CN101898200B - Direct rolling method of zinc ingots - Google Patents

Abstract

The invention provides a zinc ingot direct rolling method, which belongs to the technical field of metal material forming and processing. The main content of the method is as follows: firstly, electroplating the surface of the polished roll and spraying zinc removal solution; using zinc ingots produced by the smelter as raw material, after the surface is cleaned and dried, it is sent to an electric heating furnace for heating, in order to ensure the shape of the rolled plate To improve the yield and improve the yield, "hot roll" should be carried out before rolling the first zinc ingot, and the heated zinc ingot should be transported to the hot rolling mill for multi-pass batch cycle rolling, according to the size of the ingot and the finished product Allocate the rolling pass and pass reduction rate. After the hot-rolled zinc plate is naturally cooled to room temperature, it is longitudinally cut, cross-cut, and sheared to the finished product size. The zinc plate is inspected, marked, and packaged before being put into storage. The invention has the characteristics of short process, low comprehensive energy consumption, low production cost, high production efficiency, and high product cost performance.

Description

Zinc ingot direct rolling method

Technical field:

The invention belongs to the technical field of metal material forming and processing, and in particular relates to a method for direct rolling zinc ingots (original ingots) produced by a zinc smelter.

Background technique:

Zinc is chemically active and has fairly good corrosion resistance, mechanical properties and good formability. In metal consumption, zinc ranks fifth after steel, aluminum, copper and manganese. Zinc consumption areas are galvanized, brass and bronze, zinc-based alloys and chemical products in turn. Zinc plates are mainly used in construction and light industry.

The zinc ingot is small in size and loose in structure. For the needs of casting and demoulding, grooves with a width of 60mm and a depth of 12mm are formed on the upper surface of the zinc ingot. It is easy to crack, fold and stick to the roll during rolling, so it is not suitable for directly to the rolling process. The traditional zinc plate production process is to melt and cast zinc ingots (also known as raw ingots) produced by smelters into billets with larger specifications, surface treatment to eliminate surface grooves, and then heat and roll them into shapes; some The galvanizing enterprise melts the original zinc ingot, and then pours it into a 15-30mm thick billet for galvanizing. See attached drawing 2 of the manual for the traditional zinc plate production process.

Because the traditional zinc plate production process includes smelting and billet casting processes, the energy consumption is high, the smelting loss is large, and the production efficiency is low. Although the billet process flow for galvanizing is not long, it still needs a smelting process. In addition, the amount of galvanizing plant is not large, and the smelting equipment is relatively simple, and the zinc loss (melting loss) during smelting can reach 2-3%. , based on the current zinc price plan of 20,000 yuan/ton, equivalent to RMB, the loss will be 400-600 yuan/ton. The ideal method is to directly use zinc ingots produced by smelters as rolling raw materials, omitting the process of using zinc ingots in the traditional zinc plate rolling process to be remelted and cast into rolling raw material billets for direct rolling. On the one hand, it utilizes the good mechanical properties and recrystallization properties of pure zinc materials, on the other hand, it reduces energy consumption and melting loss, and reduces production costs. Therefore, the development of zinc ingot direct rolling technology has very important practical significance and economic benefits.

Invention content:

The purpose of the invention is to overcome the technical problems existing in the existing zinc sheet rolling method, and provide a direct rolling method of zinc ingots, the specific content of the method is as follows:

(1) First, electroplate the surface of the polished roll and spray zinc removal solution to enhance the wear resistance and smoothness of the roll and prevent the roll from sticking to zinc.

(2) Using the zinc ingots (original ingots) produced by the smelter as raw materials, the qualified zinc ingots are grouped into batches, and after the surface is cleaned and dried, they are sent to an electric heating furnace for heating. The heating temperature is 280°C-350°C, and the heating is uniform , keep warm for 60 minutes.

(3) In order to ensure the good shape of the rolling plate and improve the yield, "hot roll" should be carried out before rolling the first zinc ingot, and the temperature of the roll body of the hot rolling mill should be "hot" to 120°C-180°C, The range of roll temperature is determined according to different rolling stages and actual plate shape.

