Typical Thermal Cycle Research Articles

Corrosion effects of Na2CO3/NaCl molten salt eutectic on 316L stainless steel under isothermal and cycling conditions

Using phase-change materials in thermal energy storage systems for concentrating solar thermal plants can significantly reduce the volume of storage media and, therefore, the cost of the system. However, this approach introduces new material compatibility issues between the thermal energy storage material and the containment vessel in the form of corrosion and thermal transients, which are inherent in these systems. Rods and sheet coupons of stainless steel 316L were corroded for up to 768 h in 59.4/40.6 wt% Na2CO3/NaCl eutectic salt under isothermal (650 °C) and cycled conditions (between 600 and 650 °C). The testing methodologies correspond to actual service conditions, as isothermal degradation may not represent material loss under typical solar thermal cycling conditions. Mass losses were calculated via the Dynamic Gravimetric Analysis technique while Scanning Electron Microscopy utilizing Energy Dispersive Spectroscopy was used to analyze the corrosion layers. Isothermal mass loss plateaued at 75 mg/cm2 at 96 h with no further measurable loss after this time, while cycled samples had a fast initial mass loss rate of 60 mg/cm2 in the first 96 h and lost 0.0331 mg/cm2 every hour thereafter. The results indicate that isothermal samples corrode more slowly than the predominant industry cases of thermal cycling. Spalling is responsible for the degradation in both sets; the continual temperature changes in the cycled samples lead to additional stresses, exacerbating the effect.

Effects of thermal cycling on residual stress in alloy parts via selective laser melting

Contradictory interpretation of the parameter dependence of residual stress in alloy parts formed through selective laser melting (SLM) were found in existing research, which is thought to be clarified in the present article. Parametrical simulations and experiments were designed and conducted firstly to concentrate on the dominant significance of the typical thermal cycling in SLM. It has been proved both by the XRD, EBSD and TEM experiments that correlation between residual stress and energy density depends on the peculiar characteristic of thermal cycling. Furthermore, the microscopic characterization accompanied with simulations of computational fluid dynamics, computational thermo-elastic-plastic mechanics and molecular dynamics reveals the effects of typical thermal cycling on the patterns of residual stress.

Asymptotic numerical method for cyclic elasto-plasticity and its application to a steam turbine rotor

Flexible operation of the conventional power plants is necessary for the integration of renewables in the energy mix. Steam turbine rotors are one of the most affected components due to the daily thermal load cycling requirements. In order to accurately study the effect of cycling on fatigue, it is necessary to solve cyclic 3D elasto-plasticity problems for a large number of cycles. The established methods are iterative in nature to arrive at the current yield surface for each elasto-plastic step and are computationally extensive. In this paper, we propose the non-iterative Asymptotic Numerical Method (ANM) based solution technique for 3D cyclic elasto-plasticity problems for the first time by a novel regularized Kuhn-Tucker condition. Regularization techniques used in previous works take care of the partial cycle only, i.e., elastic loading, elastic-plastic transition, elasto-plastic flow and elastic unloading for simple linear work hardening models of plasticity. In the present work, the proposed method extends the applicability of ANM by incorporating elastic-plastic transition and elasto-plasticity in reverse loading, second unloading and repeated loading for any number of cycles so that the computationally efficient fatigue analysis can be carried out. In addition, the extension also includes the application of ANM to non-linear kinematic hardening through the Chaboche plasticity model combined with isotropic hardening. For these advancements, additional regularizations are proposed and implemented in a Finite Element Code. The obtained results are then compared to the solutions obtained from the conventional Newton Raphson (NR) solution technique. The proposed ANM is applied to a steam turbine rotor undergoing a typical thermal load cycling and the cyclic elasto-plastic response is compared with that obtained using the conventional Newton Raphson solution technique.

