阅读说明：本技术 一种改善5系铝合金扁锭表面质量的方法 (Method for improving surface quality of 5-series aluminum alloy slab ingot ) 是由 杨昆 张海平 张国良 于 2020-06-12 设计创作，主要内容包括：本发明涉及5系铝合金扁锭生产技术领域,公开了一种改善5系铝合金扁锭表面质量的方法。该方法包括以下步骤：(1)在铸造5系铝合金扁锭前,将结晶器内壁打磨光滑；(2)在浇铸过程中,采用自动加油装置向结晶器中加润滑油,并通过合理设置加油频率,使加油频次与铸造速度和脱模情况相匹配,其中,所述加油频次为1/10/2/2；(3)对铸造的扁锭进行铣面加工,得到成品。本发明通过合理设置加油频次,将加油频次设置为1/10/2/2,可以很好地和浇铸速度相匹配,拥有合适的润滑度,保证了铸锭的顺利脱模,最终制备的5系铝合金扁锭表面质量良好,没有拉痕、拉裂及冷隔缺陷。(The invention relates to the technical field of 5-series aluminum alloy slab ingot production, and discloses a method for improving the surface quality of a 5-series aluminum alloy slab ingot. The method comprises the following steps: (1) before casting a 5-series aluminum alloy slab ingot, polishing the inner wall of a crystallizer to be smooth; (2) in the casting process, an automatic oiling device is adopted to add lubricating oil into a crystallizer, and the oiling frequency is reasonably set to match the casting speed and the demolding condition, wherein the oiling frequency is 1/10/2/2; (3) and (4) carrying out face milling processing on the cast slab ingot to obtain a finished product. According to the invention, the oiling frequency is reasonably set to 1/10/2/2, so that the oiling frequency can be well matched with the casting speed, the casting ingot has proper lubrication degree, the smooth demolding of the cast ingot is ensured, and the finally prepared 5-series aluminum alloy flat ingot has good surface quality and does not have the defects of pull marks, pull cracks and cold shut.)

1. A method for improving the surface quality of a 5-series aluminum alloy slab ingot is characterized by comprising the following steps:

(1) before casting a 5-series aluminum alloy slab ingot, polishing the inner wall of a crystallizer to be smooth;

(2) in the casting process, an automatic oiling device is adopted to add lubricating oil into a crystallizer, and the oiling frequency is reasonably set to match the casting speed and the demolding condition, wherein the oiling frequency is 1/10/2/2;

(3) and (4) carrying out face milling processing on the cast slab ingot to obtain a finished product.

2. The method of claim 1, wherein the 5-series aluminum alloy is 5052 or 5754 aluminum alloy.

3. The method of claim 1, wherein the method reduces surface defects of a 5-series aluminum alloy slab ingot, wherein the defects are cold shut, tensile cracks, and corner cracks.

4. The method according to claim 1, wherein the casting speed is 43 to 45mm/min during the casting in the step (2).

5. The method as claimed in claim 1, wherein the casting temperature is 702-719 ℃ during the step (2) of casting.

6. The method as claimed in claim 5, wherein the casting temperature is 705-718 ℃ during the step (2) of casting.

7. The method according to claim 1, wherein in step (2), the temperature of the lubricating oil is 30-40 ℃.

8. The method of claim 7, wherein in step (2), the temperature of the lubricating oil is 33-37 ℃.

9. The method of claim 1, wherein in step (2), further comprising lowering the crystallizer liquid level to shorten the effective crystallization zone.

10. The method as claimed in claim 1, wherein in step (3), the finished slab has a thickness x width x length (490-510) mm x (1180-1230) mm x (5000-6000) mm.

Technical Field

The invention relates to the technical field of 5-series aluminum alloy slab ingot production, in particular to a method for improving the surface quality of a 5-series aluminum alloy slab ingot.

Background

The 5xxx series aluminum alloy is aluminum-magnesium series alloy, belongs to aluminum alloy which can not be strengthened by heat treatment, has good corrosion resistance and weldability, particularly 5052, 5754 and the like, and is a material with wide application. However, in the casting process of the 5xxx aluminum alloy slab ingot, the melt viscosity of the molten aluminum is larger and the fluidity is poorer due to the high content of Mg element and other impurity elements, and the ingot surface of the large slab ingot after casting is easy to generate the defects of segregation tumor, cold shut, tensile crack, slag inclusion and the like, thereby greatly influencing the next working procedure and the yield.

