RMC-04-91 HIGH-STRENGTH Fe-3Cr-W(Mo) STEEL FOR PETROCHEMICAL APPLICATIONS

Description:

This paper describes the development of a new class of high strength Fe-3Cr-W(Mo) ferritic steel. The new steel has two grades A and B. The Grade A is a base Fe-3Cr-W(Mo) composition that is strengthened by optimum additions of C and V. The Grade B also contains 0.10 wt % Ta for additional high-temperature creep strength. Both alloys are air hardenable and are recommended for use in the normalized and tempered condition. The best combination of strength and toughness properties is obtained when both grades are austenitized at 2012oF and tempered at 1345oF. Both grades were commercially melted in 50-ton heats by electric furnace melting. The round and slab ingots from the 50-ton heats were forged into billets and rolled into plates by using processing conditions similar to those used for Fe-2.25Cr-1Mo steels. This paper has presented the Charpy impact, tensile, and creep data available to date on both Grades A and B. Tensile and creep data on Grades A and B are compared with the data on the commercially used grades T22, T23, T24, and the modified Fe-9Cr-1Mo Grade 91.