阅读说明：本技术 一种模具扁钢及其制备方法 (Die flat steel and preparation method thereof ) 是由 康琴 蔡武 肖强 李俊洪 于 2021-06-15 设计创作，主要内容包括：本发明提供了一种模具扁钢的制备方法,包括：将合金原料采用钢锭模进行浇注,得到模具扁锭；将所述模具扁锭进行轧制,得到模具扁钢；所述钢锭模的宽面大头尺寸为690～700mm；宽面小头尺寸为590～600mm；宽面内圆角为48～52°；下浇口上端直径为100～105mm；下浇口下端直径为115～125mm；下浇口高度为135～145mm；锭身高度为3000～3020mm；窄面大头尺寸为400～410mm；窄面小头尺寸为340～350mm；绝热板高度为305～315mm；绝热板厚度为30～40mm；所述模具扁钢的锭重为4.86～4.92t。本发明通过采用特定的钢锭模并结合浇注工艺,制备得到特定规格的模具扁钢,具有较好的一次成材率和探伤合格率。(The invention provides a preparation method of die flat steel, which comprises the following steps: pouring the alloy raw material by adopting an ingot mould to obtain a mould slab ingot; rolling the die slab ingot to obtain die slab steel; the size of the wide-surface large head of the ingot mould is 690-700 mm; the size of the small head of the wide surface is 590-600 mm; the internal fillet of the broad face is 48-52 degrees; the diameter of the upper end of the lower sprue is 100-105 mm; the diameter of the lower end of the lower gate is 115-125 mm; the height of the lower gate is 135-145 mm; the height of the ingot body is 3000-3020 mm; the size of the narrow-face large head is 400-410 mm; the size of the narrow-face small end is 340-350 mm; the height of the heat insulation plate is 305-315 mm; the thickness of the heat insulation plate is 30-40 mm; the ingot weight of the die flat steel is 4.86-4.92 t. The invention prepares the die flat steel with specific specification by adopting a specific ingot die and combining a pouring process, and has better one-time yield and flaw detection qualification rate.)

1. A preparation method of die flat steel comprises the following steps:

pouring the alloy raw material by adopting an ingot mould to obtain a mould slab ingot;

rolling the die slab ingot to obtain die slab steel;

the size of the wide-surface large head of the ingot mould is 690-700 mm; the size of the small head of the wide surface is 590-600 mm; the internal fillet of the broad face is 48-52 degrees; the diameter of the upper end of the lower sprue is 100-105 mm; the diameter of the lower end of the lower gate is 115-125 mm; the height of the lower gate is 135-145 mm; the height of the ingot body is 3000-3020 mm;

the size of the narrow surface and the large head of the ingot mould is 400-410 mm; the size of the narrow-face small end is 340-350 mm; the height of the heat insulation plate is 305-315 mm; the thickness of the heat insulation plate is 30-40 mm;

the ingot weight of the die slab ingot is 4.86-4.92 tons.

2. The method according to claim 1, wherein the ingot mold has a large head size of 693 to 697 mm; the size of the small end of the wide surface is 593-597 mm; the inner fillet of the broad face is 49-51 degrees; the diameter of the upper end of the lower sprue is 101-103 mm; the diameter of the lower end of the lower gate is 118-122 mm; the height of the lower gate is 138-142 mm; the height of the ingot body is 3005-3015 mm;

the size of the narrow-face large head of the ingot mould is 403-407 mm; the small end of the narrow face is 343-347 mm in size; the height of the heat insulation plate is 308-312 mm; the thickness of the heat insulation plate is 33 to 37 mm.

3. The method according to claim 1, wherein the ingot mold has a wide face large head size of 695 mm; the size of the small head of the wide surface is 595 mm; the fillet of the broad face is 50 degrees; the diameter of the upper end of the lower sprue is 102 mm; the diameter of the lower end of the lower sprue is 120 mm; the height of the lower gate is 140 mm; the height of the ingot body is 3010 mm;

the size of the narrow surface and the large head of the ingot mould is 405 mm; the small end of the narrow face is 345mm in size; the height of the heat insulation plate is 310 mm; the thickness of the thermal insulation plate was 35 mm.

