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Investigation of Mechanical Tests for Hydrogen Embrittlement in Automotive PHS Steels
Aug 2019
Publication
The problem of hydrogen embrittlement in ultra-high-strength steels is well known. In this study slow strain rate four-point bending and permeation tests were performed with the aim of characterizing innovative materials with an ultimate tensile strength higher than 1000 MPa. Hydrogen uptake in the case of automotive components can take place in many phases of the manufacturing process: during hot stamping due to the presence of moisture in the furnace atmosphere high-temperature dissociation giving rise to atomic hydrogen or also during electrochemical treatments such as cataphoresis. Moreover possible corrosive phenomena could be a source of hydrogen during an automobile’s life. This series of tests was performed here in order to characterize two press-hardened steels (PHS)—USIBOR 1500® and USIBOR 2000®—to establish a correlation between ultimate mechanical properties and critical hydrogen concentration.
Mechanical Properties of Gas Main Steels after Long-Term Operation and Peculiarities of Their Fracture Surface Morphology
Feb 2019
Publication
Regularities of steel structure degradation of the “Novopskov-Aksay-Mozdok” gas main pipelines (Nevinnomysskaya CS) as well as the “Gorky-Center” pipelines (Gavrilovskaya CS) were studied. The revealed peculiarities of their degradation after long-term operation are suggested to be treated as a particular case of the damage accumulation classification (scheme) proposed by prof. H.M. Nykyforchyn. It is shown that the fracture surface consists of sections of ductile separation and localized zones of micro-spalling. The presence of the latter testifies to the hydrogen-induced embrittlement effect. However the steels under investigation possess sufficiently high levels of the mechanical properties required for their further safe exploitation both in terms of durability and cracking resistance.
Hydrogen Transport - Fuelling The Future
Dec 2020
Publication
Through the combustion of fossil fuels the transport sector is responsible for 20-30% of global CO2 emissions. We can support the net-zero one ambition by decarbonising transport modes using green hydrogen fuelled options – hydrogen generated from renewable energy sources such as offshore wind.<br/><br/>We have been working with clients across the hydrogen industry for several years specifically around the generation dispatch and use of hydrogen within energy systems. However interest is swiftly moving to wider hydrogen based solutions including within the fleet rail aviation and maritime sectors.<br/><br/>Our latest ‘Future of Energy’ series explores the opportunity for green fuelled hydrogen transport. We look at each industry in detail the barriers to uptake market conditions and look at how the transport industry could adapt and develop to embrace a net-zero future.
Hydrogen for Heating? Decarbonization Options for Households in the United Kingdom in 2050
Dec 2020
Publication
The heating sector makes up 10% of the United Kingdom’s carbon footprint and residential homes account for a majority of demand. At present central heating from a natural gas-fired boiler is the most common system in the UK but low or zero-carbon hydrogen and renewable electricity are the two primary energy replacement options to reduce the carbon footprint. An important consideration is how using either energy source would affect heating costs. This assessment projects the costs for a typical single-family UK household and climate performance in 2050 using low-GHG or GHG-neutral hydrogen renewable electricity or a combination of both. The cost of using boilers or fuel cells in 2050 with two types of hydrogen are assessed: produced via steam-methane reforming (SMR) combined with carbon capture and storage (CCS) and electrolysis using zero-carbon renewable electricity. The costs of heat pumps the most promising heating technology for the direct use of renewable electricity are also assessed in two scenarios: a heat pump only and a hybrid heat pump with an auxiliary hydrogen boiler.
You can download this document from the International Council On Clean Transportation website linked here
You can download this document from the International Council On Clean Transportation website linked here
Are We Building Back Better? Evidence from 2020 and Pathways for Inclusive Green Recovery Spending
Mar 2021
Publication
COVID-19 has led to a global crisis threatening the lives and livelihoods of the most vulnerable by increasing poverty exacerbating inequalities and damaging long-term economic growth prospects. The report Are We Building Back Better? Evidence from 2020 and Pathways for Inclusive Green Recovery Spending provides an analysis of over 3500 fiscal policies announced by leading economies in 2020 and calls for governments to invest more sustainably and tackle inequalities as they stimulate growth in the wake of the devastation wrought by the pandemic.
