阅读说明：本技术 一种连接铝合金型材与铝合金铸件的半空心铆钉铆接工艺 (Semi-hollow rivet riveting process for connecting aluminum alloy section and aluminum alloy casting ) 是由 马焕祥 赵云 于 2020-12-25 设计创作，主要内容包括：本发明属于合金材料加工技术领域,具体涉及一种连接铝合金型材与铝合金铸件的半空心铆钉铆接工艺。本发明采用半空心铆钉自冲铆接代替焊接工艺,在铆钉腿部形状以及铸造件凸起的共同作用下,铆钉腿部向周围扩张从而形成了铆钉与铝型材之间的机械互锁结构,将铝合金铸造件与铝合金型材紧密结合起来,且铆接强度高,避免了传统焊接产生的气孔、热裂纹等不足。该铆接工艺适用于新能源汽车铝合金电池盒、框架、支架、端板、电芯固定等的连接方式新能源电池盒、框架、支架、端板、电芯固定等的连接,相对于激光焊接设备投入以及后续的操作维修资金较少,铆接强度安全可靠,工艺简单操作方便,经济效益大。(The invention belongs to the technical field of alloy material processing, and particularly relates to a riveting process of a semi-hollow rivet for connecting an aluminum alloy section and an aluminum alloy casting. The invention adopts the self-piercing riveting of the semi-hollow rivet to replace the welding process, under the combined action of the shape of the rivet leg and the projection of the casting part, the rivet leg expands to the periphery so as to form a mechanical interlocking structure between the rivet and the aluminum profile, the aluminum alloy casting part and the aluminum alloy profile are tightly combined, the riveting strength is high, and the defects of air holes, hot cracks and the like generated by the traditional welding are avoided. The riveting process is suitable for connection modes such as fixing of a new energy automobile aluminum alloy battery box, a frame, a support, an end plate and an electric core, and connection modes such as fixing of the new energy automobile aluminum alloy battery box, the frame, the support, the end plate and the electric core are less in investment and subsequent operation and maintenance fund, safe and reliable in riveting strength, simple in process, convenient to operate and large in economic benefit.)

1. A semi-hollow rivet riveting process for connecting an aluminum alloy profile and an aluminum alloy casting is characterized by comprising the following steps:

s1, treating the surfaces to be riveted of the aluminum alloy section and the aluminum alloy casting;

s2, fixing the aluminum alloy profile subjected to surface treatment by using a blank holder, and simultaneously, vertically and downwards pre-pressing the aluminum alloy by using the rivet under the driving of a punch hammer;

s3, pressing the rivet under the action of a power source to pierce through the aluminum profile, and driving the aluminum profile to generate plastic deformation into the aluminum alloy casting by the rivet;

s4, gradually filling the aluminum profile into the casting part along with the riveting;

and S5, when the punch hammer presses the rivet down until the rivet head is in close contact with and level with the upper surface of the aluminum profile, the riveting is completed, the blank holder releases blank holding force, and the punch hammer returns to the initial station.

2. The semi-hollow rivet riveting process according to claim 1, wherein the aluminum alloy profile consists of the following components in percentage by mass Si: 8-12%, Mg: 1.4-3%, Sr: 0.05 to 0.5%, Mn: 0.8-2%, Cu: 0.1-0.7%, and the balance of Al and inevitable impurities.

3. A semi-hollow rivet riveting process according to claim 1, wherein the aluminum alloy casting consists of Mg in the following mass percent: 0.2-0.3%, Si: 1.4-1.6%, Mn: 0.05-0.2%, Cr: 0.1-0.5%, Zn: 0.1-0.4%, Ti: 0.1-0.2%, Sr: 0.2-0.3%, and the balance of Al and inevitable impurities.

4. The riveting process of a semi-hollow rivet according to claim 1, wherein the riveting surface treatment of the aluminum alloy section and the aluminum alloy casting is as follows: and (3) putting the riveting surface in a degreasing solution at the temperature of 40-50 ℃ for degreasing treatment for 1-2h, then washing the riveting surface by using deionized water, and drying the riveting surface at the temperature of 100-120 ℃.