4. The method of claim 1, wherein the alloy feedstock comprises a composition of chromium stainless type plastic mold steel.

5. The method according to claim 1, wherein the ingot mold is made of gray cast iron.

6. The method according to claim 1, wherein a heat generating agent is added in the casting process, and the mass ratio of the heat generating agent to the flat ingot of the mold is (25-30) kg: (4.86-4.92) t.

7. The method according to claim 1, characterized in that the ingot body pouring time in the pouring process is 490-540 s; the pouring time of the riser is 330-420 s.

8. The method of claim 1, further comprising, after said pouring is complete:

cooling and demolding the cast product to obtain a mold slab ingot;

the cooling time is 180-240 min.

9. The method according to claim 1, characterized in that the thickness of the die flat is 95-105 mm.

10. A die flat produced by the method of claim 1.

Technical Field

The invention belongs to the technical field of flat steel, and particularly relates to die flat steel and a preparation method thereof.

Background

The die is a mark for measuring the development of the national industrial level, and is usually manufactured by taking die flat steel as a raw material. Die steel is usually delivered as flat steel with certain thickness and width specifications, and is convenient for later sawing processing and sale use. The main economic indexes of development and production of the die flat steel are yield and flaw detection qualification rate, and the key production process links are the design of a flat ingot model and the design of a casting process, so that on one hand, the ingot weight is increased as much as possible, the casting and rolling production cost is reduced, the yield is improved, and the loss of head and tail cutting is reduced; on the other hand, the flaw detection requirements of thick flat steel are required to be met, the loosening and hole defects with different three-dimensional sizes formed in the process of welding and solidification are fully welded, and in addition, coarse grains and liquated carbides are crushed, so that the structure is fine and the size of the carbides is uniform.

With the development of economy, the size of the die is increased and the service life of the die is prolonged, which puts higher quality requirements on thick die steel.

Disclosure of Invention

In view of the above, the invention aims to provide a die flat steel and a preparation method thereof, and the die flat steel prepared by the method provided by the invention has high yield and flaw detection qualification rate.

The invention provides a preparation method of die flat steel, which comprises the following steps:

pouring the alloy raw material by adopting an ingot mould to obtain a mould slab ingot;

rolling the die slab ingot to obtain die slab steel;

the size of the wide-surface large head of the ingot mould is 690-700 mm; the size of the small head of the wide surface is 590-600 mm; the internal fillet of the broad face is 48-52 degrees; the diameter of the upper end of the lower sprue is 100-105 mm; the diameter of the lower end of the lower gate is 115-125 mm; the height of the lower gate is 135-145 mm; the height of the ingot body is 3000-3020 mm;

the size of the narrow surface and the large head of the ingot mould is 400-410 mm; the size of the narrow-face small end is 340-350 mm; the height of the heat insulation plate is 305-315 mm; the thickness of the heat insulation plate is 30-40 mm;

the ingot weight of the die slab ingot is 4.86-4.92 tons.

Preferably, the size of the wide-face big head of the ingot mould is 693-697 mm; the size of the small end of the wide surface is 593-597 mm; the inner fillet of the broad face is 49-51 degrees; the diameter of the upper end of the lower sprue is 101-103 mm; the diameter of the lower end of the lower gate is 118-122 mm; the height of the lower gate is 138-142 mm; the height of the ingot body is 3005-3015 mm;

the size of the narrow-face large head of the ingot mould is 403-407 mm; the small end of the narrow face is 343-347 mm in size; the height of the heat insulation plate is 308-312 mm; the thickness of the heat insulation plate is 33 to 37 mm.

