Structure Characteristics of Ce-Inoculated, Low Sulphur Grey Cast Irons

Solid State Phenomena ◽

10.4028/www.scientific.net/ssp.188.318 ◽

2012 ◽

Vol 188 ◽

pp. 318-323 ◽

Cited By ~ 2

Author(s):

Irina Anton ◽

Iulian Riposan

Keyword(s):

Control Parameter ◽

Structural Characteristics ◽

Sulphur Content ◽

Structure Parameters ◽

Cast Irons ◽

Structure Characteristics ◽

Grey Cast ◽

Fesi Alloy

The structural characteristics of electric melt, as-cast grey irons were studied in critical solidification conditions, such as very low sulphur content (< 0.025%) and a low (%Mn) x (%S) control parameter (< 0.015) with low Al residual (< 0.002%), without resulphurising or preconditioning. The efficiency of Ce-Ca-Al-FeSi alloy was tested at lower addition rates (0.15-0.25wt.%), as traditionally high inoculant addition rates have been employed in low sulphur grey cast irons. Ce bearing ferrosilicon with similar Ca and Al levels appears to be more efficient than a commercial Ba-Ca-Al-FeSi inoculant, especially at low addition rates (< 0.2wt.%) for the key structure parameters: fewer carbides and less undercooled graphite with small eutectic cells at a higher count.

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Ce-Bearing FeSi Alloy Inoculation of Electrically Melted, Low Sulphur Grey Cast Irons for Thin Wall Castings

Metals ◽

10.3390/met11071122 ◽

2021 ◽

Vol 11 (7) ◽

pp. 1122

Author(s):

Irina Varvara Balkan ◽

Iulian Riposan

Keyword(s):

Wall Thickness ◽

Structural Characteristics ◽

Cooling Curve ◽

Thin Wall ◽

Cast Irons ◽

Iron Castings ◽

Grey Cast ◽

The Difference ◽

Thermal Cooling ◽

Fesi Alloy

Electrically melted and over-heated (>1500 °C) grey cast iron at less than 0.04%S, as commonly used, solidifies large amounts of carbides and/or undercooled graphite, especially in thin wall castings; this is necessary to achieve a stronger inoculation. The efficiency of Ce-bearing FeSi alloy is tested for lower ladle addition rates (0.15 and 0.25 wt.%), compared to the base and conventional inoculated iron (Ba,Ca-bearing FeSi alloy). The present work explores chill and associated structures in hypoeutectic grey iron (3.6–3.8%CE, 0.02%S, (%Mn) × (%S) = 0.013–0.016, Alres < 0.002%), in wedge castings W1, W2 and W3 (ASTM A 367, furan resin sand mould), at a lower cooling modulus (1.1–3.5 mm) that is typically used to control the quality of thin wall iron castings. Relatively clear and total chill well correlated with the standard thermal (cooling curve) analysis parameters and structural characteristics in wedge castings, at different wall thickness, displayed as the carbides/graphite ratio and presence of undercooled graphite morphologies. The difference in effects of the two inoculants addition is seen as the ability to decrease the amount of carbides and undercooled graphite, with Ce-bearing FeSi alloy outperforming the conventional inoculant, especially as the wall thickness decreased. It appears that Ce-bearing FeSi alloy could be a solution for low sulphur, electric melt, thin wall iron castings production.

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