CN101579732B - Spheroidisation reaction package for producing ductile cast iron and spheroidisation method therefor - Google Patents

Abstract

The invention discloses a spheroidisation reaction package for producing ductile cast iron and a spheroidisation method therefor, belonging to the field of casting. The reaction package is composed ofa package body, a package wall and a rotatable fishhook; wherein, the fishhook is connected with the package body by a bolt; the reaction package is characterized in that a convex plate with a groove is arranged at the bottom part of the package body, the convex plate is located at one side of the center of the package bottom; a reaction tube is arranged in the groove, three small air holes are a rranged on tube wall of the reaction tube and are on a straight line. When the reaction tube is filled with nodularizers, under the heat effect of molten iron, the thinnest part of the tube wall of the reaction tube begins to melt; with the gradual melting of the tube wall, the nodularizers sequentially enter the molten iron to facilitate the nodularization reaction to be carried out under controllable conditions; as passivation magnesium serves as the nodularizers, thus putting off the reaction time between the magnesium and the molten iron, lengthening the contact time between magnesium vapor and the molten iron, improving absorptivity of the molten iron and increasing nodularization effect of magnesium.

Description

A kind of spheroidising reaction package and nodulizing process thereof of producing spheroidal graphite cast-iron

Technical field

The present invention relates to produce the spheroidising reaction package and the nodulizing process thereof of spheroidal graphite cast-iron, belong to casting field.

Background technology

Spheroidal graphite cast-iron is a kind of very important cast iron in the cast iron industry, and its metallographic structure is made up of metallic matrix and distribution globular graphite therebetween.Compare with the flake graphite in the casting pig, globular graphite is lighter to the successional destruction of matrix, so intensity and plasticity and toughness are much better than casting pig.Spheroidal graphite cast-iron has two important process procedures in process of production: spheroidising and inoculation, spheroidising process mainly comprise the selection of nodulizer and the formulation of spheronization process.

Nodulizer commonly used at present is magnesium metal and magnesium-rare earth.Magnesium metal is used for spheroidal graphite cast-iron production the earliest, and its advantage is that nodularization is effective, price is lower.But the boiling point of magnesium metal is 1108 ℃, hangs down about 350 ℃ than the temperature that molten iron is handled.Because the gasification of magnesium makes the molten iron boiling, magnesium and the reaction of airborne oxygen are burnt, and generate magnesia, and the molten iron absorptivity is low.Therefore, magnesium metal generally bears under the big external pressure effect at molten iron and uses, to prevent the effusion of magnesium vapor as nodulizer.The advantage of magnesium-rare earth is that spheronization process is simple, has the ability of anti-interference element, but occurs differential mode graphite easily, influences the performance of spheroidal graphite cast-iron.

Summary of the invention

The object of the invention is for the reaction time weak point that overcomes the magnesium metal nodulizer, easy firing, shortcoming that the molten iron absorptivity is low, proposes the nodulizing process of a kind of spheroidal graphite cast-iron in producing.

Technical scheme of the present invention

A kind of spheroidising reaction package of producing spheroidal graphite cast-iron

A kind of spheroidising reaction package of producing spheroidal graphite cast-iron, by inclusion 1, bag wall 2, rotatable fishhook 3 is formed, inclusion 1 is welded by the steel plate of 8～10mm, bag wall 2 is formed by the refractory material knotting, wherein refractory material is 20% fire clay by percentage by weight, 5% schmigel, 60% quartz sand and 15% liquid glass are formed, rotatable fishhook 3 is positioned at inclusion 1 top, fishhook 3 is connected by bolt 6 with inclusion 1, it is characterized in that the boss 4 of band groove is arranged at the inclusion bottom, boss 4 is positioned at a side at bag center, the end, decentre point 0.25D, wherein D is inclusion 1 external diameter, the recess width in the boss 4 is 0.15～0.25D, the degree of depth is 0.15～0.18D, length extends to bag wall 2, placing response pipe 5 in the groove, and reaction tube 5 internal diameters are got 0.10～0.12D; From 0.2～0.25d place, reaction tube 5 two ends two little air-vents 51 and 53 are set respectively, a little air-vent 52 is set in the middle of these two little air-vents 51 and 53 again, described three little air-vents 51,52 and 53 center are point-blank, the aperture is 2～4mm, and wherein said d is reaction tube 5 internal diameters; The thickness of reaction tube 5 tube walls is determined by test, or is estimated by the square root law:

$S=K\sqrt{t}$

S is the thickness of tube wall; T is the time, and according to the time that molten iron injects reaction package height about 40%, the thin place of tube wall begins fusing, determine the wall thickness at the thin place of tube wall, according to 1～1.5min behind the molten iron injecting reactor height about 70%, the fusing of thickness of pipe wall place finishes, and determines the wall thickness at thickness of pipe wall place in addition; K is a coefficient, depends on the physical parameter of reaction tube 5 materials and the temperature of molten iron.

