3.4 Test Result

The test result is shown in Table 6. All test specimens were fractured after load was increased continuously. At test temperature -10℃, each test specimens were broken by brittle fracture after a little ductile crack were propagated along the fusion line. Condition and section of fracture is shown in Fig. 6

Fig. 6 Condition of fracture

Fig. 7 Relation between fracture stress and temperature (thickness: 50mm)

　

3.5 Evaluation of Test Result

(1) Fracture stress

Relation between fracture stress, yield point of used steel and test temperature at plate thickness 50mm is shown in Fig. 7, Yield point of used steel standard is calculated by following formula.

　

σ_y = σ_yoexp(α(1/T_K - 1/293))

α = 329.6 - 66.5lnσ_yo

σ_yo: Yield point at ambient temperature (N/mm2 )

T_K: Test temperature (K)

　

Table 6. Notched and angular distorted cross joint tensile test results

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