Proposal and Assessment of a Multiple Cycle-Continuous Cooling Transformation (MC-CCT) Diagram for Wire Arc Additive Manufacturing of Thin Walls

Continuous cooling transformation (CCT) diagrams of base metals are common in welding. They can be built using physical or numerical simulations, each with advantages and limitations. However, those are not usual for weld metal, considering its variable composition due to the dilution of the weld into the base metal. Wire Arc Additive Manufacturing (WAAM) is a distinctive case in which the interest in materials comparable with weld composition raises attention to estimating their mechanical properties. Notwithstanding, this concept is still not used in WAAM. Therefore, the aim of this work was to address a methodology to raise MC-CCT (Multiple Cycle Continuous Cooling Transformation) diagrams for WAAM by combining physical and numerical simulations. A high-strength low-alloy steel (HSLA) feedstock (a combination of a wire and a shielding gas) was used as a case study. To keep CCT as representative as possible, the typical multiple thermal cycles for additive manufacturing thin walls were determined and replicated in physical simulations (Gleeble dilatometry). The start and end transformations were determined by the differential linear variation approach for each thermal cycle. Microstructure analyses and hardness were used to characterise the product after the multiple cycles. The same CCT diagram was raised by a commercial numerical simulation package to determine the shape of the transformation curves. A range of austenitic grain sizes was scanned for the curve position matching the experimental results. Combining the experimental data and numerically simulated curves made estimating the final CCT diagram possible.

Fabrication of Titanium Aluminides via Powder‐Cored Wire Arc Additive Manufacturing: Microstructural and Mechanical Characterization

Herein, an innovative powder‐cored wire arc additive manufacturing (PC‐WAAM) process is proposed to fabricate γ‐TiAl thin‐walled intermetallic alloy. The metallography, phase composition, and mechanical properties at different thin‐wall locations are characterized. The results show that the alternatively distributed layer‐like microstructure composed of α2 (Ti3Al) and γ (TiAl) phases is obtained along the building direction. The content of α2 phase exhibits the tendency of decreasing from the bottom to top region. This unique microstructure characteristic is closely related to the typical thermal cycling history during deposition. Moreover, the tensile strength and microhardness of the top region are lower than the middle and bottom region. In general, the current PC‐WAAM technique shows promising capability of fabricating γ‐TiAl intermetallic alloy with low cost. This work becomes a valuable reference for understanding the evolution mechanism of microstructure and paves the way for the flexible and customized additive manufacturing of γ‐TiAl alloy.

Stresses within rare-earth doped yttria-stabilized zirconia thermal barrier coatings from in-situ synchrotron X-ray diffraction at high temperatures

There is a growing interest for smart coatings that can be integrated into turbine engines for in-situ temperature measurements or health monitoring. The addition of rare-earth dopants into standard thermal barrier ceramic top coat materials is used to obtain luminescent coatings that enable spectral measurements, for real-time temperature or health monitoring. The thermomechanical performance and durability of such novel coating compositions in extreme environments still remains to be evaluated. Consequently, the ability to manufacture sensor coatings which present suitable thermal properties needs to be demonstrated. For this study, highly luminescent erbium and europium doped yttria-stabilized zirconia and state-of-the-art yttria-stabilized zirconia coatings manufactured by air plasma spray were characterized to determine the effects of the embedded rare-earth dopants on coating internal strain and stress and to quantify and compare their high temperature response using synchrotron X-ray diffraction. In-situ depth-resolved strain measurements were performed at 15 μm intervals along the depth of the coatings to evaluate materials response at key locations, specifically at layer interfaces. In-plane stress was calculated for the coatings and a finite element model was implemented to supplement the results and enable further predictions. The results show that the sensor coatings that were manufactured in this work revealed only minor variations in the strain response of sensor coatings under a typical thermal cycle and especially at temperatures closer to that of gas turbine operating conditions, compared to state-of-the-art coatings. This work demonstrates the viability of manufacturing rare-earth doped yttria-stabilized zirconia coatings that provide beneficial spectroscopic monitoring capabilities while having minimal impact on the thermomechanical response of the thermal barrier coatings.

Influence of Cooling Rate on Ice Crystallization and Melting in Sucrose-Water System

The ice crystallization and melting in systems where the equilibrium state is difficult to reach is one of the growing areas in pharmaceutical freeze-drying research. The quality of the final freeze-dried product depends on the parameters of the cooling step, which affect the ice nucleation and growth. In this paper, we present a DSC study of ice crystallization and melting in a sucrose-water system. Using two different types of thermal cycles, we examine the influence of cooling and heating rates on the thermal behavior of sucrose-water solutions with water contents between 50 and 100 wt%.The DSC results show that low cooling rates provide crystallization at higher temperatures and lead to lower amount of non-freezing water. Consequently, the glass transition and ice melting properties observed upon heating depend on the cooling conditions in the preceding step. Based on the experimental results, we investigate the reasons for the existence of the two steps on DSC heating curves in sucrose-water systems: the glass transition step and the onset of ice melting. We show that diffusion of water can be the limiting factor for ice growth and melting in the sucrose-water system when the amorphous phase is in a liquid state. In particular, when the diffusion coefficient drops below 10−14 m2/sec, the ice crystals growth or melting becomes strongly suppressed even above the glass transition temperature. Understanding the diffusion limitations in the sucrose-water system can be used for the optimization of the freeze-drying protocols for proteins and probiotics.

Microstructure evolution along build direction for thin-wall components fabricated with wire-direct energy deposition

PurposeThe use of a gas metal arc welding-based weld-deposition, referred to as wire-direct energy deposition or wire-arc additive manufacturing, is one of the notable additive manufacturing methods for producing metallic components at high deposition rates. In this method, the near-net shape is manufactured through layer-by-layer weld-deposition on a substrate. However, as a result of this sequential weld-deposition, different layers are subjected to different types of thermal cycles and partial re-melting. The resulting microstructural evolution of the material may not be uniform. Hence, the purpose of this study is to assess microstructure variation along with the lamination direction (or build direction).Design/methodology/approachThe study was carried out for two different boundary conditions, namely, isolated condition and cooled condition. The microstructural evolution across the layers is hypothesized based on experimental assessment; this included microhardness, scanning electron microscopy imaging and electron backscatter diffraction analysis. These conditions subsequently collaborated with the help of thermal modeling of the process.FindingsDuring a new layer deposition, the previous layer also is subject to re-melt. While the newly added layer undergoes rapid cooling through a combination of convection, conduction and radiation losses, the penultimate layer, sees a slower cooling curve due to its smaller exposure area. This behavior of rapid-solidification and subsequent re-melting and re-solidification is a progressing phenomenon across the layers and the bulk of the layers have uniform grains due to this remelt-re-solidification phenomenon.Research limitations/implicationsThis paper studies the microstructure variation along with the build direction for thin-walled components fabricated through weld-deposition. This study would be helpful in addressing the issue of anisotropy resulting from the distinctive thermal history of each layer in the overall theme of metal additive manufacturing.Originality/valueThe unique aspect of this paper is the postulation of a generic hypothesis, based on experimental findings and supported by thermal modeling of the process, for remelt-re-solidification phenomenon followed by temperature raising/lowering repetitively in every layer deposition across the layers. This is implemented for different types of base plate conditions, revealing the role of boundary conditions on the microstructure evolution.

Crystalline Silicon (c-Si) Solar Cell Interconnect Damage Prediction Function Based on Effect of Temperature Ramps and Dwells on Creep Damage under Field Thermal Cycling

c-Si solar cell interconnection damages from thermal cycles emanate from cumulative damage contributions from the various load steps in a typical thermal cycle. In general, a typical thermal cycle involves five thermal load steps, namely: 1st cold dwell, ramp-up, hot dwell, ramp-down, and 2nd cold dwell. To predict the contributions of each of these load steps to creep damage in soldered interconnections, each of the respective load steps needs to be profiled to accurately fit a function capable of predicting the damage contributions from a given number of thermal cycles. In this study, a field thermal cycle profile generated from in situ thermal cyclings at a test site in Kumasi, a hot humid region of sub-Saharan Africa, is used to predict damage in solar cell interconnections from accumulated creep energy density using finite element analysis (FEA). The damage was assessed for two different solder formulations, namely: Pb60Sn40 and Sn3.8Ag0.7Cu (lead-free). The results from the FEA simulations show that the cooling (ramp-down) load steps accounted for the highest accumulated creep energy density (ACED) damage in solder interconnections. The ramp-up load steps followed this closely. The cumulative contributions of the two load steps accounted for 78% and 88% of the total damage per cycle in the Pb60Sn40 and Sn3.8Ag0.7Cu solder interconnections, respectively. Furthermore, a study of the damage profiles from each of the five load steps revealed that each of the damage functions from the various load steps is a step function involving the first two thermal cycles, on one hand, and the remaining 10 thermal cycles on the other hand. The damage from the first two thermal cycles can be predicted from a logarithmic function, whereas the damage from the remaining 10 thermal cycles is predicted using six-order polynomial functions. The ACED results computed from the damage functions are in close agreement with the results from the FEA simulation. The functions generated provide useful relations for the prediction of the life (number of cycles to failure) of solder interconnections in solar cells. The systematic approach used in this study can be repeated for other test sites to generate damage functions for the prediction of the life of c-Si PV cells with SnPb and lead-free solder interconnections.

