CN105817479A - A kind of magnesium alloy sheet rolling method - Google Patents

Abstract

The invention discloses a rolling method of an AZ33m magnesium alloy thin plate. The method includes blank selection, blank pretreatment, blank preheating, heating up and heat preservation, and performing the first rolling. The heating time for the subsequent rolling is 0.5h. The temperature of the heating kiln is lowered by 6-10°C once, the roll speed is 0.5-0.7m/s, and the pressing amount is 20%-30% each time. Carry out rolling in the last rolling direction, straighten the thin plate on the straightening machine immediately after rolling, cut off the flash on the shearing machine, anneal at low temperature, remove oxides and small pits on the surface, and pack in plastic wrap. The invention solves the problems of high requirements on blanks for rolling, cumbersome heating and temperature rise control in the production process, easy cracking of AZ33m magnesium alloy rolling, and uneven performance of AZ33m magnesium alloy thin plates.

Description

A kind of magnesium alloy sheet rolling method

technical field

Plate rolling method The invention belongs to the technical field of magnesium alloy sheet rolling, and in particular relates to an AZ33m magnesium alloy sheet.

Background technique

At present, the elastic modulus of magnesium alloy is low: elastic modulus is an important performance parameter of engineering materials. When magnesium alloy is subjected to external force, the stress will be evenly distributed in the material, thus avoiding too strong stress concentration in magnesium alloy; The specific strength of the alloy is high: the specific strength is defined as the stress suffered by the material when it breaks divided by its own apparent density. The higher the specific strength of the material, the lighter the material used to achieve the corresponding strength; the magnesium alloy has excellent damping performance: the damping is It refers to the characteristic that the amplitude of any vibration system has a tendency to gradually decrease due to the external environment or the inherent characteristics of the system itself. Compared with aluminum alloys, magnesium alloys have obvious advantages in damping characteristics; magnesium alloys have strong electromagnetic shielding ability: magnesium alloys have a strong shielding effect, and can shield electromagnetic wave radiation by shielding alternating electric fields and magnetic fields; magnesium alloys have good processability: magnesium The cutting speed of the alloy is much faster than that of aluminum alloy and steel; the lattice structure of magnesium is hcp (hexagonal close-packed), the plastic deformation ability of the magnesium alloy is poor at room temperature, and the plastic forming is difficult at room temperature, but at high temperature, the magnesium alloy will Slip and twin deformation occur, and the plastic forming ability is significantly improved under the combined action of the two deformations. Considering the importance of stress state change and deformation rate on the processing and strengthening of magnesium alloys during the forming process of magnesium alloys, currently magnesium alloys are formed except Except for a small amount of rolling forming, others such as extrusion and forging are the main methods of plastic forming of magnesium alloys;

At present, the main problems in magnesium alloy rolling are: the rolling temperature is too high or too low, it is easy to crack, the temperature is too high directly affects its strength, and the temperature is too low directly affects its plasticity; the performance of the rolled plate is not uniform at present, There is anisotropy; there is no stable and mature rolling process suitable for the production and preparation of AZ33m magnesium alloy sheets; as the market demand for magnesium alloys is expanding, especially the demand for high-strength and high-toughness magnesium alloy sheets is urgent.

Contents of the invention

The purpose of the present invention is to provide a magnesium alloy thin plate rolling method, aiming to solve the problems that the magnesium alloy with high zinc content is easy to crack when rolling, and the mechanical properties of the magnesium alloy are low and uneven after rolling.

