变形高温合金表面换热系数的系统性测定研究

Research on Systematic Determination of Surface Heat Transfer Coefficient of Wrought Superalloys

摘要:

为了准确预测变形高温合金在制造过程的升温与降温过程，实现热应力准确评估与损伤控制，降低能源消耗与生产成本，有必要围绕变形高温合金各类换热情况进行系统性的表面换热系数研究，并确定可靠的表面换热系数供实际工艺设计与模拟计算使用。本文以GH4169合金盘锻件制造过程所涉及的10种典型换热情况为例，采用实验测温与有限元参数优化方法确定了GH4169合金的表面换热系数。研究发现，直接升温过程测定的表面换热系数可以全面地描述合金在不同升温过程中的温度变化规律；炉冷过程可以使用直接升温过程测定的表面换热系数进行描述；保温包套可使得合金具有极低的表面换热系数，并且在较大的温度区间范围保持稳定；采用实验室小试样测定的表面换热系数能够准确描述工业大型铸锭的升降温过程。

Abstract:

In order to accurately predict the heating and cooling process of wrought superalloys during the manufacturing process, accurately evaluate thermal stress and control damage, and reduce energy consumption and production costs, it is necessary to perform a systematic study on the surface heat transfer coefficient of various heat transfer conditions of wrought superalloys, and determine a reliable surface heat transfer coefficient for actual process design and simulation calculation. In this paper, 10 typical heat transfer conditions involved in the manufacturing process of GH4169 alloy disc forgings are taken as examples, and the surface heat transfer coefficient of GH4169 alloy is determined by experimental temperature measurement and finite element parameter optimization method. The study found that the surface heat transfer coefficient measured by the direct heating process can comprehensively describe the temperature change of the alloy in different heating processes; the furnace cooling process can be described by the surface heat transfer coefficient measured by the direct heating process; the insulation materials can make the alloy have an extremely low surface heat transfer coefficient and remain stable in a large temperature range; the surface heat transfer coefficient measured by a small laboratory sample can accurately describe the heating and cooling process of industrial large ingots.