12% chrome steel turbine rotor

Abstract

Abstract PURPOSE:To improve the bearing characteristics of 12% Cr steel turbine rotor by cutting the journal section in the diameter less than it should be for build up welding metal excellent in the bearing characteristics and working the section thus welded into the required shape following a thermal treatment. CONSTITUTION:Journal sections 1A and 1B of a 12% Cr steel turbine rotor are cut into cylindrical shapes 2A and 2B in the diameter less than it should be. Metals 3A and 3B excellent in the bearing characteristics are build up welded on the surfaces of the journal sections thus cut after they are preheated up to 200 to 250 deg.C with a composition of 0.1 to 0.3% C, 1.5 to 2.0% Mn, 0.05 to 0.1% Cr, less than 0.3% Si, less than 0.03% P, and less than 0.03% S. Then, after heated up to 200 deg.C, the rotor is kept in the sections at 120 deg.C for 10 hours and in the entire part at 680 deg.C for 12 hours. After cooled down to 300 deg.C at a cooling rate of 5 deg.C/h, it is finished to the required journal dimension. Otherwise, prior to the afore-mentioned build up welding, a build up welded metal layer is formed with the same composition as mentioned above except for 0.08 to 0.16% C and 0.8 to 1.2% Mn.

Inventors

• 👤 Tetsuya Tsuchishida

Bibliographic Details