Multimodal γ′ precipitation in Inconel-738 Ni-based superalloy during electron-beam powder bed fusion additive manufacturing

Additive manufacturing is a promising alternative method for fabricating components of Ni-based superalloys which are difficult to cast, form and join. However, typical thermal cycles associated with laser powder bed-fusion techniques suppress the formation of desirable microstructures containing γ′ particles, necessitating long-time post-process heat treatments. Here we report in-situ precipitation of γ′ (L12-ordered) particles and carbides during electron-beam powder bed-fusion of Inconel-738. The γ′ particles are homogenously distributed across the build and exhibit a multimodal size distribution. Based on atom-probe microscopy, we propose a eutectic reaction and multiple nucleation, growth, coarsening and dissolution bursts during thermal cycling as formation mechanism.

Transient Thermo-Mechanical Analysis of Steel Ladle Refractory Linings Using Mechanical Homogenization Approach

Mortarless refractory masonry structures are widely used in the steel industry for the linings of many high-temperature industrial applications including steel ladles. The design and optimization of these components require accurate numerical models that consider the presence of joints, as well as joint closure and opening due to cyclic heating and cooling. The present work reports on the formulation, numerical implementation, validation, and application of homogenized numerical models for the simulation of refractory masonry structures with dry joints. The validated constitutive model has been used to simulate a steel ladle and analyze its transient thermomechanical behavior during a typical thermal cycle of a steel ladle. A 3D solution domain and enhanced thermal and mechanical boundary conditions have been used. Parametric studies to investigate the impact of joint thickness on the thermomechanical response of the ladle have been carried out. The results clearly demonstrate that the thermomechanical behavior of mortarless masonry is orthotropic and nonlinear due to the gradual closure and reopening of the joints with the increase and decrease in temperature. In addition, resulting thermal stresses increase with the increase in temperature and decrease with the increase in joint thickness.

Process planning strategy for wire-arc additive manufacturing: Thermal behavior considerations

Wire arc additive manufacturing (WAAM) has become a promising metal 3D printing technology for fabricating large-scale and complex-shaped components. One major problem that limits the application of WAAM is the difficulty in controlling the dimensional accuracy under constantly changing interlayer temperatures. During the deposition process, as the wall height increases, the heat accumulates on the upper layers, which leads to the variation of the layer dimensions. Normal practices such as introducing idle time and actively cooling the workpiece to mitigate such problems lack efficiency and practicality, respectively. A novel process planning strategy is proposed in this paper and aims to achieve a continuous deposition process while ensuring dimensional accuracy. With the aid of a finite element model, the typical thermal transfer cycle of the workpiece was analyzed and then divided into different stages. When depositing material, the interlayer temperature of the subsequent layers can be predicted using the developed algorithm. Hence, the process parameters (e.g., wire feed speed and travel speed) can be varied according to the predicted interlayer temperature using the developed adaptive process model, and this will ensure the uniform layer dimensions. The effectiveness of the proposed technique is verified by a large-scale shell-shaped component with a total of 753 layers. The result shows that such technique succeeds in a continuous fabrication of the component with high accuracy and efficiency.

Optimization of the Continuous Galvanizing Heat Treatment Process in Ultra-High Strength Dual Phase Steels Using a Multivariate Model

The main process variables to produce galvanized dual phase (DP) steel sheets in continuous galvanizing lines are time and temperature of intercritical austenitizing (tIA and TIA), cooling rate (CR1) after intercritical austenitizing, holding time at the galvanizing temperature (tG) and finally the cooling rate (CR2) to room temperature. In this research work, the effects of CR1, tG and CR2 on the ultimate tensile strength (UTS), yield strength (YS), and elongation (EL) of cold rolled low carbon steel were investigated by applying an experimental central composite design and a multivariate regression model. A multi-objective optimization and the Pareto Front were used for the optimization of the continuous galvanizing heat treatments. Typical thermal cycles applied for the production of continuous galvanized AHSS-DP strips were simulated in a quenching dilatometer using miniature tensile specimens. The experimental results of UTS, YS and EL were used to fit the multivariate regression model for the prediction of these mechanical properties from the processing parameters (CR1, tG and CR2). In general, the results show that the proposed multivariate model correctly predicts the mechanical properties of UTS, YS and %EL for DP steels processed under continuous galvanizing conditions. Furthermore, it is demonstrated that the phase transformations that take place during the optimized tG (galvanizing time) play a dominant role in determining the values of the mechanical properties of the DP steel. The production of hot-dip galvanized DP steels with a minimum tensile strength of 1100 MPa is possible by applying the proposed methodology. The results provide important scientific and technological knowledge about the annealing/galvanizing thermal cycle effects on the microstructure and mechanical properties of DP steels.

