CN102728794A - Nodulizer and inoculant special for large-section bulb iron roll - Google Patents

Abstract

The invention relates to a nodulizer and an inoculant special for a large-section bulb iron roll. The nodulizer is characterized by comprising the following components in percentage by weight: 2-3 percent of RE, 8-10 percent of Mg, 2-3 percent of Ca, 3-4 percent of Ba, 38-41 percent of Si and the balance of Fe; and the inoculant comprises the following components in percentage by weight: 0.5-1.0 percent of RE, 1-2 percent of Mg, 2-3 percent of Ca, 3-5 percent of Ba, 1-3 percent of Mn, 1-3 percent of Cr, 0.05-0.2 percent of Sb, 38-40 percent of Si and the balance of Fe. The nodulizer and the inoculant have the advantages of prolonging the nodulizing and inoculation decay time and reducing the reject rate that the roll performance does not meet the requirements caused by serious nodulizing and inoculation decay of a core of the roll.

Description

Special-purpose nodulizer of large-section magnesium iron roll and inovulant

Technical field:

The present invention relates to special-purpose nodulizer of a kind of large-section magnesium iron roll and inovulant, belong to metallurgical technology field.

Background technology:

In large-section magnesium iron roll manufacture process, often there is the decaying spheroidisation phenomenon in roll heart portion, influences the intensity of roll, when serious roll breakage can take place.Conventional method is that the light section roll can adopt and pours method spheroidising and inoculated easily; Processing cost is lower; But the big section roll that cross dimensions is surpassed 600mm; The traditional nodulizer of this usefulness, inovulant are handled and roll heart portion's decaying spheroidisation and inoculation fade will be occurred producing, reduce roll safety in utilization and the possibility that is judged to waste product, and promptly traditional nodulizer, the composition of inovulant are not suitable for handling the large-section magnesium iron roll that cross dimensions surpasses 600mm.The production technology that adopts pressure of magnesium adding to make the large-section magnesium iron roll is also arranged, but problem such as that this method exists is strict to spheroidization device, complicated operation is loaded down with trivial details, and have the danger of pressure blast.

Summary of the invention:

The objective of the invention is to; To the deficiency that exists than the method that pours that adopts traditional nodulizer, inovulant under the elongate member in the molten steel solidification time; Special-purpose nodulizer of a kind of large-section magnesium iron roll and inovulant are provided, are intended to improve the nodularization efficient of molten iron, add stable decaying spheroidisation and the inoculation fade time of breeding the prolongation molten iron of strong effect; Improve large-section magnesium iron roll heart portion performance, thereby improve the quality of final products.

The objective of the invention is to realize through following technical proposals:

The composition range of said nodulizer (percentage by weight) is: 2-3%RE, and 8-10%Mg, 2-3%Ca, 3-4%Ba, 38-41%Si, surplus is Fe;

The composition range of said inovulant (percentage by weight) is: 0.5-1.0%RE, and 1-2%Mg, 2-3%Ca, 3-5%Ba, 1-3%Mn, 1-3%Cr, 0.05-0.2%Sb, 38-40%Si, surplus is Fe.

Rare earth composition in said nodulizer, the inovulant is the mishmetal of lanthanum, cerium.

The making and use method of nodulizer of the present invention and inovulant is following:

1. manufacture craft: with molten nodulizer and the inovulant of joining of medium-frequency induction furnace.

2. use technology: nodulizer and inovulant must be removed moisture through 200-300 ℃ of low-temperature bake before use; The furnace melting molten iron, by weight adding nodulizer and inovulant, nodulizer places the bag end according to the iron water amount of wanting nodularization, and with sheet metal bag end nodulizer is covered and to cover; Inovulant adds with pouring method.The molten iron temperature of the furnace melting that nodularization and inoculated are used is 1390-1420 ℃, and 2/3rds molten iron are used for spheroidising, and 1/3rd molten iron are used for inoculated.

Effect of the present invention is: 1, can prolong nodularization and inoculation fade time.2, can reduce because of the nodularization of roll heart portion, inoculation fade and seriously cause the undesirable percent defective of roller performance.

The specific embodiment:

Embodiment 1: the application in Φ 710 chrome molybdenums half magnesium chilled iron roll, and nodularization, inoculated adopt traditional approach, i.e. ladle bottom pouring process nodularization, secondary taps a blast furnace and adds inovulant, and tapping temperature is 1390～1410 ℃.The nodulizer addition is decided to be 1.6～2.0wt% of iron water amount, and innoculant adding quantity is decided to be 0.4～0.8wt% of iron water amount.Detect metallographic and performance from last roll neck sampling, metallographic structure is pearlite+spherical graphite+carbide, and nodulizing grade is 3 grades; Average tensile strength is 408MPa, and average percentage elongation is 3.6%, and average ballistic work is 4.1J, and last roll neck average hardness is 44.3HSD, and each item performance indications meet GB GB1504/T-91 standard.

Embodiment 2: ladle bottom pouring process is adopted in the application in Φ 840 automatic tube rolling mill stripper rollss, spheroidising, once breed when secondary taps a blast furnace, during cast with the stream late inoculation.To heavy-section ductile iron, the nodulizer addition should suitably increase, and is decided to be 1.4～2.0wt% of iron water amount.One time pregnant amount fixes in 0.5～0.9wt% scope of iron water amount.The late inoculation amount is 0.05～0.2wt% of iron water amount, and the mould cavity inoculation amount is 0.05～0.1wt% of iron water amount.Detect metallographic and performance from last roll neck sampling, metallographic structure is pearlite+spherical graphite+carbide, and nodulizing grade is 3 grades; Average tensile strength is 553MPa, and average percentage elongation is 3.3%, and body of roll average hardness is 44.7HSD, and each item performance indications meet GB GB1504/T-91 standard.

Claims (2)

1. special-purpose nodulizer of a large-section magnesium iron roll and inovulant is characterized in that:

The composition range of said nodulizer (percentage by weight) is: 2-3%RE, and 8-10%Mg, 2-3%Ca, 3-4%Ba, 38-41%Si, surplus is Fe;

The composition range of said inovulant (percentage by weight) is: 0.5-1.0%RE, and 1-2%Mg, 2-3%Ca, 3-5%Ba, 1-3%Mn, 1-3%Cr, 0.05-0.2%Sb, 38-40%Si, surplus is Fe.

2. special-purpose nodulizer of large-section magnesium iron roll according to claim 1 and inovulant, it is characterized in that: the rare earth composition in said nodulizer, the inovulant is the mishmetal of lanthanum, cerium.