Resin sand thin-wall steel casting often produces cracks, deformation and other casting defects, the main reason is that the resistance of resin sand thin-wall steel casting is particularly large during the solidification and shrinkage process, so the process of resin sand thin-wall steel casting is different from that of general resin sand steel casting. The solidification of thin-wall steel casting should not only follow the principle of sequence solidification, but also take into account the principle of simultaneous solidification. In this way, it is necessary to reasonably open the pouring gate, arrange the cold iron and tensile steel, so that the resistance is reduced during the solidification and contraction of the thin-wall cast steel, the reasonable use of cold iron and tensile steel can eliminate the adverse effect of stress, avoid cracks and large deformation, and now only the process improvement of the box castings to summarize the process characteristics of the resin sand thin-wall cast steel. Changshu Hongqiao Casting steel Co., LTD. Customized steel casting Marine steel casting ABS Marine engineering service BOP casting steel cast
The box casting of an external machinery factory, the outline size of 1360×980×436, the basic wall thickness of 25/28mm, the first two pieces of work, due to the unreasonable process cracks, insufficient pouring defects, etc., so that the casting is scrapped, after the relevant personnel on the resin sand thin-wall steel casting process characteristics were studied, the box casting process has been improved. Compared with the original process, the improved process has the following characteristics:
one The sprue and the sprue are set separately to avoid the sprue doubling as the sprue, which makes the sprue not play a role, and to eliminate the insufficient expansion of the size of the inner frame of the casting due to deformation.
2. The position of the original tension bar is overlapped with the riser, and the anti-deformation effect of the tension bar is greatly increased by avoiding the tension bar from the riser.
3. The two open boxes into three open boxes, the runner into the step along the two parting surface into, the original runner is from the rib through the top pouring, due to the thin wall, the bottom of the box there is insufficient pouring phenomenon, and the molten steel through the newly opened runner uniform, smooth, sequential filling cavity, through the upper and lower step runner into the cast, coupled with the riser separation, the casting heat is not concentrated, Finally, the molten steel flows into the sprue through the top gate, and the casting first follows the principle of simultaneous solidification, and finally follows the principle of sequential solidification, which not only greatly reduces the tendency of casting deformation and cracking, but also obtains a denser casting.
4. At the four corners of the box, a 20-bar cold iron is added, which adds a cold iron to the vulnerable part to eliminate the crack there.
5. In order to make up for the lack of the larger size of the overall inner frame of the non-shrinking casting, the process correction amount of the inner frame was increased from the original 3mm to 5mm.
After the above process improvement, qualified castings were obtained.
Changshu Hongqiao Cast Steel Co., Ltd. mainly produces various specifications of carbon steel, high, middle and low alloy steel, stainless steel, heat-resistant steel, high manganese steel, high chromium cast iron. For petroleum, chemical industry, metallurgy, mining machinery, coal mining machinery, wind power, nuclear power, Marine and other industries to provide high-quality steel casting, and export abroad. Changshu Hongqiao Casting steel Co., LTD. Customized steel casting Marine steel casting ABS Marine engineering service BOP casting steel cast