Evaluation of Sorbents for High Temperature Removal of Tars, Hydrogen Sulphide, Hydrogen Chloride and Ammonia from Biomass-derived Syngas by Using Aspen Plus
Jan 2020
Publication
Biomass gasification is a promising technology to produce secondary fuels or heat and power offering considerable advantages over fossil fuels. An important aspect in the usage of producer gas is the removal of harmful contaminants from the raw syngas. Thus the object of this study is the development of a simulation model for a gasifier including gas clean-up for which a fluidized-bed gasifier for biomass-derived syngas production was considered based on a quasi-equilibrium approach through Gibbs free energy minimisation and including an innovative hot gas cleaning constituted by a combination of catalyst sorbents inside the gasification reactor catalysts in the freeboard and subsequent sorbent reactors by using Aspen Plus software. The gas cleaning chain simulates the raw syngas clean-up for several organic and inorganic contaminants i.e. toluene benzene naphthalene hydrogen sulphide hydrogen chloride and ammonia. The tar and inorganic contaminants final values achieved are under 1 g/Nm3 and 1 ppm respectively.
Strategic Research and Innovation Agenda
Jul 2020
Publication
The FCH1JU and FCH2JU have proven effective in developing hydrogen technologies to a high Technology Readiness Level (TRL) allowing for large-scale deployment. Yet there is still an important work to be performed in terms of Research and Innovation in order to develop the next generation of products as well as technologies that did not reach a sufficiently high TRL to envisage a large-scale deployment.<br/><br/>Within the framework of the preparation of the foreseen Clean Hydrogen for Europe (the third public-private partnership continuation of the FCH2JU) Hydrogen Europe and Hydrogen Europe Research have prepared their Strategic Research and Innovation Agenda (SRIA) which is made of a set of approximately 20 roadmaps. This SRIA represents the view of the private partner and will be used as a basis to develop the Multi Annual Work Plan (MAWP) of the Clean Hydrogen for Europe partnership. The current version (July 2020) is the final draft that has been submitted to the European Commission.
Effects of Quantum Confinement of Hydrogen in Nanocavities – Experimental INS Results and New Insights
Jun 2020
Publication
Current developments of non-relativistic quantum mechanics appear to predict and reveal counter-intuitive dynamical effects of hydrogen in nanostructured materials that are of considerable importance for basic research as well as for technological applications. In this review the experimental focus is on H2O and H molecules in carbon nanotubes and other nanocavities that have been experimentally investigated using the well-established technique of incoherent inelastic neutron scattering (INS). For instance the momentum and energy transfers as obtained from the commonly used standard data analysis techniques from a
(I) H2 molecule in a C-nanotube resulting in a roto-translational motion along the nanotube axis seems to (1) either violate the standard conservation laws or (2) to attribute to the H molecule undergoing translation the effective mass a.m.u. (atomic mass units) instead of the expected 2 a.m.u. A similar striking anomalous effect has been found in the neutron-H scattering from the
(II) H2O molecules in nano-channels of some solid materials in which O-H stretching vibrations along the channel axis are created.
The results of this scattering process seem to once again either violate the standard conservation laws or to attribute to the effective mass of the struck H2 molecule as a.m.u. instead of the expected value of 1 a.m.u. We show that these counterintuitive observations from the INS studies have no conventional interpretation within the standard non-relativistic scattering theory. However they can be qualitatively interpreted “from first principles” within the framework of modern theories of
(III) time-symmetric quantum dynamics as provided by the weak values (WV) and two-state- vector formalism (TSVF)
and/or
(IV) quantum correlations especially quantum discord (QD) and quantum thermodynamics (QTD).
The theoretical analysis provides an intuitive understanding of the experimental results gives strong evidence that the nano-structured cavities do represent quantum systems which participate significantly in the dynamics of the neutron-H scattering and surprisingly shows that new physical information can be derived from the experimental data. This latter point may also have far-reaching consequences for technology and material sciences (e.g. fuel cells H storage materials etc.). Moreover novel insights into the short-lived quantum dynamics and/or quantum information theory can be gained.
(I) H2 molecule in a C-nanotube resulting in a roto-translational motion along the nanotube axis seems to (1) either violate the standard conservation laws or (2) to attribute to the H molecule undergoing translation the effective mass a.m.u. (atomic mass units) instead of the expected 2 a.m.u. A similar striking anomalous effect has been found in the neutron-H scattering from the
(II) H2O molecules in nano-channels of some solid materials in which O-H stretching vibrations along the channel axis are created.
