CN101817072B - Casting equipment and method using solid-liquid two-phase region temperature as casting mold temperature - Google Patents

Abstract

The invention discloses a casting equipment and method whose mold temperature is the temperature of a solid-liquid two-phase region, belonging to the technical field of metal casting. It is characterized in that: the casting equipment is composed of a crucible, a two-phase area mold, a heater, a cooler and a traction mechanism; one or several two-phase area molds are set under, on, or beside the crucible, and the mold is carried out by the heater. Insulation and heating, or use the heat conducted by the molten metal before entering the mold to heat the mold, so that the temperature of the mold is kept between the solidus temperature and the liquidus temperature of the metal being cast; through the vicinity of the mold outlet The set cooler or the cooling device at the outlet of the mold that can move along the direction of the billet are used to forcibly cool the cast metal; the metal casting billet is drawn by a traction mechanism. The equipment of the invention has simple structure, convenient operation and maintenance, high production efficiency, wide application range, and can industrially produce high-quality metal billets with high strength and plasticity, good surface finish, high dimensional accuracy, high density, and low or no segregation .

Description

A kind of casting equipment and method whose mold temperature is the temperature of solid-liquid two-phase region

technical field

The invention belongs to the technical field of metal casting, and in particular provides a casting equipment and method in which the mold temperature is the temperature of the solid-liquid two-phase region of the metal to be cast.

Background technique

With the continuous development of metallurgical technology and material science and engineering technology, casting technology has been more and more widely used in metal production. The quality of the slab affects the metal forming process, product quality and production cost to a large extent. Improving the surface finish and plastic processing performance of the slab can effectively improve the quality of the formed product and the utilization rate of the material. The surface is smooth and the structure is dense. The slab with uniform composition can be directly applied or plastically processed into products. With the development of metal materials and processing technology, the requirements for billet quality are getting higher and higher.

Metals with a solid-liquid two-phase region are a class of materials with many varieties, large amounts, and wide uses, such as most steel, aluminum alloys, copper alloys, titanium alloys, magnesium alloys, etc. Currently, casting methods for such metals include traditional Continuous casting or semi-continuous casting, hot-type continuous casting and directional solidification, etc.

The traditional continuous casting and semi-continuous casting methods for metals with a solid-liquid two-phase region use a cooling mold (mold), that is, the temperature of the mold is much lower than the solidus temperature of the metal to be cast, and the molten metal is first cast It solidifies under the rapid cooling of the mold and gradually grows towards the center, easily forming dendrites, resulting in defects such as segregation, shrinkage cavity and porosity; due to the friction between the billet and the wall of the mold, it is generally necessary to vibrate the mold or the billet to The surface finish of the formed slab is not good, and the subsequent plastic processing performance is generally poor, and the quality and performance of the product are difficult to meet the requirements of higher performance [Zhang Xiaoping, Liang Aisheng. Near net shape continuous casting technology. Beijing: Metallurgy Industrial Press, 2001].

The hot-type continuous casting method (also known as the continuous directional solidification method) is to change the cooling mold of the traditional continuous casting into a heating mold (that is, the temperature of the mold is higher than the liquidus temperature of the metal to be cast). A high temperature gradient along the casting direction is established among the solidified melts, which makes it have directional solidification conditions, thereby obtaining a cast slab with unidirectional solidified continuous columnar crystal or single crystal structure. The method can be used to obtain products with good surface finish, continuous columnar crystal or single crystal structure and excellent subsequent processing performance. However, there are disadvantages such as low production efficiency, small cross-sectional area of the product, and difficulty in casting metals with a wide solid-liquid two-phase region [Xie Jianxin, et al. New technologies and new processes for material processing. Beijing: Metallurgy Industrial Press, 2004].

The directional solidification method also uses the heating mold, which can obtain a slab with unidirectional solidified columnar crystal or single crystal structure and excellent performance, but there is a limited length of the slab, and equiaxed crystals are prone to appear on the top of the slab, and Coarse grains, difficulty in casting metals with a wide solid-liquid two-phase region, and low production efficiency [Zhou Yaohe, Hu Zhuangqi, Jie Wanqi. Solidification Technology. Beijing: Machinery Industry Press, 1998].

