02-25-2018, 07:00 AM
Professional knowledge of aluminum processing and production:
1. Causes and elimination methods of extruded product bubbles and peeling defects?
Bubble or peeling: a convex bubble on the surface of the product, usually seen in the head and tail, complete with a bubble, and a broken bark.
(1) extruded product bubbles and the causes of peeling.
extrusion cylinder, pressure pad wear out-of-tolerance, extrusion cylinder and the pressure pad size mismatch, and at the same time using two diameter difference exceeds allowable values of gasket;
The extrusion cylinder and the extrusion pad are too dirty, with oil, water, graphite, etc.
The lubricating oil contains water;
There is too much spatula on the surface, too deep; The surface of cast ingots has pores, sand holes, loose tissue and oil, etc.
... When replacing the alloy, the tube is not cleaned;
The temperature of the extruded cylinder and the temperature of the extruded ingot are too high;
‡ ingot casting temperature, size more than allow the negative deviation;
ˆ ingot is too long, fill quickly, ingot casting temperature, cause the drum fills, and so are not entirely within the cylinder exhaust, or improper operation, not execute exhaust process;
The design of the die is not reasonable, or the residual material is improper. The residual material in the shunt hole and the guide hole is partially brought out.
(2) the method of eliminating bubble and peeling of products.
container and dummy blocks with the size of the reasonable design; Check the size of the tool regularly to ensure that it meets the requirements. The extruded cylinder should be repaired in time, and the extrusion pad should not be too poor.
The surface of the caster is clean, smooth and dry.
When the alloy is replaced, the cylinder is completely cleaned;
... frequently check equipment and equipment to prevent excessive temperature and speed;
... Strict implementation of technical procedures and systems;
† reasonable design, manufacturing mold, diversion hole and diversion hole design into 1 ° ~ 3 ° slope;
‡ operation strictly, shearing residual material correctly and completely exhaust.
2. Causes and elimination methods of extrusion crack defects of extruded products?
Crush crack: the jagged (periodic), cracking or tearing of the edge of the extruded material or the thickness difference. Macroscopic and microscopic observation shows that there are more cracks at regular intervals, and the high strength aluminum alloy is prone to this cracking. When the extrusion temperature or extrusion speed is high, the extrusion material is embrittled at high temperature, and the angular radius is easy to produce.
(1) the cause of extrusion cracking of extrusion products.
extrusion wool temperature too high;
It's squeezing too fast;
The throttle valve is out of control;
The list of heating furnace fails;
... When the hole is extruded, the hole arrangement is too close to the center, so that the center metal supply is insufficient, so that the center and the side flow velocity are very different.
The design of the mold is not good;
‡ ingot homogenizing annealing is bad.
(2) elimination method of extruded product extrusion crack.
reduce extrusion temperature and extrusion speed;
To ensure the normal operation of the instrument and equipment;
The design of the mould design and elaboration, especially the transverse bridge, welding room and corner radius, should be reasonable. The edge radius of the extruded part is as large as possible;
... reduce Na content in high Mg alloys;
... The ingot is homogenized and improves the plasticity and uniformity.
3. Causes and elimination methods of shrinkage defects of extruded products?
The tail is the surface layer of the billet and the dirt attached to the extruded cylinder, or the lubricant, and the defects formed in the extrusion in the late extrusion. Metal discontinuous defects mostly ring or funnel-shaped. Because it is an internal defect, it can be found after corrosion. The shape of the extruded material is different and different, but most of them occur in the ring and the central part, and there is also the formation of tubular hollow holes. At the end of the extrusion, the center part of the billet gives priority to the surface layer of the billet. „
(1) the causes of the compression of the extrusion products.
scrap leave too short;
The end velocity is too fast or sudden;
The surface of the cast ingots is not clean, there is oil pollution, and there is no net segregation of the car.
The temperature of the extrusion cylinder is too high;
... The extrusion cylinder and the extrusion shaft are not correct;
The inner liner is not smooth or deformed in the extrusion cylinder, and the lining is not cleaned in time.
‡ dummy blocks size bad cooperation, gasket not cooling, surface with oil pollution or gasket anointed with oil.
(2) the elimination method of extruding products.
leave residual material according to the rules and cut the tail;
Keep the mould clean and clean;
To improve the surface quality of ingots;
The extrusion temperature and speed should be controlled reasonably, and the extrusion should be smooth.
... In addition to special cases, it is strictly prohibited to apply oil on the surface of the mold or mold.
The die gasket is cooled properly.
4. Causes and elimination methods for the defect of the extruded product?
Coarse grain ring: some aluminum alloy products from the low power inspection after quenching treatment, on the face grain sizes and grain surrounding the special thick, the defects of annular organization, the more close to the end of the greater depth of coarse grain ring.
(1) the causes of the extrusion of coarse crystal rings.
Uneven extrusion deformation, metal extrusion wall friction, deformation degree, grain serious breakage and heat treatment heating surface grain grew up and became thicker significantly;
The quenching temperature is too high or the heat preservation time is too long;
It is related to alloy composition and ingot.
(2) the elimination method of extruded product's coarse crystal ring.
extrusion cylinder wall smooth, form a complete set of aluminum, reduce the friction when extrusion;
The deformation is as uniform as possible (control temperature, speed, etc.);
Avoid quenching temperature too high;
() extruded by porous mold;
... Extrusion with anti-extrusion and hydrostatic extrusion;
The composition of alloy was adjusted to increase the recrystallization inhibition element.
‡ using high temperature extrusion;
ˆ some alloy homogenization processing, coarse grain ring shallow during extrusion.
