines. According to the Levene and Fisher test, Line 650 products were more homogeneous in terms of the tensile strength and yield stress while Line 630 products were more homogeneous with regard to elongation. Moreover, the length of the production line and the cooling time seem to affect the mechanical properties. In addition, an inverse relationship between tensile strength and beam elongation was observed in this study.