Therefore, for metals with solid-liquid two-phase region, develop a new casting equipment and method with high production efficiency, so that the produced metal billet has good surface finish, compact structure, relatively uniform distribution of components, plastic processing performance and mechanical properties. Excellent comprehensive properties such as performance will further promote the preparation and processing of metals with solid-liquid two-phase regions, and expand their product varieties, specifications and application scope, which is of great significance.

Contents of the invention

The object of the present invention is to provide a kind of mold temperature that is the temperature of the solid-liquid two-phase region of the metal being cast (that is, the mold temperature is kept between the solidus temperature and the liquidus temperature of the metal to be cast, hereinafter referred to as this casting The casting equipment and method (hereinafter referred to as "two-phase zone casting") (hereinafter referred to as "two-phase zone casting mold") can solve the problem of poor surface finish, quality and performance of slabs produced by traditional continuous casting and semi-continuous casting methods , hot-type continuous casting and directional solidification methods are difficult to be used in the casting of metals with a wide solid-liquid two-phase region and low production efficiency.

A casting equipment whose mold temperature is the temperature of the solid-liquid two-phase region, is characterized in that the casting equipment is composed of a crucible (2), a two-phase region mold (4), a heater (5), a cooler (7 ) and traction mechanism (8). One or several two-phase zone casting molds (4) are arranged under (or on, or beside) the crucible (2), and the casting molds can be kept warm and heated by heaters (5) such as external heat sources or induction heating coils, or can be The mold is heated by the heat conducted by the cast metal melt (1) before entering the mold, so that the temperature of the mold is kept between the solidus temperature and the liquidus temperature of the metal being cast, and obtained in the mold The purpose of the solid-liquid mixture (3) of the cast metal in which the partially solidified crystal grains and the melt of the cast metal coexist; the crucible (2) can also be replaced by a tundish to facilitate continuous production; it is set near the outlet of the mold The cooler (7) is used to forcibly cool the metal to be cast, so that the heat is mainly transmitted from the casting mold outlet to the forced cooling zone along the axial direction of the slab, and the slab is solidified in the opposite direction; cooling is carried out along the drawing direction of the slab. A traction mechanism (8) is installed behind the device (7) to continuously draw the metal casting slab (6); a cooling device that can move along the direction of the slab can also be installed at the outlet of the mold to force the bottom of the cast metal to Cooling and continuous drawing; a secondary cooler can also be set between the cooler (7) and the traction mechanism (8).

The two-phase zone casting process of the present invention is: the cast metal melt (1) whose temperature is higher than the liquidus temperature of the cast metal flows into the two-phase zone mold (4) from the crucible (2); Under the action of heat conduction, the device (5) or the cast metal melt (1) is heated to the temperature range of the solid-liquid two-phase region of the cast metal, and the solid-liquid mixture (3) of the cast metal is obtained in the mold; through the mold The cooler (7) installed near the outlet or the cooling device at the outlet of the mold that can move along the direction of the billet is used to forcibly cool the cast metal, or the cooler (7) or the cooling device at the outlet of the mold that can be moved along the drawing direction The cooling device moving in the billet direction basically implements secondary cooling; under the action of the traction mechanism (8), the metal casting billet (6) is continuously drawn. The required cooling speed of the cast metal is controlled by the casting speed V of the traction mechanism (8), the cooling intensity of the cooler (7) and the heater (5). In addition, the crucible (2) can be placed in a vacuum or in an environment protected by an inert gas such as argon as required. The entire casting forming process can be controlled manually or by computer. Two-phase zone casting methods can be pull-down, horizontal or up-draw. According to the needs, the subsequent plastic processing can be directly carried out with a large reduction rate of 10% to 40%, and generally no intermediate annealing and other processes are required.

The main advantages of the present invention are:

1. The metal casting slab formed by the two-phase zone casting method has a good surface finish and a special structure (mainly composed of columnar crystals parallel to the casting direction and oblique columnar crystals at a certain angle to the casting direction, And some columnar grain boundaries have fine grains, a large number of columnar grains contain one or several other grains, and some grain boundaries are obviously jagged), and the structure is dense and the composition distribution is relatively uniform, so it has a relatively Ordinary continuous casting blanks of the same composition metal have better plastic processing properties, as well as mechanical, physical and chemical properties.