Preferably, the size of the wide-face big head of the ingot mould is 695 mm; the size of the small head of the wide surface is 595 mm; the fillet of the broad face is 50 degrees; the diameter of the upper end of the lower sprue is 102 mm; the diameter of the lower end of the lower sprue is 120 mm; the height of the lower gate is 140 mm; the height of the ingot body is 3010 mm;

the size of the narrow surface and the large head of the ingot mould is 405 mm; the small end of the narrow face is 345mm in size; the height of the heat insulation plate is 310 mm; the thickness of the thermal insulation plate was 35 mm.

Preferably, the alloy raw material comprises chromium stainless plastic die steel.

Preferably, the ingot mould is made of grey cast iron.

Preferably, a heating agent is added in the casting process, and the mass ratio of the heating agent to the flat ingot of the mold is (25-30) kg: (4.86-4.92) t.

Preferably, the ingot body pouring time in the pouring process is 490-540 s; the pouring time of the riser is 330-420 s.

Preferably, the method further comprises the following steps after the pouring is finished:

cooling and demolding the cast product to obtain a mold slab ingot;

the cooling time is 180-240 min.

Preferably, the thickness of the die flat steel is 95-105 mm.

The invention provides the die flat steel prepared by the method in the technical scheme.

The invention provides a special ingot mold and a pouring process, which are specially used for producing mold flat steel with the thickness of 95-105 mm and the width of 580-620 mm. The thick-specification die flat steel prepared by adopting the specially designed ingot die and the pouring process matched with the ingot die has better yield and flaw detection qualification rate.

Drawings

FIG. 1 is a broad-area projection of an ingot mold according to an embodiment of the present invention;

FIG. 2 is a narrow-plane projection of an ingot mold according to an embodiment of the invention;

FIG. 3 is a microstructure of a die flat produced according to example 1 of the invention;

FIG. 4 is a microstructure of a die flat produced according to example 2 of the invention.

Detailed Description

The technical solutions in the embodiments of the present invention will be clearly and completely described below, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all embodiments. All other examples, which may be modified or appreciated by those of ordinary skill in the art based on the examples given herein, are intended to be within the scope of the present invention. It should be understood that the embodiments of the present invention are only for illustrating the technical effects of the present invention, and are not intended to limit the scope of the present invention. In the examples, the methods used were all conventional methods unless otherwise specified.

The invention provides a preparation method of thick-specification straight rolling die flat steel, which comprises the following steps:

pouring the alloy raw material by adopting an ingot mould to obtain a mould slab ingot;

rolling the die slab ingot to obtain die slab steel;

the size of the wide-surface large head of the ingot mould is 690-700 mm; the size of the small head of the wide surface is 590-600 mm; the internal fillet of the broad face is 48-52 degrees; the diameter of the upper end of the lower sprue is 100-105 mm; the diameter of the lower end of the lower gate is 115-125 mm; the height of the lower gate is 135-145 mm; the height of the ingot body is 3000-3020 mm;

the size of the narrow surface and the large head of the ingot mould is 400-410 mm; the size of the narrow-face small end is 340-350 mm; the height of the heat insulation plate is 305-315 mm; the thickness of the heat insulation plate is 30-40 mm;

the ingot weight of the die slab ingot is 4.86-4.92 tons.

In the present invention, the composition of the alloy raw material is preferably chromium stainless type plastic die steel, more preferably 3Cr13, 4Cr13 or 3Cr17 NiMo.

In the present invention, the alloy raw material preferably has the following composition:

0.3 to 0.42 wt% of C;

12.5-13.5 wt% of Cr;

0.18 to 0.3 wt% of Ni;

less than or equal to 1.0 wt% of Si;

mn less than or equal to 1.0 wt%;

less than or equal to 0.02 wt% of S;

p is less than or equal to 0.035 wt%;

the balance being Fe.

