Effect of Isothermal Holding Temperature on NGS Kinetics of Phosphorus and Temper Embrittlement

2007 ◽  
pp. 549-552
Author(s):  
Jun Wang ◽  
Qing Fen Li ◽  
Er Bao Liu
Keyword(s):  
Isothermal Holding ◽  
Temper Embrittlement ◽  
Kinetics Of ◽  
Holding Temperature

Effect of Isothermal Holding Temperature on NGS Kinetics of Phosphorus and Temper Embrittlement

2007 ◽  
Vol 348-349 ◽  
pp. 549-552
Author(s):  
Jun Wang ◽  
Qing Fen Li ◽  
Er Bao Liu
Keyword(s):  
Grain Boundary ◽  
Grain Boundaries ◽  
Isothermal Holding ◽  
Boundary Segregation ◽  
Temper Embrittlement ◽  
Solution Treatment ◽  
Grain Boundary Segregation ◽  
Solution Temperature ◽  
Kinetics Of ◽  
Holding Temperature

When failure occurs in material, it is often occurs by fracture along some grain boundaries and often by the micro-segregation of embrittling impurity to the grain boundaries. In the present work, the non-equilibrium grain-boundary segregation (NGS) kinetics of phosphorus and the temper embrittlement at the same solution treatment and different isothermal holding temperature in steel 2.25Cr1Mo are studied. The NGS kinetics curves of phosphorus at the same solution temperature （1050 oC ）and different isothermal holding temperature (540 oC and 600 oC) are given. Experimental results provide a direct evidence of NGS kinetic model and show that the grain boundary segregation concentrations of phosphorus for specimen isothermal holding at 540 oC are higher than those at 600 oC. The peak values of AES patterns of solute atoms for specimen isothermal holding at 540 oC are also higher than those at 600 oC. It is therefore concluded that the lower the isothermal holding temperature, the higher the segregation concentration of phosphorus at the grain-boundaries, and also the higher the degree of embrittlement.

scholarly journals Microstructural and Mechanical Characterization of a Nanostructured Bainitic Cast Steel

Metals ◽  
2020 ◽  
Vol 10 (5) ◽  
pp. 612 ◽  
Author(s):  
Andrés Felipe Santacruz-Londoño ◽  
Oscar Rios-Diez ◽  
José A. Jiménez ◽  
Carlos Garcia-Mateo ◽  
Ricardo Aristizábal-Sierra
Keyword(s):  
Cast Steel ◽  
Isothermal Holding ◽  
High Strength ◽  
Cast Steels ◽  
Final Microstructure ◽  
Potential Applications ◽  
Steel Castings ◽  
Kinetics Of ◽  
Holding Temperature

Nanoscale bainite is a remarkable microstructure that exhibits a very promising combination of high strength with good ductility and toughness. The development of these types of microstructures has been focused on wrought materials, and very little information is available for steel castings. In this work, a specially designed cast steel with 0.76 wt % C was fabricated, and the heat treatment cycles to develop bainitic nanostructures were determined by studying the kinetics of the bainitic transformation using high-resolution dilatometry. The effects of isothermal holding temperature and time on the final microstructure and mechanical properties were thoroughly characterized in order to evaluate a future industrial implementation of the process in an effort to contribute to enhance and widen the potential applications for cast steels.

Study on Temper Embrittlement of Phosphorus in Steel 12Cr1MoV

2005 ◽  
Vol 297-300 ◽  
pp. 1183-1188 ◽  
Author(s):  
Li Li ◽  
Qing Fen Li ◽  
Er Jun Guo ◽  
Er Bao Liu ◽  
Xin Fang Cui ◽  
...  
Keyword(s):  
Grain Boundary ◽  
Isothermal Holding ◽  
Boundary Segregation ◽  
Temper Embrittlement ◽  
Critical Time ◽  
Charpy Impact ◽  
Grain Boundary Segregation ◽  
Solution Temperature ◽  
Segregation Process ◽  
Holding Temperature

According to the non-equilibrium grain-boundary segregation (NGS) kinetics curve of phosphorus, a series of Charpy impact tests was performed in an industrial steel 12Cr1MoV, at solution temperature 1050oC, with isothermal holding temperature 540oC, on specimens of different holding time (at the segregation process, the critical time, and the desegregation process respectively). The DBTT values were measured and a temper embrittlement kinetics curve was given. The reverse temper embrittlement NGS mechanism for steel 12Cr1MoV was proposed.

