• Korean Journal of Metals and Materials
• /
• v.50 no.7
• /
• pp.511-516
• /
• 2012

Low temperature ${\delta}$-precipitation phenomenon below 2-step aging ($718^{\circ}C$, $8hr+621^{\circ}C$, 8 hr) temperature of cold drawn Inconel 718 alloy wire was investigated. The investigation was carried out on wires with a cold drawn ratio of 0, 20, 50 and 70% using OM, SEM, XRD, TEM, and DSC. In microstructures of 50 and 70% drawn wire, many precipitates were found along the grain boundaries and the twin boundaries in deformation band. From the results of the XRD and TEM analysis, the precipitates were identified as plate-like ${\delta}$-phase. From the results of the DSC analysis, it was also found that a temperature of ${\delta}$-precipitation decreases with an increase of the cold drawn ratio. We concluded that cold drawing of inconel 718 wire promotes the ${\delta}$-precipitation, and under the condition of a high drawing ratio, the ${\delta}$-phase could be precipitated at a temperature below the aging temperature ($718^{\circ}C$).

• Proceedings of the KSME Conference
• /
• 2007.05a
• /
• pp.1373-1378
• /
• 2007

Metal forming ins the process changing shapes and mechanical properties of the workpiece without initial material reduction through plastic deformation. Above all, because of hot working carried out above recrystallization temperature can be generated large deformation with one blow, it can produce with forging complicated parts or heat resisting super alloy such as Inconel 718 has the worst forgeability. In this paper, we established optimal variation of hot heading precess of the Inconel 718 used in heat resisting component and evaluated mechanical properties hot worked produce. Die material is SKD61 and initial temperature is $300^{\circ}C$. Initial billet temperature and punch velocity changed, relatively. Friction coefficient is 0.3 as lubricated condition of hot working. CAE is carried out suing DEFORM software before making the tryout part, and it is manufactured 150 ton screw press with optimal condition. It is known that forming load was decreased according to decreasing punch velocity.

• Proceedings of the Korean Society of Precision Engineering Conference
• /
• 2006.10a
• /
• pp.631-632
• /
• 2006

• Proceedings of the Korean Society of Precision Engineering Conference
• /
• 2007.06a
• /
• pp.19-20
• /
• 2007

• Proceedings of the Korean Society for Technology of Plasticity Conference
• /
• 1997.10a
• /
• pp.220-223
• /
• 1997

This paper presents the prediction of microstructure of Inconel 718 disk forgings. The experiments are carried out to examine the recrystallization ratio and grain growth in the forgings. In the experiments, cylindrical billets are forged by two operations with variations of forging temperature and reduction ratio of deformation. Also the finite element program, developed here for the prediction, is used for the analysis, and the results are compared with the experimental ones. It is noted that the comparison appears in sound agreement.

• Proceedings of the Korean Society of Precision Engineering Conference
• /
• 2013.05a
• /
• pp.1329-1330
• /
• 2013

• Proceedings of the Korean Society of Precision Engineering Conference
• /
• 2009.06a
• /
• pp.465-466
• /
• 2009

• Proceedings of the Korean Society of Precision Engineering Conference
• /
• 2011.06a
• /
• pp.1153-1154
• /
• 2011

• Journal of the Korean Society of Manufacturing Technology Engineers
• /
• v.4 no.3
• /
• pp.67-76
• /
• 1995

An experimental study of hot machining has performed to improve the machinability of Inconel718. This experiment used plasma are for heating materials and Whisker0reinforce aluminum oxide ceramic tool insert. An assembled plasma heating system are described and experimental results from both conventional and plasma hot machining of Inconel 718 are compared. The experiments with plasma heating demonstrated the following effectiveness. 1)The cutting force was reduced with increasing surface temperature of workpiece from 450$^{\circ}C$ up to 720$^{\circ}C$ as much as approximately from 20 to 40%. 2) Surface roughness(Ra) was improved by as much as a factor 2 in case of one pass cutting with new ceramic tool inserts.3) The depth of cut notch were at promary cutting tool was significantly reduced.

• Journal of the Korean Society of Manufacturing Technology Engineers
• /
• v.19 no.2
• /
• pp.295-300
• /
• 2010

Inconel 718 alloy, widely used as material of aircraft engine, has a good mechanical property in high temperature, strong anti-oxidation characteristics in oxidated current over $900^{\circ}C$, and also is not easily digested in the air containing sulfur, therefore, its usage as mechanical component is expanding rapidly. Even though Inconel alloy 718 is difficult to machine, it requires highly precise processing/machining to sustain its component quality of high accuracy. In this paper, general turning operation conditions arc tested to select the best cutting process condition by measuring surface roughness through implementing experiments with orthogonal array of cutting speed, feeding speed and cutting depth as processing parameters based on the Taguchi method. Optimal turning operation conditions are extracted from the proposed experimental models.