The present invention is achieved in this way, a magnesium alloy thin plate rolling method, the magnesium alloy thin plate rolling method comprises the following steps:

Billet selection: select AZ33m cast plate or extruded plate;

Billet pretreatment: Mill the surface of the cast plate to remove oxides, and use a polishing machine to locally polish the surface with a small number of cracks, and the extruded plate does not need to be processed;

Billet preheating: Turn on the heating roller kiln, set the temperature to 330-350°C, heat the billet with the furnace, and set the roll temperature to (130-180°C);

The first rolling is carried out after heating up and holding time totaling 1.5h, and the heating time after each subsequent rolling is 0.5h, and the temperature of the heating kiln is lowered by 6-10°C for each rolling;

The speed of the roll is 0.5-0.7m/s, and the amount of pressing is 20%-30% each time;

After rolling for 3 to 6 times, it is cut into 400-600mm long plates along the rolling direction, returned to the furnace for heating, and then rolled along the direction perpendicular to the previous rolling until the thickness of the thin plate reaches the target thickness;

Immediately straighten the rolled thin plate on the straightening machine, and cut off the flash on the shearing machine;

Low temperature annealing, (100～150℃) for 1 hour

Remove oxides and small pits on the surface of the thin plate after low-temperature annealing on a polishing machine, and finally pack it with plastic wrap.

Furthermore, the size of the blank in the blank pretreatment is 500mm (width)*10-20mm (thickness)*300-1500mm (length).

Further, the blank is preheated: the heating raceway kiln is turned on, the temperature is set at 330-350°C, the blank is heated with the furnace, and the temperature of the roll is set at 130-180°C.

Further, after the first rolling of the billet is completed, the subsequent rolling is carried out, and the heating time after each rolling is 0.5h, and the temperature of the heating kiln is lowered by 6-10°C each time rolling.

The present invention solves the problem of difficult rolling of AZ33M magnesium alloy. Generally, for rolling magnesium alloy thin plates, only those with low alloy elements, especially those with low zinc elements, are used. Most of the magnesium alloy extruded plates are used. The process of the invention is easy to control, and The rolled sheet has excellent and uniform properties without anisotropy; it solves the cumbersome problem of heating and temperature rise control in the production process; it solves the problem of easy cracking and difficult forming of AZ33m magnesium alloy rolling; it solves the problem of poor performance of AZ33m magnesium alloy sheet Uniformity issue; improved AZ33m magnesium alloy sheet properties. At present, there is no prior art scheme that can reach the effect of the present invention in rolling AZ33m magnesium alloy sheet;

The present invention is applicable to the pretreatment method of AZ33m magnesium alloy billet; to the heating and temperature control scheme of AZ33m magnesium alloy billet; to the rolling mode of exchange rolling direction of AZ33m magnesium alloy billet; Until the final low temperature annealing method.

Description of drawings

Fig. 1 is a flow chart of the AZ33m magnesium alloy sheet rolling method provided by the embodiment of the present invention.

detailed description

In order to make the object, technical solution and advantages of the present invention more clear, the present invention will be further described in detail below in conjunction with the examples. It should be understood that the specific embodiments described here are only used to explain the present invention, not to limit the present invention.

Example one

Billet selection: select AZ33m extruded plate 400mm*400mm*10mm blank;

Billet pretreatment: extruded sheet does not need to be processed;

Billet preheating: turn on the heating raceway kiln, set the temperature to 340°C, heat the billet with the furnace, and set the roll temperature to 150°C;

The heating and holding time totaled 1.5h before rolling for the first time, and the subsequent heating time after each rolling was 0.5h, and the temperature of the heating kiln was lowered by 8°C every time rolling;

The speed of the roll is 0.6m/s, and the amount of pressing each time is 25% of the thickness of the sheet material;

After rolling for 3 times, cut it into 400 long plates along the rolling direction, return to the furnace to heat and then roll along the direction perpendicular to the previous rolling, and roll along this direction 4 times, each time the pressing amount is 25%, and the final thin plate The thickness reaches 1.33mm.

Immediately straighten the rolled thin plate on the straightening machine, and cut off the flash on the shearing machine;

Low temperature annealing, (100～150℃) for 1 hour

Remove oxides and small pits on the surface of the thin plate after low-temperature annealing on a polishing machine. The final size of the finished plate is 400mm*1300mm*1.2mm, and then packaged with plastic wrap.