Investigation of Temperature Deformations and Burning of Models from Polymers

2021 ◽  
Vol 316 ◽  
pp. 40-45
Author(s):  
Aksaule A. Mamayeva ◽  
Akerke T. Imbarova ◽  
Marzhan T. Chukmanova
Keyword(s):  
3D Printing ◽  
Isothermal Holding ◽  
Printing Technology ◽  
Temperature Expansion ◽  
3D Printing Technology ◽  
Linear Dimensions ◽  
Temperature Deformations ◽  
Thin Walled ◽  
Subsequent Decomposition ◽  
Holding Temperature

The usage of 3D printing technology SLA and DLP is promising for obtaining casting models. The article presents the results of a study of temperature deformations, developing during the burning of models from polymers “Fun to Do Castable Blend”, “Oh-All! Red” and “Orange Fluor”. In the performance of the experiments, photopolymer models were exposed to an impact of isothermal at temperatures from 50 to 330 °C, and their linear dimensions measured; changes developing on their surface were noted. It is shown that, with an increase of the isothermal holding temperature, the models expand first and narrow later. It has been linked to temperature expansion and subsequent decomposition of the photopolymer. It is shown that the casting molds ,obtained with the usied thin-walled hollow casting models from these photopolymers, are destroyed at the stage of their burning.

Microstructure Evolution and Coarsening Mechanism of 7075 Semi-Solid Aluminum Alloy Pre-Deformed by ECAP Method

2016 ◽  
Vol 256 ◽  
pp. 294-300 ◽  
Author(s):  
Jin Long Fu ◽  
Yu Wei Wang ◽  
Kai Kun Wang ◽  
Xiao Wei Li
Keyword(s):  
Aluminum Alloy ◽  
Solid State ◽  
Ostwald Ripening ◽  
Liquid Fraction ◽  
Isothermal Holding ◽  
Angular Pressing ◽  
Average Grain Size ◽  
Semi Solid ◽  
Equiaxed Grains ◽  
Kinetics Of

To investigate the influence of refined grains on the microstructure of 7075 aluminum alloy in semi-solid state, a new strain induced melting activation (SIMA) method was put forward containing two main stages: pre-deformation with equal channel angular pressing (ECAP) method and isothermally holding in the semi-solid temperature range. The breaking up and growth mechanisms of the grains and kinetics of equiaxed grains coarsening during the semi-solid holding were investigated. The results showed that the average grain size after ECAP extrusion decreased significantly, e.g., microstructure with average globular diameter less than 5μm was achieved after four-pass ECAP extrusion. Obvious grain coarsening had been found during isothermal holding in the semi-solid state and the roundness of the grains increased with the increasing holding time. The proper microstructure of 66.8μm in diameter and 1.22 in shape factor was obtained under proper soaking condition (at 590°C for 15 min). Two coarsening mechanisms, namely, coalescence in lower liquid fraction and Ostwald ripening in higher liquid fraction contributed to the grain growth process.

Microstructural Control of 7075 Al Wrought Alloys through Thixoextrusion Route

2006 ◽  
Vol 510-511 ◽  
pp. 362-365 ◽  
Author(s):  
Young Ok Yoon ◽  
Hyung Ho Jo ◽  
Jin Kyu Lee ◽  
Dong In Jang ◽  
Shae K. Kim
Keyword(s):  
Grain Size ◽  
Liquid Fraction ◽  
Isothermal Holding ◽  
High Strength ◽  
Industrial Applications ◽  
High Productivity ◽  
Die Life ◽  
Average Grain Size ◽  
Low Energy Consumption ◽  
Holding Temperature