In the invention, the mass content of C is preferably 0.32-0.38%, more preferably 0.34-0.36%, and most preferably 0.35%; the mass content of Cr is preferably 12.8-13.2%, more preferably 12.90-13%, and most preferably 12.95%; the mass content of the Ni is preferably 0.18-0.3%, and more preferably 0.21%; the mass content of Si is preferably 0.1-0.9%, more preferably 0.2-0.8%, more preferably 0.3-0.6%, and most preferably 0.4-0.5%; the mass content of Mn is preferably 0.1-0.9%, more preferably 0.2-0.8%, more preferably 0.3-0.6%, and most preferably 0.4-0.5%; the mass content of S is preferably 0.01-0.02%, and more preferably 0.015%; the mass content of P is preferably 0.01-0.03%, and more preferably 0.02%.

In the invention, the alloy raw materials are preferably smelted to obtain molten steel, and then the molten steel is cast by using an ingot mould; the smelting method is not particularly limited, and the smelting can be carried out by adopting a method well known by the technical personnel in the field; the components of the molten steel are consistent with those of the alloy raw material.

In the present invention, the shape of the ingot mold is preferably a slab shape; the size of the wide-face large head of the ingot mould is 690-700 mm, preferably 692-698 mm, more preferably 694-696 mm, and most preferably 695 mm; the size of the small head of the wide surface is 590-600 mm, preferably 592-598 mm, more preferably 594-596 mm, and most preferably 595 mm; the fillet of the wide surface is 48-52 degrees, preferably 49-51 degrees, and more preferably 50 degrees; the diameter of the upper end of the lower gate is 100-105 mm, preferably 101-104 mm, more preferably 102-103 mm, and most preferably 102 mm; the diameter of the lower end of the lower gate is 115-125 mm, preferably 118-122 mm, and more preferably 120 mm; the height of the lower gate is 135-145 mm, preferably 138-142 mm, and more preferably 140 mm; the height of the ingot body is 3000-3020 mm, preferably 3005-3015 mm, and most preferably 3010 mm.

In the invention, the size of the narrow-face large head of the ingot mould is 400-410 mm, preferably 402-408 mm, more preferably 404-406 mm, and most preferably 405 mm; the small end size of the narrow face is 340-350 mm, preferably 342-348 mm, more preferably 344-346 mm, and most preferably 345 mm; the height of the heat insulation plate is 305-315 mm, preferably 308-312 mm, and more preferably 310 mm; the thickness of the heat insulation plate is 30-40 mm, preferably 32-38 mm, more preferably 34-36 mm, and most preferably 35 mm.

In the present invention, the ingot mold is preferably made of gray cast iron, more preferably gray cast iron of HT200 or HT250, and most preferably gray cast iron of HT 200.

In the present invention, the ingot weight of the die slab ingot is preferably 4.86 to 4.92 tons, more preferably 4.88 to 4.90 tons, and most preferably 4.89 tons.

In the invention, a heat generating agent is preferably added in the casting process; aluminum is preferably contained in the heat generating agent; the mass content of the aluminum in the heat generating agent is preferably 15-20%, more preferably 16-19%, and most preferably 17-18%.

In the present invention, the mass ratio of the exothermic agent to the mold slab is preferably (25 to 30) kg: (4.86-4.92) tons, more preferably (26-29) kg: (4.88-4.90) tons, most preferably (27-28) kg: 4.89 tons.

In the invention, the temperature of the ladle in the pouring process is preferably 50-80 ℃ higher than the liquidus line of the molten steel, more preferably 55-75 ℃, more preferably 60-70 ℃, and most preferably 65 ℃; the preferable temperature of the hoisting ladle is 1575-1580 ℃, and the more preferable temperature is 1576-1578 ℃; the superheat degree of casting is preferably 40-70 ℃, more preferably 45-65 ℃, more preferably 50-60 ℃, and most preferably 55 ℃, and the casting temperature is preferably 1545-1555 ℃, more preferably 1548-1552 ℃, and most preferably 1550 ℃; the casting time of the ingot body is preferably 490-540 s, more preferably 500-530 s, and most preferably 510-520 s; the casting time of the feeder is preferably 330 to 420s, more preferably 350 to 400s, and most preferably 360 to 380 s.

In the present invention, after the pouring is completed, it is preferable to further include:

and cooling and demolding the cast product to obtain the die slab ingot.

