| 摘要 |
PROBLEM TO BE SOLVED: To provide a method for specifying a dangerous state in a heat treatment. SOLUTION: This method for estimating a heat treatment state is used when applying the heat treatment to accumulated round steel bars in a substantially trapezoidal bundle state in a heating furnace. The method includes a step of determining the material diameter [ϕD] of the round steel bars, the number [n] of the round steel bars, and the accumulated state of the round steel bar bundle, a step of calculating the total sectional area [S_air] of gaps between the round steel bars inside the bundle, and the heat inflow efficiency [L/S] for the entire bundle (where L denotes the peripheral length of the entire bundle, and S denotes the sectional area of the entire bundle) from the condition of the stacked state of the round steel bar bundle, and a step of deriving the numeral valueαindicating the magnitude of the temperature difference at the outer surface and the center part of the round steel bar bundle by expressionα=D×n×S_air×¾ln(L/S)¾. COPYRIGHT: (C)2011,JPO&INPIT
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