2. The two-phase region casting method has a wide range of applications. All metals with solid-liquid two-phase regions can be formed by two-phase region casting, such as most steel, aluminum alloys, copper alloys, titanium alloys, magnesium alloys, etc., can also be used for Forming of layered composite materials, gradient composite materials and homogeneous composite materials of such metals, and can be near-finally formed to produce metal wires, pipes, plates, strips, bars and profiles and other products.

3. The two-phase zone casting method has great promotion value, as long as the cooling mold of the traditional continuous casting method and semi-continuous casting method and the heating mold of the hot type continuous casting method and directional solidification method are changed to two-phase zone casting Type, can develop the corresponding two-phase zone casting method.

4. The metal casting slab formed by the two-phase zone casting method can be subjected to subsequent plastic processing at a large reduction rate as required, and generally no intermediate annealing and other processes are required, which greatly simplifies the process, reduces production costs, and improves product quality.

5. The casting equipment in the two-phase area has simple structure, convenient operation and maintenance, high production efficiency, wide application range, high strength and plasticity, good surface finish, high dimensional accuracy, high density and low or no segregation. Quality metal billets.

Description of drawings

Fig. 1 is a schematic configuration diagram of a two-phase zone casting equipment of the present invention. Among them (1) is the molten metal to be cast; (2) is the crucible; (3) is the solid-liquid mixture of the metal to be cast; (4) is the two-phase zone mold; (5) is the heater; (6) is Metal casting slab; (7) is a cooler; (8) is a traction mechanism.

Figure 2 is the cross-sectional microstructure of QSn6.5-0.1 tin bronze cast in the two-phase region.

Figure 3 shows the microstructure of the longitudinal section of QSn6.5-0.1 tin bronze cast in the two-phase region.

Detailed ways

The present invention is specifically described below in conjunction with the examples, it is necessary to point out that the present examples are only used to further illustrate the present invention, and can not be interpreted as limiting the protection scope of the present invention, those skilled in the art can according to the above-mentioned present invention Make some non-essential improvements and adjustments to the content.

Example 1:

QSn6.5-0.1 tin-bronze wire with a diameter of 10mm was formed by continuous casting in two-phase zone. QSn6.5-0.1 tin bronze melt (1) flows into the mold (4) in the two-phase region from the crucible (2); adjust the power of the induction heater (5), and control the temperature of the mold to 940 ° C. Obtain QSn6.5-0.1 tin bronze solid-liquid mixture (3); cooler (7) adopts the cooling water that temperature is 25 ℃, flow rate is 1700L/h to carry out forced cooling to QSn6.5-0.1 tin bronze; traction mechanism ( 8) Continuous drawing at a drawing speed of 90 mm/min to obtain a QSn6.5-0.1 tin bronze wire (6). The prepared QSn6.5-0.1 tin bronze wire has good surface finish, relatively uniform distribution of chemical components, and dense internal structure. There are fine grains in some columnar grain boundaries, a large number of columnar grains contain one or several other grains, and some grain boundaries are obviously zigzag.

Example 2:

The QSn6.5-0.1 tin bronze pipe with an outer diameter of 12mm and a wall thickness of 2mm is cast in the two-phase zone. QSn6.5-0.1 tin bronze melt (1) flows into the two-phase region mold (4) from the crucible (2); adjust the power of the induction heater (5) to control the mold temperature to 1020°C, Obtain QSn6.5-0.1 tin bronze solid-liquid mixture (3); Cooler (7) adopts the cooling water that temperature is 15 ℃, flow rate is 900L/h to carry out forced cooling to QSn6.5-0.1 tin bronze; Traction mechanism ( 8) Continuous drawing at a drawing speed of 200 mm/min to obtain a QSn6.5-0.1 tin bronze pipe (6). The prepared QSn6.5-0.1 tin bronze pipe has good internal and external surface finish, relatively uniform distribution of chemical components, and dense internal structure. Composed of columnar grains, and some columnar grain boundaries have fine grains, a large number of columnar grains contain one or several other grains, and some grain boundaries are obviously zigzag.