In the invention, the cooling time is preferably 180-240 min, more preferably 190-230 min, more preferably 200-220 min, and most preferably 210 min; the cooling method is preferably air natural cooling.

In the invention, the components of the die slab ingot are consistent with the components of the alloy raw material in the technical scheme.

In the present invention, before the rolling, it is preferable to further include:

and heating and temperature equalization are carried out on the die slab ingot.

In the invention, the heating temperature is preferably 1250-1270 ℃, more preferably 1255-1265 ℃, and most preferably 1260 ℃.

In the invention, an 1100mm blooming mill is preferably adopted in the rolling process; the pass reduction in the rolling process is preferably 45-60 mm, more preferably 50-55 mm, and most preferably 52-53 mm; preferably, in the rolling process, horizontal and vertical alternate rolling is adopted, and the main purpose is to reduce the thickness by flat rolling; the pass of the flat rolling is preferably 7-9 times, and more preferably 8 times; the pass of the vertical rolling is preferably 4-5 times.

In the present invention, it is preferable that the rolling process further includes:

and carrying out spheroidizing annealing on the rolled product.

In the invention, the spheroidizing annealing temperature is preferably 760-800 ℃, more preferably 770-790 ℃, and most preferably 780 ℃; the time of the spheroidizing annealing is preferably 3 to 5 hours, more preferably 3.5 to 4.5 hours, and most preferably 4 hours.

In the present invention, it is preferable that the annealing further includes:

and flaw detection is carried out on the annealed product.

In the invention, the thickness of the die flat steel is preferably 95-105 mm; the width of the die flat steel is preferably 580-620 mm, more preferably 590-610 mm, and most preferably 600 mm.

In the invention, the components of the die flat steel are consistent with the components of the alloy raw material in the technical scheme.

The invention provides the die flat steel prepared by the method in the technical scheme.

The invention provides a special ingot mold and a pouring process, which are specially used for producing mold flat steel with the thickness of 95-105 mm and the width of 580-620 mm. The thick-specification die flat steel prepared by adopting the specially designed ingot die and the pouring process matched with the ingot die has better yield and flaw detection qualification rate.

Example 1

Pouring molten steel of plastic die steel with the component of 4Cr13 by using an ingot mould to obtain a mould slab ingot; the shape of the ingot mold is shown in figures 1-2: the size of the large head of the wide surface is 695mm, the size of the small head of the wide surface is 595mm, the inner fillet of the wide surface is 50 degrees, the diameter of the upper end of the lower sprue is 102mm, the diameter of the lower end of the lower sprue is 120mm, the height of the lower sprue is 140mm, and the height of the ingot body is 3010 mm; the size of the narrow-face large head is 405mm, the size of the narrow-face small head is 345mm, the height of the heat insulation plate is 310mm, and the thickness of the heat insulation plate is 35 mm.

The ingot mould is made of HT200 gray cast iron.

And adding a heating agent in the casting process, wherein the adding amount of the heating agent is 25 kg/ingot (the weight of each flat ingot of the mold is 4.88 tons), the mass content of aluminum in the heating agent is 18 percent, the ladle temperature is 1580 ℃, the casting temperature is 1545 ℃, the casting time of the ingot body is 520s, and the casting time of a riser is 400 s. And after the pouring is finished, naturally cooling the ingot in air for 200min, demoulding, and taking out a steel ingot, wherein the weight of a single ingot is 4.88 tons.

And (3) after demoulding the steel ingot, heating to the uniform temperature, wherein the heating temperature is 1260 ℃, rolling by using a 1100mm primary rolling mill, rolling by using a pass reduction of 60mm, performing horizontal and vertical alternate rolling, performing vertical rolling for 4 passes, and performing horizontal rolling for 9 passes to obtain plastic die flat steel with the thickness of 95mm multiplied by 620mm multiplied by the width of L.

And (3) annealing the plastic die flat steel, wherein the annealing temperature is 780 ℃ and the annealing time is 4 hours.