Laser Wire Deposition of Thick Ti-6Al-4V Buildups: Heat Transfer Model, Microstructure, and Mechanical Properties Evaluations

This paper investigates the effect of depositing thick laser wire Ti-6Al-4V samples on the developed microstructure and subsequent mechanical properties. First, a thermal model is proposed to get a better understanding on the typical thermal cycles that the material has undergone. It is followed by a discussion on the typical structural features that developed in the as-built condition and following three post deposition heat treatments. A stress relief cycle did not substantially affect the morphology of the developed α platelets. Annealing and HIP followed by aging favored the coarsening of the post-deposited microstructure. A strengthening in terms of hardness has been observed only after the stress relief heat treatment. Developed static tensile properties were globally below the wrought levels. Stress-relieved specimens developed the higher strengths, whereas the annealed or HIPed samples followed by aging were associated with a better elongation. Charpy impact properties were higher in the annealed or HIPed condition followed by aging when compared with the stress-relieved ones. No anisotropy in the impact toughness properties was observed. The annealed and aged samples and the HIPed and aged samples produced overall very similar results showing that HIP is not required for enhance materials properties of laser wire deposition applications.

A Simple Whole-Blood Polymerase Chain Reaction without DNA Extraction for Thalassemia Diagnosis

Polymerase chain reaction (PCR) diagnosis of thalassemia usually relies on using genomic DNA. Preparing the genomic DNA can lead to sample-to-sample contamination. This report was aimed to establish the PCR protocol using whole-blood for detecting mutations of α- and β-globin genes causing the thalassemia syndrome. First, the PCR facilitators, betaine and bovine serum albumin (BSA), were tested, simultaneously with an adjustment of PCR thermal cycler and of whole-blood volume. Thereafter, the established whole-blood PCR was applied for detecting, in both known and unknown samples, the HBA1 Southeast Asian (– –SEA) (NG_000006.1: g.26264_45564del19301) deletion, Hb Constant Spring (Hb CS, HBA2: c.427T>C, αCSα), codon 17 (A>T) (HBB: c.52A>T), codons 41/42 (–TTCT) (HBB: c.126_129delCTTT) deletion, –28 (A>G) (HBB: c.-78A>G) and codon 26 (G>A) (Hb E or HBB: c.79G>A). It was shown that the whole-blood PCR worked successfully in 9.0% (w/v) betaine, with 1 μL of EDTA whole blood and with addition of 10 heat-cool steps (3 min. at 94 °C, followed by 3 min. at 55 °C) prior to the typical thermal cycles for the mutations. The capability of the new whole-blood PCR was similar to that of the typical DNA-based PCR. Therefore, the newly established whole-blood PCR could be performed for PCR diagnosis of thalassemia. Using this platform, sample-to-sample contamination should be eliminated.

Thermal cycles and its effect on HAZ microstructure and mechanical properties of 10CrNi3MoV steel in double-sided double arc welding

Thermal cycles of heat-affected zones (HAZs) in double-sided double arc welding (DSDAW) were measured in this study. The microstructure and impact toughness of specimens imposing typical thermal cycles of coarse-grained heat-affected zone (CGHAZ) were analysed by using thermal simulation. The results show that the two arcs influenced each other even during the deposition of the fourth layer in each side. Both of the two arcs could reduce the cooling rate of HAZs. Besides, the heating of the rear arc may make HAZ sustain in bainite transformation interval for a long time and lead to the formation of granular bainite which could deteriorate welding joint. To obtain good toughness of joint by DSDAW, the arc distance during filling pass depositing should be properly enlarged to eliminate granular baintie under the premise that the trough temperature (T t) is higher than 200 °C.