(4) Transport the heated zinc ingots to the hot rolling mill for multi-pass batch cycle rolling. The rolling temperature is within the range of 180°C-250°C, and the rolling passes and passes are allocated according to the size of the ingot and the finished product. Second reduction rate, considering the groove of the billet, the thickness deviation is large, and it is a casting structure, the reduction rate of the first pass is ≤15%, and the reduction rate of the middle pass is 25-30%, considering the finished plate The plate shape, thickness tolerance and performance, the reduction rate of the finished pass is controlled at 15-20%.

(5) After the hot-rolled zinc plate is naturally cooled to room temperature, it is longitudinally cut, cross-cut, and sheared to the finished product size, and the zinc plate is inspected, marked, and packaged before being put into storage.

Process flow of the present invention is shown in accompanying drawing 1 of description.

The preparation of raw materials includes the preparation of zinc ingots and the cleaning of the surface of zinc ingots. Since there are grooves on the surface of zinc ingots, it may be stained with oil and dust during transportation and storage. In order to improve the surface quality of the product, a surface cleaning process is required before heating and rolling. In order to prevent the roll from sticking to zinc, the surface of the roll is treated and sprayed with zinc removal solution. According to the size and production capacity of zinc ingots and finished zinc sheets, the type, specification and production capacity of the heating furnace and hot rolling mill and the heating temperature range of the heating furnace are selected. Due to the large heat of deformation during zinc rolling, batch cycle rolling is adopted during hot rolling to reduce the temperature rise caused by heat of deformation, and the roll temperature and rolling temperature of each rolling stage should be controlled. The finishing process includes cooling the rolled zinc sheet to room temperature, longitudinally cutting, cross-cutting, cutting to the finished product size, and then being inspected, marked, packaged and put into storage. The process requirements of the finishing process and its subsequent processes are the same as those of the traditional process.

The special significance of the present invention is that the smelting and billet casting processes of the traditional zinc plate rolling process are omitted, the energy consumption of the heating process is more than 50% lower than that of the smelting process, the production efficiency is greatly improved, and the metal consumption (melting process) during smelting is eliminated. The loss is 2%-3%). Compared with the traditional rolling zinc plate production process, the present invention has the following outstanding advantages: ① short process, simple process equipment, and small investment; ② no need for smelting, billet casting equipment, low comprehensive energy consumption, small metal consumption, and good working conditions ; ③Short production cycle and fast capital turnover; ④Low production cost, high production efficiency, better product quality than billet, high cost performance, and strong product market competitiveness; ⑤Good economic benefits, new profit per unit product ≥ 400 yuan/ton , short payback period.

Description of drawings:

Fig. 1: Process flow chart of the present invention.

Figure 2: Traditional zinc plate production process flow chart.

Detailed ways:

Preparation before rolling: Select 33 qualified zinc ingots with a purity of 99.9%, each with a thickness of 50mm, a width of 200mm, and a length of 400mm; groove. Clean the surface of each zinc ingot, inspect it with the naked eye, and dry it, then divide it into 3 groups and stack it in sequence. Single-stand reciprocating rolling is adopted, and the surface treatment of the rolls is carried out to enhance the wear resistance of the rolls and prevent zinc sticking during rolling.

Embodiment 1: First, spray the zinc solution on the surface of the roll, select 11 warp knitting 1-2-3-...-11 zinc ingots from the first group, heat to 320° C. in a heating furnace and keep the temperature for 60 minutes. Use the ingot taker to take it out at one time and stack it on the front stand of the rolling mill in order. The first piece of zinc ingot is used to "hot roll", the temperature of the roll body is "hot" to 150°C, and then rolling is carried out. The rolling start temperature is 250°C, and the rolling of the first pass is carried out in sequence according to the number 1-2-3-…-11, and the reduction rate is 10%; is 26.7%; the third rolling pass is cyclically rolled, and the reduction rate is 27.3%, the fourth pass is cyclically rolled, the final rolling temperature is 240°C, and the reduction rate is 16.7%, after four passes of rolling Finally, a hot-rolled zinc plate for galvanizing with a thickness of 20mm, a width of 200mm, a length of 760mm, a bright surface, a good shape, a lateral thickness difference of ±0.5μm, a purity of 99.9%, and σ _s > 80MPa was obtained. After natural cooling to After room temperature, carry out slitting, cross-cutting, and shearing to the finished product size, and put it into storage after inspection, marking, and packaging.