Instance performance test

According to the national standard GB/T16865, sample the thin plate of the appeal example, and the test results of mechanical properties are as follows:

The present invention is applicable to the pretreatment method of AZ33m magnesium alloy billet; to the heating and temperature control scheme of AZ33m magnesium alloy billet; to the rolling mode of exchange rolling direction of AZ33m magnesium alloy billet; Until the final low temperature annealing method.

The application principle of the present invention will be further described below in conjunction with the accompanying drawings.

A kind of AZ33m magnesium alloy sheet rolling method, this AZ33m magnesium alloy sheet rolling method comprises the following steps:

S101: Billet: AZ33m cast plate or extruded plate;

S102: Billet pretreatment: The cast plate needs to be milled on the surface to remove oxides. If there are still a few cracks, use a polishing machine to polish it locally. Extruded plates do not need to be processed. The size of the billet in this plan is 500mm (width) *10～20mm(thickness)*300～1500mm(length);

S103: billet preheating: turn on the heating raceway kiln, set the temperature to 330-350°C, heat the billet with the furnace, and set the roll temperature to (130-180°C);

S104: The first rolling is carried out after the total heating and holding time is 1.5 hours, the subsequent rolling heating time is 0.5 hours, and the temperature of the heating kiln is lowered by 6-10°C every time rolling;

S105: The speed of the roll is 0.5-0.7m/s, and the pressing amount is 20%-30% each time;

S106: After rolling for 3 to 6 times, cut it into 400-600 mm long plates along the rolling direction, return to the furnace for heating, and then roll along the direction perpendicular to the previous rolling until the thickness of the thin plate reaches the target thickness;

S107: Immediately straighten the rolled thin plate on the straightening machine, and cut off the flash on the shearing machine;

S108: Low temperature annealing, (100-150°C) for 1 hour;

S109: Remove oxides and small pits on the surface on a polishing machine, and finally pack with plastic wrap to complete the product.

The above descriptions are only preferred embodiments of the present invention, and are not intended to limit the present invention. Any modifications, equivalent replacements and improvements made within the spirit and principles of the present invention should be included in the protection of the present invention. within range.

Claims (4)

1. A method for rolling a magnesium alloy sheet, characterized in that, the method for rolling a magnesium alloy sheet comprises the following steps: Billet selection: select casting plate blanks or extruded plate blanks; Billet pretreatment: Mill the surface of the cast plate to remove oxides, and use a polishing machine to locally polish the surface with a small number of cracks, and the extruded plate does not need to be processed; Billet preheating: open the heating raceway kiln, the billet is heated with the furnace, and the temperature of the roll is set; After the total heating and holding time is 1.5 hours, the first rolling is carried out, and the temperature is raised for 1 hour and kept for 0.5 hours; after the first rolling is completed, the subsequent rolling is carried out. The temperature drops by 6-10°C; The speed of the roll is 0.5-0.7m/s, and the amount of pressing is 20%-30% each time; After rolling for 3 to 6 times, it is cut into 400-600mm long plates along the rolling direction, returned to the furnace for heating, and then rolled along the direction perpendicular to the previous rolling until the thickness of the thin plate reaches the target thickness; Immediately straighten the rolled thin plate on the straightening machine, and cut off the flash on the shearing machine; Low-temperature annealing at 100-150°C for 1 hour; Remove oxides and small pits on the surface of the thin plate after low-temperature annealing on a polishing machine, and finally pack it with plastic wrap. 2 . The magnesium alloy sheet rolling method according to claim 1 , wherein the size of the billet in the billet pretreatment is 500 mm wide*10-20 mm thick*300-1500 mm long. 3. The magnesium alloy thin plate rolling method according to claim 1, characterized in that the preheating of the billet: turn on the heating raceway kiln, set the temperature to 330-350°C, heat the billet with the furnace, and set the roll temperature to 130°C ~180°C. 4. The magnesium alloy thin plate rolling method as claimed in claim 1, characterized in that, after the rolling of the billet for the first time, subsequent rolling, the heating time after each rolling is 0.5h, each rolling The temperature of the primary heating kiln is reduced by 6-10°C.