After the casting and processing of the flat ingot are finished, the surface of the flat ingot is smooth and neat mainly by sawing and milling the surface, and the requirement of hot rolling and subsequent rolling is met. The surface defects generated by different reasons have the common characteristics that the surface of the flat ingot is not good, the various concave-convex defects are shown, the surface appearance of the flat ingot is influenced, the defects cannot be eliminated by normal surface milling in serious cases, the defects need to be eliminated by methods such as increasing the surface milling amount, the defects with shallow surface layers cannot be milled, and the fatal defects such as slag inclusion holes and the like can be generated after hot rolling. Has great influence on the yield of the flat ingots. Generally, the milling surface thickness of the slab ingot is controlled to be 8-12mm, and if the depth of the surface defect of the slab ingot is more than 12mm, the yield of the slab ingot is affected.

At present, the generation of surface defects of a 5xxx series aluminum alloy slab ingot is a difficult point for controlling the yield of the aluminum alloy slab ingot, and the reasons for generating the surface defects are many, thereby bringing great difficulty to analysis and rectification. Aluminum alloy ingot casting is a slow, complex solidification process involving high to low temperatures, and is carried out at temperatures that are continuously above the ignition point of typical oils. The amount of oil used as a lubricant should be neither too large nor too small. The lubricating oil is too much, so that combustion is easily generated to influence the working environment, the production safety and the product quality; if the amount of lubricating oil is too small, the purpose of lubrication cannot be achieved. Therefore, the casting lubricating oil can be injected in a micro-scale, continuous and controllable manner only, so that the lubricating oil is uniformly distributed on the wall of the inner cavity of the crystallizer, the uniform distribution of the lubricating oil on the cross section of the crystallizer is kept, and the consistency of the length lubricating conditions of the cast ingot is realized by uniformly adding and injecting the lubricating oil. The unsmooth or uneven oil discharge can cause additional defects on the surface of the ingot, so that the defects of the ingot are increased or the ingot is scrapped. Therefore, in order to ensure the surface quality of the cast ingot, special attention must be paid to the frequency of oil discharge and the uniformity of oil supply.

Disclosure of Invention

The invention aims to overcome the problems that the frequency of adding lubricating oil is not matched with the casting speed and the demoulding condition in the prior art, and the produced 5-series aluminum alloy flat ingot has defects on the surface, and provides a method for improving the surface quality of the 5-series aluminum alloy flat ingot.

In order to achieve the above object, the present invention provides a method for improving the surface quality of a 5-series aluminum alloy slab ingot, comprising the steps of:

(1) before casting a 5-series aluminum alloy slab ingot, polishing the inner wall of a crystallizer to be smooth;

(2) in the casting process, an automatic oiling device is adopted to add lubricating oil into a crystallizer, and the oiling frequency is reasonably set to match the casting speed and the demolding condition, wherein the oiling frequency is 1/10/2/2;

(3) and (4) carrying out face milling processing on the cast slab ingot to obtain a finished product.

Preferably, the 5-series aluminum alloy is 5052 or 5754 aluminum alloy.

Preferably, the method can reduce surface defects of the 5-series aluminum alloy slab ingot, wherein the defects are cold shut, tensile cracks and corner cracks.

Preferably, in the step (2) casting process, the casting speed is 43-45 mm/min.

Preferably, the casting temperature is 702-719 ℃ during the step (2) of casting.

More preferably, the casting temperature is 705-718 ℃ during the step (2) of casting.

Preferably, in step (2), the temperature of the lubricating oil is 30-40 ℃.

More preferably, in step (2), the temperature of the lubricating oil is 33-37 ℃.

Preferably, in the step (2), the liquid level of the crystallizer is lowered, and the effective crystallization interval is shortened.

Preferably, in the step (3), the specification of the slab ingot finished product is (490-.

According to the invention, the oiling frequency is reasonably set to 1/10/2/2, so that the oiling frequency can be well matched with the casting speed, the casting ingot has proper lubrication degree, the smooth demolding of the cast ingot is ensured, and the finally prepared 5-series aluminum alloy flat ingot has good surface quality and does not have the defects of pull marks, pull cracks and cold shut.

Detailed Description

The following describes in detail specific embodiments of the present invention. It should be understood that the detailed description and specific examples, while indicating the present invention, are given by way of illustration and explanation only, not limitation.

