Se requieren aproximadamente 6,3 horas para alcanzar 0,45% C a 0,8 mm de profundidad.

I understand you're looking for a long write-up related to the solution manual for "Ciencia e Ingeniería de los Materiales" (The Science and Engineering of Materials) by Donald R. Askeland, 3rd edition (Spanish version).

Usamos la función error complementaria: