scholarly journals The Effects of Various Conditions of Short-Term Rejuvenation Heat Treatment on Room-Temperature Mechanical Properties of Thermally Aged P92 Boiler Steel

Materials ◽  
2021 ◽  
Vol 14 (20) ◽  
pp. 6076
Author(s):  
Ladislav Falat ◽  
Lucia Čiripová ◽  
Viera Homolová ◽  
Miroslav Džupon ◽  
Róbert Džunda ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Heat Treatment ◽  
Impact Toughness ◽  
Room Temperature ◽  
Laves Phase ◽  
Short Term ◽  
Boiler Steel ◽  
P92 Steel ◽  
The Impact

In this work, the effects of various conditions of short-term rejuvenation heat treatment on room-temperature mechanical properties of long-term aged P92 boiler steel were investigated. Normalized and tempered P92 steel pipe was thermally exposed at 600 °C for time durations up to 5000 h in order to simulate high-temperature material degradation, as also occurring in service conditions. Thus, thermally embrittled material states of P92 steel were prepared, showing tempered martensitic microstructures with coarsened secondary phase precipitates of Cr23C6-based carbides and Fe2W-based Laves phase. Compared with the initial normalized and tempered material condition, thermally aged materials exhibited a slight decrease in strength properties (i.e., yield stress and ultimate tensile strength) and deformation properties (i.e., total elongation and reduction of area). The hardness values were almost unaffected, whereas the impact toughness values showed a steep decrease after long-term ageing. An idea for designing the rejuvenation heat treatments for restoration of impact toughness was based on tuning the material properties by short-term annealing effects at various selected temperatures somewhat above the long-term ageing temperature of P92 material. Specifically, the proposed heat treatments were performed within the temperature range between 680 °C and 740 °C, employing variable heating up and cooling down conditions. It was revealed that short-term annealing at 740 °C for 1 h with subsequent rapid cooling into water represents the most efficient rejuvenation heat treatment procedure of thermally aged P92 steel for full restoration of impact toughness up to original values of normalized and tempered material state. Microstructural observations clearly indicated partial dissolution of the Laves phase precipitates to be the crucial phenomenon that played a key role in restoring the impact toughness.

Research on Substitution of Molybdenum by Manganese in Low Alloyed Bainite Ductile Iron

2011 ◽  
Vol 299-300 ◽  
pp. 57-60
Author(s):  
De Qiang Wei ◽  
Ke Liu
Keyword(s):  
Mechanical Properties ◽  
Heat Treatment ◽  
Electron Microscope ◽  
Impact Toughness ◽  
Ductile Iron ◽  
Retained Austenite ◽  
Room Temperature ◽  
The Matrix ◽  
The Impact ◽  
Scanning Electron

The low alloyed bainite ductile iron is obtained by alloying and austempering in room-temperature machine oil. The microstructure is investigated. The mechanical properties are discussed. In general, the number of white-bright zones and segregation is increasing with the increasing in the content of Mn, but the impact toughness is decreased. Therefore, the content of Mn is no more than 0.5 wt.%. The microstructure of bainite, martensite and a little retained austenite in the matrix of the ductile iron was investigated by scanning electron microscope (SEM). The hardness and impact toughness of the ductile iron subjected to heat-treatment are 54~56 HRC and 14.2 J/cm2, respectively. The substitution of 0.3~0.5wt.% Mo by 0.7~1.0 wt.% Mn can be realized in the bainite ductile iron.

Application of Tailored Heat Treated Blanks under Quasi Series Conditions

2007 ◽  
Vol 344 ◽  
pp. 383-390 ◽  
Author(s):  
Marion Merklein ◽  
Uwe Vogt
Keyword(s):  
Mechanical Properties ◽  
Heat Treatment ◽  
Local Heat ◽  
Strength Distribution ◽  
Process Window ◽  
Short Term ◽  
Forming Process ◽  
Heat Treated ◽  
Set Up ◽  
The Impact