5. A semi-hollow rivet riveting process according to claim 4, wherein the degreasing solution consists of the following components in percentage by mass: sodium dodecylbenzenesulfonate: 0.5-1.0%, sodium bicarbonate: 7.5-10%, sodium citrate: 0.5-1.5%, sodium hydroxide: 15-20% and the balance of deionized water.

6. A semi-blind rivet riveting process according to claim 1, wherein the total thickness of the rivet riveting can be up to 1.5-6 mm.

7. The riveting process of a semi-hollow rivet according to claim 1, characterized in that the pre-pressing pressure in step S1 is 4000- > 5000N.

8. A semi-hollow rivet riveting process according to claim 1, wherein the pressing pressure provided by the power source in step S2 is not less than 10000N.

Technical Field

The invention belongs to the technical field of alloy material processing, and particularly relates to a riveting process of a semi-hollow rivet for connecting an aluminum alloy section and an aluminum alloy casting.

Background

The existing new energy automobile is used for connecting the aluminum alloy cast end plate of the battery fixing structure with the section bar piece by adopting a laser welding process, but the welding process currently faces the following problems:

the surface of the aluminum alloy at high temperature is easy to form an oxide film, the oxide film is easy to absorb moisture in the environment, the moisture is decomposed to generate hydrogen during laser heating, the solubility of the hydrogen in liquid aluminum is about 20 times of that of the hydrogen in solid aluminum, the solubility of the hydrogen is sharply reduced when the liquid aluminum is converted into a solid state in the instantaneous solidification process of the alloy, and the hydrogen holes are formed if redundant hydrogen in the liquid aluminum cannot smoothly float upwards and overflow;

secondly, the keyhole collapses, the self gravity and the atmospheric pressure in the welding small hole are in a balanced state, once the balance is broken, the liquid metal in the molten pool cannot flow in time to fill and form an irregular hole, and researches find that the content of magnesium on the inner wall of the hole is about 4 times of that near the welding seam; the problem of hydrogen holes is more serious because the cooling speed of laser welding is too high, and holes generated due to collapse of small holes are also increased in the laser welding;

thirdly, hot cracks are formed, the aluminum alloy belongs to typical eutectic alloy, and the hot cracks are easy to occur during welding, including weld crystallization cracks and liquefaction cracks; generally, crystallization cracks appear in a weld zone, and liquefaction cracks appear in a near-weld zone; the crack sensitivity of 6000 series Al-Mg-Si alloy in aluminum alloy is large, the base metal is rapidly heated and cooled, and in the process of instantaneous solidification and crystallization, because of larger supercooling degree, crystal grains grow along the direction vertical to the center of a welding seam, and Al-Si or Mg-Si, Al-Mg are formed at the boundary of columnar crystal₂Low-melting point eutectic compounds such as Si and the like weaken the bonding force of crystal faces and are easy to generate crystal cracks under the action of thermal stress; welding on aluminium alloyIn the process, some low boiling point elements (Mg, Zn, Mn, Si and the like) are easy to evaporate and burn, and the slower the welding speed is, the more serious the burning is, so that the chemical composition of the weld metal is changed; because the composition segregation of the welding seam area can generate eutectic segregation and the crystal boundary is melted, a liquefied crack can be formed at the crystal boundary under the action of stress, and the performance of a welding joint is reduced;

welding through is easy, the aluminum has strong light and heat reflecting capacity, no obvious color change exists in solid and liquid state conversion, and judgment is difficult during welding operation; the high-temperature aluminum has low strength, difficult supporting of a molten pool and easy penetration;

therefore, a new process is needed to achieve better bonding of the alloy profile to the casting.

Disclosure of Invention

The invention aims to solve the problems in the prior art, and provides a novel semi-hollow rivet riveting process for connecting an aluminum alloy section and an aluminum alloy casting, which completely avoids the defects of air holes, hot cracks and the like generated by welding, and is high in riveting strength, safe and reliable.

The above object of the present invention can be achieved by the following technical solutions: a semi-hollow rivet riveting process for connecting an aluminum alloy section and an aluminum alloy casting comprises the following process steps:

s1, treating the surfaces to be riveted of the aluminum alloy section and the aluminum alloy casting;

s2, fixing the aluminum alloy profile subjected to surface treatment by using a blank holder, and simultaneously, vertically and downwards pre-pressing the aluminum alloy by using the rivet under the driving of a punch hammer;

s3, pressing the rivet under the action of a power source to pierce through the aluminum profile, and driving the aluminum profile to generate plastic deformation into the aluminum alloy casting by the rivet;

s4, gradually filling the aluminum profile into the casting part along with the riveting;

and S5, when the punch hammer presses the rivet down until the rivet head is in close contact with and level with the upper surface of the aluminum profile, the riveting is completed, the blank holder releases blank holding force, and the punch hammer returns to the initial station.