A kind of nodulizing process of producing the spheroidising reaction package of spheroidal graphite cast-iron comprises the steps:

(1), the nodulizer passivated magnesium reaction tube of packing into

With the nodulizer passivated magnesium reaction tube 5 of packing into, charge weight is 0.2～0.26% of an iron water amount, adds ferrosilicon powder every 30mm, addition is 20～30g, seal with fire clay at reaction tube 5 two ends, puts into baking oven baking 60～90min subsequently, and baking temperature is 100～120 ℃;

The quality percentage composition of silicon is 55～75% in the ferrosilicon powder, and all the other are iron, and particle diameter is 1～2mm;

The effect of ferrosilicon powder is, do not make nodulizer in the molten iron ignitron, prevents the string combustion.Thereby finish the filling process of nodulizer passivated magnesium and ferrosilicon powder.

(2), the reaction tube spheroidizing reacion bag of packing into

Pack into the reaction tube 5 of passivated magnesium of step (1) is packed in the groove of spheroidizing reacion bag bottom boss 4,3 little air-vents 51,52 and 53 position up, the gap between reaction tube 5 and the groove is inserted with fire clay;

(3), spheroidising reaction

Step (2) is preheated to 250～400 ℃ with reaction package after finishing, when reaction package is preheating to predetermined temperature, add the inovulant ferrosilicon, implantation temperature is 1480～1500 ℃ a molten iron in bag then, and the injection iron water amount is 70% of a total amount, the no obvious flame in molten iron surface in waiting to wrap, the reaction of molten iron and nodulizer finishes, and removes slag and inject molten iron for the second time in reaction package, and injecting iron water amount is 30% of total amount, add the inovulant ferrosilicon powder at last, promptly finish the spheroidising reaction of producing spheroidal graphite cast-iron;

Wherein the siliceous amount percentage in the inovulant ferrosilicon is 55～75%, and all the other are iron, particle diameter 5～10mm; The addition of inovulant ferrosilicon is 0.48% of a molten iron total amount;

Siliceous amount percentage in the inovulant ferrosilicon powder is 55～75%, and all the other are iron, and particle diameter is 1～2mm; The addition of inovulant ferrosilicon powder is 0.32% of a molten iron total amount.

Technique effect of the present invention

The present invention has designed a reaction tube that is used to load nodulizer especially in reaction package, tube inner diameter unanimity, but pipe thickness difference.Behind the casing pack nodulizer, under the heat effect of molten iron, the tube wall thinnest part begins fusing in the reaction tube, and along with dissolving gradually of reaction tube wall, nodulizer enters molten iron successively, and the spheroidizing reacion process is carried out under controlled condition.Owing in the spheroidizing reacion bag, adopt passivated magnesium, postpone the reaction time of magnesium and molten iron simultaneously, prolong the time of contact of magnesium vapor and molten iron, improve the absorptivity of molten iron, strengthen the nodularization effect of magnesium as nodulizer.

Description of drawings

Fig. 1, spheroidizing reacion bag

Fig. 2, reaction tube cutaway view

Fig. 3 sample 1 metallographic structure 500X

Fig. 4, sample 4 metallographic structure 500X

The specific embodiment

Also in conjunction with the accompanying drawings the present invention is described in further detail below by specific embodiment, but do not limit the present invention.

