Infiltration technology of the hottest automotive

2022-08-24
  • Detail

Infiltration technology of automotive power system castings

in automotive power system castings and powder metallurgy parts, the existence of micropores will lead to leakage and affect the dynamic performance of vehicles. The infiltration technology introduced in this paper can play a role of densification and no leakage for all kinds of pressure castings, and plays an important role in improving the economic benefits of enterprises

micropores and infiltration of castings

generation and influence of micropores

pores are a phenomenon that occurs in materials, especially in metal parts during the casting process: shrinkage pores caused by volume changes in the process of changing from liquid to solid; Insufficient pressure state leads to liquid flow holes on the surface or inside; Pores caused by the interception of various gases in the mold. If some of the micro pores or defects that are difficult to be found by the naked eye are penetrated by gas or liquid, they will cause casting wall leakage or surface defects, so that the parts will lose their due functions in the process of use and affect the performance of the products; Noise will be produced during machining, which will accelerate the wear of cutting tools; Shorten the service life of castings. In addition, the increase of scrap rate affects the cost saving. Microporosity is also common in powder metallurgy manufacturing

casting infiltration

casting infiltration is to fill all micropores and interconnected air gaps of the casting with stable and flexible sealing materials (infiltration can cover micropores of 1/10000 mm to 0.5mm in size), so that the infiltrated part has resistance to heat, oil, chemicals or other external effects (such as vibration), and obtain high-quality surface treatment. The infiltration process will not lead to the change of the overall dimensions of the components that have been subjected to surface treatment and other processing procedures, or will cause any pollution to them, and can shorten the production time, improve the product quality, and reduce waste. It is a permanent solution for micropores and the best solution to save costs. At present, infiltration technology has been widely used and become an indispensable process in the casting process of automotive parts

typical infiltration castings of automotive power system, such as engine block color, cylinder head, crankcase, intake manifold, oil pump, nozzle, water pump, valve cover, gearbox housing, compressor, etc. The infiltration treatment can cover micropores with a diameter ranging from 1/10000 mm to 0.5 mm, and the pressure bearing capacity of the treated castings can reach the fracture strength of the castings

infiltration technology

infiltration technology mainly includes three elements: sealant, equipment and process flow

sealant

the performance of infiltration sealant directly affects the effect of infiltration. Traditional infiltration sealants, such as sodium silicate (also known as sodium silicate), are cheap, but their performance is poor - they are easy to crack when the temperature changes, and because of their high viscosity, they are attached to the surface of components, which is a serious waste. In addition, the production cycle is too long; Polyester has good sealing effect and good chemical corrosion resistance, but it contains toxins and harmful solvents, which is not easy to produce. These two sealants have gradually been replaced by high-quality sealants that are more effective and more environmentally friendly. British ultraseal international has more than 30 years of experience in providing complete infiltration technology, including high-quality sealants, modern infiltration equipment and unique and professional infiltration services. It took the lead in developing commercial methacrylate sealant, introduced higher quality pc504/66 sealant in 1970, and developed recyclable sealant ultraseal MX2 in 1987. Sinterseal 100, which can be directly obtained by ultraseal development, is especially suitable for powder metallurgy parts

the methacrylate pc504/66 sealant is cured under heating conditions, providing outstanding micropore filling ability with its low shrinkage during polymerization. At the same time, its low viscosity helps the sealant quickly and deeply penetrate into the micropores. The cured sealant can work normally in the range of -50 ℃ to 200 ℃. After continuous improvement, pc504/66 sealant has become a high-quality, efficient, stable and environmental friendly infiltration sealant, and has passed the U.S. military standard mil-i-17563c level 1 to 3 certification. It is the preferred sealant for aerospace and automotive engine infiltration treatment

equipment

the basic equipment required for vacuum infiltration mainly includes: vacuum infiltration tank, recovery infiltration agent tank, cold water cleaning tank, hot water curing tank, etc

vacuum infiltration process

there are many infiltration methods for parts, among which vacuum infiltration is the most commonly used infiltration process method for automotive powertrain castings. The main process includes four steps: microporous pretreatment, sealant injection, excess sealant removal, and sealant curing (see Figure 2)

microporous pretreatment: clean the workpiece to be infiltrated, and then dry it in vacuum

inject sealant: inject sealant into the tank containing the pretreated workpiece, and the sealant penetrates into the micropore of the workpiece through 10mbar vacuum

remove excess sealant: clean the excess sealant with cold water after emptying

curing sealant: immerse the workpiece in hot water at 90 ℃ to 95 ℃, and cure the sealant in the micropore after 10 minutes

according to the requirements of customers, infiltration can be completed before or after the mechanical processing of castings, and powder metallurgy parts should be carried out after sintering and before other processing. For power train castings with high requirements for accuracy and air tightness, automobile manufacturers such as Toyota, Honda and Daewoo of South Korea require that all castings be impregnated before machining, which can improve the machining performance of castings, prolong the service life of cutters and ensure product quality

modern infiltration treatment process

the disadvantages of traditional infiltration treatment are: long process cycle, delayed production, and produced a large number of products in process; Use static containers with large loads, basket packaging, labor-intensive, and polluting parts; A large amount of wastewater will be generated, which must be arranged in a remote place. The design focus of modern infiltration treatment process is: faster and consistent production cycle; Adopt production integration system; Improve the pretreatment process of parts; Non polluting parts; Reduce waste liquid; Be able to identify productivity improvements. Therefore, the current infiltration equipment has adopted automatic operation, including the whole infiltration process is also automatic control. Ultraseal adopts the rotary pretreatment method, which is characterized by: shortening the cycle (the vacuum infiltration system of ultraseal can complete the treatment of 3 to 5 batches of parts per hour), more effective drainage, adopting the filtration solution, and better heat transfer effect in the curing cycle, so as to optimize the infiltration process, improve production efficiency, achieve lean production (minimum WIP), and good parts pretreatment, No pollution when used in the factory

infiltration is equipped with flat jaw and large and small V-shaped jaw for tensile test. This analysis is selected

for the cast cylinder body blank, the most common method to ensure the safety of workers is: weathering treatment before machining; The cylinder block after weathering treatment must be subject to quality leakage inspection; If there is obvious leakage, the cylinder shall be scrapped; For example, slight leakage can be treated by infiltration. The cost of infiltration per cylinder is approximately $6 to $8. Take a V6 aluminum cylinder block weighing about 20 to 30 kg as an example. If it is impregnated, the cost-benefit analysis is as follows (see Table 1)

obviously, the quality of the cylinder block after infiltration treatment has been improved, the cost has been reduced, and the productivity has been improved. Therefore, infiltration technology is a thorough solution to the problem of casting microporosity. (end)

Copyright © 2011 JIN SHI