Surface stress modification for repair of stress-relieved carbon steel fabrications
Pitting corrosion was observed in welded carbon steel tanks which had been stress relieved to improve resistance to stress corrosion cracking. Successful repair required the development of a cleaning and repair method which would not increase residual tensile stresses at the steel surface. An experimental study indicated that uniform residual tensile stresses of 27.6 to 34.5 megapascals (4000 to 5000 psi) remained in the plate after the original stress relief. Grinding, shot peening, and grit blasting were evaluated. In laboratory tests, metal grit blasting changed the average residual stresses at the surface to 34.5 to 69 megalpascals (5000 to 10,000 psi) compressive. Moreover, the depth of the compressive zone was substantial - perhaps 138 megapascals (20,000 psi) at 0.25 mm (0.010 inch). This is beneficial and will contribute to an increase in resistance to stress corrosion cracking. The repair technique employed on the tanks consisted of blast cleaning the entire surface to a uniform Class II finish with minimum change in the configuration of the pits. 9 refs., 9 figs., 2 tabs.
- Research Organization:
- Du Pont de Nemours (E.I.) and Co., Aiken, SC (USA). Savannah River Plant
- DOE Contract Number:
- AC09-76SR00001
- OSTI ID:
- 5266521
- Report Number(s):
- DP-MS-85-3; CONF-8510160-1; ON: DE86000563
- Resource Relation:
- Conference: ASM metals congress, international conference on surface modifications, Toronto, Ontario, Canada, 13 Oct 1985
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
CARBON STEELS
PITTING CORROSION
RESIDUAL STRESSES
STEEL-ASTM-A537
TANKS
DESCALING
EXPERIMENTAL DATA
GRINDING
SHOT PEENING
STRESS RELAXATION
SURFACE CLEANING
WELDED JOINTS
ALLOYS
CHEMICAL REACTIONS
CLEANING
COLD WORKING
COMMINUTION
CONTAINERS
CORROSION
DATA
FABRICATION
INFORMATION
IRON ALLOYS
IRON BASE ALLOYS
JOINTS
MACHINING
MATERIALS WORKING
NUMERICAL DATA
RELAXATION
STEELS
STRESSES
SURFACE FINISHING
SURFACE TREATMENTS
360103* - Metals & Alloys- Mechanical Properties
360101 - Metals & Alloys- Preparation & Fabrication
360105 - Metals & Alloys- Corrosion & Erosion