Embodiment 1

A kind of spheroidising reaction package of producing spheroidal graphite cast-iron

Inclusion 1 is welded by the 8mm steel plate, and bag wall 2 is formed by refractory material knotting, and wherein refractory material is that 20% fire clay, 5% schmigel, 60% quartz sand and 15% waterglass are formed by percentage by weight.Rotatable fishhook 3 is arranged at inclusion 1 top, and suspension hook 3 links inclusion 1 high 1700mm by bolt 6 with inclusion 1, external diameter 700mm, bag wall 2 thickness: suitable for reading is 80mm, and the bottom is 120mm, inclusion bottom thickness 150mm, the inclusion bottom is provided with the boss 4 of band groove, boss 4 decentre point 175mm, highly be 120mm, width is 150mm, and length extends to bag wall 2, and recess width is 120mm, the degree of depth is 80mm, and length extends to bag wall 2;

Reaction tube 5 internal diameters are 70mm, the thick size 2mm of thin-walled end wall of reaction tube 5, the thick size 5mm of heavy wall end wall, open 3 little air-vents 51,52,53 on the reaction tube 5, open 2 little air-vents 51,53 that are of a size of 3mm from 15mm place, reaction tube 5 two ends, 52, three the little air-vents 51,52 of little air-vent and 53 that in the middle of these two little air-vents 51 and 53, have 1 3mm again point-blank, the material of reaction tube 5 is a common grey iron.

A kind of nodulizing process of producing the spheroidising reaction package of spheroidal graphite cast-iron

(1), the nodulizer passivated magnesium reaction tube of packing into

With nodulizer passivated magnesium (magnesium content greater than 92%, 1～2 millimeter of the particle diameter) reaction tube 5 of packing into, charge weight is 1Kg, add ferrosilicon powder (silicon: 75%, all the other are iron, particle diameter is 1mm) every 30mm, addition is 25g, puts into baking oven baking 60min subsequently, and baking temperature is 100 ℃;

(2), the reaction tube spheroidizing reacion bag of packing into

Pack into the reaction tube 5 of passivated magnesium of step (1) is packed in the groove of spheroidizing reacion bag bottom boss 4,3 little air-vents 51,52 and 53 position up, the gap between reaction tube 5 and the groove is inserted with fire clay;

(3), spheroidising reaction

Step (2) is preheated to 300 ℃ with the spheroidizing reacion bag after finishing.Add the inovulant ferrosilicon, implantation temperature is 1500 ℃ molten iron 350Kg in bag then, and hot metal composition and temperature see Table 1.

Treat molten iron and nodulizer reaction finishing back (the no obvious flame in molten iron surface in the bag), remove slag and inject molten iron for the second time that injecting iron water amount is the 150Kg of total amount, adds the inovulant ferrosilicon powder at last, promptly finishes the spheroidising of producing spheroidal graphite cast-iron and reacts to molten iron.

Wherein the siliceous amount percentage in the inovulant ferrosilicon is 75%, and all the other are iron, particle diameter 5mm; The addition of inovulant ferrosilicon is 2.4Kg;

Siliceous amount percentage in the inovulant ferrosilicon powder is 55%, and all the other are iron, and particle diameter is 1mm; The addition of inovulant ferrosilicon powder is 1.6Kg;

The nodularization process is steady, and response intensity is even.After spheroidising, the magnesium content in the molten iron is 0.045%.

Through check, accompanying drawing 3 is seen in the metallographic structure of nodularization quality.

Table 1. molten iron composition and temperature

Embodiment 2

A kind of spheroidising reaction package of producing spheroidal graphite cast-iron is as embodiment 1.

A kind of nodulizing process of producing the spheroidising reaction package of spheroidal graphite cast-iron

(1), the nodulizer passivated magnesium reaction tube of packing into

With nodulizer passivated magnesium (magnesium content greater than 92%, the particle diameter 2mm) reaction tube 5 of packing into, charge weight is 1.3Kg, add ferrosilicon powder (silicon: 55%, all the other are iron, particle diameter is 2mm) every 30mm, addition is 30g, puts into baking oven baking 90min subsequently, and baking temperature is 120 ℃;

(2), the reaction tube spheroidizing reacion bag of packing into

Pack into the reaction tube 5 of passivated magnesium of step (1) is packed in the groove of spheroidizing reacion bag bottom boss 4,3 little air-vents 51,52 and 53 position up, the gap between reaction tube 5 and the groove is inserted with fire clay;

(3), spheroidising reaction

Step (2) is preheated to 400 ℃ with the spheroidizing reacion bag after finishing.Add the inovulant ferrosilicon, implantation temperature is 1500 ℃ molten iron 350Kg in bag then, and hot metal composition and temperature are seen the table 1 of embodiment;

Treat that the reaction of molten iron and nodulizer finishes back (the no obvious flame in molten iron surface in the bag), inject molten iron for the second time to molten iron, injecting iron water amount is the 150Kg of total amount, adds the inovulant ferrosilicon powder at last, promptly finishes the spheroidising reaction of producing spheroidal graphite cast-iron.

