Evaluation of Steel Plate Quality by Through Thickness Testing

Abstract

The mechanical properties and degrees of isotropy of SA-516 grade 70 plate steels produced by conventional, ladle flux-treated, calcium-treated, and electroslag remelting procedures were characterized by tension and impact testing in three orientations. The primary variables influencing these factors included the sulfur content and degree of sulfide shape control. For the practices examined, tensile elongation and reduction of area, and Charpy impact strength improved with decreasing sulfur content, leading to the conclusion that the volume fraction of sulfide inclusions determines the levels of ductility. The isotropy of the ESR, CaT, and LFT plates, highest in the order ESR CaT>LFT demonstrated that at equivalent sulfur levels, the type, size and distribution of inclusions also exhibited a strong influence. Based on through-thickness ductility, the susceptibility of A516-70 plate steels to lamellar tearing was highest in the order CON>LFT>CaT>ESR. Conventionally melted plate steels are not suitable for applications where lamellar tearing might occur.