Solid casting in doubt, cooling, shakeout, cleaning, heat treatment, welding, handling and machining process, due to improper structure or treatment process stainless steel castings, and at a temperature, external and internal stress will deform, causing casting The shape and size does not match the pattern. Bracket elongated and irregular casting and shrinkage of large stainless steel castings, deformation is particularly serious.
Freedom correction correction method and mold correction, cold and hot correction correction points.
1. Free correction and mold correction
Freedom correction is cast on a stainless steel plate or on a dedicated simple jig, with a hammer until the size, shape to meet the requirements so far. Used for small pieces. Great casting is generally on the specified orthotic device to correct. Should have corrected before deformation of the casting, and casting with the necessary corrective part geometry and dimensions adapted to correct the mold, the mold is corrected in the casting mold is placed (on general points, lower die), and in selected pressure casting with the selected overall correction on straightening machine. When the overall correction, the general use of lifting equipment or robot loading or unloading the casting mold correction. Correction mold overall orthodontic needs specially designed and manufactured high precision, suitable for mass production lines, high production efficiency, low labor intensity, small size castings after correction bias.
2. Cold and hot correction correction
Correction is cold hammer, manual presses, jacks, friction or hydraulic press machine correct for normal casting. Suitable for simple geometry, a small amount of deformation, the small thin-walled castings, or plastic deformation of the large but well-cast aluminum alloy castings, and large deformation of quenched aluminum castings. When casting complex structure, it can be corrected by means of correction of the mold.
Thermal correction divided into local and overall heating two heating. Stainless steel castings more difficult when some cold correction, can be partially heated by hammering or press to correct. Large thick-walled castings correction should be heated as a whole, before correcting measured amount of deformation need to correct, and then put on the horns of the heat treatment furnace, pad proper pads, the load applied to the appropriate parts of the above require correction, in the heat treatment process With the load in the deformation corrective action will come. If, after the heat treatment, correction, should be to eliminate stress after tempering correction, correction of temperature and stress relief tempering heat treatment temperature should be lower than the tempering temperature 10-20 ℃. |
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