Large 718 Forgings for Land Based Turbines

Schwant, R.C.; Thamboo, S.V.; Anderson, Angela; Adasczik, C.B.; Bond, Betsy J.; Jackman, L.A.; Uginet, J.F.

doi:10.7449/1997/superalloys_1997_141_152

Cited by 14 publications

(4 citation statements)

References 7 publications

(1 reference statement)

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The high-alloy steels receive mounting attention in the iron and steel industry, due to its high added value in the manufacturing market. However, there are difficulties in the quality control of these steels due to their high carbon and alloy content, and hence high cracking susceptibility [5, 6, 7, 8, 9]. The high quality mould steel is produced after forging, which should qualify via flaw detection, high surface quality, and ±2HRC (Rockwell hardness) difference in hardness uniformity (between the surface and core).…”

Section: Introductionmentioning

confidence: 99%

Cracking and segregation in high-alloy steel 0.4C1.5Mn2Cr0.35Mo1.5Ni produced by thick continuous casting

Chu

Fan

et al. 2019

Heliyon

View full text Add to dashboard Cite

Based on our innovative application of using thick continuous casting slab 0.4C1.5Mn2Cr0.35Mo1.5Ni (high alloy) for the production of high-quality mould steel, the present study investigated the high cracking susceptibility of high-alloy steel and segregation in continuous casting slab. The thermal expansion and the continuous cooling transformation (CCT) curve measurement, together with a high temperature in situ observation, confirmed the martensite phase transition happening at approximately 583 K that would result in an increase in the hardenability and cracking susceptibility. The cracking susceptibility zone was determined by high-temperature mechanical properties measurement. The high-alloy mould steel has no II brittle zone, and III brittle zone is 973–1148 K. As a conclusion, the straightening temperature should be above 1148 K to avoid the cracking during the continuous casting. Moreover, the elemental segregation of carbon, sulfur, chromium, and molybdenum along the cracking was examined by electron probe microanalysis (EPMA) quantitative analysis that might be another reason for the steel crack formation. It shows that Martensite phase transition happened at approximately 583 K that would result in an increase in the hardenability and cracking susceptibility.

show abstract

Section: Introductionmentioning

confidence: 99%

Cracking and segregation in high-alloy steel 0.4C1.5Mn2Cr0.35Mo1.5Ni produced by thick continuous casting

Chu

Fan

et al. 2019

Heliyon

View full text Add to dashboard Cite

show abstract

“…It is estimated that an increase of 110°C in the firing temperature leads to a potential 4 pct increase in the combined cycle efficiency. [1] The new land-based turbines for power generation require the use of Nb-containing superalloys such as INCONEL/WASPALOY* 718 for the rotor disk, to avoid overaging of the microstructure during the forging process, [2] but its applicability is being limited by difficulties in the reliable production of large ingots (33 to~35 in. in diameter) without macrosegregation defects such as freckles and center segregation.…”

Section: Jairo Valdes Shun-li Shang Zi-kui Liu Paul King and Xingmentioning

confidence: 99%

Quenching Differential Thermal Analysis and Thermodynamic Calculation to Determine Partition Coefficients of Solute Elements in Simplified Ni-Base Superalloys

Valdés

Shang

Liu

et al. 2009

Metall Mater Trans A

View full text Add to dashboard Cite

In this article, a profile-fitting methodology was developed to measure the partition coefficients of solute elements during the solidification of Ni-base alloys. Better agreement with the theoretically calculated values is expected if the accuracy of the composition and the homogeneity of the model alloys are enhanced. Regular differential thermal analysis (DTA) measurements were consistently higher than the theoretical transition temperatures, and the differences were smaller when compared to the predictions performed with the thermodynamical database developed by Du et al. The better agreement between the experimental results and the theoretical predictions made with the newly developed database suggests that improvements in the accuracy of the theoretical predictions can still be obtained and are necessary for accurate freckling prediction. Quenching modified DTA (MDTA) experiments were proven to be appropriate for directly measuring the average partition coefficients of the solute elements. Regarding the cooling rate of the first stage of the quenching experiments, it was assumed successfully that the cooling rate prior to the quenching step of 0.083 Ks À1 was sufficiently slow to permit easy quenching, while being fast enough for the primary solidification reaction to depart from the equilibrium model and being closer to the Scheil model of segregation. The minimization of the error function defined from the Scheil equation was found to be an appropriate method for describing the segregation profiles of the quenched samples and permitted good estimations of the partition coefficients of the solute elements. The reliability of the methodology was found to be satisfactory given that the magnitudes calculated for the partition coefficients of the solutes in the multicomponent alloy 718 were found to be very close to the values reported in the literature.

show abstract

“…In the present study, closed die hammer forging was employed due to nonavailability of large press. Even though published work is available on development of large forgings, it is mostly confined to processing using press [3][4][5]. There are no reports on production of IN-718 hemispherical domes by closed die hammer forging or press forging in open literature.…”

Section: Introductionmentioning

confidence: 99%

Closed Die Hammer Forging of Inconel 718

Krishna

Singh

Murty

et al. 2014

Journal of Metallurgy

View full text Add to dashboard Cite

A method for the production of Inconel 718 (IN-718) hemispherical domes by closed die hammer forging is proposed. Different combination of operations employed for production are as follows: (i) preforging + final forging + air cooling, (ii) preforging + final forging + controlled cooling, (iii) direct forging + controlled cooling, and (iv) direct forging + air cooling. Last three combinations yielded a crack free hemispherical dome. The forged hemispherical domes were solution annealed at 980°C for 1 h and air cooled. The grain size of the domes at all locations was finer than ASTM No 4. Mechanical properties of the forged dome in solution treated and aged condition (STA) were better than feedstock used.

show abstract

Large 718 Forgings for Land Based Turbines

Cited by 14 publications

References 7 publications

Cracking and segregation in high-alloy steel 0.4C1.5Mn2Cr0.35Mo1.5Ni produced by thick continuous casting

Cracking and segregation in high-alloy steel 0.4C1.5Mn2Cr0.35Mo1.5Ni produced by thick continuous casting

Quenching Differential Thermal Analysis and Thermodynamic Calculation to Determine Partition Coefficients of Solute Elements in Simplified Ni-Base Superalloys

Closed Die Hammer Forging of Inconel 718

Contact Info

Product

Resources

About