JB/T 5354-1991 Die-casting process guide for aluminum castings for power tools JB/T5354-1991 Standard download decompression password: www.bzxz.net

Mechanical Industry Standard of the People's Republic of China
Guidelines for Die-casting Process of Aluminum Castings for Power Tools
1 Subject Content and Scope of Application
JB/T5354-—1991
This standard specifies the selection of materials, equipment, die-casting mold requirements and die-casting process for aluminum alloy die-castings for power tools. This standard applies to the cold chamber pressure casting production of aluminum alloy castings for the production of power tool housings. 2 Reference standards
GB8733
Casting aluminum alloy ingot (replacement of YB143-75)GB4457.3
Mechanical drawing
JB2702
Technical conditions for zinc alloy, aluminum alloy and copper alloy die castingsJB/Z187.3Format and filling rules of process specifications3 Preparation of main materials
The selected aluminum alloy should have the following characteristics:
Good flowability, and can obtain castings with clear contours and good surface quality: b.
Good demoulding performance;
The shrinkage rate (linear shrinkage, volume shrinkage) should be small, and the castings are not prone to defects such as cracks, shrinkage holes, looseness, etc.; d.
It has high mechanical properties and good wear resistance; e.
It has good cutting performance;
It has strong corrosion resistance.
3.2 Acceptance of aluminum alloybzxz.net
The acceptance of raw materials entering the warehouse must be done well, and the inspection and acceptance should be carried out in accordance with the provisions of GB8733. 4 Equipment selection
The selection of die-casting machines is mainly determined by factors such as the size of the projection area of ​​the casting (including the pouring system), the location of the gate, the mold structure, convenient operation and maintenance, and high production efficiency, and has a secondary or higher injection function. The alloy melting furnace and alloy holding furnace should be able to meet the requirements of: low energy consumption, less impurity infiltration of alloys that are not easy to oxidize, good insulation performance, convenient operation, safety and reliability, long life, and high economic benefits, and have automatic temperature control devices. 5 Requirements for die-casting molds
5.1 The die-casting mold should have sufficient rigidity and will not deform under the impact of high-pressure and high-speed metal liquid flow. 5.2 The position of the die-casting mold installation structure on the die-casting machine should be consistent with the specifications of the die-casting machine and can be reliably fastened. 5.3 The total thickness of the mold must meet the minimum mold spacing and maximum mold opening distance of the selected die-casting machine. 5.4 The surface roughness parameter Ra value of the mold core cavity is: 0.4μm, and the surface roughness parameter Ra value of other mold surfaces is: 0.8μm. 5.5 The main parts of the mold should be heat treated to achieve the required hardness and strength. 5.6 After the fixed and movable molds are closed, the local gap between the parting surfaces should be less than 0.05mm5.7 The molding part of the mold should have a reasonable demoulding slope. The minimum demoulding slope is recommended in Table 1.6
Minimum demoulding slope of the matching surface
External surface of the same part
0°15'
Processability of die casting structure
Choice of wall thickness
Inner surface of casting
0°30°
JB/T5354-1991
Minimum demoulding slope of non-matching surface (or processed surface)External surface of casting
Inner surface of casting
The choice of wall thickness of die casting is closely related to the forming quality of the casting. When the wall is too thin, the filling conditions are poor and the forming of the part is difficult. When the wall is too thick, it is easy to produce pores and shrinkage holes. Table 2 Recommended wall thickness values ​​for die castings. Table 2
Maximum wheel size
>25~100
>100～500
6.2 Setting reasonable casting fillet
Setting reasonable fillet for castings not only improves the rigidity of castings and prolongs the life of molds, but also facilitates filling and forming. Therefore, reasonable casting fillets should be set at the intersections between casting surfaces and the structure of designed ribs without affecting the assembly quality. The calculation of casting fillet radius (R, r) is shown in Table 3.
Thickness of two connected walls
Equal wall thickness
Different wall thickness
(h
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