Weldment evaluation of high pressure steam rotors

Journal Article · Tue Nov 01 04:00:00 EST 1994 · Journal of Engineering for Industry; (United States)

DOI:https://doi.org/10.1115/1.2902124· OSTI ID:6602813

Wojnowski, D; Kasapbasioglu, H; Indacochea, J E ^[1]; Galanes, G W; Spry, T D ^[2]

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1. Univ. of Illinois, Chicago, IL (United States). Civil Engineering, Mechanics and Metallurgical Engineering Dept.
2. Commonwealth Edison, Maywood, IL (United States). Systems Materials Analysis Dept.

Life extension of high pressures and intermediate pressure rotors by weld repair is a viable alternative considering the latest developments. The objective is to select a filler wire that will produce a weld with mechanical properties compatible with those of the rotor material. Three filler metals, (CrMoV, 12% Cr and 5% Cr) were used in the investigation. Multipass submerged arc groove welds were produced, pot weld heat treated a 677 C, and submitted to a series of mechanical tests a room and elevated temperatures. A limited metallurgical evaluation was also performed. The room temperature tensile properties of the CrMoV and 12% Cr crossweld samples exceeded those of the rotor metal, but the tensile properties of the 5% Cr crosswelds did not match those of the rotor metal. The 12% Cr crossweld samples failed in the weld metal during hot tensile and stress rupture testing, and these failures were attributed to slag entrapment; yet the yield and tensile strengths of these weldments just exceeded those of the rotor base metal. The CrMoV crossweld specimens performed the best at the high temperature testing; the failure for the hot tensile specimens occurred in the weld metal and the values matched those of the all weld metal (longitudinal) specimens which greatly exceeded the rotor base metal strengths. The crossweld stress rupture samples failed outside the weld metal at the heat affected zone (HAZ) near the unaffected base metal with rupture lives lower than the rotor base metal. Microhardnes evaluations in the CrMoV and 12% Cr cross weldments about the HAZ/base metal boundary identify a soft region at this location. The mechanical properties of the 5% weldment were in general inferior to the rotor base metal. The weld metal's hardness was lower than the rotor base metal given its superior Charpy energy values; however, the creep rupture strength was inferior.

• OSTI ID: 6602813
• Journal Information: Journal of Engineering for Industry; (United States), Journal Name: Journal of Engineering for Industry; (United States) Vol. 116:4; ISSN JEFIA8; ISSN 0022-0817
• Country of Publication: United States
• Language: English

Related Subjects

20 FOSSIL-FUELED POWER PLANTS
200104* -- Fossil-Fueled Power Plants-- Components
36 MATERIALS SCIENCE
360103 -- Metals & Alloys-- Mechanical Properties
ALLOYS
CHROMIUM ALLOYS
COMPARATIVE EVALUATIONS
EQUIPMENT
EVALUATION
FILLER METALS
FOSSIL-FUEL POWER PLANTS
IRON ALLOYS
IRON BASE ALLOYS
JOINTS
LIFETIME
LOW ALLOY STEELS
MACHINERY
MATERIALS TESTING
MECHANICAL PROPERTIES
MOLYBDENUM ALLOYS
POWER PLANTS
REPAIR
ROTORS
SERVICE LIFE
STEAM TURBINES
STEELS
TESTING
THERMAL POWER PLANTS
TURBINES
TURBOMACHINERY
VANADIUM ALLOYS
WELDED JOINTS