Copper castings play a huge potential role in the devel […]
Copper castings play a huge potential role in the development of modern technology, whether it is spacecraft entering space or intelligent robots entering the deep sea; whether it is the renewal of computer equipment, or the rapid development of engineering science and technology, it is inseparable Use and support of high quality castings. Most cast copper alloys (cast copper parts 4) are not heat treated and strengthened, but are used in the as-cast condition. However, there are also a few cast copper alloys that are used after heat treatment, such as beryllium bronze, chrome bronze, silicon bronze, and some high copper alloys. In addition, aluminum bronze with ω(Al) ≥ 9.4% can improve its mechanical properties, especially corrosion resistance, to some extent after proper heat treatment.
The heat treatment of the copper alloy cast copper alloy of crusher can be divided into: 1. The purpose of stress relief annealing is to eliminate the internal stress generated after casting and repair welding. 2. Intensified heat treatment, including solution treatment and aging treatment, aims to improve the physical properties, mechanical properties and corrosion resistance of the alloy. 3. Heat treatment for eliminating casting defects Casting tin bronze When heated to 400-500 ° C, the δ phase between the α dendrites diffuses into the α phase, causing the volume expansion of the alloy, thereby blocking the microscopic shrinkage of the tin bronze, improving Its pressure resistance.
Generally, a copper sleeve is used as the bearing on the gear pump. Before assembling the copper sleeve, the surface condition of the copper sleeve and the pump body should be checked first, and the interference should meet the requirements, then the outer circle should be coated with lubricating oil and pressed into the end cover bearing chamber. Sometimes, in order to prevent rotation, it is fixed by screws. If the matching clearance is not suitable, the scraping correction can be performed to achieve the specified standard. The matching clearance is generally (0.01~0.02)d, and d is the diameter of the journal.
After extrusion processing, the hardness of the pressed surface of the copper sleeve is improved, and the structural density of the material is increased. Therefore, the extruded steel sleeve can more than double the service life compared to the boring steel sleeve.
The use of extrusion processing saves labor and time, reduces consumption, reduces labor intensity, and work efficiency is five times that of boring processing. The surface roughness value Ra after extrusion processing does not exceed 0.02 mm, and the roundness, cylindricity and dimensional tolerance of the inner hole of the copper sleeve meet the requirements, and are more stable and reliable than the quality of the boring processing.
Sand casting is the most common method used in production. It has the advantages of wide adaptability and simple production preparation. However, the dimensional accuracy, surface quality and internal quality of castings produced by this method are far from meeting the requirements of mechanical parts, and the production process is more complicated. The mechanization and automation of production are huge, and some special parts and special technical requirements are produced. When casting, the technical and economic indicators are low. Therefore, the application of sand casting in casting production has been limited.