Embodiment 2: First, spray the zinc liquid on the surface of the roll, and then select the 2nd group of 11 warp-knitted zinc ingots No. 1-2-3-...-11, heat to 300°C in a heating furnace and keep it warm for 60 minutes. Use the ingot taker to take it out at one time and stack it on the front stand of the rolling mill in order. The first piece of zinc ingot is used to "hot roll", the temperature of the roll body is "hot" to 130°C, and then rolling is carried out. The rolling start temperature is 230°C, and the rolling of the first pass is carried out in sequence according to the number 1-2-3-...-11, and the reduction ratio is 10%; the second rolling is also carried out according to the number cycle, and the reduction ratio is 26.7%; the third pass is cyclically rolled, and the reduction rate is 27.3%; the fourth pass is cyclically rolled, and the reduction rate is 25%; the fifth pass is cyclically rolled, and the final rolling temperature is 220 ℃, the reduction rate is 16.7%, after five passes of rolling, the thickness is 15mm, the width is 200mm, the length is 1000mm, the surface is bright, the plate shape is good, the transverse thickness difference is ±0.5μm, the purity is 99.9%, σ _s The hot-rolled zinc sheet > 80MPa is naturally cooled to room temperature, then longitudinally cut, cross-cut, and sheared to the finished product size, and put into storage after inspection, marking, and packaging.

Embodiment 3: First, spray the zinc solution on the surface of the roll, and then select 11 warp-knitted zinc ingots of No. 1-2-3-...-11 in the third group, heat them to 280°C in a heating furnace and keep them warm for 60 minutes. Use the ingot taking machine to take out and stack in order on the front stand of the rolling mill. The first piece of zinc ingot is used to "hot roll", the temperature of the roll body is "hot" to 120°C, and then rolling is carried out. The rolling start temperature is 180°C, and the rolling of the first pass is carried out in sequence according to the number 1-2-3-…-11, and the reduction rate is 15%; the second rolling is also carried out according to the number cycle, and the reduction rate is 25.9%; the third pass cyclic rolling, the reduction ratio is 30.2%; the fourth pass cyclic rolling, the reduction ratio is 29.5%; the fifth pass cyclic rolling, the reduction ratio is 25.8%, the first Six passes of cyclic rolling, the final rolling temperature is 180°C, and the reduction rate is 15%. After six passes of rolling, the thickness is 10mm, the width is 200mm, and the length is 1500mm. The surface is bright, the plate shape is good, and the transverse thickness difference ±0.5μm, 99.9% purity, σ _s >80MPa hot-rolled zinc plate, after natural cooling to room temperature, longitudinal cutting, cross cutting, shearing to finished product size, inspection, marking and packaging before storage.

Claims (1)

1. A zinc ingot direct rolling method, the method specific content is as follows: (1) First, electroplate the surface of the polished roll and spray zinc removal solution to enhance the wear resistance and smoothness of the roll and prevent the roll from sticking to zinc; (2) Using the zinc ingots produced by the smelter as raw materials, the qualified zinc ingots are grouped into batches, and after the surface is cleaned and dried, they are sent to a heating furnace for heating. The heating temperature is 280°C-350°C, the heating is uniform, and the heat preservation is 60 minutes. ; (3) In order to ensure the good shape of the rolling plate and improve the yield, "hot roll" should be carried out before rolling the first zinc ingot, and the temperature of the roll body of the hot rolling mill should be "hot" to 120°C-180°C, Determine the range of roll temperature according to different rolling stages and actual shape; (4) Transport the heated zinc ingots to the hot rolling mill for multi-pass batch cycle rolling. The rolling temperature is within the range of 180°C-250°C, and the rolling passes and passes are allocated according to the size of the ingot and the finished product. Second reduction rate, considering the groove of the billet, the thickness deviation is large, and it is a casting structure, the reduction rate of the first pass is ≤15%, and the reduction rate of the middle pass is 25-30%, considering the finished plate The plate shape, thickness tolerance and performance, the reduction rate of the finished product pass is controlled at 15-20%; (5) After the hot-rolled zinc plate is naturally cooled to room temperature, it is longitudinally cut, cross-cut, and sheared to the finished product size, and the zinc plate is inspected, marked, and packaged before being put into storage.

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