LIFE is the EU’s financial instrument supporting environmental and climate action projects throughout the EU.
The general objective of LIFE is to contribute to the implementation, updating and development of EU environmental and climate policy and legislation by co-financing projects with European added value.
LIFE began in 1992 and there have been four phases of the program: LIFE I, LIFE II, LIFE III and LIFE+. During this period, LIFE has co-financed 3954 projects across the EU, contributing approximately €3.1 billion to the protection of the environment.
EU Regulation no. 1293/2013 launched the fifth phase of LIFE for the period 2014-2020. The European Commission (DG Environment and DG Climate Action) manages the LIFE program together with the Executive Agency for Small and Medium-sized Enterprises (EASME).
The LIFE program is divided into two sub-programs: environment and climate action.
The Environment Sub-programs includes three priority areas:
- Environment and resource efficiency;
- Nature and biodiversity;
- Environmental governance and information.
The Climate Action Sub-programs includes three priority areas:
- Climate change mitigation;
- Climate change adaptation;
- Climate governance and information.
The general objectives of the new LIFE programme can be summarized as follows:
- To contribute to the shift towards a resource-efficient, low-carbon and climate-resilient economy, to the protection and improvement of the quality of the environment and to halting and reversing biodiversity loss, including the support of the Natura 2000 network and tackling the degradation of ecosystems
- To improve the development, implementation and enforcement of Union environmental and climate policy and legislation, and to act as a catalyst for, and promote, the integration and mainstreaming of environmental and climate objectives into other Union policies and public and private sector practice, including by increasing the public and private sector’s capacity
- Support better climate and environmental governance at all levels
The production process for high performance steel components for the automotive industry has a considerable impact on the environment and on human health that could be alleviated with more efficient use of raw materials and energy, and reductions in waste chemicals and greenhouse gas emissions.
High performance steel components, such as gears, are currently produced by machining technology, mainly due to high requirements in terms of mechanical properties and dimensional stability. The Powder Metallurgy (PM) technology is a sustainable manufacturing process recognized as a green technology and the high mechanical and dimensional requirements above mentioned could also be theoretically met by means of an innovative Die Wall Lubrication (DWL) compaction stage, in combination with high-temperature vacuum sintering and thermochemical treatment.
The design of a structural component based not only on the mechanical performances but which also considers all its life cycle, in a perspective of a circular economy, represents a very important issue.
The main environmental issue tackled by the project regards the efficiency in use of raw materials and energy, combined with the removal of chemicals that have an impact on the environment and on human health in the production process of high density steel components. Moreover, more and more steel PM components from standard practice present recyclability problems due to the presence of alloying elements like copper.
A further environmental problem faced in the project is the elimination and/or drastic reduction of solid pre-mixed lubricants normally added to the metal powder in the standard practice. Thanks to this the delubrication or debinding phase that involve a thermal process having environmental impact, can be avoided.
The aim of the LIFE 4GreenSteel project is to demonstrate the feasibility to replace the traditional energy-intensive and material-consuming machining of wrought metals with a new and innovative High Density Powder Metallurgy (HDPM) technology for the manufacturing of widely used high performance steel components, particularly gears and components for the automotive market.
The project actions will contribute to the implementation of the Circular Economy Action Plan, the Roadmap to a Resource Efficient Europe, the Directive on Energy end-use efficiency and energy services, and Decision (406/2009/CE) on Energy Efficiency. Furthermore, LIFE 4GreenSteel is relevant to EU policy on sustainable growth and will also provide European enterprises with tools to enhance their competitiveness.
The project objectives can be divided into technical end environmental as following presented:
- Development of an effective pressing system, operating with DWL technique, to produce sintered steel parts having density greater than 7.3 g/cc and high dimensional stability;
- Tailoring the high-temperature vacuum sintering stage and development of a reliable case-hardened profile of PM steel by means of the thermochemical treatment Low Pressure Carburising (LPC)
- Alloy design of powder steel chemical composition avoiding alloying elements that are harmful (nickel), or that make the recycling process difficult and ineffective (copper)
- Achieve energy and material saving through the innovative HDPM technology, which has a very high coefficient of material use (95%) and therefore minimizes energy input.