The results of this scattering process seem to once again either violate the standard conservation laws or to attribute to the effective mass of the struck H2 molecule as a.m.u. instead of the expected value of 1 a.m.u. We show that these counterintuitive observations from the INS studies have no conventional interpretation within the standard non-relativistic scattering theory. However they can be qualitatively interpreted “from first principles” within the framework of modern theories of
(III) time-symmetric quantum dynamics as provided by the weak values (WV) and two-state- vector formalism (TSVF)
and/or
(IV) quantum correlations especially quantum discord (QD) and quantum thermodynamics (QTD).
The theoretical analysis provides an intuitive understanding of the experimental results gives strong evidence that the nano-structured cavities do represent quantum systems which participate significantly in the dynamics of the neutron-H scattering and surprisingly shows that new physical information can be derived from the experimental data. This latter point may also have far-reaching consequences for technology and material sciences (e.g. fuel cells H storage materials etc.). Moreover novel insights into the short-lived quantum dynamics and/or quantum information theory can be gained.
Hydrogen Diffusion Mechanism around a Crack Tip in Type 304L Austenite Stainless Steel Considering the Influence of the Volume Expansion of Strain-Induced Martensite Transformation
Sep 2019
Publication
Strain-induced martensite transformation (SIMT) commonly exists around a crack tip of metastable austenite stainless steels. The influence of the volume expansion of the SIMT on the hydrogen diffusion was investigated by hydrogen diffusion modelling around a crack tip in type 304L austenite stainless steel. The volume expansion changed the tensile stress state into pressure stress state at the crack tip resulting in a large stress gradient along the crack propagation direction. Compared to the analysis without considering the volume expansion effect this volume expansion further accelerated the hydrogen transport from the inner surface to a critical region ahead of the crack tip and further increased the maximum value of the hydrogen concentration at the critical position where the strain-induced martensite fraction approximates to 0.1 indicating that the volume expansion of the SIMT further increased the hydrogen embrittlement susceptibility.
H21- Leeds City Gate Project Report
Jul 2016
Publication
The H21 Leeds City Gate project is a study with the aim of determining the feasibility from both a technical and economic viewpoint of converting the existing natural gas network in Leeds one of the largest UK cities to 100% hydrogen. The project has been designed to minimise disruption for existing customers and to deliver heat at the same cost as current natural gas to customers. The project has shown that:
The project has provided costs for the scheme and has modelled these costs in a regulatory finance model. In addition the availability of low-cost bulk hydrogen in a gas network could revolutionise the potential for hydrogen vehicles and via fuel cells support a decentralised model of combined heat and power and localised power generation.
This report and any attachment is freely available on the ENA Smarter Networks Portal here. IGEM Members can download the report and any attachment directly by clicking on the pdf icon above.
- The gas network has the correct capacity for such a conversion
- It can be converted incrementally with minimal disruption to customers
- Minimal new energy infrastructure will be required compared to alternatives
- The existing heat demand for Leeds can be met via steam methane reforming and salt cavern storage using technology in use around the world today
The project has provided costs for the scheme and has modelled these costs in a regulatory finance model. In addition the availability of low-cost bulk hydrogen in a gas network could revolutionise the potential for hydrogen vehicles and via fuel cells support a decentralised model of combined heat and power and localised power generation.
This report and any attachment is freely available on the ENA Smarter Networks Portal here. IGEM Members can download the report and any attachment directly by clicking on the pdf icon above.
Hydrolysis-Based Hydrogen Generation Investigation of Aluminium System Adding Low-Melting Metals
Mar 2021
Publication
In this age of human civilization there is a need for more efficient cleaner and renewable energy as opposed to that provided by nonrenewable sources such as coal and oil. In this sense hydrogen energy has been proven to be a better choice. In this paper a portable graphite crucible metal smelting furnace was used to prepare ten multi-element aluminum alloy ingots with different components. The microstructure and phase composition of the ingots and reaction products were analyzed by X-ray diffraction (XRD) scanning electron microscopy (SEM) and differential scanning calorimetry (DSC). The reaction was carried out in a constant temperature water bath furnace at 60°C and the hydrogen production performance of the multi-element aluminum alloys in different proportions was compared by the drainage gas collection method. The experimental results show that the as-cast microstructure of Al–Ga–In–Sn aluminum alloy is composed of a solid solution of Al and part of Ga and a second phase of In3Sn. After the hydrolysis reaction the products were dried at 150°C and then analyzed by XRD. The products were mainly composed of AlOOH and In3Sn. Alloys with different compositions react at the same hydrolysis temperature and the hydrogen production performance is related to the ratio of low-melting-point metal elements. By comparing two different ratios of Ga–In–Sn (GIS) the hydrogen production capacity and production rate when the ratio is 6:3:1 are generally higher than those when the ratio is 7:2:1. The second phase content affects the hydrogen production performance.
