摘要:
The present invention provides Cr-containing steel superior in heat fatigue characteristics, that is, Cr-containing steel superior in heat fatigue characteristics, characterized by containing, by mass %, C: 0.01% or less, N: 0.015% or less, Si: 0.8 to 1.0%, Mn: 0.2 to 1.5%, P: 0.03% or less, S: 0.01% or less, Ni: 0.2% or less, Cu: 0.2% or less, Cr: 13 to 15%, Mo: 0.1% or less, Nb: 0.3 to 0.5%, Ti: 0.05 to 0.2%, V: 0.01 to 0.2%, Al: 0.015 to 1.0%, and B: 0.0002 to 0.0010%, satisfying (Nb+1.9×Ti)/(C+N)≦50, and having a balance of Fe and unavoidable impurities, wherein a 0.2% yield strength at 800° C. after aging at 800° C. for 100 hours or more is 20 MPa or more and a drawability value at 200° C. is 35% or more and wherein a soluble Nb amount+soluble Ti amount after aging at 800° C. for 100 hours or more is 0.08% or more.
摘要:
A titanium ring for an electrodeposition drum has an attractive, uniform surface without patterns comprising bright and dark spots which are formed during surface polishing. The ring has a thickness of 4-30 mm and a surface hardness when it has been polished to an average surface roughness Ra of at most 0.3 .mu.m such that the difference between the maximum and minimum Vickers hardness measured with a load of at most 1 kg at 10 or more points disposed at a pitch of 0.3-1 mm along a line in an arbitrary direction along the surface is at most 10. The ring can be manufactured by welding of a rolled plate or by ring rolling of a tube. When the temperature of the material forming the ring is heated to at least its .beta. transformation point, cooling past the .beta. transformation point is carried out at a rate of at least 1000.degree. C. per hour. Subsequent working or heat treatment is carried out below the .beta. transformation point.