Effect of welding conditions on transformation and properties of heat-affected zones in LWR (light-water reactor) vessel steels

Technical Report · Thu Nov 01 04:00:00 EST 1990

DOI:https://doi.org/10.2172/6337784· OSTI ID:6337784

Lundin, C D; Mohammed, S ^[1]

---

1. Tennessee Univ., Knoxville, TN (USA). Welding Research and Engineering

The continuous cooling transformation behavior (CCT) and isothermal transformation (IT) behavior were determined for SA-508 and SA-533 materials for conditions pertaining to standard heat treatment and for the coarse-grained region of the heat-affected zone (HAZ). The resulting diagrams help to select welding conditions that produce the most favorable microconstituent for the development of optimum postweld heat treatment (PWHT) toughness levels. In the case of SA-508 and SA-533, martensite responds more favorably to PWHT than does bainite. Bainite is to be avoided for the optimum toughness characteristics of the HAZ. The reheat cracking tendency for both steels was evaluated by metallographic studies of simulated HAZ structures subjected to PWHT cycles and simultaneous restraint. Both SA-533, Grade B, Class 1, and SA-508, Class 2, cracked intergranularly. The stress rupture parameter (the product of the stress for a rupture life of 10 min and the corresponding reduction of area) calculated for both steels showed that SA-508, Class 2, was more susceptible to reheat cracking than SA-533, Grade B, Class 1. Cold cracking tests (Battelle Test and University of Tennessee modified hydrogen susceptibility test) indicated that a higher preheat temperature is required for SA-508, Class 2, to avoid cracking than is required for SA-533, Grade B, Class 1. Further, the Hydrogen Susceptibility Test showed that SA-508, Class 2, is more susceptible to hydrogen embrittlement than is SA-533, Grade B, Class 1.

• Research Organization: Nuclear Regulatory Commission, Washington, DC (USA). Div. of Engineering; Tennessee Univ., Knoxville, TN (USA). Welding Research and Engineering; Oak Ridge National Lab., TN (USA)
• Sponsoring Organization: NRC
• DOE Contract Number: AC05-84OR21400
• OSTI ID: 6337784
• Report Number(s): NUREG/CR-3873; ORNL/Sub--78-7637/1; ON: TI91004247
• Country of Publication: United States
• Language: English

Related Subjects

21 SPECIFIC NUCLEAR REACTORS AND ASSOCIATED PLANTS
210100 -- Power Reactors
Nonbreeding
Light-Water Moderated
Boiling Water Cooled
210200 -- Power Reactors
Nonbreeding
Light-Water Moderated
Nonboiling Water Cooled
36 MATERIALS SCIENCE
360103* -- Metals & Alloys-- Mechanical Properties
ALLOYS
BWR TYPE REACTORS
CHARPY TEST
CONTAINERS
CRACKS
CRYSTAL STRUCTURE
DESTRUCTIVE TESTING
ELEMENTS
EMBRITTLEMENT
FABRICATION
HEAT TREATMENTS
HYDROGEN
IMPACT TESTS
IRON ALLOYS
IRON BASE ALLOYS
ISOTHERMAL PROCESSES
JOINING
JOINTS
LOW ALLOY STEELS
MATERIALS TESTING
MECHANICAL PROPERTIES
MECHANICAL TESTS
MICROSTRUCTURE
NONMETALS
PRESSURE VESSELS
PWR TYPE REACTORS
REACTORS
STANDARDS
STEEL-ASTM-A508
STEEL-ASTM-A533
STEELS
STRESSES
TESTING
WATER COOLED REACTORS
WATER MODERATED REACTORS
WELDED JOINTS
WELDING