The 4Cr13 plastic die flat steel prepared in the embodiment 1 of the invention comprises the following components: 0.42 wt% of C; 12.90 wt% Cr; 0.18 wt% Ni; 0.45 wt% Si; 0.64 wt% Mn; 0.005 wt% S; 0.02 wt% of P; the balance being Fe.

The annealed plastic die flat steel is subjected to steel ingot head and tail cutting and flaw detection, and the yield and flaw detection (GB/T4162-2008 ultrasonic detection method for forged and rolled steel bars) are performed, and the detection result shows that the yield of the die flat steel with the head and the tail cut off is 94% and the flaw detection is qualified.

The microstructure of the die flat steel prepared in example 1 of the present invention was examined, and the examined core microstructure was as shown in fig. 3, and it can be seen from fig. 3 that the microstructure was uniform and fine and had no flaw detection defects.

Example 2

Pouring molten steel of plastic die steel with the component of 4Cr13 by using an ingot mould to obtain a mould slab ingot; the shape of the ingot mold is shown in figures 1-2: the size of the large head of the wide surface is 695mm, the size of the small head of the wide surface is 595mm, the inner fillet of the wide surface is 50 degrees, the diameter of the upper end of the lower sprue is 102mm, the diameter of the lower end of the lower sprue is 120mm, the height of the lower sprue is 140mm, and the height of the ingot body is 3010 mm; the size of the narrow-face large head is 405mm, the size of the narrow-face small head is 345mm, the height of the heat insulation plate is 310mm, and the thickness of the heat insulation plate is 35 mm.

The ingot mould is made of HT200 gray cast iron.

Adding a heating agent in the casting process, wherein the adding amount of the heating agent is 30 kg/mold (the weight of each mold flat ingot is 4.91 tons), and the mass percent of aluminum in the heating agent is 18%; the ladle temperature is 1575 ℃, the pouring temperature is 1552 ℃, the ingot pouring time is 495s, and the riser pouring time is 418 s. And after the pouring is finished, naturally cooling the ingot in air for 190min, demolding, and taking out the steel ingot, wherein the weight of a single ingot is 4.91 tons.

And (3) after demoulding the steel ingot, heating to the uniform temperature, wherein the heating temperature is 1260 ℃, rolling by using an 1100mm primary rolling mill, rolling by using a pass reduction of 55mm, performing horizontal and vertical alternate rolling, performing vertical rolling for 5 passes, and performing horizontal rolling for 7 passes to obtain the plastic die flat steel with the thickness of 105mm multiplied by 585mm multiplied by L.

And (3) annealing the plastic die flat steel, wherein the annealing temperature is 780 ℃ and the annealing time is 4 hours.

The 4Cr13 plastic die flat steel prepared in the embodiment 2 of the invention comprises the following components: 0.40 wt% of C; 12.95 wt% Cr; 0.21 wt% Ni; 0.43 wt% Si; 0.62 wt% Mn; 0.005 wt% S; 0.018 wt% P; the balance being Fe.

The annealed plastic die flat steel is subjected to steel ingot head and tail cutting and flaw detection (GB/T4162-2008 'forged and rolled steel bar ultrasonic detection method'), and the detection result shows that the yield of the die flat steel prepared by the method provided by the embodiment 2 is 92.5% after the head and the tail are cut off, and the flaw detection is qualified.

The microstructure of the die flat steel prepared in example 2 of the present invention was examined, and the examination result showed that the core microstructure was as shown in fig. 4, and it was found from fig. 4 that the microstructure was uniform and fine and had no flaw detection defects.

The invention provides a special ingot mold and a pouring process, which are specially used for producing mold flat steel with the thickness of 95-105 mm and the width of 580-620 mm. The thick-specification die flat steel prepared by adopting the specially designed ingot die and the pouring process matched with the ingot die has better yield and flaw detection qualification rate.

While only the preferred embodiments of the present invention have been shown and described, it will be understood by those skilled in the art that various changes in form and details may be made therein without departing from the spirit and scope of the invention.