Sandvik Materials Technology, Sweden, reports that its Sandvik 253 MA tubing has extended the service life of pulverized coal injection (PCI) lance tubes to a year at a Chinese iron and steel plant. Previous tube materials lasted as little as one month. Sandvik 253 MA is an austenitic chromium-nickel steel that is designed for good high temperature strength and excellent resistance to high-temperature oxidation and carburization corrosion.
“Sandvik 253 MA has higher creep rupture strength, abrasion resistance, and corrosion resistance at higher temperatures. The grade has improved high-temperature strength and structural stability to give added safety benefits,” said David Zhou, Technical Marketing Specialist, Sandvik.
Whereas standard grades last between one and two months, or for as little as two-to-three weeks with standard AISI 304L, Sandvik 253 MA can increase PCI lance tube life by more than three times. It has been widely used abroad to replace familiar PCI lance tubes manufactured from conventional materials such as 310S, TP 321H and 316L. The increased cost can be quickly offset by the extended lifecycles and reduced maintenance costs.
The Sandvik material exhibits high oxide scale density and strong adhesion due in part to its extra 0.05% cerium (Ce) content. In combination with added 1.5% silicon (Si), this gives the grade excellent high-temperature oxidation resistance and high temperature carburization resistance properties. Added 0.17% nitrogen (N) improves high temperature creep rupture strength over standard grades like AISI 310.
