For example, reducing the diameter of the lll-reducing feeder and strengthening the feeding of the feeder is an important technical measure to prevent the casting from producing shrinkage defects. Statistics show that after the casting solidifies, the shrinkage volume of the ordinary riser only accounts for 1014% of the riser volume, and only 6%~10% of the volume is actually used for feeding the casting. 11. Insulation riser can increase the feeding efficiency of the riser. Increased to 20%~25% 12. The combination of heat preservation and heat generation constitutes a heating and heat riser, which can increase the feeding efficiency of the riser to 45%. 11. The metal subsidy process for steel castings also widely uses thermal insulation subsidies and heat insulation. Subsidies, and with the development of thermal insulation and heating materials, thermal insulation subsidies and thermal insulation subsidies have gradually replaced metal subsidies. This will not only improve the casting process yield and yield, but also eliminate the need for cutting metal subsidy processes, reduce energy consumption, to avoid cracks due to cutting subsidies, as well as uneven cutting marks on the subsequent processing. This article describes the application of thermal insulation, heat insulation, riser and steel casting insulation subsidies and heating and thermal insulation subsidies.
1 Insulating Riser China began researching insulation risers in the 1970s. 121. There are currently hollow microspheres 31, hollow microspheres-expanded perlite 14, and composites composed of inorganic refractory fibers, organic refractory fibers, and refractory aggregates. Type 151 and other types of insulated feeders are used in production.
1.1 Application Example of Insulating Riser The application of heavy-duty casting steel castings on sea stern sleeves requires a compactness of 1700 kg. Trial production using lost foam casting, negative pressure 0.04MPa, injection process. A Y-shaped insulated feeder of 280mm X 420mm X 360mm was installed at the top of the casting. The in-situ sprue was an inner diameter of 060mm refractory burning pipe. The cross-sectional area of ​​the upper and lower inner burning channels was 30mm, and the upper inner pouring spout was inclined upward by 30° (eg). After pouring, hold pressure for 10 minutes, and then box after 6 hours. After pouring the riser, the riser receives the date: 2008-0 column 1; revision date: 200i - casting quality control.
450m2 sintering machine body material QT50C-7, weight 4 480kg contour size 5 465mm original process rice with normal top feeder feeding. As the top of the riser is first solidified and crusted, the unreasonable temperature distribution of the upper cooling and lower heating is caused, the physical thermal node in the riser is lowered to the root of the riser, and the actual hot section of the casting is increased, due to the solidification of the riser prior to the casting. The final solidified hot spot is not properly replenished, and the gas migrates therein, causing the casting to produce shrinkage, shrinkage, and porosity defects.
Insulation riser made of microbead insulation material instead of the ordinary riser eliminates the above-mentioned defects of the casting in the riser root and increases the production process by 8%. 8.(3) Application on cast steel rolls Hollow microbead insulation Mouthpieces instead of ordinary risers for the production of cast steel risers Reinforce exhaust for insulting darker risers: Reduce liquid flow shing a solidification; Reliance on the thermal insulation properties of insulation Keep the heat in the riser bookmark4(4) at 150 Manganese steel mining gold bucket casting application material is ZGMnl3, weight 670kg using expanded perlite - hollow micro-beads composite insulation riser, set in the front axle hole 2 size 180mmX160mmX300mm insulated riser, in the lip part 2 Only size 150mmX 300mm insulation riser, such as the insulation riser size is 85% of the size of ordinary riser three-dimensional space volume is 1/2 of the ordinary riser process yield from the original 61.6% to 75%, feeding The efficiency is increased from 12% to 20%~25%. 41. 1.2 Precautions for the use of heat riser When using a seat, a gating system with a combination of a sprue, a runner, and an in-gate is used. The top of the runner is placed. 1 Insulated riser 300mm in diameter, as shown. As the molten metal enters the cavity, the high-temperature air stream decomposes and separates the insulating riser material, falls back into the molten metal, and flows into the casting body to form inclusions or even pores. The simulated state is as follows. The test verified the authenticity of the simulation. Therefore, during the design of the casting process, the flow of the pouring system should be avoided as far as possible. The insulation covering agent and the heat-generating covering agent are used to directly insulate the insulation. The heat-removing covering agent is used to reduce the heat dissipation rate on the side of the riser. The riser covering agent is used to reduce Riser cooling speed. Studies have shown that covering an ordinary riser with an insulating agent can increase the solidifying time of the riser by 1 time, and covering the insulating riser with a heat insulating agent can prolong the solidification time by a factor of 1111. The main function of the riser coverage is to reduce the top surface radiation and Convective heat losses, research and production practices have proved that during the solidification of the riser, 55% of the total heat is lost by the radiation from the top of the riser. Obviously, insulation material is added to the insulation cover material and heat material is added to form the insulation. Rising heat coverage.
2.1 The application of heat covering agent in the application of large steel castings on the rudder rudder arm ~157t, casting wall thickness changes greatly, almost all surfaces are curved, the streamline shape, each section size is not the same, in the casting production Easy to produce shrinkage. The use of covering agent to produce 4 pieces of rudder arm steel weighs over 80t, the surface is smooth, all ultrasonic testing and magnetic particle testing are qualified, meet the technical requirements, reduce the size of the riser, the process yield rate increased by 3% in After the necessary assumptions, using the Fourier heat conduction differential equation, the aluminum silicate fiber type thermal insulation subsidy block with good insulation effect, high subsidy intensity and stable subsidy effect was obtained: 19 databases (websites) of “Casting Technology†were included. Core Journals Database China Science Citation Database China Academic Journals Comprehensive Evaluation Database China Science Papers Statistics and Analysis Database China Science Papers and Citation Database China Metal Dismantling Database China Metallurgical Literature Dismantlement Database China Science and Technology Journal Title Database China Science and Technology Periodical Database USA "Chemical Textual Evacuation" (CA) Database United States "Textual Evacuation (MA) Database" Huayi Digital Art Co., Ltd. Databases China Academic Journals Digest (English) Database China Journal Net (http:(Chongqing) Weipu Information Network China Newsletter Subscription Guide Information Library Journal 4.2 Steel Castings Thermal Insulation Subsidy In the 1980s, China introduced a casting material technology with a heating subsidy. 171. Domestic research and production applications showed that 1181, using microbeads as insulation material, high-alumina bauxite clinker as refractory aggregate, with Al> Ninety-seven percent of aluminum-silver paste is used as a heat-generating material, and a heat-preserving material (B23) containing Fe23>95% industrial pure iron oxide and sodium nitrate (NaNOO as an oxidant, water glass, and modified polyvinyl alcohol (PVA) as a binder, is used. ), Comparison of low-heat insulation material (DFB) and high heat insulation material (GFB) made of the subsidy block, and cast in situ with ZG45 gear castings with cylinder and T-shaped structure, B, DFB, GFB three The subsidy block, its wet compressive strength, dry compressive strength, density, refractoriness and ignition temperature can meet the requirements of the steel castings insulation or heating and thermal insulation subsidies. From the comprehensive effect, the DFB effect is better.
5 Conclusion Insulation and heat insulation riser casting process designers in the process design to use one of the technological measures. This article lists its successful use in several castings. In order to improve the quality of the casting company's products and energy-saving emission reduction work in depth.
From the perspective of improving China's casting process, energy conservation, and consumption reduction, it is recommended that foundry companies, foundry materials companies, universities, and research institutes should cooperate closely to increase applied research in this area.
Accelerate the research and development of quality standards for heat preservation and heat insulation riser sets and subsidy blocks, and standard quality inspection methods.
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