Ingots in the production of aluminum alloy ingots, whether ingots or ingots, often suffer from porosity and porosity defects. Swelling and loosening, like twin sisters, often accompany each other and cause many problems for aluminum processing. A circular hole in the aluminum alloy ingot structure is called a blowhole. It is a bubble defect in which the gas precipitated during the cooling and solidification of the metal liquid remains in the ingot. Looseness is in the process of solidification of the aluminum alloy ingot structure. Due to the aluminum alloy in the liquid state and the solidification process, the volume is not compensated in the contraction to produce a dispersion hole.
The main factor of pore formation: In the dissolved melt gas is saturated, there is a large amount of non-metallic inclusions in the solution, the gas floats slowly during the casting process, then the bubbles will stay in the ingot to produce pores. The causes of air holes are as follows: 1. The raw materials are moist, oily, and watery. 2. Furnace overhaul or repair. Incomplete drying after long-term shutdown. 3. The melt is overheated in the furnace. 4. The smelting time is too long. 5. The tool is completely dry at the end. 6. The quality of the lubricant is not good. 7. The gas moisture is too large.
Looseness is generally divided into two types: one is the loosening generated between the shrinkage, and the other is the loosening formed by removing the dissolved gas at the end. The main factors for the formation of porosity and the gas content of the melt are related to the size, shape, and structure of the overlying band during ingot formation. There are several reasons for the analysis of looseness: 1. The gas content in the melt is too high; 2. The melt is overheated; 3. The oven is not complete. The shutdown time is too long; 4. The strength is low but the casting speed is too fast. ; 5 Casting temperature is too low; 6. Tools and refining gas. Solvent and other wet or incomplete; 7. Funnel supply uneven; 8. High magnesium alloy coverage is not good.
Aluminum alloy ingot porosity and porosity is one of the most common defects, aluminum alloy melting and casting technology (process specification); are developed around the pore and loose defects. How to solve the problem of stomatal and loose defects? Here are some examples that may give you some inspiration. Case 1. There is an aluminum processing company in the north. When the furnace is repaired and ovend, the thermocouple malfunctions. It is mistaken for the time to reach the oven and it is put into production in advance. As a result, all 4 furnace products are scrapped. The reason is simple (stomatal. Loose). In order to reduce losses, the smelting technicians took a few measures to brainstorm: 1) Transfer of solid materials into liquid materials (shortening of smelting time) 2. Control of chemical composition of impurity content (reduction of non-metallic inclusions) 3. Enhancement of refining degassing 4 It is to change the original small ingot specifications to large ingots (to reduce the casting speed and change the oversize dimension) to avoid losses.
From the above cases, although the incident has passed for more than 30 years, it has provided invaluable data and lessons for our exploration and development of aluminum processing. Summary: 1. The use of liquid feed reduces the residence time of the metal in the oven, allowing the gases in the oven to be released and decomposed under the effect of unsaturation. 2. Strengthen the control of component impurities and effectively reduce the increase of non-metallic inclusions. 3. Effective degassing refining, 4. Casting temperature upper limit, 5. Reduce the casting speed to change the structure of the liquid transition zone, so that the remaining gas has enough space to float, 6. The formulation of the casting process technology is not static, Under special circumstances, decisive use of plans to prevent the occurrence of product quality defects.
The main factor of pore formation: In the dissolved melt gas is saturated, there is a large amount of non-metallic inclusions in the solution, the gas floats slowly during the casting process, then the bubbles will stay in the ingot to produce pores. The causes of air holes are as follows: 1. The raw materials are moist, oily, and watery. 2. Furnace overhaul or repair. Incomplete drying after long-term shutdown. 3. The melt is overheated in the furnace. 4. The smelting time is too long. 5. The tool is completely dry at the end. 6. The quality of the lubricant is not good. 7. The gas moisture is too large.
Looseness is generally divided into two types: one is the loosening generated between the shrinkage, and the other is the loosening formed by removing the dissolved gas at the end. The main factors for the formation of porosity and the gas content of the melt are related to the size, shape, and structure of the overlying band during ingot formation. There are several reasons for the analysis of looseness: 1. The gas content in the melt is too high; 2. The melt is overheated; 3. The oven is not complete. The shutdown time is too long; 4. The strength is low but the casting speed is too fast. ; 5 Casting temperature is too low; 6. Tools and refining gas. Solvent and other wet or incomplete; 7. Funnel supply uneven; 8. High magnesium alloy coverage is not good.
Aluminum alloy ingot porosity and porosity is one of the most common defects, aluminum alloy melting and casting technology (process specification); are developed around the pore and loose defects. How to solve the problem of stomatal and loose defects? Here are some examples that may give you some inspiration. Case 1. There is an aluminum processing company in the north. When the furnace is repaired and ovend, the thermocouple malfunctions. It is mistaken for the time to reach the oven and it is put into production in advance. As a result, all 4 furnace products are scrapped. The reason is simple (stomatal. Loose). In order to reduce losses, the smelting technicians took a few measures to brainstorm: 1) Transfer of solid materials into liquid materials (shortening of smelting time) 2. Control of chemical composition of impurity content (reduction of non-metallic inclusions) 3. Enhancement of refining degassing 4 It is to change the original small ingot specifications to large ingots (to reduce the casting speed and change the oversize dimension) to avoid losses.
From the above cases, although the incident has passed for more than 30 years, it has provided invaluable data and lessons for our exploration and development of aluminum processing. Summary: 1. The use of liquid feed reduces the residence time of the metal in the oven, allowing the gases in the oven to be released and decomposed under the effect of unsaturation. 2. Strengthen the control of component impurities and effectively reduce the increase of non-metallic inclusions. 3. Effective degassing refining, 4. Casting temperature upper limit, 5. Reduce the casting speed to change the structure of the liquid transition zone, so that the remaining gas has enough space to float, 6. The formulation of the casting process technology is not static, Under special circumstances, decisive use of plans to prevent the occurrence of product quality defects.