Example 3:

A QSn6.5-0.1 tin bronze plate with a width of 25mm and a thickness of 5mm was formed by semi-continuous casting in the two-phase region. QSn6.5-0.1 tin bronze melt (1) flows into the two-phase region mold (4) from the crucible (2); adjust the power of the induction heater (5) to control the mold temperature to 980°C, Obtain QSn6.5-0.1 tin bronze solid-liquid mixture (3); Cooler (7) adopts the cooling water that temperature is 20 ℃, flow rate is 1300L/h to carry out forced cooling to QSn6.5-0.1 tin bronze; Traction mechanism ( 8) Continuous drawing at a drawing speed of 150 mm/min to obtain a QSn6.5-0.1 tin bronze sheet (6). The prepared QSn6.5-0.1 tin bronze plate has good surface finish, relatively uniform distribution of chemical components, and dense internal structure. There are fine grains in some columnar grain boundaries, a large number of columnar grains contain one or several other grains, and some grain boundaries are obviously zigzag.

Claims (6)

1. casting method that mold temperature is the solid-liquid two-phase region temperature; It is characterized in that: adopting mold temperature is the Casting Equipment of solid-liquid two-phase region temperature, and said Casting Equipment constitutes: be made up of crucible (2), two-phase section casting mold (4), heater (5), cooler (7) and haulage gear (8); At crucible (2) down or go up or the side is provided with one or several two-phase section casting mold (4); Casting mold is incubated through heater (5) and heats; Perhaps utilize entering casting mold heat before that casting mold is heated by ingot metal melt (1) conduction; Reach mold temperature remained on by between the solidus temperature of ingot metal and the liquidus temperature, in casting mold, obtain partial coagulation crystallization crystal grain and by the coexistence of ingot metal melt mixed by the purpose of ingot metal solid-liquid mixture (3); Near the casting mold outlet, cooler (7) is set, to forced cooling by ingot metal, heat is mainly axially transmitted along strand by the casting mold outlet to the pressure cooling zone, strand then solidifies in opposite direction; In cooler (7) back haulage gear (8) is installed along the strand draw direction, metal strand (6) is carried out continuous drawing; The two-phase section casting technique is: temperature is higher than and from crucible (2), is flowed into two-phase section casting mold (4) by ingot metal melt (1) more than the ingot metal liquidus temperature; Casting mold is heated to by the solid-liquid two-phase region temperature range of ingot metal under at heater (5) or by ingot metal melt (1) conductive force, in casting mold, obtains by ingot metal solid-liquid mixture (3); Near through being provided with the casting mold outlet cooler (7) cools off being forced by ingot metal, under the effect of haulage gear (8), and continuous drawing metal strand (6); Cooling velocity by ingot metal is required is controlled by the casting speed V of haulage gear (8), the intensity of cooling and the heater (5) of cooler (7).

2. a kind of mold temperature as claimed in claim 1 is the casting method of solid-liquid two-phase region temperature, it is characterized in that, near the cooler (7) that is provided with the said casting mold outlet is the packaged type cooling device in casting mold exit.

3. a kind of mold temperature as claimed in claim 1 is the casting method of solid-liquid two-phase region temperature, it is characterized in that, near the basis of the cooler (7) that is provided with the said casting mold outlet, implements the secondary cooling.

4. a kind of mold temperature as claimed in claim 2 is the casting method of solid-liquid two-phase region temperature, it is characterized in that, implements the secondary cooling on the basis of the packaged type cooling device that is provided with in said casting mold exit.

5. a kind of mold temperature as claimed in claim 1 is the casting method of solid-liquid two-phase region temperature, it is characterized in that, the crucible of said Casting Equipment (2) replaces with tundish, and heater (5) adopts external heat source or load coil; Between cooler (7) and haulage gear (8), recoler is set, said cooler (7) is that a cooling device that can move along the throwing direction is set in the casting mold exit.

6. a kind of mold temperature as claimed in claim 1 is the casting method of solid-liquid two-phase region temperature, it is characterized in that crucible (2) is positioned over vacuum or charges in the environment of argon shield; Whole cast form process adopts Artificial Control or computer control; It is pull-down, horizontal or top-guiding type that two-phase section is cast into; Adopt 10%～40% passage heavy reduction rate directly to carry out follow-up plastic working as required, need not the intermediate annealing operation.

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