低膨胀GH2909合金锻造工艺研究

Study on the Forging Pocess of Low Expansion Alloy GH2909

本文根据实验室对GH2909合金不同温度热模拟塑性变形的研究和楔形试块落锤锻造试验,确定了GH2909合金的锻造温度窗口和晶粒尺寸与锻造温度和热变形量的关系,再结合现场的实际生产情况,提出了GH2909合金大尺寸棒材细化晶粒的分级降温锻造工艺:首先,GH2909合金自耗锭在1080℃~1100℃温度范围内进行开坯锻造,并达到30%以上热变形量以消除铸态组织,所得到中间坯组织为0~2级粗大等轴晶;然后,在1020℃~1050℃温度范围内加热,对开坯后的中间坯进行锻造,并控制每火变形量在40%以上,可使中间坯的晶粒度进一步细化;最后,在980℃~1000℃加热中间坯,一火锻造成最终所要求的合金棒材,并控制热变形量在30%以上;可使最终所锻造GH2909合金大尺寸棒材的晶粒度进一步细化到6级,满足超声波探伤检测要求。

According to the research about the thermal simulated plastic deformation of GH2909 alloy at differenttemperatures at laboratory and the drop forging test of the wedge blocks, the relationship between the forging tempera-ture and grain size of GH2909 alloy, and the relationship between forging temperature and hot deformation of GH2909 alloy are determined. Combined with the actual production situation at site, a graded cooling forging process for refin-ing grain of large size bar of GH2909 alloy is proposed: first, the consumable ingot of GH2909 alloy is forged in the tem-perature range of 1080℃~1100℃, and more than 30% thermal deformation is achieved so as to eliminate the cast struc-ture, the obtained microstructure of the intermediate billet is 0~2 grade thick equiax crystal; then, heating at the tem-perature range of 1020℃~1050℃, forging the intermediate billet after blooming, and controlling deformation at eachheat more than 40%, the further refinement of the grain in the intermediate billet can be done; finally, heating the inter-mediate billet at the temperature range of 980℃~1000 ℃, the final required alloy bar is forged at a heat and the ther-mal deformation amount is controlled to be more than 30%, by which the grain size of the final forged large size bar ofGH2909 alloy can be further refined to be 6 grade to meet the requirements of ultrasonic flaw detection.