Size of Non-Metallic Inclusions in High-Grade Medium Carbon Steel

Abstract

Non-metallic inclusions found in steel can affect its performance characteristics. Their impact depends not only on their quality, but also, among others, on their size and distribution in the steel volume. The literature mainly describes the results of tests on hard steels, particularly bearing steels. The amount of non-metallic inclusions found in steel with a medium carbon content melted under industrial conditions is rarely presented in the literature. The tested steel was melted in an electric arc furnace and then desulfurized and argonrefined. Seven typical industrial melts were analyzed, in which ca. 75% secondary raw materials were used. The amount of non-metallic inclusions was determined by optical and extraction methods. The test results are presented using stereometric indices. Inclusions are characterized by measuring ranges. The chemical composition of steel and contents of inclusions in every melts are presented. The results are shown in graphical form. The presented analysis of the tests results on the amount and size of non-metallic inclusions can be used to assess them operational strength and durability of steel melted and refined in the desulfurization and argon refining processes.

The Effect of Fine Non-Metallic Inclusions on the Fatigue Strength of Structural Steel

“…Non-metallic inclusions are one of the factors that influence the fatigue strength of steel [9][10][11][12]. Despite vast progress in manufacturing technologies, non-metallic inclusions have not been completely eliminated from steel [12][13][14].…”

Effect Of The Spacing Between Submicroscopic Oxide Impurities On The Fatigue Strength Of Structural Steel

“…The level of fatigue-inducing load was adapted to the strength properties of steel. Maximum load was set for steel tempered at a temperature of: 200°C -650 MPa, from 300°C to 500°C -600 MPa, 600°C -540 MPa [13][14][15][16]27,28]. During the test, the applied load was gradually reduced in steps of 40 MPa (to support the determinations within the endurance limit).…”

“…Non-metallic inclusions are one of such defects [26][27][28][29]. The quantity and quality of non-metallic inclusions determine the mechanical properties and fatigue strength of materials [30,31].…”

“…The mechanical properties and fatigue strength of structural materials should also be evaluated in view of crystallization conditions [5][6][7][8][9][10][11], the manufacturing process [12][13][14][15], microstructure [16,17], microsegregation [18][19][20][21][22] and the existing defects [23][24][25].…”

The Effect of the Production Process and Heat Processing Parameters on the Fatigue Strength of High-Grade Medium-Carbon Steel

“…The addition of small amounts of aluminum leads to partial deoxydation of steel and the formation of inclusions along the boundaries of austenite grains. Excessive amounts of powerful deoxidants contribute to the formation of large faceted inclusions [1][2][3][4][5][6][7][8].…”