Analysis of the Hydrogen Induced Cracking by Means of the Small Punch Test: Effect of the Specimen Geometry and the Hydrogen Pre-Charge Mode
Nov 2018
Publication
This paper presents a simplified procedure to analyse the Hydrogen Induced Cracking (HIC) of structural steels by means of the Small Punch Test (SPT). Two types of notched specimens were used: one with through-thickness lateral notch and another with surface longitudinal notch. The results for conventional specimens were compared with those for hydrogen pre-charged specimens. For this purpose two different methods to introduce hydrogen in the specimens were used: cathodic/electrochemical pre-charging and pressurized gaseous hydrogen pre-charging. The results obtained with both methods are also discussed.
Hydrogen from Renewable Power
Sep 2018
Publication
As the world strives to cut carbon emissions electric power from renewables has emerged as a vital energy source. Yet transport and industry will still require combustible fuels for many purposes. Such needs could be met with hydrogen which itself can be produced using renewable power.
Hydrogen provides high-grade heat helping to meet a range of energy needs that would be difficult to address through direct electrification. This could make hydrogen the missing link in the transformation of the global energy system.
Key sectors for renewable-based hydrogen uptake include:
Electrolysers – which split hydrogen and oxygen – can make power systems more flexible helping to integrate high shares of variable renewables. Power consumption for electrolysis can be adjusted to follow actual solar and wind output while producing the hydrogen needed for transport industry or injection into the gas grid.
In the long run hydrogen could become a key element in 100% renewable energy systems. With technologies maturing actual scale-up should yield major cost reductions. The right policy and regulatory framework however remains crucial to stimulate private investment in in hydrogen production in the first place.
Hydrogen provides high-grade heat helping to meet a range of energy needs that would be difficult to address through direct electrification. This could make hydrogen the missing link in the transformation of the global energy system.
Key sectors for renewable-based hydrogen uptake include:
- Industry where it could replace fossil-based feedstocks including natural gas in high-emission applications.
- Buildings and power where it could be mixed with natural gas or combined with industrial carbon dioxide (CO2) emissions to produce syngas.
- Transport where it can provide low-carbon mobility through fuel-cell electric vehicles.
Electrolysers – which split hydrogen and oxygen – can make power systems more flexible helping to integrate high shares of variable renewables. Power consumption for electrolysis can be adjusted to follow actual solar and wind output while producing the hydrogen needed for transport industry or injection into the gas grid.
In the long run hydrogen could become a key element in 100% renewable energy systems. With technologies maturing actual scale-up should yield major cost reductions. The right policy and regulatory framework however remains crucial to stimulate private investment in in hydrogen production in the first place.
Cost Optimization of a Stand-Alone Hybrid Energy System with Fuel Cell and PV
Mar 2020
Publication
Renewable energy has become very popular in recent years. The amount of renewable generation has increased in both grid-connected and stand-alone systems. This is because it can provide clean energy in a cost-effective and environmentally friendly fashion. Among all varieties photovoltaic (PV) is the ultimate rising star. Integration of other technologies with solar is enhancing the efficiency and reliability of the system. In this paper a fuel cell–solar photovoltaic (FC-PV)-based hybrid energy system has been proposed to meet the electrical load demand of a small community center in India. The system is developed with PV panels fuel cell an electrolyzer and hydrogen storage tank. Detailed mathematical modeling of this system as well as its operation algorithm have been presented. Furthermore cost optimization has been performed to determine ratings of PV and Hydrogen system components. The objective is to minimize the levelized cost of electricity (LCOE) of this standalone system. This optimization is performed in HOMER software as well as another tool using an artificial bee colony (ABC). The results obtained by both methods have been compared in terms of cost effectiveness. It is evident from the results that for a 68 MWh/yr of electricity demand is met by the 129 kW Solar PV 15 kW Fuel cell along with a 34 kW electrolyzer and a 20 kg hydrogen tank with a LPSP of 0.053%. The LCOE is found to be in 0.228 $/kWh. Results also show that use of more sophisticated algorithms such as ABC yields more optimized solutions than package programs such as HOMER. Finally operational details for FC-PV hybrid system using IEC 61850 inter-operable communication is presented. IEC 61850 information models for FC electrolyzer hydrogen tank were developed and relevent IEC 61850 message exchanges for energy management in FC-PV hybrid system are demonstrated.