Tailored Heat Treated Blanks (THTB) are blanks that exhibit locally different strength specifically optimized for the succeeding forming process. The strength distribution is set by a local, short-term heat treatment modifying the mechanical properties of the material. Hence, THTB allow enhancing forming limits significantly leading to shorter and more robust manufacture process chains. In order to qualify the use of THTB under quasi series conditions, the interdependencies of the blank’s local heat treatment and the entire process chain of the car body manufacture have to be analyzed. In this respect, the impact of a short-term heat treatment on the mechanical properties of AA6181PX, a commonly used aluminum alloy in today’s car bodies, was studied. Also the influence of a short-term heat treatment on the coil lubricant, usually already applied by the material supplier, was given a closer look. Based on these experiments process restrictions for the application of THTB in an industrial automotive environment were derived and a process window for the THTB design was set up. In conclusion, strategies were defined how to enhance the found process boundaries leading to a more robust process window.

The Influence of Boron on Structure and Mechanical Properties of Bainite Ductile Iron in the Step Austempering in Room Temperature Machine Oil

2010 ◽  
Vol 139-141 ◽  
pp. 235-238
Author(s):  
De Qiang Wei
Keyword(s):  
Mechanical Properties ◽  
Heat Treatment ◽  
Cast Iron ◽  
Impact Strength ◽  
Ductile Iron ◽  
Room Temperature ◽  
Solute Drag ◽  
Ductile Cast Iron ◽  
Treatment Technique ◽  
The Impact

In this paper, the low alloy bainite ductile cast iron has been obtained by a new heat treatment technique of the step austempering in room-temperature machine oil. The effects of element boron, manganese and copper on structure and mechanical properties of the bainite ductile cast Iron in above-mentioned process are investigated. The phenomenon, hardness lag of the alloyed bainite ductile cast Iron, has been discussed. It shows that after the step austempering in room-temperature machine oil, the hardness will increases with the time. It is found that boron and manganese can increase the hardness and reduce the impact strength while copper can increase the impact strength. The results show that reasonable alloyed elements can improve mechanical properties of the bainite ductile cast Iron. Essentially, hardness lag of the alloyed bainite ductile cast Iron is resulted from solute drag-like effect.

Investigation of Heat Treatment on Mechanical Properties of SAE4320 and SAE8620 Alloys

2013 ◽  
Vol 834-836 ◽  
pp. 816-819 ◽  
Author(s):  
Li Jun Tan ◽  
Jun Qiao Wang ◽  
Qing Qun Wang ◽  
Xin Long Chen ◽  
Si Zhu Zhou
Keyword(s):  
Mechanical Properties ◽  
Heat Treatment ◽  
Tensile Strength ◽  
Impact Toughness ◽  
Deformation Property ◽  
New Product ◽  
Heat Treatments ◽  
Impact Properties ◽  
The Impact

The tensile and impact properties of SAE4320 and SAE8620 alloys were investigated. Various heat treatments were applied to these two alloys, including different pre-heat treatment. The results shown that after Carburizing and Quenching, both SAE4320 and SAE8620 alloys were highly sensitively to V-notches for their impact samples. In any case, SAE4320 alloy revealed higher tensile strength, better impact toughness and deformation property. Previous work shown that after Carburizing and Quenching, the impact toughness of SAE8620 alloy was too low, the products made of it was very dangerous. Based on the results, a new advanced product was made of SAE4320 alloy instead of SAE8620 alloy. And the new product exhibited good properties. The impact value of the new product far exceeded the older products.

scholarly journals On the Impact of the Intermetallic Fe2Nb Laves Phase on the Mechanical Properties of Fe-6 Al-1.25 Nb-X W/ Mo Fully Ferritic Light-Weight Steels

Metals ◽  
2021 ◽  
Vol 11 (11) ◽  
pp. 1693
Author(s):  
Robin Emmrich ◽  
Ulrich Krupp
Keyword(s):  
Mechanical Properties ◽  
Room Temperature ◽  
Elevated Temperatures ◽  
Xrd Analysis ◽  
Tensile Tests ◽  
Laves Phase ◽  
Particle Analysis ◽  
Strength Increase ◽  
Niobium Content ◽  
The Impact

The present study aims at the development of precipitation hardening fully ferritic steels with increased aluminum and niobium content for application at elevated temperatures. The first and second material batch were alloyed with tungsten or molybdenum, respectively. To analyze the influence of these elements on the thermally induced precipitation of the intermetallic Fe2Nb Laves phase and thus on the mechanical properties, aging treatments with varying temperature and holding time are performed followed by X-ray diffraction (XRD) analysis and scanning electron microscopy (SEM) including elemental contrast based particle analysis as well as hardness measurements and tensile tests at room temperature and at 500 °C. The incorporation of molybdenum into the Laves phase sets in at an earlier stage of aging than the incorporation of tungsten, which leads to faster growth and coarsening of the Laves phase in the molybdenum-alloyed steel. Nevertheless, both concepts show a fast and massive increase in hardness (280 HV10) due to precipitation of Laves phase during aging at 650 °C. After 4 h aging, the yield strength increase at room temperature is 100 MPa, which stays stable at operation temperatures up to 500 °C.

Influence of Mn and Heat Treatment Technology on Microstructure and Mechanical Properties of a Low-Alloy Wear-Resistant Cast Steel Shovel Tooth

2012 ◽  
Vol 557-559 ◽  
pp. 34-37
Author(s):  
Jing Qiang Zhang ◽  
Jie Min Du ◽  
Ji Wei Guo ◽  
Shou Fan Rong ◽  
Guang Zhou Wang
Keyword(s):  
Mechanical Properties ◽  
Heat Treatment ◽  
Impact Toughness ◽  
Cast Steel ◽  
Treatment Technology ◽  
Wear Resistant ◽  
Heat Treatment Technology ◽  
Microstructure And Mechanical Properties ◽  
Mn Content ◽  
The Impact

The influences of Mn and heat-treatment technology on microstructure and mechanical properties of medium-carbon-low-alloy wear-resistant cast steel were investigated. The results show that the hardness first increases and then drops down with the increase of Mn content, and the best hardness is 54HRC with Mn content 1.5%. The impact toughness first increases and then drops down with the increase of Mn content. The hardness and impact toughness first increase and then drop down with the increases of quenching temperature. The optimal impact toughness can be obtaind by quenching at 920°C and tempering at 200°C. Part of lower bainite and residual austenite and mass of tempered martensite are obtaind after tempering.

scholarly journals Microstructure Evolution and Mechanical Properties of 0.4C-Si-Mn-Cr Steel during High Temperature Deformation

Materials ◽  
2020 ◽  
Vol 13 (1) ◽  
pp. 172 ◽  
Author(s):  
Fei Zhang ◽  
Yang Yang ◽  
Quan Shan ◽  
Zulai Li ◽  
Jinfeng Bi ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Heat Treatment ◽  
High Temperature ◽  
Impact Toughness ◽  
Microstructure Evolution ◽  
Cast Steel ◽  
High Temperature Deformation ◽  
Temperature Deformation ◽  
Grain Sizes ◽  
The Impact

Herein, the effects of height-diameter ratios (H/D) on the microstructure evolution and mechanical properties of 0.4C-Si-Mn-Cr steel during high temperature deformation are reported. The compression experiments were performed on steel samples using Gleeble to obtain a reasonable deformation temperature, and the degree of deformation was assessed in the range of 1.5 to 2.0 H/D via forging. The forged specimens were quenched using the same heat treatment process. The hardness and impact toughness of the steel samples were tested before and after heat treatment. Grain sizes gradually increased with an increase in the compression temperature from 950 °C to 1150 °C, and the grain sizes decreased with an increase in H/D. The microstructure of the steel samples contained pearlite, bainite, martensite, and retained austenite phase. The microstructure after forging was more uniform and finer as compared to that of as-cast steel samples. The hardness and impact toughness of the steel samples were evaluated after forging; hardness first increased and then decreased with an increase in H/D, while the impact toughness continuously increased with an increase in H/D. Hence, the microstructure and properties of steel could be improved via high temperature deformation, and this was primarily related to grain refinement.

