Low-alloy heat-resistant steel having improved creep strength and toughness

A low-alloy steel having improved creep strength and toughness, which consists essentially, on a weight basis, of:

• ______________________________________ C:
• 0.03-0.12%, Si:
• at most 0.7%, Mn:
• 0.1-1.5%, Ni:
• at most 0.8%, P:
• at most 0.03%, S:
• at most 0.015%, Cr:
• 1.5-3.5%, W:
• 1-3%, V:
• 0.1-0.35%, Nb:
• 0.01-0.1%, B:
• 0.0001-0.02%, N:
• less than 0.005%, Al:
• less than 0.005%, Ti:
• 0.001-0.1%, and ______________________________________
• a balance of Fe and incidental impurities,
• wherein the Ti and N contents satisfy the following inequality:
• 0.080.gtoreq.Ti(%)-(48/14).times.N(%).gtoreq.0.003.

A low-alloy steel having improved creep strength and toughness, which consists essentially, on a weight basis, of:

• ______________________________________ C:
• 0.03-0.12%, Si:
• at most 0.7%, Mn:
• 0.1-1.5%, Ni:
• at most 0.8%, P:
• at most 0.03%, S:
• at most 0.015%, Cr:
• 1.5-3.5%, W:
• 1-3%, V:
• 0.1-0.35%, Nb:
• 0.01-0.1%, B:
• 0.0001-0.02%, N:
• less than 0.005%, Al:
• less than 0.005%, Ti:
• 0.001-0.1%, ______________________________________
• one or more elements selected from the group consisting of La, Ce, Y, Ca, Zr, and Ta:
• 0.01-0.2% each, Mg:
• 0.0005-0.05%, and Mo:
• 0.01-0.4%, and
• a balance of Fe and incidental impurities,
• wherein the Ti and N contents satisfy the following inequality:
• 0.080.gtoreq.Ti(%)-(48/14).times.N(%).gtoreq.0.003.