Closure to “Discussions of ‘Long Arc Shrouding—A Reliability Improvement for Untuned Steam Turbine Blading’” (1981, ASME J. Eng. Power, 103, pp. 527–530)

1981 ◽  
Vol 103 (3) ◽  
pp. 530-531
Author(s):  
W. P. Welch
Keyword(s):  
Steam Turbine ◽  
Reliability Improvement ◽  
Turbine Blading

Long Arc Shrouding—A Reliability Improvement for Untuned Steam Turbine Blading

1981 ◽  
Vol 103 (3) ◽  
pp. 522-527 ◽  
Author(s):  
R. J. Ortolano ◽  
J. A. La Rosa ◽  
W. P. Welch
Keyword(s):  
Steam Turbine ◽  
Arc Length ◽  
Variable Speed ◽  
Butt Welding ◽  
Reliability Improvement ◽  
Fatigue Failures ◽  
Short Arc ◽  
Turbine Blading ◽  
Turbine Exhaust

An approach to the design and modification of untuned variable speed steam turbine exhaust blading has been found to be highly successful in eliminating fatigue failures due to the first tangential in-phase mode resonance. The approach consists of butt-welding the shrouds on the short arc blade groups to form a substantially longer arc length. The result is a significant reduction in vibratory stress at resonant speeds. Because of the ease with which the approach can be implemented in the field, backfitting is highly attractive to turbine operators. Availability benefits to the marine, utility, petrochemical, refining, industrial and commercial fields are anticipated.

High Temperature Rupture, Fatigue, and Damping Properties of AISI Designation 616 (Type 422 Stainless) Steel

1965 ◽  
Vol 87 (2) ◽  
pp. 325-332 ◽  
Author(s):  
R. G. Matters ◽  
A. A. Blatherwick
Keyword(s):  
Stainless Steel ◽  
High Temperature ◽  
Steam Turbine ◽  
Stress Rupture ◽  
Fatigue Tests ◽  
Damping Properties ◽  
Temperature Range ◽  
Stress Ratios ◽  
Mean Stresses ◽  
Turbine Blading

This paper covers the high temperature rupture, fatigue, and damping properties of AISI Designation 616 (Type 422) steel conforming substantially to the requirements of ASTM specification A437 grade B4C. This material has been extensively used for boiling and for steam turbine blading for service in the temperature range of 850 to 1000 F. The results of stress rupture and fatigue tests of smooth and notched bars at 800, 950, and 1050 F are presented. Stress rupture tests extend to 2000 hr or more and fatigue tests generally extend to 2 × 107 cycles or about 100 hr. The fatigue tests were performed in a direct stress machine at stress ratios A = infinity, 2.5, and 1.0. Vibration decay damping tests with various mean stresses were performed at 75, 800, 950, and 1050 F.

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