Effect of Heat Treatment on the Properties of Inconel X-750

2005 ◽  
Vol 297-300 ◽  
pp. 1220-1222
Author(s):  
Shi Chang Cheng ◽  
Zhao Jie Lin ◽  
Gang Yang ◽  
Zheng Dong Liu
Keyword(s):  
Mechanical Properties ◽  
Heat Treatment ◽  
Solid Solution ◽  
Impact Toughness ◽  
Room Temperature ◽  
Solution Treatment ◽  
Heat Treatments ◽  
Air Cooling ◽  
Solid Solution Treatment ◽  
Different Temperatures

The authors experimentally investigated the change of mechanical properties of Inconel X-750 alloy under various heat treatments. For the selected specimens, solid solution treatment under different temperatures was carried out, followed air cooling or furnace cooling. Results show that suitable solid solution treatment and air cooling enhances the strength, plasticity, impact toughness at room temperature of the alloy and lowers the hardness of the alloy at room temperature.

scholarly journals Microstructure Evolution and Mechanical Properties of X6CrNiMoVNb11-2 Stainless Steel after Heat Treatment

Materials ◽  
2021 ◽  
Vol 14 (18) ◽  
pp. 5243
Author(s):  
Jia Fu ◽  
Chaoqi Xia
Keyword(s):  
Mechanical Properties ◽  
Heat Treatment ◽  
Stainless Steel ◽  
Impact Toughness ◽  
Martensite Phase ◽  
High Density ◽  
Air Cooling ◽  
Rocket Engines ◽  
Forming Process ◽  
The Impact

X6CrNiMoVNb11-2 supermartensitic stainless steel, a special type of stainless steel, is commonly used in the production of gas turbine discs in liquid rocket engines and compressor disks in aero engines. By optimizing the parameters of the heat-treatment process, its mechanical properties are specially adjusted to meet the performance requirement in that particular practical application during the advanced composite casting-rolling forming process. The relationship between the microstructure and mechanical properties after quenching from 1040 °C and tempering at 300–670 °C was studied, where the yield strength, tensile strength, elongation and impact toughness under different cooling conditions are obtained by means of mechanical property tests. A certain amount of high-density nanophase precipitation is found in the martensite phase transformation through the heat treatment involved in the quenching and tempering processes, where M23C6 carbides are dispersed in lamellar martensite, with the close-packed Ni3Mo and Ni3Nb phases of high-density co-lattice nanocrystalline precipitation created during the tempering process. The ideal process parameters are to quench at 1040 °C in an oil-cooling medium and to temper at 650 °C by air-cooling; final hardness is averaged about 313 HV, with an elongation of 17.9%, the cross-area reduction ratio is 52%, and the impact toughness is about 65 J, respectively. Moreover, the tempered hardness equation, considering various tempering temperatures, is precisely fitted. This investigation helps us to better understand the strengthening mechanism and performance controlling scheme of martensite stainless steel during the cast-rolling forming process in future applications.

Comprehensive Material Characterization for an Intermediate Heat Treatment

2013 ◽  
Vol 549 ◽  
pp. 39-44 ◽  
Author(s):  
Michael Lechner ◽  
Andreas Kuppert ◽  
Marion Merklein
Keyword(s):  
Mechanical Properties ◽  
Heat Treatment ◽  
New Technologies ◽  
Process Window ◽  
Short Term ◽  
Intermediate Heat Treatment ◽  
Comprehensive Knowledge ◽  
New Strategy ◽  
Two Parameters ◽  
The Impact

Encouraged by increasing climate regulations there is a trend to lightweight constructions in the transportation sector, particularly in the automotive industry. An auspicious possibility to reduce the weight of the vehicle is the substitution of conventional steel by aluminum alloys. However, aluminum has a low formability and therefore new technologies have to be found in order to enhance the materials spectrum of application. A new strategy to extend the process limit is the short-term aluminum intermediate heat treatment between two forming operations. Key idea is the partial adaption of the mechanical properties with a short term heat treatment. By the interaction of soft and hard areas the material flow during the forming operation can be improved and the formability can be enhanced. Prerequisite for a successful application of the technology and the numerical simulation is a comprehensive knowledge about the interaction of pre-straining and a subsequent short term heat treatment. Within this paper the mechanical properties in dependency of the two parameters will be presented and a process window for the heat treatment after first forming operations will be derived. Moreover, the influence of batch fluctuations and the impact of ageing will be demonstrated.

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