Requirements for machined castings

　　 1. The surface of the casting is not allowed to have cold partitions, cracks, shrinkage holes, penetrating defects, and serious incomplete defects, such as under-casting and mechanical damage;

　　2, the castings are not allowed to have casting defects such as cold partitions, cracks and holes that damage the use;

　　3. The castings should be cleaned up, and there should be no burrs, flashes, and the pouring riser on the surface of the pilot should be cleaned and flush with the surface of the casting;

　　4. The surface of the casting should be flat, and the gate, sand, burrs, etc. should be cleaned;

　　5. The casting characters and marks on the non-machined surface of the casting should be clear and identifiable, and the position and font should meet the drawing requirements;

　　6. The non-processed surface of the machine product castings needs to be shot blasted or roller treated to meet the requirements of Sa21/2 level of cleanliness;

　　7, the right and wrong type, boss casting deviation, etc. should be corrected to achieve a smooth transition to ensure the appearance quality;

　　 8. The roughness of the non-machined surface of the casting, the R value of sand casting shall not be greater than 50Um

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9. The castings have inclined parts, and their dimensional tolerances should be arranged symmetrically along the inclined plane;

　　 10. Castings should be cleaned of pouring risers and spurs, etc., and the pouring riser residues on the non-processed surface should be leveled and polished to meet the surface quality requirements;

　　11. The molding sand, core bone, core sand, fleshy, sticky sand, etc. on the castings should be smoothed and cleaned;

　　12. The molding sand, core sand and core bone on the casting should be cleaned up;

　　 13. The wrinkles on the non-processed surface of the casting should be less than 2mm in depth and more than 100mm apart;

　　14. Castings must be water toughened;

Heat treatment requirements for machining

　　 1. The parts are subjected to high frequency quenching, tempered at 350~370°C, HRC40~45;

　　2, after modulation treatment, HRC50~55;

　　3. Carry out high temperature aging treatment;

Machining tolerance requirements

　　1. The allowable deviation of the length dimension without indication is ±0.5mm;

　　2, the shape tolerance should meet the requirements of GB1184-80;

　　3. Casting tolerances are stacked on the basic size configuration of rough castings;