The invention adopts self-piercing riveting suitable for the aluminum alloy semi-hollow rivet to replace a welding process, under the combined action of the shape of the rivet leg and the projection of the casting part, the rivet leg expands to the periphery so as to form a mechanical interlocking structure between the rivet and the aluminum profile, the aluminum alloy casting part and the aluminum alloy profile are tightly combined, the riveting strength is high, and the defects of air holes, hot cracks and the like generated by the traditional welding are avoided.

Preferably, the aluminum alloy profile consists of the following components in percentage by mass: 8-12%, Mg: 1.4-3%, Sr: 0.05 to 0.5%, Mn: 0.8-2%, Cu: 0.1-0.7%, and the balance of Al and inevitable impurities. In the aluminum alloy section bar, Si forms Mg with Mg₂Si phase improves the mechanical property of the aluminum profile, and Cu can enhance the wear resistance of the aluminum profile and reduce intergranular corrosion. The aluminum alloy section has better comprehensive performance, but the components contain high-content low-melting-point Mg, Mn, Si and other components, the low-melting-point components are easy to evaporate and burn by adopting the traditional welding method, the chemical components of weld metal are changed, the component segregation in a weld zone can generate eutectic segregation to melt a crystal boundary, a liquefaction crack can be formed at the crystal boundary under the action of stress, and the defects can be completely overcome by adopting a riveting process to connect high-content low-melting-point aluminum alloy.

Preferably, the aluminum alloy casting comprises the following components in percentage by mass: 0.2-0.3%, Si: 1.4-1.6%, Mn: 0.05-0.2%, Cr: 0.1-0.5%, Zn: 0.1-0.4%, Ti: 0.1-0.2%, Sr: 0.2-0.3%, and the balance of Al and inevitable impurities. Similarly, the adopted aluminum alloy casting also contains more low-melting-point components, so that the aluminum alloy casting is not suitable for a welding process, the expansion coefficient of the aluminum alloy casting is relatively close to that of the aluminum alloy section, and when the aluminum alloy casting and the aluminum alloy section are used in a complex environment of the connecting piece, particularly in a high-temperature environment, the riveting part cannot expand or separate, and the good bonding strength can still be maintained.

Preferably, the riveting surface treatment of the aluminum alloy section and the aluminum alloy casting is as follows: and (3) putting the riveting surface in a degreasing solution at the temperature of 40-50 ℃ for degreasing treatment for 1-2h, then washing the riveting surface by using deionized water, and drying the riveting surface at the temperature of 100-120 ℃.

Further preferably, the degreasing solution comprises the following components in percentage by mass: sodium dodecylbenzenesulfonate: 0.5-1.0%, sodium bicarbonate: 7.5-10%, sodium citrate: 0.5-1.5%, sodium hydroxide: 15-20% and the balance of deionized water. In the preparation process of the aluminum alloy part, for better fusion of the components, a lubricant and a binder substance are generally added, and the additives are easy to burn into cohesive harmful substances under a high-temperature environment and can influence the use of the product after being removed in time, so that the riveting surfaces of the two aluminum alloy connecting parts are degreased to avoid the influence on the use performance of the product due to the occurrence of harmful bonding substances on the riveting parts, and the degreasing liquid is green and environment-friendly and has high degreasing efficiency.

Preferably, the total thickness of the rivet can reach 1.5-6 mm.

Preferably, the pre-pressing pressure in the step S1 is 4000-.

Preferably, the pressing pressure provided by the power source in the step S2 is not lower than 10000N.

The invention has the beneficial effects that:

(1) the invention adopts the self-piercing riveting of the semi-hollow rivet to replace the welding process, under the combined action of the shape of the rivet leg and the projection of the casting part, the rivet leg expands to the periphery so as to form a mechanical interlocking structure between the rivet and the aluminum profile, the aluminum alloy casting part and the aluminum alloy profile are tightly combined, the riveting strength is high, and the defects of air holes, hot cracks and the like generated by the traditional welding are avoided.