Scottish Hydrogen Assessment
Dec 2020
Publication
During 2020 the Scottish Government in partnership with Highlands and Islands Enterprise and Scottish Enterprise commissioned Arup and E4Tech to carry out a hydrogen assessment to deepen our evidence base in order to inform our policies on hydrogen going forward. The assessment aims to investigate how and where hydrogen may fit within the evolving energy system technically geographically and economically. To assist in this consideration a key part of the Hydrogen Assessment is the development of distinct viable scenarios for hydrogen deployment in Scotland and the economic assessment of those scenarios.<br/>From our assessment it is clear that hydrogen is not just an energy and emissions reduction opportunity; it could also have an important role in generating new economic opportunities in Scotland. The assessment forms an important part of the evidence base that informed the development of the Hydrogen Policy Statement.
A Production and Delivery Model of Hydrogen from Solar Thermal Energy in the United Arab Emirates
May 2022
Publication
Hydrogen production from surplus solar electricity as energy storage for export purposes can push towards large-scale application of solar energy in the United Arab Emirates and the Middle East region; this region’s properties of high solar irradiance and vast empty lands provide a good fit for solar technologies such as concentrated solar power and photovoltaics. However a thorough comparison between the two solar technologies as well as investigating the infrastructure of the United Arab Emirates for a well-to-ship hydrogen pathway is yet to be fully carried out. Therefore in this study we aim to provide a full model for solar hydrogen production and delivery by evaluating the potential of concentrated solar power and photovoltaics in the UAE then comparing two different pathways for hydrogen delivery based on the location of hydrogen production sites. A Solid Oxide Cell Electrolyzer (SOEC) is used for technical comparison while the shortest routes for hydrogen transport were analyzed using Geographical Information System (GIS). The results show that CSP technology coupled with SOEC is the most favorable pathway for large-scale hydrogen from solar energy production in the UAE for export purposes. Although PV has a slightly higher electricity potential compared to CSP around 42 GWh/km2 to 41.1 GWh/km2 respectively CSP show the highest productions rates of over 6 megatons of hydrogen when the electrolyzer is placed at the same site as the CSP plant while PV generates 5.15 megatons when hydrogen is produced at the same site with PV plants; meanwhile hydrogen from PV and CSP shows similar levels of 4.8 and 4.6 megatons of hydrogen respectively when electrolyzers are placed at port sites. Even considering the constraints in the UAE’s infrastructure and suggesting new shorter electrical transmission lines that could save up to 0.1 megatons of hydrogen in the second pathway production at the same site with CSP is still the most advantageous scenario.
Towards a CO2-neutral Steel Industry: Justice Aspects of CO2 Capture and Storage, Biomass- and Green Hydrogen-based Emission Reductions
Apr 2022
Publication
A rapid transition towards a CO2-neutral steel industry is required to limit climate change. Such a transition raises questions of justice as it entails positive and negative impacts unevenly distributed across societal stakeholders. To enable stakeholders to address such concerns this paper assesses the justice implications of three options that reduce emissions: CO2 capture and storage (CCS) on steel (up to 70%) bio-based steelmaking (up to 50%) and green hydrogen-based steel production (up to 100%). We select justice indicators from the energy climate labour and environmental justice literature and assess these indicators qualitatively for each of the technological routes based on literature and desk research. We find context-dependent differences in justness between the different technological routes. The impact on stakeholders varies across regions. There are justice concerns for local communities because of economic dependence on and environmental impact of the industry. Communities elsewhere are impacted through the siting of infrastructure and feedstock production. CCS and bio-based steelmaking routes can help retain industry and associated economic benefits on location while hydrogen-based steelmaking may deal better with environmental concerns. We conclude that besides techno-economic and environmental information transparency on sector-specific justice implications of transforming steel industries is essential for decision-making on technological routes
Progress in Biofuel Production from Gasification
May 2017
Publication
