A method of making steel by deeply dephosphorization in a hot metal tank and decarburization using semi-steel with nearly zero phosphorus load in a converter includes the following steps: putting an efficient dephosphorization agent into the hot metal tank in advance, and conducting dephosphorization during blast furnace tapping and transportation of blast furnace hot metal by the hot metal tank to obtain semi-steel with [P] less than 0.04 wt. % and [C] greater than or equal to 3.5 wt. %; and removing dephosphorization slag, and pouring the semi-steel into the converter for decarburization to obtain molten steel. The efficient dephosphorization agent includes iron oxide scale, lime, and composite calcium ferrite. According to the method, a phosphorus content of the blast furnace hot metal is reduced to be less than or equal to 0.04 wt. % through the efficient dephosphorization agent.

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.

The invention relates to a process for injecting particulate material into a liquid metal bath wherein the liquid metal bath contains species to be oxidized, wherein the particulate material is carried to the liquid bath by means of a first gas stream. The solids injection rate is controlled such that the liquid bath temperature and/or the evolution of the liquid bath temperature is maintained within a pre-defined temperature range and the penetration depth of the first gas stream into the liquid bath is controlled by adjusting the flow of the first gas stream. At least one second gas stream is injected into the liquid, wherein the first and the second gas streams are an oxidizing gas, in particular oxygen, and the sum of the gas flows of the first and the second gas streams is determined based on the mass of the species to be oxidized and on the desired time for oxidizing the mass of the species.

The invention relates to a process for injecting particulate material into a liquid metal bath wherein the liquid metal bath contains species to be oxidized, wherein the particulate material is carried to the liquid bath by means of a first gas stream. The solids injection rate is controlled such that the liquid bath temperature and/or the evolution of the liquid bath temperature is maintained within a pre-defined temperature range and the penetration depth of the first gas stream into the liquid bath is controlled by adjusting the flow of the first gas stream. At least one second gas stream is injected into the liquid, wherein the first and the second gas streams are an oxidizing gas, in particular oxygen, and the sum of the gas flows of the first and the second gas streams is determined based on the mass of the species to be oxidized and on the desired time for oxidizing the mass of the species.

A decarburization refining method for molten steel under reduced pressure. The method includes an oxygen-blowing decarburization and a rimmed decarburization. Using operation data taken at a time when oxygen-blowing decarburization is started and a time when oxygen-blowing decarburization is ended, an amount of carbon removed while the oxygen-blowing decarburization is performed is estimated. Based on the estimated amount of carbon removed, a carbon concentration in molten steel at a time when the rimmed decarburization is started is estimated. Using the estimated value as the carbon concentration in molten steel at the time when the rimmed decarburization is started, a change over time in the carbon concentration in molten steel while the rimmed decarburization is performed is calculated. Based on the calculated change over time in the carbon concentration in molten steel while the rimmed decarburization is performed, a determination is made about a time when the rimmed decarburization is ended.

A decarburization refining method for molten steel under reduced pressure. The method includes an oxygen-blowing decarburization and a rimmed decarburization. Using operation data taken at a time when oxygen-blowing decarburization is started and a time when oxygen-blowing decarburization is ended, an amount of carbon removed while the oxygen-blowing decarburization is performed is estimated. Based on the estimated amount of carbon removed, a carbon concentration in molten steel at a time when the rimmed decarburization is started is estimated. Using the estimated value as the carbon concentration in molten steel at the time when the rimmed decarburization is started, a change over time in the carbon concentration in molten steel while the rimmed decarburization is performed is calculated. Based on the calculated change over time in the carbon concentration in molten steel while the rimmed decarburization is performed, a determination is made about a time when the rimmed decarburization is ended.

A method of making steel by deeply dephosphorization in a hot metal tank and decarburization using semi-steel with nearly zero phosphorus load in a converter includes the following steps: putting an efficient dephosphorization agent into the hot metal tank in advance, and conducting dephosphorization during blast furnace tapping and transportation of blast furnace hot metal by the hot metal tank to obtain semi-steel with [P] less than 0.04 wt. % and [C] greater than or equal to 3.5 wt. %; and removing dephosphorization slag, and pouring the semi-steel into the converter for decarburization to obtain molten steel. The efficient dephosphorization agent includes iron oxide scale, lime, and composite calcium ferrite. According to the method, a phosphorus content of the blast furnace hot metal is reduced to be less than or equal to 0.04 wt. % through the efficient dephosphorization agent.

A method of making steel by deeply dephosphorization in a hot metal tank and decarburization using semi-steel with nearly zero phosphorus load in a converter includes the following steps: putting an efficient dephosphorization agent into the hot metal tank in advance, and conducting dephosphorization during blast furnace tapping and transportation of blast furnace hot metal by the hot metal tank to obtain semi-steel with [P] less than 0.04 wt. % and [C] greater than or equal to 3.5 wt. %; and removing dephosphorization slag, and pouring the semi-steel into the converter for decarburization to obtain molten steel. The efficient dephosphorization agent includes iron oxide scale, lime, and composite calcium ferrite. According to the method, a phosphorus content of the blast furnace hot metal is reduced to be less than or equal to 0.04 wt. % through the efficient dephosphorization agent.

A method for producing low-carbon ferromanganese capable of achieving a high Mn yield. In producing low-carbon ferromanganese by blowing an oxidizing gas from a top-blowing lance onto a bath face of high-carbon ferromanganese molten metal accommodated in a reaction vessel provided with a top-blowing lance and bottom-blowing tuyere to perform decarburization, the slag composition during the blowing is adjusted so that a value of (CaO+MgO)/(Al.sub.2O.sub.3+SiO.sub.2) on a mass basis in the slag composition is not less than 0.4 but not more than 5.0. Also, agitation is performed under a condition that an agitation power density ε of an agitation gas blown through the bottom-blowing tuyere is not less than 500 W/t.

A method for producing low-carbon ferromanganese capable of achieving a high Mn yield. In producing low-carbon ferromanganese by blowing an oxidizing gas from a top-blowing lance onto a bath face of high-carbon ferromanganese molten metal accommodated in a reaction vessel provided with a top-blowing lance and bottom-blowing tuyere to perform decarburization, the slag composition during the blowing is adjusted so that a value of (CaO+MgO)/(Al.sub.2O.sub.3+SiO.sub.2) on a mass basis in the slag composition is not less than 0.4 but not more than 5.0. Also, agitation is performed under a condition that an agitation power density ε of an agitation gas blown through the bottom-blowing tuyere is not less than 500 W/t.