The correlation between V Charpy test and COD test is investigated for the structural steel with strength range from mild steel to HT80 including their weld zone. The results are summerized as follows:
(1) The transition temperature T*
i of δ
c is defined as the temperature at which δ
c=δ
i=0.16 mm. Temperature shift ΔT* between T*
i and vTs is expressed as a function of yield strength at the room temperature and the plate thickness by the following relation.
ΔT*=vTs-T*
i=120-σY
0-5(√t-√20) (1)
where ΔT*, T*
i:(°C)
vTs:V Charpy 50% crystallinity transition temperature (°C)
σYo:yield stress at R.T. (kg/mm
2)
t:plate thickness (mm)
(2) The relation between δ
c(T) and vE(T+ΔT*) is obtained for the vE transition range.
δ
c(T)=0.02vE(T+ΔT*) (2)
where δ
c(T):δ
c at T=T (mm)
vE(T+ΔT*):vE at T=T+ΔT* (kg-m)
For the upper shelf range of vE, δ
c can be estimated from Eq. (2) by using vE* value instead of VE.
Where vE* is defined by the following relation.
vE*=vE*
0 exp (-T
0/T) (3)
Ev*
0 and T
0 are material constants, which are determined empirically from the assumption that temperature dependence of vE in the transition range is of Arrhenius type, i.e., vE* is an extrapolated value of Eq. (3) to the upper shelf temperature of T.
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