焼入油の老化について (II) : 礦油の老化

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The deterioration of mineral oils for quenching was studied under the same procedure as described in the lst report (The Deterioration of Fatty Oils : Tetsu-to-Hagane No.2, Feb. 1954 p.103∿111). The properties of mineral oils vary with the blowing with air as follows : (1) The quenching ability of mineral oils increases at the beginning and then decreases slowly with the blowing time, and the time required to cool from 700°to 350℃ is given approximately as a function of the blowing time by the following formula : t=cτ^2+bτ+t_0, then, τ_<min>=-b/2c, ρ_<max>=2c. The changes of cooling ability with the blowing time abovernentioned are attributed to the rise of the characteristic temperature in cooling process, at which vapour film breaks down, due to the formation of polar substances with the blowing time and the rise of the beginning temperature of the convection stage due to the increase of the amount of polymerized product. the τ_<min> offers a criterion for the life of oil and the ρ_<max> gives a degree of variation of cooling ability during the deterioration of oil. (2) The viscosity increases with the blowing time : logη-logη_0=αη・τ. The amount of sludge increases with the blowing time : S-S_0=α_S・τ. The specific gravity increases with the blowing time : G-G_0=α_G・τ. The flash point decreases with the blowing time : F_0-F=α_F・τ. The acid value increases with the blowing time : A-A_0=α_A・τ. The iodine value decreases and the saponification value increases with the blowing time. (3) When oil is highly refined, the t_0, the τ_<min> and the α_F are larger and the ρ_<max>, α_η, α_S, α_G and α_A are smaller respectvely, that is, highly refined oil is more stable. (4) Lighter oil is more stable than heavier oil, but this difference of stability becomes smaller according to better refining. (5) Highly refined naphthenic oil is stable as paraffinic oil. (6) Among a series of mineral oils produced from identical crude oil, the larger the iodine value and the more the residual carbon, the deterioration of oil is the more rapid. (7) It is observed that the τ_<min> becomes larger for higher temperature of oil in the measurement of cooling curves at various temperatures below 100℃ with a same oil. (8) The t_0, the τ_<min> and the α_S of mineral oil are larger and the α_η and α_G are smaller than those of fatty oil. Then, the deterioration of mineral oil is much slower than that of fatty oil. (9) The deterioration of mineral oil containing fatty oil is more rapid than that of straight mineral oil. (10) Quenching oil must be evaluated synthetically with values of the t_0, τ_<min>, ρ_<max>, α_η, α_S, etc. Note : t : Time required to cool from 700°to 350℃ for oil blown with air, sec. t_0 : Time required to cool from 700℃ to 350℃ for fresh oil, sec. t_<min> : Minimun value of t, sec. ρ_<max> : Curvature at the point of t=t_<min> on the curve. η : Viscosity of oil blown with air, Redwood, sec. η_0 : Viscosity of fresh oil. S : Amount of sludge of oil blown with air, mg/10g. S_0 : Amount of sludge of fresh oil. G : Specific gravity of oil blown with air. G_0 : Specific gravity of fresh oil. F : Flash point of oil blown with air, ℃. F_0 : Flash point of fresh oil. A : Acid value of oil blown with air. A_0 : Acid value of fresh oil. τ : Blowing time, hr. τ_<min> : Blowing time for the minimum value of t, hr. c, b, α_η, α_S, α_G, α_F and α_A : the constants.
社団法人日本鉄鋼協会の論文
1955-01-01

焼入油の老化について (II) : 礦油の老化

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