Forming method for medium-high-speed high-power diesel nodular cast iron flywheel

Abstract

The invention belongs to the technical field of cast iron casting, and discloses a forming method for a medium-high-speed high-power diesel nodular cast iron flywheel. The forming method comprises thesteps: a pouring position is selected, a casting placed in a lower mold, a large plane faces upwards, molding is conducted through a real sample mold, parting is conducted from the maximum plane, andingates are uniformly distributed around the casting in a short, thin and wide form, and a slag collecting ladle is arranged at the tail end of a cross gate; and then through pouring system design, pouring system layout, chiller arrangement, riser arrangement, computer simulation and final melting process design, pig iron and scrap steel are selected, a long-acting inoculant and a nodulizing agent are adopted, chemical components, the size and shape of graphite nodules and the grain size of residual free cementite and ferrite are controlled, and a good ferrite matrix structure is obtained. According to the forming method, the mechanical performance requirements of a medium-high-speed high-power diesel nodular cast iron flywheel iron casting can be effectively met, and casting defects suchas slag inclusion, shrinkage porosity, coarse defect structures and graphite floating are not found.

Description

technical field [0001] The invention belongs to the technical field of cast iron casting, and in particular relates to a molding method for a nodular cast iron flywheel of a medium-high-speed and high-power diesel engine. Background technique [0002] At present, the flywheel of a diesel engine is an important part of a diesel engine, and the maximum size of the part is: φ 1107×298mm. The material is QT400-15, the main thickness of the casting is greater than 100mm, the maximum hot pitch circle diameter is φ150mm, the blank weight is 1100Kg, and the liquid weight is about 1600Kg. Tensile strength: σb>400[N / mm2], σ0.2>250[N / mm2], elongation δ>15%, Brinell strength: 130~180HBs, metallographic structure: ferrite≥90% . Ultrasonic inspection is carried out before drilling, and no defects are allowed. Magnetic particle inspection after drilling is prone to problems such as slag inclusion, shrinkage porosity, coarse structure, and graphite floating defects. [0003] Th...

AI Technical Summary

Problems solved by technology

Magnetic particle inspection after drilling is prone to problems such as slag inclusion, shrinkage porosity, coarse structure, and graphite floating defects

[0003] Through the above analysis, the existing problems and defects of the prior art are: the existing diesel engine flywheel is drilled and subjected to magnetic particle inspection, which is easy to cause slag inclusion, shrinkage porosity, coarse tissue, and graphite floating defects

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