Effect of Carbon on Hot Ductility of As-cast Low Alloy Steels

Effect of High Temperature Deformation on the Hot Ductility of Nb Microalloyed Steel

“…It has been well known that surface cracking susceptibility depends on C content in low alloy steel, Figure 2.26. [66,99] This is attributed to the large austenite grain size. The grain sizecan be very large in the vicinity of the peritectic composition, i.e.…”

“…[3] Microalloyed steels generally show little indication, from hot tensile tests, that grain size has a significant influence on their hot ductilities, because of the overriding effect of the precipitation of AIN or Nb(C,N) at austenite boundariesY] Where an attempt has been made to keep the precipitate distribution constant, the changes in hot ductility with grain size were similar to those observed in plain C-Mn steels. [66] …”

“…However, in hot tensile test of the reheated specimens without remelting, such C dependency of the ductility could not be recognized as shown in Figure 2.27. [66] ------ .27. Effect of C content on the hot ductility.…”

“…the D-ferrite or liquid phases associated with the lower or higher carbon contents than the peritectic composition, respectively, to retard austenite grain growth. [66] Note that the peritectic composition moves to lower carbon contents in steels containing…”

“…The specimens were deformed at 800 and 900°C after solution treatment at 13 OO°c. [66] The surface cracking during the pro cess of continuous casting or the direct rolling is mainly caused by the precipitation of carbonitrides or sulfides or by the segregation of impurity atoms to the austenite grain boundaries in the temperature range from austenite to austenite/ferrite duplex phase region, accompanying the intergranular fracture of austenite. [1,30,37,50,78,96,100,101] Such ductility, as explained before, has been weIl known to depend largely on the grain size and to decrease inversely proportional to the initial grain size.…”