A refining process control device includes: a past similar performance extraction unit configured to extract, from the refining performance database, a performance value of a past refining process in which a refining condition being a refining process condition acquired before the start of the refining process and including a result of an immediately preceding refining process in the refining facility, is similar to a refining process condition as a calculation target and the evaluation value is high; and an operation amount determination unit configured to determine an initial operation amount at the start of a refining process based on the performance value of the past refining process extracted by the past similar performance extraction unit, and determine an operation amount based on a change amount of the initial operation amount after the start of the refining process.

A refining process control device includes: a past similar performance extraction unit configured to extract, from the refining performance database, a performance value of a past refining process in which a refining condition being a refining process condition acquired before the start of the refining process and including a result of an immediately preceding refining process in the refining facility, is similar to a refining process condition as a calculation target and the evaluation value is high; and an operation amount determination unit configured to determine an initial operation amount at the start of a refining process based on the performance value of the past refining process extracted by the past similar performance extraction unit, and determine an operation amount based on a change amount of the initial operation amount after the start of the refining process.

A method for efficiently manufacturing low-phosphorus molten steel by use of a steelmaking electric furnace, in which slag resulting from melting a solid iron source is effectively separated from molten steel, and thus a unit consumption of lime required to reduce a phosphorus content in the molten steel is reduced. The method includes: charging a solid iron source and an optional molten iron source and melting and heating these raw materials by using electric energy; partly or entirely removing slag generated during the melting; performing dephosphorization by adding dephosphorization flux; and tapping low-phosphorus molten steel thus refined, and in the method, a slag composition ratio being [CaO]/([SiO.sub.2]+[Al.sub.2O.sub.3]) of the slag to be removed is adjusted to be not less than 0.25 and not more than 0.70.

A control process of inclusions in ultra-clean rare earth steel, wherein the content of rare earth elements REM in the ultra-clean rare earth steel, the total oxygen content T[O]m, the total sulfur content T[S]m in the steel, and the total oxygen content T[O]r in a rare earth metal or alloy added to the steel are controlled to satisfy the following formula: −500<REM−(m*T[O]m+n*T[O]r+k*T[S]m)<−30, where REM is the content of rare earth elements in the steel, in ppm; T[O]m is the total oxygen content in the steel, in ppm; T[O]r is the total oxygen content in a rare earth metal or alloy added to the steel, in ppm; T[S]m is the total sulfur content in the steel, in ppm; m is a first correction coefficient, with a value of 2-4.5;n is a second correction coefficient; and k is a third correction coefficient.

Provided is steel for a wind power gear with improved purity and reliability. The chemical components thereof comprise, in percentages by mass: 0.15-0.19% of C, ≤0.4% of Si, 0.5-0.7% of Mn, ≤0.012% of P, ≤0.006% of S, 1.5-1.8% of Cr, 0.28-0.35% of Mo, 1.4-1.7% of Ni, and 0.02-0.04% of Al, with the balance being Fe and inevitable impurities. A smelting method therefor comprises adding raw materials to a converter for primary melting, transferring same to a refining furnace for refining, carrying out continuous casting after vacuum degassing, and transferring same to a gas protection furnace for electroslag remelting. According to the present invention, a pure electroslag master batch is obtained by continuous casting, and the purity of the material is further improved by means of an electroslag remelting procedure; and the prepared steel material is used in a wind power gear, such that the flaw detection pass rate is significantly increased, large-particle inclusions in the steel material are significantly reduced, and the inclusions are fine and dispersed.

Provided is a mold flux used for casing a cast slab, the mold flux including, bases on a total wt % of thereof, 32-38 wt % of aluminum oxide (Al.sub.2O.sub.3), 8-12 wt % of strontium oxide (SrO), 8-12 wt % of potassium oxide (K.sub.2O), 8-12 wt % of fluorine (F), 5-8 wt % of boron oxide (B.sub.2O.sub.3), 3-5 wt % of lithium oxide (Li.sub.2O), and inevitable impurities. Thus, according to the mold flux, a change in components due to silicon oxide (SiO.sub.2) and calcium oxide (CaO) may be suppressed or prevented compared to those in the conventional art.

Provided is a mold flux used for casing a cast slab, the mold flux including, bases on a total wt % of thereof, 32-38 wt % of aluminum oxide (Al.sub.2O.sub.3), 8-12 wt % of strontium oxide (SrO), 8-12 wt % of potassium oxide (K.sub.2O), 8-12 wt % of fluorine (F), 5-8 wt % of boron oxide (B.sub.2O.sub.3), 3-5 wt % of lithium oxide (Li.sub.2O), and inevitable impurities. Thus, according to the mold flux, a change in components due to silicon oxide (SiO.sub.2) and calcium oxide (CaO) may be suppressed or prevented compared to those in the conventional art.

Technologies are disclosed herein for cross-correlating metrics for anomaly root cause detection. Primary and secondary metrics associated with an anomaly are cross-correlated by first using the derivative of an interpolant of data points of the primary metric to identify a time window for analysis. Impact scores for the secondary metrics can be then be generated by computing the standard deviation of a derivative of data points of the secondary metrics during the identified time window. The impact scores can be utilized to collect data relating to the secondary metrics most likely to have caused the anomaly. Remedial action can then be taken based upon the collected data in order to address the root cause of the anomaly.

Provided are an ultra-clean rare earth steel and an occluded foreign substance modification control method, the steel includes 10-200 ppm of rare earth elements, 50% or more occluded foreign substances in the steel are dispersed into RE-oxygen-sulfide with the average equivalent diameter D.sub.mean ranging from 1-5 μm in a spherical shape or a substantially spherical shape or a granular shape; according to the method, at least 80%, preferably at least 90%, of Al2O3 occluded foreign substances in the steel are modified into RE-oxygen-sulfide, compared with steel with the same components without rare earth, the total amount of the occluded foreign substances in the steel is reduced by 18% or higher, the cracking probability caused by occluded foreign substances such as Al2O3 in traditional pure steel is reduced, the mechanical performance such as the fatigue life of the steel is remarkably improved.

Provided is a method for producing alloy steel, the method comprising producing first alloy steel in a temperature holding furnace; maintaining the first alloy steel at a temperature of no lower than a melting point in the temperature holding furnace; and producing second alloy steel having an alloy content lower than the alloy content in the first alloy steel by melt mixing of the first alloy steel and molten steel. In the producing of the alloy steel, melting and storing of the ferroalloy are continuously performed, and thus, the temperature drop of the ferroalloy may be suppressed or prevented.