Summary of the invention
The object of the present invention is to provide a kind of high manganese steel casting grain refinement casting technique, solved problems such as high manganese steel casting crystal grain is thick, loose, micro-crack, produced grain refinement, high manganese steel casting that intensity is high; Adopt advanced alloying process and metallic particles to accelerate the foundry goods cooling technology and improved material property, the railroad crossing of high manganese steel mechanical property has had large increase, σ
b〉=850MPa, ak 〉=240J/cm
2, δ 〉=45%.
Technical scheme of the present invention is:
The present invention has developed a kind of high manganese steel casting grain refinement casting technique, comprises the steps:
1) potassium steel is in smelting process, and molten steel high temperature is come out of the stove, and carries out the outer blowing argon gas of stove after coming out of the stove, feeds the silk refining, phosphorus, sulfur content in the strict control molten steel;
2) in the high manganese steel casting casting process, adopt with stream and add metallic particles, reduce the molten metal energy storage and accelerate the foundry goods cooling;
3) metallic particles adds from the running gate system of foundry goods, and the joining day carried out in the middle and later periods of whole casting process, disposable or evenly adding in batches;
4) foundry goods will be poured into a mould fast, adopts end bottom pour ladle to avoid being mingled with and is involved in.
Described step 1), tapping temperature are 1580 ± 20 ℃.
Described step 1), in the refining process, argon pressure is 0.3~0.6MPa, the pressure pipeline internal diameter
5~10mm, 0.5~1 minute/ton molten steel of argon blowing time is fed the silk amount and is 0.5~2% of pour steel gross weight.
Described step 1), phosphorus, sulfur content in the strict control molten steel, P≤0.025%, S≤0.018%, pouring temperature is 1480 ± 20 ℃.
Described step 2), the weight of adding metallic particles is 0.5~10% of pour steel gross weight.
Described step 2), adding metal particle size is
0.5~10mm, 150 ℃~350 ℃ of metallic particles preheat temperatures.
Described step 2), add the metallic particles kind: straight carbon steel or potassium steel.
Described step 3), metallic particles adds with molten metal from the running gate system of foundry goods, and the metallic particles interpolation time is 1/3~1/2 of the casting pouring time.
Described step 4), poring rate are 20kg/s~40kg/s.
The used potassium steel of the present invention be a kind of serve as main traditional steel grade with elements such as carbon, manganese, by weight percentage, the potassium steel chemical composition comprises: C 0.7~1.1%, Si 0.6~0.7%, Mn 12.5~13.5%, P≤0.025%, S≤0.018%, in the high manganese steel casting casting process, add weight ratio with molten metal and be 0.5~10%, be of a size of
0.5 the metallic particles of~10mm.Metallic particles adds from the running gate system of foundry goods, and the joining day should carry out in the middle and later periods of whole casting process, disposable or evenly adding in batches.
The present invention has following beneficial effect:
1. the present invention reduces the temperature of molten metal by adding metallic particles in casting process, increases forming core particle crystal grain thinning, the rapid solidification foundry goods, significantly refinement the crystal grain of high manganese steel casting, reduce the field trash size simultaneously, significantly improved casting quality.
2. technological design of the present invention is reasonable, shortens the high manganese steel casting setting time, reduces the production cycle of foundry goods, has improved productivity ratio.
3. the present invention is applicable to the manufacturing of thick big high manganese steel casting.The high manganese steel casting that utilizes the present invention to produce has high-performance, characteristics cheaply.
4. railway frog is because crystal grain is thick, and shrinkage cavity, casting flaw such as loose in use, are easy to wearing and tearing, and generally speaking, the goods of high manganese steel frog is no more than 1.2 hundred million tons by gross weight.Adopt the high manganese steel frog goods of grain refining of the present invention can reach 200,000,000 tons by gross weight.Therefore, this technology has obtained railway user's abundant affirmation.
The specific embodiment
The concrete operations of a kind of high manganese steel casting crystal fining method of the present invention are as follows:
1) material is prepared: straight carbon steel or potassium steel metallic particles are of a size of
0.5~
The metallic particles of 10mm, 150 ℃~350 ℃ of metallic particles preheat temperatures;
2) equipment is prepared: special funnel.
3) molten steel is smelted: molten steel high temperature is come out of the stove, and tapping temperature is 1580 ± 20 ℃, carries out the outer blowing argon gas of stove after coming out of the stove, feeds the silk refining, strict control phosphorus, sulfur content, P≤0.025%, S≤0.018%;
In the refining process, argon pressure is 0.3~0.6MPa, the pressure pipeline
internal diameter
5~10mm, 0.5~1 minute/ton molten steel of argon blowing time is fed the silk amount and is 0.5~2% of pour steel gross weight, feeds silk and is refining Si-Ca silk commonly used, and its effect is deoxidation, refining.
4) strict control pouring temperature, pouring temperature is 1480 ± 20 ℃.Potassium steel is when selecting pouring temperature, and simple heavy section casting pouring temperature is taken off limit, complex thin-wall spare pouring temperature capping.
