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高温、高压的主蒸汽首先进入自动主汽门。它的任务是一旦汽轮机出现故障要迅速可靠地切断主蒸汽汽源迫使机组停止运转。因此,保证铸件质量对实现汽轮机安全可靠地运行具有十分重要的意义。十万瓩机组主汽阀壳是用ZG20CrMoV珠光体低合金耐热钢铸造的。毛重5100公斤,轮廓尺寸1400×1675×1450。此件结构较复杂,因此给模型制造及造型操作带来了一定的困难。另一方面这种材质虽然具有较好的热强性和热稳定性但对热处理较敏感,长期在高温高压负荷下工作,钢的脆性倾向增加,易产生热疲劳
Main steam of high temperature and high pressure will enter the automatic main steam valve first. Its mission is to shut down the main steam source quickly and reliably to force the unit to stop operating once the turbine fails. Therefore, to ensure the quality of castings to achieve safe and reliable operation of steam turbine is of great significance. One hundred thousand 瓩 unit main steam valve shell is ZG20CrMoV pearlite low alloy heat-resistant steel casting. Gross weight 5100 kg, outline size 1400 × 1675 × 1450. This structure is more complex, so the model manufacturing and modeling operations has brought some difficulties. On the other hand, although this kind of material has good thermal strength and thermal stability but is more sensitive to heat treatment, long-term work under high temperature and high pressure load, the brittleness tendency of steel increases, thermal fatigue easily occurs