A copper ingot of the present invention which is casted by a belt-caster type continuous casting apparatus includes: 1 ppm by mass or less of carbon; 10 ppm by mass or less of oxygen; 0.8 ppm by mass or less of hydrogen; 15 ppm by mass to 35 ppm by mass of phosphorus; and a balance of Cu and inevitable impurities, and includes inclusions formed of oxides containing carbon, phosphorus, and Cu.

Provided are a method for analyzing nitrogen in a metal sample, an apparatus for analyzing nitrogen in a metal sample, a method for adjusting nitrogen concentration in molten steel, and a method for manufacturing steel. The method includes: a melting process in which a metal sample containing a nitrogen component is melted in an argon gas atmosphere by performing impulse heating to gasify the nitrogen component; and an analyzing process in which nitrogen content in the metal sample is determined by analyzing nitrogen gas generated in the melting process and the argon gas by using a gas discharge optical emission method. By analyzing the nitrogen concentration of a sample taken from molten steel by using the analysis method described above, and by determining treatment conditions for adjusting nitrogen concentration on the basis of the nitrogen analysis value derived by the analysis, nitrogen concentration in molten steel is adjusted.

Provided are a method for analyzing nitrogen in a metal sample, an apparatus for analyzing nitrogen in a metal sample, a method for adjusting nitrogen concentration in molten steel, and a method for manufacturing steel. The method includes: a melting process in which a metal sample containing a nitrogen component is melted in an argon gas atmosphere by performing impulse heating to gasify the nitrogen component; and an analyzing process in which nitrogen content in the metal sample is determined by analyzing nitrogen gas generated in the melting process and the argon gas by using a gas discharge optical emission method. By analyzing the nitrogen concentration of a sample taken from molten steel by using the analysis method described above, and by determining treatment conditions for adjusting nitrogen concentration on the basis of the nitrogen analysis value derived by the analysis, nitrogen concentration in molten steel is adjusted.

[Problem]

To provide a method for producing a metal ingot, which makes it possible to inhibit impurities contained in molten metal in a hearth from being mixed into the ingot.

[Solution]

A method for producing a metal ingot by using an electron-beam melting furnace having an electron gun and a hearth that accumulates a molten metal of a metal raw material, wherein the metal raw material is supplied to the position on a supply line disposed along a second side wall of the hearth that accumulates the molten metal of the metal raw material. A first electron beam is radiated along a first irradiation line that is disposed along the supply line and is closer to a central part of the hearth relative to the supply line on the surface of the molten metal. By this means, a surface temperature (T2) of the molten metal at the first irradiation line is made higher than an average surface temperature (T0) of the entire surface of the molten metal in the hearth, and in an outer layer of the molten metal, a first molten metal flow is formed from the first irradiation line toward the supply line.

Methods of billet casting are provided herein. The methods may include the steps of assembling a billet caster with a shroud extending from a tundish to above a mold such that the shroud does not reach molten metal in the mold, delivering molten metal from a ladle into the tundish, delivering molten metal from the tundish through the shroud to the mold, the shroud inhibiting contact between the molten metal and air, casting the molten metal into billets in the mold and cooling the billets below the mold with a coolant spray, and delivering the cooled billet to a runout table to be cut to length.

Methods of billet casting are provided herein. The methods may include the steps of assembling a billet caster with a shroud extending from a tundish to above a mold such that the shroud does not reach molten metal in the mold, delivering molten metal from a ladle into the tundish, delivering molten metal from the tundish through the shroud to the mold, the shroud inhibiting contact between the molten metal and air, casting the molten metal into billets in the mold and cooling the billets below the mold with a coolant spray, and delivering the cooled billet to a runout table to be cut to length.

A primary object of the present invention is to provide a technique of avoiding occurrence of surface defects caused by an electromagnetic brake while checking internal defects with this electromagnetic brake, so that cleanliness of a cast steel can be improved compared with prior arts, and the present invention provides a method for continuously casting steel, the method comprising supplying molten steel into a funnel mold while applying an electromagnetic brake to an outlet flow discharged from an outlet port of an immersion nozzle, wherein magnetic flux density (B) of the electromagnetic brake is within a range of the following (Formula 1): $\begin{array}{c}{B}_{\min }B{B}_{\max },B_{\min }=\frac{800.Math.{\left(\frac{D_{\max }}{D_0}\right)}^3.Math.\left(\frac{H_{\mathrm{SEN}}}{H_0}\right)}{.Math.(v.Math.\sin }\end{array}$

A primary object of the present invention is to provide a technique of avoiding occurrence of surface defects caused by an electromagnetic brake while checking internal defects with this electromagnetic brake, so that cleanliness of a cast steel can be improved compared with prior arts, and the present invention provides a method for continuously casting steel, the method comprising supplying molten steel into a funnel mold while applying an electromagnetic brake to an outlet flow discharged from an outlet port of an immersion nozzle, wherein magnetic flux density (B) of the electromagnetic brake is within a range of the following (Formula 1): $\begin{array}{c}{B}_{\min }B{B}_{\max },B_{\min }=\frac{800.Math.{\left(\frac{D_{\max }}{D_0}\right)}^3.Math.\left(\frac{H_{\mathrm{SEN}}}{H_0}\right)}{.Math.(v.Math.\sin }\end{array}$

Grain size of a deliverable metal product can be improved by pre-setting recrystallization-suppressing dispersoids during casting. The outer regions of a direct chill cast embryonic ingot can undergo reheating before casting is complete. Through unique wiper placement and/or other reheating techniques, the temperature of the ingot can be permitted to reheat (e.g., up to approximately 410 C. to approximately 420 C.), allowing dispersoids to form. Stirring and/or agitation of the molten sump can facilitate formation of a deeper sump and desirably fine grain size as-cast. The formation of dispersoids during and/or immediately after casting can pin the grain boundaries at the desirably fine grain size, encouraging the same grain sizes even after a later recrystallization and/or solutionizing step.

Methods of billet casting are provided herein. The methods may include the steps of assembling a billet caster with a shroud extending from a tundish to above a mold such that the shroud does not reach molten metal in the mold, delivering molten metal from a ladle into the tundish, delivering molten metal from the tundish through the shroud to the mold, the shroud inhibiting contact between the molten metal and air, casting the molten metal into billets in the mold and cooling the billets below the mold with a coolant spray, and delivering the cooled billet to a runout table to be cut to length.