5) addition: in the high manganese steel casting casting process, add weight ratio with metal liquid stream and be 0.5~10%, be of a size of
0.5~
The metallic particles of 10mm is seen Fig. 1 (a)-Fig. 1 (c), 150 ℃~350 ℃ of metallic particles preheat temperatures.
6) adding method: foundry goods will be poured into a mould fast, adopts end bottom pour ladle to avoid being mingled with and is involved in, and cast is applying argon gas in die cavity before, pours into a mould under argon shield; Utilize special equipment to add metallic particles, metallic particles adds from the running gate system of foundry goods, and the joining day should carry out in the middle and later periods of whole casting process, disposable or evenly adding in batches;
7) foundry goods is handled: adopt hot shake-out technology, in order to reduce the tension of foundry goods, casting temperature is not less than 800 ℃ during shake out.Adopt Methods of OFC-A to carry out heat and cut rising head, cutting temperature is not less than 600 ℃, and the cutting after heat is fed into heat treatment kiln, carries out homogenising and handles.
Below in conjunction with drawings and Examples in detail the present invention is described in detail.
Embodiment 1
As shown in Figure 2, adopt insulated feeder and thermal-insulating covering agent.The molten steel tapping temperature is 1580 ℃, carries out refining in the refining bag, remove to be mingled with, and 0.6 ton of casting of molten metal weight, 32 seconds durations of pouring, the cast of end bottom pour ladle, 1480 ℃ of pouring temperatures, cast is applying argon gas in die cavity before, pours into a mould under argon shield.In casting process from running gate system add the molten steel
gross weight 5%, be of a size of
The metallic particles of 2mm, metallic particles are ZG 55,180 ℃ of metallic particles temperature; Metallic particles begins in the time of 11 seconds to add at casting pouring, and the metallic particles joining day is 12 seconds.Foundry goods adopts hot shake-out technology, carries out heat with Methods of OFC-A and cuts rising head, and heat is cut 650 ℃ of rising head temperature, and the cutting after heat is fed into heat treatment kiln, carries out homogenising and handles, and homogenization temperature is 1080 ℃, and temperature retention time is 4.5h.
In the present embodiment refining process, argon pressure is 0.4MPa, the pressure pipeline internal diameter
8mm, 0.8 minute/ton molten steel of argon blowing time is fed the silk amount and is 1% of pour steel gross weight, feeds silk and is refining Si-Ca silk commonly used.By weight percentage, potassium steel chemical composition: C 1.0, Si 0.6%, and Mn 12.5%, and P 0.022%, and S 0.012%.
Adopt following technology: (1) is adopted and is steadily filled the cup of type running gate system, helps the adding of metallic particles.(2) use insulated feeder and thermal-insulating covering agent, foundry goods (Fig. 3, Fig. 4) is inner without any shrinkage cavity, rarefaction defect.(3) add metallic particles, accelerate the setting time of solidifying the shortening foundry goods of foundry goods, crystal grain thinning.(4) the foundry goods gate end has inclusion defect, and the field trash size is big and have pore, but these defectives are all within the range of work of foundry goods, and genus can be removed defective.
The present invention adopts the interpolation metallic particles, increases foundry goods forming core particle, reduces the foundry goods energy storage, accelerates casting solidification speed, shortens technology such as casting solidification time, and the casting crystalline grain size significantly reduces, uniform crystal particles.Thereby make the performance of high manganese steel casting be significantly improved σ
b〉=850MPa, ak 〉=240J/cm
2, δ 〉=45%.The grain refining casting crystalline grain pattern of Fig. 8 (a)-Fig. 8 (b) for adopting the present invention to produce.
Embodiment 2
Difference from Example 1 is:
As shown in Figure 2, adopt insulated feeder and thermal-insulating covering agent.The molten steel tapping temperature is 1560 ℃, carries out refining in the refining bag, remove to be mingled with, and 0.6 ton of casting of molten metal weight, 30 seconds durations of pouring, the cast of end bottom pour ladle, 1470 ℃ of pouring temperatures are poured into a mould under argon shield.In casting process, from running gate system, add account for the molten steel gross weight 2%, be of a size of
The metallic particles of 5mm, metallic particles are ZG65,245 ℃ of metallic particles temperature; Metallic particles begins in the time of 10 seconds to add at casting pouring, and the metallic particles joining day is 14 seconds.Foundry goods adopts hot shake-out technology, carries out heat with Methods of OFC-A and cuts rising head, and heat is cut 630 ℃ of rising head temperature, and the cutting after heat is fed into heat treatment kiln, carries out homogenising and handles, and homogenization temperature is 1075 ℃, and temperature retention time is 5h.
In the present embodiment refining process, argon pressure is 0.3MPa, the pressure pipeline internal diameter
8mm, 1 minute/ton molten steel of argon blowing time is fed the silk amount and is 2% of pour steel gross weight, feeds silk and is refining Si-Ca silk commonly used.By weight percentage, potassium steel chemical composition: C 1.05%, Si 0.62%, and Mn 12.8%, and P 0.021%, and S 0.016%.
