Aluminum alloy is the main material of industrial large ceiling fans. Aluminum alloy has high strength, small specific gravity and thermal expansion coefficient, good plasticity, thermal stability, electrical and thermal conductivity, and process performance, certain high-temperature strength, high chemical activity of aluminum, easy to mix with Oxygen in the air forms a firm and dense film, which has certain corrosion resistance, can be processed under quenching state, and can be strengthened by heat treatment. It is widely used in the aerospace industry and civil industry.
Some aluminum alloy structural parts of industrial large ceiling fans are riveted with rivets, such as fan blades, frame frames, etc. The quality of the rivets directly affects the safety, reliability, stability, and life of the structural parts.
According to the performance of the aluminum alloy material of industrial large ceiling fans, it is necessary to reasonably select rivets of different aluminum alloy grades, conduct heat treatment of the rivets correctly and rivet into the structural parts strictly according to the specified time. Hard aluminum alloy rivets have high plasticity in the just-quenched state and are easy to rivet to produce thick plasticity. Riveting must be carried out within the time of retaining high plasticity in the quenched state to avoid riveting after age hardening. Hard aluminum alloy rivets are easy to age and harden after quenching, the hardness and strength increase, and the plasticity decreases sharply. In addition, when the rivet is riveted, the head is plastically deformed and hardened by cold work, which will easily lead to rivet cracking and reduce the aluminum alloy structural parts of the large ceiling fan. Quality and longevity, even accidents when using. The length of age hardening depends on the rivet material, and the riveting of rivets must be completed before age hardening.
There are 6 grades of hard aluminum alloy rivets commonly used: LY1, LY4, LY8, LY9, LY11, and LY12, here we will introduce and analyze their advantages and disadvantages one by one.
1. LY1 is the main material of rivets. The degree of supersaturation of a solid solution is low, and the insoluble second phase is less. Although it is a low-alloy, low-strength duralumin, it has high plasticity in the quenched state and good plasticity in hot or cold states. Good process performance and cold cutting performance, good spot welding performance, but chlorine arc welding tends to intergranular striae, corrosion resistance is not high, rivet riveting is carried out after quenching and natural aging, and the riveting process is not limited by heat treatment time. For structural parts with medium strength and working temperature <100°, the rivets are riveted into the structural part after surface anodization treatment or anodized together with the structural part after riveting. LY1 is a widely used rivet material.
2. LY4 has high shear strength and heat resistance, good cold cutting performance in the quenched aging state, poor cold processing performance in the annealed state, good plasticity in the annealed state and just quenched state that can be heat treated, and good plasticity in the 150-250 Intergranular corrosion tendency, low corrosion resistance. Structural rivets are used for medium strength and high working temperatures of 120-250°. Surface anodizing can improve the corrosion resistance of rivets or anodize simultaneously with riveted components. The quenching heating temperature is 500-510°C, after heat preservation, it is air-cooled and quenched, and the natural aging at room temperature is 120h. The rivets are riveted into the structural parts within 2-6 hours in the quenched state.
3.LY8 has higher shear strength and is used as a medium-strength rivet. The cold-cutting performance in the quenched aging state is still good, but the annealed state is poor. It can be strengthened by heat treatment, and its corrosion resistance is average. The corrosion resistance can be improved by anodizing or painting. It has better plasticity in the annealed state, just quenched state and hot state. The quenching heating temperature is 495.505 ° C, water cooling after heat preservation, and natural aging for 96 hours. Rivets are riveted into structural parts within 2 hours after quenching.
4. Alloy for LY9 rivets. Quenching aging cold cutting performance is still good, but the annealed state is poor, no matter in the annealed state, quenched state, or aging state and hot state, it has enough plasticity for riveting. Corrosion resistance is not high, rivets are anodized before riveting or anodized together with structural parts after bridging. It is suitable for the manufacture of rivets with higher strength and the working temperature is not higher than 100°C, and the service temperature is higher than 100°C, which tends to cause intergranular corrosion. The quenching heating temperature is 510-520°C, and water cooling after heat preservation, it can be artificially aged at 70-80°C, heat preservation for 24 hours, or natural aging at room temperature for 240 hours. Although the riveting process is not limited by the heat treatment time, it is best carried out in the quenched state.
5. LY11 is an early standard duralumin with medium strength and can be strengthened by heat treatment. It has good plasticity in the annealed state, just quenched state and hot state, and has good spot welding performance. Hydrogen arc welding tends to produce intergranular cracks. The cold-cutting performance of the quenched aging state is good, and the cold-working performance of the annealed state is poor. The corrosion resistance is not high, and the surface anodization treatment or painting method is required to improve the corrosion resistance. It is suitable for manufacturing medium-strength rivets with a working temperature of <100C. The quenching heating temperature is 495-510°C, water quenching after heat preservation, can be carried out at 155-165°C, heat preservation for 6-10h, artificial aging in air cooling, or natural aging at room temperature for 96h. Rivets shall be internally riveted into structural parts after quenching.
6. LY12 high-strength duralumin, in the annealed state, has medium plasticity in the just-quenched state and can be strengthened by heat treatment. The cold-cutting performance is better in the quenched aging state or after cold work hardening, and the annealed state is poorer. The spot welding performance is good, hydrogen arc welding tends to form intergranular cracks, and the corrosion resistance is not high. The surface anodization treatment or painting method of the rivet structure is often used to increase corrosion resistance. It is suitable for manufacturing rivets with high strength, high load, and service temperature of s150. Quenching heating temperature 595-505 ° C, water quenching after heat preservation. It can be kept at 185-195°C for 6-12 hours, air-cooled for artificial aging, or left at room temperature for 96 hours for natural aging. The nails should be riveted into the structural parts within 1.5h after the fire
Industrial large ceiling fan manufacturers need to choose aluminum alloy rivets that meet the technical requirements according to the performance of different fans. Some require high cutting strength, and some require high corrosion resistance. Generally speaking, LY4 and LY8 are more suitable for industrial large ceiling fans. Of course, if you choose the appropriate rivet material, you also need to master the heat treatment and process performance characteristics of the hard aluminum alloy rivet to ensure that the rivet head is thickened and hardened during riveting without cracks, and the structural parts of the industrial ceiling fan are safe. performance, reliability stability, and long life.