Method for manufacturing large-sized high purity 12Cr% low-ilicon low-aluminum electroslag remelting steel ingot

Abstract

The invention discloses a method for manufacturing a large-size high-purity 12Cr percent low-silicon low-aluminum electroslag remelting steel ingot, which comprises the concrete steps of: 1, preparation, in which nitrogen with the pressure of between 0.50 and 0.55MPa is aerated into a crystallizer; 2, refining melt-casting, in which the pressure of the nitrogen in the crystallizer is adjusted to ensure that the slag making is performed when the pressure of the nitrogen is between 0.45 and 0.5MPa, a graphite electrode is taken out after a slag material is entirely melted, the pressure of the nitrogen is adjusted to ensure that the pressure of the nitrogen is between 0.40 and 0.50MPa, and a consumable electrode is arranged for remelting; and 3, ingot stripping. The method utilizes the dry nitrogen which is aerated into the crystallizer in a large quantity during the electroslag remelting to replace air in the crystallizer to ensure that the pressure of the nitrogen in the crystallizer keeps positive pressure, thereby achieving the effect of reducing or removing the oxygen content in gas in a furnace during the electroslag remelting in similar manner. The method has the advantages of small investment, low application cost, and easy realization.

Description

technical field [0001] The invention relates to a method for manufacturing a steel ingot, in particular to a method for manufacturing a large-scale high-purity 12Cr% low-silicon and low-aluminum electroslag remelted steel ingot. Background technique [0002] When the silicon content in steel is ≤0.15%, and the aluminum content is ≤0.015%, it is called low-silicon and low-aluminum steel. At present, the steam turbine rotor material of the mega-kilowatt supercritical thermal power generation unit needs to use high-purity 12Cr% low-silicon and low-aluminum steel. Low (Al≤0.010%). This type of steel is characterized by high purity requirements, narrow chemical composition range, and high mechanical performance indicators. [0003] The electroslag remelting steel ingot produced by the electroslag remelting method has the advantages of uniform chemical composition, dense material, and high purity. Therefore, the current production of 12Cr% low-silicon and low-aluminum steel also...

AI Technical Summary

Problems solved by technology

However, for large electroslag ingots of more than 40 tons, vacuum electroslag remelting is not only a huge investment, but also quite difficult to implement technically.

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