Adopt following technology: (1) is adopted and is steadily filled the cup of type running gate system, is convenient to metallic particles and adds.Adopt end bottom pour ladle cast, reduce volume gas and slag inclusion, reduced secondary oxidation.(2) add metallic particles, accelerate solidifying of foundry goods, shorten the setting time of foundry goods, significantly crystal grain thinning.And using insulation to emit, foundry goods is without any shrinkage cavity, rarefaction defect.(4) cast(ing) surface, subsurface all are mingled with less than finding.Casting crystalline grain is tiny, and evenly it is more that the field trash size significantly reduces quantity in the foundry goods, and casting quality is intact.
Embodiment 3
Difference from Example 1 is:
As shown in Figure 2, adopt insulated feeder and thermal-insulating covering agent.The molten steel tapping temperature is 1590 ℃, carries out refining in the refining bag, remove to be mingled with, and 0.6 ton of casting of molten metal weight, 28 seconds durations of pouring, the cast of end bottom pour ladle, 1480 ℃ of pouring temperatures are poured into a mould under argon shield.In casting process, from running gate system, add the molten steel gross weight 1.5%, be of a size of

The metallic particles of 10mm, metallic particles are common potassium steel, 320 ℃ of metallic particles temperature; Metallic particles begins in the time of 14 seconds to add at casting pouring, and the metallic particles joining day is 8 seconds.Foundry goods adopts hot shake-out technology, carries out heat with Methods of OFC-A and cuts rising head, and heat is cut 600 ℃ of rising head temperature, and the cutting after heat is fed into heat treatment kiln, carries out homogenising and handles, and homogenization temperature is 1080 ℃, and temperature retention time is 5h.
In the present embodiment refining process, argon pressure is 0.6MPa, the pressure pipeline internal diameter
5mm, 1 minute/ton molten steel of argon blowing time is fed the silk amount and is 2% of pour steel gross weight, feeds silk and is refining Si-Ca silk commonly used.By weight percentage, potassium steel chemical composition: C 0.95%, Si 0.67%, and Mn 12.4%, and P 0.020%, and S 0.016%.
Adopt following technology: (1) is adopted and is steadily filled the cup of type running gate system, is convenient to metallic particles and adds.Adopt end bottom pour ladle cast, reduce volume gas and slag inclusion, reduced secondary oxidation.(2) add metallic particles, the casting solidification time significantly shortens, grain refinement.And using insulation to emit and the effect of adding metallic particles, foundry goods is without any shrinkage cavity, rarefaction defect.(4) cast(ing) surface, subsurface all are mingled with less than finding.Casting crystalline grain is carefully less, and uniformity is relatively poor, and the field trash size reduces in the foundry goods, and grade improves, no unreacted refractory metal particle in the foundry goods, and casting quality is intact.
The course of work of the present invention and result:
As shown in Figure 2, the cup 7 of running gate system is connected to foundry goods 1 by sprue 6, cross gate 5, and metallic particles 8 is introduced in the foundry goods 7 by cup 7, and foundry goods 7 tops are provided with insulated feeder 2, and rising head 2 outsides are provided with warming plate 3, and rising head 2 tops are placed with coverture 4.Carried out external refining because the present invention adopts in smelting process, carried out argon shield in casting process, and used steady stream and filled the type running gate system, in casting process, added metallic particles from running gate system with molten metal, liquid metal filling is steady; The setting time of foundry goods has been shortened in the adding of metallic particles, has accelerated solidifying of foundry goods, reduce the temperature of molten metal, refinement crystal grain, reduced the field trash size, reduce crackle and produced tendency, in the service life of improving foundry goods greatly, produced the high-performance foundry goods.
Potassium steel is a kind of based on elements such as carbon, manganese and contain traditional steel grade of multiple microalloy element, by weight percentage, its concrete composition C 0.7~1.1%, Si 0.6~0.7%, and Mn 12.5~13.5%.Adopt railway high manganese steel frog foundry goods to carry out the grain refining process implementing, THE STRUCTURE OF CASTINGS has obviously obtained refinement.Wherein, Fig. 5 is the metallograph of the field trash distribution situation of the high manganese steel frog foundry goods produced of traditional handicraft, and multiplication factor is 100 times, and the rank of field trash is the 2A level; Fig. 6 is the metallograph of the field trash distribution situation of the high manganese steel frog foundry goods produced of the present invention, and multiplication factor is 100 times, and the rank of field trash is the 1A level; Fig. 7 (a)-Fig. 7 (b) is the metallograph of the crystal grain situation of the high manganese steel frog foundry goods produced of traditional handicraft, and crystallite dimension is bigger as seen from the figure; Fig. 8 (a)-Fig. 8 (b) is the metallograph of the crystal grain situation of the high manganese steel frog foundry goods produced of the present invention, and crystal grain is tiny and even as seen from the figure.
0.6 ton of the weight of cast steel liquid metal of the present invention is carried out argon shield during cast, add the metallic particles of some and size with molten metal, makes the crystal grain of foundry goods obtain the service life that refinement improves foundry goods.Observe casting process, metallic particles adds evenly, plays the effect of accelerating cooling, and crystal grain is tiny evenly, and the field trash size reduces, and the high manganese steel casting performance significantly improves.