SEDL / STP / STP919-EB / STP18394S

Evaluation of Valid Nil-Ductility Transition Temperatures for Nuclear Vessel Steels

Satoh, M
Assistant chief research engineers and senior research engineer, Mitsubishi Heavy Industries, Ltd., Takasago Technical Institute, Takasago,

Funada, T
Assistant chief research engineers and senior research engineer, Mitsubishi Heavy Industries, Ltd., Takasago Technical Institute, Takasago,

Tomimatsu, M
Assistant chief research engineers and senior research engineer, Mitsubishi Heavy Industries, Ltd., Takasago Technical Institute, Takasago,

Pages: 18    Published: Jan 1986

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Abstract

The causes of data scatter in nil-ductility transition (NDT) temperature were investigated to establish appropriate conditions for crack-starter bead welding. Drop-weight tests were carried out for nuclear vessel steels by changing the welding conditions to examine the effects of welding amperage and shapes of heat sinks on NDT temperature. The results show that preparation of the crack-starter bead by low welding amperage should not be allowed, because it makes the measured NDT temperature nonconservative, and that it is important to use a heat sink which increases the cooling rate of the specimen.

In addition, the authors propose methods for estimating the NDT temperature of nuclear vessel steels by using Charpy transition temperatures.