Shot peening to prevent the corrosion cracking of austenitic stainless steels
Rockwell International and Metal Improvement Company have conducted a joint test program to develop shot peening as a technique for preventing corrosion cracking in austenitic stainless steels. Initial laboratory-scale tests demonstrated the feasibility of preventing stress corrosion cracking by shot peening to impose compressive stresses on the surface of the work pieces. Conventional U-bend test specimens, when peened, survived 1000 h tests in the boiling 42% magnesium chloride stress corrosion test. Unpeened reference specimens commonly fractured within one or two hours in this test. Component tests were conducted to demonstrate the practicality of the peening process for sizes and shapes that typify components in a reactor piping system. Pipe sections and cold worked, hexagonal tubes were tested. In all components, unpeened sections developed stress corrosion cracks within a few hours in the magnesium chloride test; in contrast, the shot peened surfaces survived hundreds of hours. It was discovered at Rockwell International that intergranular corrosion can be prevented in austenitic stainless steels by severe shot peening prior to exposure to sensitizing temperatures. For this purpose, the surfaces must be severely cold worked by the shot peening to break up surface grains and grain boundaries. Two nondestructive testing techniques show promise as methods for measuring the stress or cold work imparted on the surface of the work piece by peening. In one method, eddy currents are used to measure differences in electrical properties induced by cold working of metals. Another method is a magnetic technique which measures the changes in magnetic properties due to the transformation of austenite to ferrite by cold working.
- OSTI ID:
- 6199541
- Journal Information:
- J. Mater. Energy Syst.; (United States), Vol. 1:1
- Country of Publication:
- United States
- Language:
- English
Similar Records
Mitigation of Tensile Weld Stresses in Alloy 22 Using Laser Peening
Very High-Cycle Fatigue Properties and Residual Stress Relaxation of Micro-shot-Peened EA4T Axle Steel
Related Subjects
22 GENERAL STUDIES OF NUCLEAR REACTORS
AUSTENITIC STEELS
CORROSION PROTECTION
SHOT PEENING
STRESS CORROSION
NUCLEAR POWER PLANTS
PIPELINES
STAINLESS STEEL-18-8
STAINLESS STEEL-304
STAINLESS STEEL-321
STAINLESS STEEL-347
CRACKS
EDDY CURRENT TESTING
ELECTRICAL PROPERTIES
FERRITES
GRAIN BOUNDARIES
MAGNETIC PROPERTIES
PHASE TRANSFORMATIONS
SURFACE TREATMENTS
ALLOYS
CHEMICAL REACTIONS
CHROMIUM ALLOYS
CHROMIUM STEELS
CHROMIUM-NICKEL STEELS
COLD WORKING
CORROSION
CORROSION RESISTANT ALLOYS
CRYSTAL STRUCTURE
ELECTROMAGNETIC TESTING
FABRICATION
FERRIMAGNETIC MATERIALS
HEAT RESISTANT MATERIALS
HEAT RESISTING ALLOYS
IRON ALLOYS
IRON BASE ALLOYS
IRON COMPOUNDS
MAGNETIC MATERIALS
MATERIALS
MATERIALS TESTING
MATERIALS WORKING
MICROSTRUCTURE
NICKEL ALLOYS
NIOBIUM ADDITIONS
NIOBIUM ALLOYS
NONDESTRUCTIVE TESTING
NUCLEAR FACILITIES
OXYGEN COMPOUNDS
PHYSICAL PROPERTIES
POWER PLANTS
STAINLESS STEELS
STEELS
TESTING
THERMAL POWER PLANTS
TITANIUM ADDITIONS
TITANIUM ALLOYS
TRANSITION ELEMENT COMPOUNDS
360105* - Metals & Alloys- Corrosion & Erosion
220200 - Nuclear Reactor Technology- Components & Accessories