(2) The riveting process is suitable for connection of a new energy automobile aluminum alloy battery box, a frame, a support, an end plate, a battery cell and the like in a connection mode of fixing the new energy automobile aluminum alloy battery box, the frame, the support, the end plate, the battery cell and the like, and has the advantages of less investment and subsequent operation and maintenance funds, safe and reliable riveting strength, simple process, convenience in operation and great economic benefit compared with laser welding equipment.

Drawings

FIG. 1: the invention discloses a schematic diagram of a riveting process of an aluminum alloy section and an aluminum alloy casting;

FIG. 2 is a drawing: the riveting effect of the aluminum alloy section and the aluminum alloy casting is schematically shown;

FIG. 3: detailed schematic before riveting by a rivet;

FIG. 4 is a drawing: a detailed schematic diagram after riveting by a rivet;

reference numerals: 1-aluminum alloy casting, 2-aluminum alloy section bar and 3-rivet.

Detailed Description

The following are specific examples of the present invention and illustrate the technical solutions of the present invention for further description, but the present invention is not limited to these examples.

Example 1

Placing the riveted surfaces of the aluminum alloy section and the aluminum alloy die casting in a degreasing solution at the temperature of 40 ℃ for degreasing treatment for 1h, then cleaning with deionized water, and drying at the temperature of 100 ℃ for later use; the aluminum alloy section comprises the following components in percentage by mass: 8%, Mg: 1.4%, Sr: 0.05%, Mn: 0.8%, Cu: 0.1%, and the balance of Al and inevitable impurities; the aluminum alloy casting comprises the following components in percentage by mass: 0.2%, Si: 1.4%, Mn: 0.05%, Cr: 0.1%, Zn: 0.1%, Ti: 0.1%, Sr: 0.2%, the balance being Al and unavoidable impurities; the degreasing solution comprises the following components in percentage by mass: 0.5%, sodium bicarbonate: 7.5%, sodium citrate: 0.5%, sodium hydroxide: 15 percent of deionized water;

fixing the aluminum alloy profile subjected to the treatment by using a blank holder, and simultaneously, vertically and downwards pre-pressing the aluminum alloy profile at 4000N pressure by using a rivet under the driving of a punch hammer;

the power source applies 10000N to press the rivet downwards to pierce the aluminum profile, and meanwhile, the rivet drives the aluminum profile to generate plastic deformation into the processed aluminum alloy casting; gradually filling the aluminum profile into the casting part along with the riveting;

when the punch hammer presses the rivet down until the rivet head is in close contact with and flush with the upper surface of the aluminum profile, the riveting is completed, the blank holder releases blank holding force, and the punch hammer returns to the initial station.

Example 2

Placing the riveted surfaces of the aluminum alloy section and the aluminum alloy die casting in a degreasing solution at the temperature of 42 ℃ for degreasing treatment for 2 hours, then cleaning with deionized water, and drying at 105 ℃ for later use; the aluminum alloy section comprises the following components in percentage by mass: 9%, Mg: 1.8%, Sr: 0.2%, Mn: 1.2%, Cu: 0.3%, the balance being Al and inevitable impurities; the aluminum alloy casting comprises the following components in percentage by mass: 0.23%, Si: 1.5%, Mn: 0.1%, Cr: 0.2%, Zn: 0.2%, Ti: 0.15%, Sr: 0.21%, the balance being Al and unavoidable impurities; the degreasing solution comprises the following components in percentage by mass: 0.6%, sodium bicarbonate: 8%, sodium citrate: 1.0%, sodium hydroxide: 16 percent and the balance of deionized water;

fixing the aluminum alloy profile subjected to the treatment by using a blank holder, and simultaneously, vertically and downwards pre-pressing the aluminum alloy profile at 4500N pressure by using a rivet under the driving of a punch hammer;

the power source applies force to 11000N to press the rivet downwards to pierce through the aluminum profile, and meanwhile, the rivet drives the aluminum profile to generate plastic deformation into the processed aluminum alloy casting;

gradually filling the aluminum profile into the casting part along with the riveting;

when the punch hammer presses the rivet down until the rivet head is in close contact with and flush with the upper surface of the aluminum profile, the riveting is completed, the blank holder releases blank holding force, and the punch hammer returns to the initial station.