Biofuels from biomass gasification are reviewed here and demonstrated to be an attractive option. Recent progress in gasification techniques and key generation pathways for biofuels production process design and integration and socio-environmental impacts of biofuel generation are discussed with the goal of investigating gasification-to-biofuels’ credentials as a sustainable and eco-friendly technology. The synthesis of important biofuels such as bio-methanol bio-ethanol and higher alcohols bio-dimethyl ether Fischer Tropsch fuels bio-methane bio-hydrogen and algae-based fuels is reviewed together with recent technologies catalysts and reactors. Significant thermodynamic studies for each biofuel are also examined. Syngas cleaning is demonstrated to be a critical issue for biofuel production and innovative pathways such as those employed by Choren Industrietechnik Germany and BioMCN the Netherlands are shown to allow efficient methanol generation. The conversion of syngas to FT transportation fuels such as gasoline and diesel over Co or Fe catalysts is reviewed and demonstrated to be a promising option for the future of biofuels. Bio-methane has emerged as a lucrative alternative for conventional transportation fuel with all the advantages of natural gas including a dense distribution trade and supply network. Routes to produce H2 are discussed though critical issues such as storage expensive production routes with low efficiencies remain. Algae-based fuels are in the research and development stage but are shown to have immense potential to become commercially important because of their capability to fix large amounts of CO2 to rapidly grow in many environments and versatile end uses. However suitable process configurations resulting in optimal plant designs are crucial so detailed process integration is a powerful tool to optimize current and develop new processes. LCA and ethical issues are also discussed in brief. It is clear that the use of food crops as opposed to food wastes represents an area fraught with challenges which must be resolved on a case by case basis.
A Developed Plasmatron Design to Enhance Production of Hydrogen in Synthesis Gas Produced by a Fuel Reformer System
Jan 2022
Publication
Feeding IC engines with hydrogen‐rich syngas as an admixture to hydrocarbon fuels can decrease pollutant emissions particularly NOx. It offers a potential technique for low‐environmen‐ tal impact hydrocarbon fuel use in automotive applications. However hydrogen‐rich reformate gas (syngas) production via fuel reforming still needs more research and optimization. In this paper we describe the effect of a plasma torch assembly design on syngas yield and composition during plasma‐assisted reforming of gasoline. Additionally erosion resistance of the cathode‐emitting ma‐ terial under the conditions of gasoline reforming was studied using hafnium metal and lanthanated tungsten alloy. The gasoline reforming was performed with a noncatalytic nonthermal low‐current plasma system in the conditions of partial oxidation in an air and steam mixture. To find the most efficient plasma torch assembly configuration in terms of hydrogen production yield four types of anode design were tested i.e. two types of the swirl ring and two cathode materials while varying the inlet air and fuel flow rates. The experimental results showed that hydrogen was the highest proportion of the produced syngas. The smooth funnel shape anode design in Ring 1 at air/fuel flow rates of 24/4 27/4.5 and 30/5 g/min respectively was more effective than the edged funnel shape. Lanthanated tungsten alloy displayed higher erosion resistance than hafnium metal.
Effects of Hot Stamping and Tempering on Hydrogen Embrittlement of a Low-Carbon Boron-Alloyed Steel
Dec 2018
Publication
The effects of hot stamping (HS) and tempering on the hydrogen embrittlement (HE) behavior of a low-carbon boron-alloyed steel were studied by using slow strain rate tensile (SSRT) tests on notched sheet specimens. It was found that an additional significant hydrogen desorption peak at round 65–80 °C appeared after hydrogen-charging the corresponding hydrogen concentration (CHr) of the HS specimen was higher than that of the directed quenched (DQ) specimen and subsequent low-temperature tempering gave rise to a decrease of CHr. The DQ specimen exhibited a comparatively high HE susceptibility while tempering treatment at 100 °C could notably alleviate it by a relative decrease of ~24% at no expanse of strength and ductility. The HS specimen demonstrated much lower HE susceptibility compared with the DQ specimen and tempering at 200 °C could further alleviate its HE susceptibility. SEM analysis of fractured SSRT surfaces revealed that the DQ specimen showed a mixed transgranular-intergranular fracture while the HS and low-temperature tempered specimens exhibited a predominant quasi-cleavage transgranular fracture. Based on the obtained results we propose that a modified HS process coupled with low-temperature tempering treatment is a promising and feasible approach to ensure a low HE susceptibility for high-strength automobile parts made of this type of steel.
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