Wherein the siliceous amount percentage in the inovulant ferrosilicon is 75%, and all the other are iron, particle diameter 5mm; The addition of inovulant ferrosilicon is 2.4Kg;

Siliceous amount percentage in the inovulant ferrosilicon powder is 75%, and all the other are iron, and particle diameter is 2mm; The addition of inovulant ferrosilicon powder is 1.6Kg.

The nodularization process is steady, and response intensity is even.After spheroidising, the magnesium content in the molten iron is 0.056%.

Through check, Fig. 4 is seen in the metallographic structure of nodularization quality.

Claims (2)

1. spheroidising reaction package of producing spheroidal graphite cast-iron, by inclusion (1), bag wall (2), rotatable fishhook (3) is formed, inclusion (1) is welded by the steel plate of 8～10mm, bag wall (2) is formed by the refractory material knotting, refractory material is 20% fire clay by percentage by weight, 5% schmigel, 60% quartz sand and 15% liquid glass are formed, rotatable fishhook (3) is positioned at inclusion (1) top, fishhook (3) is connected by bolt (6) with inclusion (1), it is characterized in that the boss (4) of band groove is arranged at the inclusion bottom, boss (4) is positioned at a side at bag center, the end, decentre point 0.25D, wherein D is inclusion (a 1) external diameter, recess width in the boss (4) is 0.15～0.25D, the degree of depth is 0.15～0.18D, length extends to bag wall (2), placing response pipe (5) in the groove, and reaction tube (5) internal diameter is got 0.10～0.12D; From 0.2～0.25d place, reaction tube (5) two ends two little air-vents (51,53) are set respectively, a little air-vent (52) is set in the middle of these two little air-vents (51,53) again, the center of described three little air-vents (51,52,53) point-blank, the aperture is 2～4mm, and wherein said d is the internal diameter of reaction tube (5); The thickness of reaction tube (5) tube wall is determined by test, or is estimated by the square root law:

$S=K\sqrt{t}$

S is the thickness of tube wall; T is the time, and according to the time that molten iron injects reaction package height about 40%, the thin place of tube wall begins fusing, determine the wall thickness at the thin place of tube wall, according to 1～1.5min behind the molten iron injecting reactor height about 70%, the fusing of thickness of pipe wall place finishes, and determines the wall thickness at thickness of pipe wall place in addition; K is a coefficient, depends on the physical parameter of reaction tube (5) material and the temperature of molten iron.

2. a nodulizing process of producing the spheroidising reaction package of spheroidal graphite cast-iron comprises the steps:

(1), the nodulizer passivated magnesium reaction tube of packing into

With the nodulizer passivated magnesium reaction tube (5) of packing into, charge weight is 0.2～0.26% of an iron water amount, adds ferrosilicon powder every 30mm, addition is 20～30g, seal with fire clay at reaction tube (5) two ends, puts into baking oven baking 60～90min subsequently, and baking temperature is 100～120 ℃;

The quality percentage composition of silicon is 55～75% in the ferrosilicon powder, and all the other are iron, and particle diameter is 1～2mm;

(2), the reaction tube spheroidizing reacion bag of packing into

Pack into the reaction tube (5) of passivated magnesium of step (1) is packed in the groove of spheroidizing reacion bag bottom boss (4), the position of 3 little air-vents (51,52,53) up, the gap between reaction tube (5) and the groove is inserted with fire clay;

(3), spheroidising reaction

Step (2) is preheated to 250～400 ℃ with reaction package after finishing, when reaction package is preheating to predetermined temperature, add the inovulant ferrosilicon, implantation temperature is 1480～1500 ℃ a molten iron in bag then, and the injection iron water amount is 70% of a total amount, the no obvious flame in molten iron surface in waiting to wrap, the reaction of molten iron and nodulizer finishes, and removes slag and inject molten iron for the second time in reaction package, and injecting iron water amount is 30% of total amount, add the inovulant ferrosilicon powder at last, promptly finish the spheroidising reaction of producing spheroidal graphite cast-iron;

Wherein the siliceous amount percentage in the inovulant ferrosilicon is 55～75%, and all the other are iron, particle diameter 5～10mm; The addition of inovulant ferrosilicon is 0.48% of a molten iron total amount;

Siliceous amount percentage in the inovulant ferrosilicon powder is 55～75%, and all the other are iron, and particle diameter is 1～2mm; The addition of inovulant ferrosilicon powder is 0.32% of a molten iron total amount.

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