Example 3

Placing the riveted surfaces of the aluminum alloy section and the aluminum alloy die casting in a degreasing solution at the temperature of 45 ℃ for degreasing treatment for 2 hours, then cleaning the degreased surfaces by using deionized water, and drying the degreased surfaces at the temperature of 110 ℃ for later use; the aluminum alloy section comprises the following components in percentage by mass: 10%, Mg: 2.5%, Sr: 0.4%, Mn: 1.5%, Cu: 0.5%, the balance being Al and inevitable impurities; the aluminum alloy casting comprises the following components in percentage by mass: 0.25%, Si: 1.4-1.6%, Mn: 0.05-0.2%, Cr: 0.1-0.5%, Zn: 0.1-0.4%, Ti: 0.1-0.2%, Sr: 0.27%, the balance being Al and unavoidable impurities; the degreasing solution comprises the following components in percentage by mass: 0.5-1.0%, sodium bicarbonate: 7.5-10%, sodium citrate: 0.5-1.5%, sodium hydroxide: 15-20% and the balance of deionized water;

fixing the aluminum alloy profile subjected to the treatment by using a blank holder, and simultaneously, vertically and downwards pre-pressing the aluminum alloy profile at 5000N pressure by using a rivet under the driving of a punch hammer;

a power source is used for applying force 12000N to press the rivet downwards to pierce the aluminum profile, and meanwhile, the rivet drives the aluminum profile to generate plastic deformation into the processed aluminum alloy casting;

gradually filling the aluminum profile into the casting part along with the riveting;

when the punch hammer presses the rivet down until the rivet head is in close contact with and flush with the upper surface of the aluminum profile, the riveting is completed, the blank holder releases blank holding force, and the punch hammer returns to the initial station.

Example 4

Placing the riveted surfaces of the aluminum alloy section and the aluminum alloy die casting in a degreasing solution at the temperature of 50 ℃ for degreasing treatment for 1h, then cleaning the aluminum alloy section and the aluminum alloy die casting by using deionized water, and drying the aluminum alloy section and the aluminum alloy die casting at the temperature of 120 ℃ for later use; the aluminum alloy section comprises the following components in percentage by mass: 12%, Mg: 3%, Sr: 0.5%, Mn: 2%, Cu: 0.7%, and the balance of Al and inevitable impurities; the aluminum alloy casting comprises the following components in percentage by mass: 0.3%, Si: 1.6%, Mn: 0.2%, Cr: 0.5%, Zn: 0.4%, Ti: 0.2%, Sr: 0.3%, the balance being Al and inevitable impurities; the degreasing solution comprises the following components in percentage by mass: 1.0%, sodium bicarbonate: 10%, sodium citrate: 1.5%, sodium hydroxide: 20 percent of deionized water in balance;

fixing the aluminum alloy profile subjected to the treatment by using a blank holder, and simultaneously, vertically and downwards pre-pressing the aluminum alloy profile at 4800N pressure by using a rivet under the driving of a punch hammer;

a power source is used for applying force of 13000N to press the rivet downwards to pierce through the aluminum profile, and meanwhile, the rivet drives the aluminum profile to generate plastic deformation into the processed aluminum alloy casting;

gradually filling the aluminum profile into the casting part along with the riveting;

when the punch hammer presses the rivet down until the rivet head is in close contact with and flush with the upper surface of the aluminum profile, the riveting is completed, the blank holder releases blank holding force, and the punch hammer returns to the initial station.

The riveting process of the invention is also suitable for mixing dissimilar plates, such as galvanized, organic or precoated steel plates and aluminum-steel mixed plates or plastic-metal mixed plates.

The technical scope of the invention claimed by the embodiments herein is not exhaustive and new solutions formed by equivalent replacement of single or multiple technical features in the embodiments are also within the scope of the invention, and all parameters involved in the solutions of the invention do not have mutually exclusive combinations if not specifically stated.

While the invention has been described in detail and with reference to specific embodiments thereof, it will be apparent to one skilled in the art that various changes and modifications can be made therein without departing from the spirit and scope thereof.