1. Causes and elimination methods of extruded product bubbles and peeling defects?
Bubble or peeling: a convex bubble on the surface of the product, usually seen in the head and tail, complete with a bubble, and a broken bark.
(1) extruded product bubbles and the causes of peeling.
extrusion cylinder, pressure pad wear out-of-tolerance, extrusion cylinder and the pressure pad size mismatch, and at the same time using two diameter difference exceeds allowable values of gasket;
The extrusion cylinder and the extrusion pad are too dirty, with oil, water, graphite, etc.
The lubricating oil contains water;
There is too much spatula on the surface, too deep; The surface of cast ingots has pores, sand holes, loose tissue and oil, etc.
... When replacing the alloy, the tube is not cleaned;
The temperature of the extruded cylinder and the temperature of the extruded ingot are too high;
‡ ingot casting temperature, size more than allow the negative deviation;
ˆ ingot is too long, fill quickly, ingot casting temperature, cause the drum fills, and so are not entirely within the cylinder exhaust, or improper operation, not execute exhaust process;
The design of the die is not reasonable, or the residual material is improper. The residual material in the shunt hole and the guide hole is partially brought out.
(2) the method of eliminating bubble and peeling of products.
container and dummy blocks with the size of the reasonable design; Check the size of the tool regularly to ensure that it meets the requirements. The extruded cylinder should be repaired in time, and the extrusion pad should not be too poor.
The surface of the caster is clean, smooth and dry.
When the alloy is replaced, the cylinder is completely cleaned;
... frequently check equipment and equipment to prevent excessive temperature and speed;
... Strict implementation of technical procedures and systems;
† reasonable design, manufacturing mold, diversion hole and diversion hole design into 1 ° ~ 3 ° slope;
‡ operation strictly, shearing residual material correctly and completely exhaust.
2. Causes and elimination methods of extrusion crack defects of extruded products?
Crush crack: the jagged (periodic), cracking or tearing of the edge of the extruded material or the thickness difference. Macroscopic and microscopic observation shows that there are more cracks at regular intervals, and the high strength aluminum alloy is prone to this cracking. When the extrusion temperature or extrusion speed is high, the extrusion material is embrittled at high temperature, and the angular radius is easy to produce.
(1) the cause of extrusion cracking of extrusion products.
extrusion wool temperature too high;
It's squeezing too fast;
The throttle valve is out of control;
The list of heating furnace fails;
... When the hole is extruded, the hole arrangement is too close to the center, so that the center metal supply is insufficient, so that the center and the side flow velocity are very different.
The design of the mold is not good;
‡ ingot homogenizing annealing is bad.
(2) elimination method of extruded product extrusion crack.
reduce extrusion temperature and extrusion speed;
To ensure the normal operation of the instrument and equipment;
The design of the mould design and elaboration, especially the transverse bridge, welding room and corner radius, should be reasonable. The edge radius of the extruded part is as large as possible;
... reduce Na content in high Mg alloys;
... The ingot is homogenized and improves the plasticity and uniformity.
3. Causes and elimination methods of shrinkage defects of extruded products?
The tail is the surface layer of the billet and the dirt attached to the extruded cylinder, or the lubricant, and the defects formed in the extrusion in the late extrusion. Metal discontinuous defects mostly ring or funnel-shaped. Because it is an internal defect, it can be found after corrosion. The shape of the extruded material is different and different, but most of them occur in the ring and the central part, and there is also the formation of tubular hollow holes. At the end of the extrusion, the center part of the billet gives priority to the surface layer of the billet. „
(1) the causes of the compression of the extrusion products.
scrap leave too short;
The end velocity is too fast or sudden;
The surface of the cast ingots is not clean, there is oil pollution, and there is no net segregation of the car.
The temperature of the extrusion cylinder is too high;
... The extrusion cylinder and the extrusion shaft are not correct;
The inner liner is not smooth or deformed in the extrusion cylinder, and the lining is not cleaned in time.
‡ dummy blocks size bad cooperation, gasket not cooling, surface with oil pollution or gasket anointed with oil.
(2) the elimination method of extruding products.
leave residual material according to the rules and cut the tail;
Keep the mould clean and clean;
To improve the surface quality of ingots;
The extrusion temperature and speed should be controlled reasonably, and the extrusion should be smooth.
... In addition to special cases, it is strictly prohibited to apply oil on the surface of the mold or mold.
The die gasket is cooled properly.
4. Causes and elimination methods for the defect of the extruded product?
Coarse grain ring: some aluminum alloy products from the low power inspection after quenching treatment, on the face grain sizes and grain surrounding the special thick, the defects of annular organization, the more close to the end of the greater depth of coarse grain ring.
(1) the causes of the extrusion of coarse crystal rings.
Uneven extrusion deformation, metal extrusion wall friction, deformation degree, grain serious breakage and heat treatment heating surface grain grew up and became thicker significantly;
The quenching temperature is too high or the heat preservation time is too long;
It is related to alloy composition and ingot.
(2) the elimination method of extruded product's coarse crystal ring.
extrusion cylinder wall smooth, form a complete set of aluminum, reduce the friction when extrusion;
The deformation is as uniform as possible (control temperature, speed, etc.);
Avoid quenching temperature too high;
() extruded by porous mold;
... Extrusion with anti-extrusion and hydrostatic extrusion;
The composition of alloy was adjusted to increase the recrystallization inhibition element.
‡ using high temperature extrusion;
ˆ some alloy homogenization processing, coarse grain ring shallow during extrusion.