PURPOSE: To obtain ferrite type stainless steel excellent in moldability in a welded part and good in oxidation resistance at 900°C or less, by a method wherein a Cr content is reduced as compared to SUS430 while Ti is reduced as compared to SUH409 and Si is added.
CONSTITUTION: Ferrite type stainless steel consists of, on the basis of wt%, 0.020 or less C, 3.00 or less Si, 1.00 or less Mn, more than 12.00 and 14.00 or less Cr, 0.20 or less Ti, 0.30 or less Al and the remainder Fe and inevitable impurities. Herein, Cr is the most effective element in improvement of oxidation resistance but limited to the minimum addition amount to the extent the economical efficiency permits, Ti is strong austenite suppressing element and stabilizes the ferrite phase of a welded part, but because adverse effect is imparted to oxidation resistance when a large amount of Ti is added, where the adding amount thereof is limited. Si is inexpensive and has high effect in improvement of oxidation resistance and is an element for producing ferrite and the available utilization thereof is attained, but when a large amount thereof is used, the strength of a matrix material is increased while the amount of nonmetal inclusions increases and processability and moldability are deteriorated.
FUKUI FUTOSHI
TANAKA KOUICHI
YAMAMOTO KENICHIROU