The endpoints of the ranges and any values disclosed herein are not limited to the precise range or value, and such ranges or values should be understood to encompass values close to those ranges or values. For ranges of values, between the endpoints of each of the ranges and the individual points, and between the individual points may be combined with each other to give one or more new ranges of values, and these ranges of values should be considered as specifically disclosed herein.

The invention relates to a method for improving the surface quality of a 5-series aluminum alloy slab ingot, which comprises the following steps of:

(1) before casting a 5-series aluminum alloy slab ingot, polishing the inner wall of a crystallizer to be smooth;

(2) in the casting process, an automatic oiling device is adopted to add lubricating oil into a crystallizer, and the oiling frequency is reasonably set to match the casting speed and the demolding condition, wherein the oiling frequency is 1/10/2/2;

(3) and (4) carrying out face milling processing on the cast slab ingot to obtain a finished product.

The invention ensures the lubrication between the inner wall of the crystallizer and the cast ingot by polishing the crystallizer and reasonably setting the oiling frequency, reduces the friction force between the crystallizer and the periphery of the cast ingot and mills the finished product, and can prepare the 5-series aluminum alloy flat ingot with no defect on the surface by reasonably setting the oiling frequency.

After the oiling frequency is adjusted to 1/10/2/2, the surface defects of the 5-series aluminum alloy slab ingot can be greatly reduced, and the surface quality is improved. 1/10/2/2 shows a 10s refuelling cycle with 2 charges of oil from the lubricator and 2 discharges from the crystalliser.

The structure of the automatic oiling device is as follows: the upper part of the crystallizer body is provided with an annular oil groove, an annular pressure plate is pressed on the crystallizer body and used for sealing the annular oil groove; the crystallizer body is internally provided with a plurality of oil outlet capillary holes, the oil inlets of the oil outlet capillary holes are communicated with the annular oil groove, the oil outlets are communicated with the inner cavity of the crystallizer body, and the plurality of oil outlet capillary holes are distributed around the inner cavity of the crystallizer body. An annular oil groove is formed in the upper portion of the crystallizer body, and an annular pressure plate seals the annular oil groove, so that a closed structure is formed. In addition, the oil outlet capillary hole is also embedded in the crystallizer body, so that the whole oil supply channel is of a closed structure, thereby avoiding the entry of impurities and ensuring the smoothness of oil supply. In addition, a plurality of oil outlet capillary holes arranged around the inner cavity of the crystallizer body can ensure the uniformity of oil outlet, improve the surface quality of cast ingots and improve the production efficiency.

The method of the invention can be used for preparing 5-series aluminum alloy flat ingots common in the field, and is particularly suitable for preparing 5052 or 5754 aluminum alloy flat ingots.

In a specific embodiment, the method can reduce the defects of cold shut, tensile crack and angular crack on the surface of the 5-series aluminum alloy slab ingot.

In the method, in the step (2) of casting, the casting speed is 43-45 mm/min; specifically, for example, the average particle diameter may be 43mm/min, 43.5mm/min, 44mm/min, 44.5mm/min, 45mm/min, or any value in a range formed by any two of these values; preferably, the casting speed is 44 mm/min.

In the method, in the step (2), the casting temperature is 702-719 ℃; specifically, for example, 702 ℃, 704 ℃, 706 ℃, 708 ℃, 710 ℃, 712 ℃, 714 ℃, 716 ℃, 718 ℃ or 719 ℃; preferably, the casting temperature is 705-718 ℃ during the step (2) of casting.

In the method of the invention, in the step (2), the temperature of the lubricating oil is 30-40 ℃; specifically, for example, the temperature may be 30 ℃, 32 ℃, 34 ℃, 36 ℃, 38 ℃ or 40 ℃; preferably, in step (2), the temperature of the lubricating oil is 33 to 37 ℃.

In the method of the present invention, in order to reduce the defects on the surface of the 5-series aluminum alloy, in the step (2), the liquid level of the crystallizer is lowered, and the effective crystallization interval is shortened.

In the method of the present invention, in a specific embodiment, in the step (3), the specification of the slab ingot product obtained is (490) -510-mm (1180-1230) -mm (5000-6000) -mm.

The method also comprises a cooling process, wherein the flow rate of cooling water is 6000-³/h。

The technical scheme of the invention is a key technical point, and in the specific implementation, the technical scheme is implemented by matching with the conventional operation of aluminum alloy casting.

The present invention will be described in detail by way of examples, but the scope of the present invention is not limited thereto.