The Correlation of the TBC Lifetimes in Burner Cycling Test with Thermal Gradient and Furnace Isothermal Cycling Test by TGO Effects

Two types of typical thermal cycling tests are used for the evaluation of thermal cycling lifetime of thermal barrier coatings. Those are the burner cycling test with a thermal gradient and the isothermal furnace cycling test. There are diverse explanations to test results up to now. Although certain correlations should exist between the results obtained by two types of the tests, no evident parameters in two tests were directly related, possibly due to large range of difference test conditions. In this investigation, a series of TBC samples with carefully prepared Al2O3-based TGO of different thicknesses were used for both the burner cycling and the furnace cycling tests. The relationships between thermal cycling lifetime and TGO thickness were obtained for two types of the tests. It was found that TGO thickness presents the same influence tendency despite of different types of thermal cycling test. The results reveal the existence of the critical TGO thickness by which the transition of failure mode takes place. Moreover, the values of the critical TGO thickness for two tests are comparable. The results evidently suggest that the lifetimes during different thermal cycling tests can be correlated by TGO effects on failure behavior. However, it is clear that the apparent dominant driving factors to TBC failure are different in two types of tests. Accordingly, the burner cycling test could be used for optimizing the durability of ceramic top coat by separating the effect of individual factors through test condition design, while the furnace cycling test results represent the integrated TBC durable performance of the bond coat and top ceramic coating.

Development of high strength ductile eutectoid steel through cyclic heat treatment involving incomplete austenitization followed by forced air cooling

Annealed AISI 1080 steel bars were subjected to cyclic heat treatment up to 3cycles. Each cycle consisted of short duration holding (incomplete austenization) for 6min at 775°C (in fully austenitic region) followed by forced air cooling (air flow rate: 38.4m3h−1) to the room temperature. Such a typical thermal cycling resulted in a significant increase in hardness and strength on execution of 2cycles. This was attributed to a novel microstructure consisting of matted fine pearlite containing submicroscopic cementite spheroids. The hardness (368HV) and strength (UTS=1095MPa) achieved after 2cycles of heat treatment was much higher and ductility (%Elongation=16) was quite reasonable when compared with that in annealed condition (Hardness=222HV, UTS=740MPa, %Elongation=21). Execution of third cycle resulted in decrease in hardness and strength due to disappearance of matted fine pearlite region. Furthermore, with regard to previously carried out research by the authors, the process efficiency has been greatly enhanced (heat treatment duration is reduced) on adoption of more intense forced air cooling without compromising strength and ductility.

Microstructural Modifications in AISI 1080 Eutectoid Steel Under Combined Cyclic Heat Treatment

In this research work annealed AISI 1080 steel bars are subjected to a typical combined cyclic heat treatment involving two cycles. The first cycle consist of inserting the specimen in an electric resistance furnace at a temperature of 775 °C (in fully austenitic region) and holding for a short duration (6 min), followed by forced air cooling to the room temperature. In second cycle holding temperature and time being same, the specimen is subjected to oil quenching. Such a typical combined thermal cycling results in the evolution of a novel microstructure that comprises of submicroscopic cementite spheroids and fine microscopic cementite clusters in a matrix of martensite. Accordingly, very high hardness (894 HV) is achieved which envisaged a new heat treatment route of the development of plain carbon tool steel.

Structure–property correlation of AISI 1080 steel subjected to cyclic quenching treatment

Annealed AISI 1080 steel bars were subjected to cyclic heat treatment for different number of cycles, viz. 1-cycle, 2-cycle and 3-cycle. Each cycle consisted of inserting the specimen in an electric resistance furnace at a temperature of 775°C (in fully austenitic region) and holding for a short duration (6min), followed by oil quenching to the room temperature. Besides, tempering treatment (at 300°C for 1h) was also provided after 3 cycles of heat treatment. Such a typical thermal cycling resulted in the evolution of a novel microstructure that comprised of microscopic clusters and submicroscopic spheroids of cementite in a matrix of martensite after 3 cycles of heat treatment. Accordingly, much higher hardness (845HV), strength (UTS=1609MPa) and equivalent ductility (% Elongation=8) were achieved with 3 cycles of heat treatment as compared to conventional hardened and tempered AISI 1080 steel (Hardness=616HV, UTS= 1206MPa, % Elongation=9). Execution of tempering after 3 cycles of heat treatment resulted in reasonable strength (UTS=1256MPa) with higher ductility (% Elongation=13).