Thixoextrusion, one of the thixoforming processes, has advantages of high productivity, reduction of the extrusion pressure, extension of the die life, and cost saving owing to its low energy consumption compared with the conventional extrusion processes. Especially, thixoextrusion process is expected to be very effective for hard-to-form materials with high strength. The present study focuses on 7075 Al wrought alloy to investigate the potential industrial applications of the thixoextrusion process. The microstructural evolution of 7075 Al wrought alloy for thixoextrusion was investigated with respect to isothermal holding temperature and time in the partially remelted semisolid state. The results showed that the liquid fraction increased with increasing isothermal holding temperature and time while the average grain size was inversely proportional to isothermal holding temperature and time up to 5min. However, there was no big change of liquid fraction and average grain size with respect to isothermal holding temperature and time. The important fact that the liquid fraction and average grain size were almost uniform after 5 min holding time is considered very useful for thixoextrusion in terms of process control.

Kinetics of temper embrittlement

1978 ◽  
Vol 26 (9) ◽  
pp. 1471-1478 ◽  
Author(s):  
W.R. Tyson
Keyword(s):  
Temper Embrittlement ◽  
Kinetics Of

Influence of Reheating Profile on Microstructural Evolution of 2024 Al Wrought Alloy for Thixoextrusion

2007 ◽  
Vol 544-545 ◽  
pp. 371-374
Author(s):  
Dong In Jang ◽  
Young Ok Yoon ◽  
Hyung Ho Jo ◽  
Shae K. Kim
Keyword(s):  
Grain Size ◽  
Liquid Fraction ◽  
Isothermal Holding ◽  
Low Energy ◽  
Billet Temperature ◽  
High Productivity ◽  
Main Emphasis ◽  
Average Grain Size ◽  
Low Energy Consumption ◽  
Holding Temperature

Thixoextrusion, one of the thixoforming processes, has advantages of high productivity, reduction of the extrusion pressure and cost saving because of the low energy consumption compared with the conventional extrusion processes. For the thixoextrusion, the low liquid fraction (fL<0.3) should be achieved and also the liquid fraction and average grain size should be uniform according to the reheating profile at the desired low liquid fraction. The main emphasis of this study is to investigate the feasibility of thixoextrusion for 2024 Al wrought alloy without additional pretreatment. The results show that the liquid fraction and average grain size were almost uniform with respect to isothermal holding temperature and time. It was very useful for thixoextrusion in terms of process control such as billet temperature control and actual extrusion time.

Effect of Isothermal Holding Temperature on Globularization of Primary Solid Phase in Multiplex-Type Slurry Cup

2006 ◽  
Vol 116-117 ◽  
pp. 239-242 ◽  
Author(s):  
Suk Won Kang ◽  
Dock Young Lee ◽  
Ki Bae Kim
Keyword(s):  
Automobile Industry ◽  
Solid Phase ◽  
Isothermal Holding ◽  
Cost Effective ◽  
Al Alloy ◽  
Liquid Region ◽  
Globular Structure ◽  
Semi Solid ◽  
Solid Liquid ◽  
Holding Temperature

In order to produce a high quality and cost effective part in the rheocasting process for an automobile industry it has been important to develop a slurry-on-demand process, which can manufacture the semi-solid slurry having a fine and globular structure of primary solid phase. The morphology of primary solid phase of semi-solid slurry is coarsened and globularized during an isothermal holding process in a solid-liquid region. Accordingly, in this paper, the microstructural evolution of semi-solid slurry during the isothermal holding at a various temperature in solid-liquid region was investigated to examine a coarsening and globularization behavior of primary solid phase. The semi-solid slurry of Al alloy was produced in a slurry maker using a multiplex-type slurry cup that we developed recently. A size of primary solid phase was the finer at the higher holding temperature, but under a constant holding time a roundness degree of primary solid phase was the lower at the lower holding temperature. Also, a coarsening rate of primary solid phase was not considered to be affected significantly by a holding temperature even though a little lower coarsening rate was obtained at the higher holding temperature.

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