Effect of strain frequency on development of corrosion-fatigue cracks in 08KP steel

1975 ◽  
Vol 10 (3) ◽  
pp. 345-346
Author(s):  
M. O. Levitskii
Keyword(s):  
Corrosion Fatigue ◽  
Fatigue Cracks ◽  
08Kp Steel ◽  
Strain Frequency

Lifetime Enhancement of Propulsion Shafts Against Corrosion-Fatigue by Laser Peening

2018 ◽  
Author(s):  
Lloyd A. Hackel ◽  
Jon E. Rankin
Keyword(s):  
Corrosion Fatigue ◽  
Fatigue Testing ◽  
Salt Water ◽  
Fatigue Cracks ◽  
Water Immersion ◽  
High Energy ◽  
General Corrosion ◽  
Laser Peening ◽  
Corrosion Pits ◽  
Deep Pits

This paper reports substantially enhanced fatigue and corrosion-fatigue lifetimes of propulsion shaft materials, 23284A steel and 23284A steel with In625 weld overlay cladding, as a result of shot or laser peening. Glass reinforced plastic (GRP) coatings and Inconel claddings are used to protect shafts against general corrosion and corrosion pitting. However salt water leakage penetrating under a GRP can actually enhance pitting leading to crack initiation and growth. Fatigue coupons, untreated and with shot or laser peening were tested, including with simultaneous salt water immersion. Controlled corrosion of the surfaces was simulated with electric discharge machining (EDM) of deep pits enabling evaluation of fatigue and corrosion-fatigue lifetimes. Results specifically show high energy laser peening (HELP) to be a superior solution, improving corrosion-fatigue resistance of shaft and cladding metal, reducing the potential for corrosion pits to initiate fatigue cracks and dramatically slowing crack growth rates. At a heavy loading of 110% of the 23284A steel yield stress and with 0.020 inch deep pits, laser peening increased fatigue life of the steel by 1370% and by 350% in the corrosion-fatigue testing.

Investigation and modeling of the kinetics of the development of corrosion-fatigue cracks

1978 ◽  
Vol 13 (3) ◽  
pp. 235-239
Author(s):  
N. N. Vasserman ◽  
V. A. Merkushev ◽  
M. S. Nemanov
Keyword(s):  
Corrosion Fatigue ◽  
Fatigue Cracks ◽  
Kinetics Of

Effect of Organic Corrosion Inhibitors on Corrosion Fatigue

CORROSION ◽  
1967 ◽  
Vol 23 (3) ◽  
pp. 65-71 ◽  
Author(s):  
PARVIZ MEHDIZADEH ◽  
R. L. McGLASSON ◽  
J. E. LANDERS
Keyword(s):  
Corrosion Fatigue ◽  
Diesel Fuel ◽  
Corrosion Inhibitors ◽  
Fatigue Cracks ◽  
Material Surface ◽  
Significant Protection ◽  
Inhibitor Concentration ◽  
Degree Of Protection ◽  
Organic Inhibitors ◽  
Organic Corrosion Inhibitors

Abstract The effect of organic inhibitors on corrosion fatigue performance of steel in a mixture of brine containing H2S-CO2 and diesel fuel is reported. The inhibitor concentration required to give significant protection to steel under corrosion fatigue conditions is much higher than that for corrosion control. This is due to the fact that corrosion fatigue cracks initiated at incompletely protected spots on the material surface influence fatigue failure regardless of the degree of protection achieved on neighboring areas. Effects of fatigue stress and concentration of corrosion inhibitors were investigated. Results were analyzed in terms of the proposed mechanism for corrosion inhibition in these environments.

Solute Transport in Corrosion Fatigue Cracks

1991 ◽  
Vol 138 (10) ◽  
pp. 2891-2896 ◽  
Author(s):  
C. J. van der Wekken ◽  
M. Janssen
Keyword(s):  
Solute Transport ◽  
Corrosion Fatigue ◽  
Fatigue Cracks

Fatigue and Corrosion Fatigue Failures

2005 ◽  
Author(s):  
Fred V. Ellis
Keyword(s):  
Fracture Surface ◽  
Corrosion Fatigue ◽  
Fatigue Cracks ◽  
Fatigue Crack Initiation ◽  
Applied Loading ◽  
Root Area ◽  
Waterwall Tube ◽  
Two Factors ◽  
Fracture Appearance ◽  
Thread Root

A metallurgical failure analysis was performed for a hanger rod and a waterwall tube sample. The hanger is a rigid type and supports a long vertical run of piping. The fracture is in one of the threaded ends and the fracture surface consists of three regions. The outermost portion adjacent to the thread root has ratchet marks that are an indication of fatigue crack initiation. The center portion has concentric, oval shaped beachmarks. The oval shape is consistent with an applied loading due to two bending moments. The inner portion is the final fracture and is approximately 1/4 of the thread root area indicating relatively low remote stresses. The failure mechanism is fatigue based on the beachmarks on the fracture surface and the transgranular cracking. The lower slope waterwall tube failure had a window opening fracture appearance. The axial fractures forming the window are located at the edge of the membrane welds on the cold or backside. There are shallow toe cracks at the membrane weld on the tube outside surface. The fracture surface had multiple, thumbnail-shaped fatigue cracks connected to the inside surface. These fatigue cracks are due to the corrosion fatigue mechanism based on two factors: (1) the stress responsible for their growth is related to the unit thermal cycling and the welded panel geometry near the corner of the boiler, and (2) they are oxidized indicating a corrosion contribution.

Sign in / Sign up

Export Citation Format

Share Document