[CHINA ALUMINUM NETWORK] Smelting and pouring of alloys is a major part of casting production. Strictly controlling the entire process of smelting and casting plays an important role in preventing casting defects such as pinholes, inclusions, undercasting, cracks, porosity, and shrinkage.
Due to the large tendency of aluminum melt to absorb hydrogen, strong oxidizing ability, and easy dissolution of iron, it is necessary to adopt simple and prudent precautions in the smelting and casting process to obtain high-quality castings.
First, aluminum alloy charge sneer and quality control In order to smelt a high-quality aluminum melt, first of all should use qualified raw materials. The raw materials must be subject to scientific management and appropriate treatment, otherwise it will seriously affect the quality of the alloy. The production practice proves that the poor control of raw materials (including metal materials and auxiliary materials) will cause the castings to be scrapped in batches.
(1) Raw materials must have qualified chemical composition and organization. Specific requirements are as follows:
In addition to the analysis of the main components and impurity content of the alloy ingots, they are still inspecting low accompaniment and fractures. Practice has proved that the use of a liquid containing a serious shrinkage, pinholes, and air bubbles, it is difficult to obtain a dense casting, and even cause the entire furnace, the entire batch of castings scrapped.
Someone was studying the effect of aluminum-silicon alloy ingots on the pinholes of aluminum alloys. It was found that pinholes did not appear when using melted pure cast sand-type test pieces. When adding low-tissue and unqualified aluminum-silicon alloy ingots, the pinholes of the test pieces were Serious and large grains. The reason is due to the heredity of the material. Al-Si alloys and hereditary properties increase with the increase of the content, and when the amount of silicon reaches 7%, the heredity is significant. Continue to increase the silicon content to the eutectic composition, and the heritability decreases slightly. In order to solve the casting defects caused by the inheritance of the charge, aluminum ingots, intermediate alloys and other charge materials with high metallurgical quality must be used. The specific criteria are as follows:
(1) There should be no pinholes on the fractures, and the pinholes of the stomata should be within three grades. Partial (not exceeding 25% of the examined area) should not exceed three grades. Those who exceed three grades must adopt remelting methods to reduce needles. Porosity. The remelting refining method is the same as general aluminum alloy smelting. The casting temperature should not exceed 660°C. For those aluminum ingots, alloy ingots, etc. with large primary crystal grains, the lower ingot temperature should be used to rapidly solidify them. grain.
(II) Before the charge processing charge is used, it should be blown with sand to remove surface rust, grease and other dirt. The aluminum alloy ingots and metal return materials with relatively clean surfaces may not be blown, but the iron filters and inserts mixed in the charge should be eliminated. All charge materials should be pre-heated before entering the furnace. Heat to remove the attached surface moisture and shorten the smelting time to more than 3 hours.
(3) The management of the charge and the reasonable preservation and management of the charge are of great importance to ensure the quality of the alloy. The charge should be stored in a dry, dry warehouse.
Second, the preparation of helium and smelting tools (a) å©åŸš commonly used casting aluminum alloy shovel, can also be used to cast steel and steel plate welding å©åŸš.
The new sorghum and long-term unused sorghum should be blown before use, and heated to 700--800 degrees for 2 to 4 hours to burn off the moisture and combustible substances attached to the inside wall of the sampan and cool to 300. When the temperature is lower, carefully clean the inside of the crucible and spray the paint at a temperature not lower than 200 degrees.
å©åŸš Before use, warm up to dark red (500--600 degrees) and keep warm for more than 2 hours. Before the new crucible is smelted, it is better to first melt the return material of the same brand.
(II) Preparation of Melting Tools Bell jars, pressure scoops, stirring spoons, pouring molds, etc. shall be preheated before use, and protective coatings shall be applied at a temperature of 150°C to 200°C and thoroughly dried. The drying temperature is 200--400 degrees, and the holding time is more than 2 hours. After use, the oxides and fluorides adhered to the surface should be completely removed (better to blow sand).
PRODUCT NAME:Aluminum Phosphate, Aluminum Metaphosphate ,Potassium Silicate Curing Agent,Aluminum Phosphate Crystal
PRODUCT TYPE:High Temperature Materials, Binder
PRODUCT APPEARANCE:White Powder
CHEMICAL CLASS:AlPO4
CAS No．:7784-30-7.
PRODUCT APPLICATION:It can solidify potassium silicate (other name: potassium water glass) at room temperature. It is mostly used as binder and curing agent in the production of Hi-Temp Refractory Materials for kiln. It also serves as fluxing agent in the production of special glass, as binder in fabrication of ceramics or tooth, and so on.
Aluminum phosphate adhesive has excellent heat-resistance and weather-resistance, not only a widely used adhesive in refractories, it`s also an importantingredient in inorganic coatings(such as powder coating). It also used in the production of siliceous,high-aluminum,magnesian,siliconcarbide and oxides of concrete.
TECHNICAL DATA
|
Test Items |
Technical Parameters |
|
Appearance |
White Powder |
|
The PH Value |
2-4 |
|
Residue on sieve(45um)% |
≤0.5% |
|
P2O5 % |
60-70 |
|
Al2O3 % |
25-35 |
STANDARD PACKAGING: 25kg/bag, Plastic-lined and plastic-coated woven bags or Composite paper bags.
TRANSPORT AND STORAGE
Protect against weathering and exposed under the blazing sun. Store in a cool,dry place and avoid extreme fluctuations in temperature.
Special conditions for opened packaging: Close bags after use to prevent the absorption of moisture and contamination.
Condensed Aluminum Phosphate
Condensed Aluminum Phosphate,Aluminum Phosphate Binder,Aluminum Phosphate White Powder, Refractory Matter Aluminum Phosphate,Aluminum Phosphate Crystal
shijiazhuang city xinsheng chemical co.,ltd , http://www.xsphos.com