- Reduce more than 70% of the lubricant premixed with metal powder, so eliminating the burning stage, increasing energy efficiency and solving related emission problems.
The expected results have been evaluated comparing the HDPM technology respect to the machining technology (M_baseline) and the Standard PM (PM_baseline).
expected environmental results:
- Reduction in use of raw materials: -47.4% (M_baseline)
- Energy saving: -50% (M_baseline)
- Strong reduction of cutting fluids lubricants avoiding machining operations
- Reduction of metal powder admixed lubricant: -70% (PM_baseline)
- CO2 reduction: -49.3 % (M_baseline)
expected technical results:
- Development of an innovative HDPM process to produce a high-performance steel component (Pilot Line)
- Sintered steel parts having density greater than 7.3 g/cc and high dimensional stability
- Case-hardened high density steel parts
- Elimination of dewaxing/burning process step. (PM_baseline)
During the project will be developed the following activities:
- Study, design and development of a compaction press prototype operating with the die wall lubrication system (DWL);
- Study, evaluation and definition of an efficient lubricant for the DWL system;
- Design and manufacturing of simple and complex dies;
- Alloy design: steel metal powder, nickel and copper free;
- Compaction, Sintering, Heat Treatments (HT): Study, tuning;
- Characterization of Sintered / HT products: microstructure, mechanical tests;
- Study and design of effective case hardening profile via Low Pressure Carburizing (LPC);
- Life Cycle Assessment;
- Dissemination and Networking.
Name: LIFE16 ENV/IT/000231
Duration: 01-JUL-2017 to 31-DEC -2020
Coordinator: TFM Automotive & Industry S.p.A.
Partners: Università degli Studi di Trento, Italy Sacmi Cooperativa Meccanici Imola S.C., Italy K4Sint S.r.l., Italy
Info: https://www.tfmgroup.it/ – Valentina.Zampogna@tfmgroup.it
The project started on July 1, 2017 with an estimated duration of 42 month. The project partners have established a management team and identified the strategic plans and practices to be implemented in order to achieve the expected results. All the activities are going on time in agreement with the project program. The project updates are here presented:
The main tasks developed from July up to December 2017 regarded the study and development of a ‘green’ lubricant and lubrication techniques, combined to the press prototype specifications, integrating a die wall lubrication (also DWL) automatic system.
Different lubricant deposition system have been considered as well as different kind of lubricants. The adhesion, thickness and homogeneity properties have been tested. Good results have been obtained and lubricant and deposition system have been identified.
The expected goal was achieved and then allowed to carry out an initial compaction phase adopting the Die Wall Lubrication system, as reported in the 2018 activities.
The main tasks of the 2018 activities regarded:
- design and manufacture of one level molds
- design and construction of the press prototype integrating the Die Wall Lubrication system (DWL)
- sintering study and dimensional analysis
The expected results foreseen in 2018 were targeted. Samples with density more than 7.40 g/cc are routinely produced by DWL using the studied lubricant.
Details about this are following presented.
Density & Extraction Force
In order to validate the lubricant efficiency comparison test have been developed. Compression test about metal powder Astaloy Mo (0.6wt%C) mixed with 0.7wt% of solid lubricant have been performed and assumed as standard benchmark. Adopting same compression load also metal powder free of internal lubricant have been pressed under DWL condition.
Green density and the extraction force have been measured and used as test variable
Figure 01 and figure 02 highlights the benefits of DWL in term of green density and extraction force. High density can be related to high mechanical properties whereas low extraction force with low wear rate of the die. DWL allows to reduce the extraction force around 50%.
Figure 01: Green density Astaloy Mo 0.5Cwt%. Internal lubrication vs DWL
Figure 02: Green density Astaloy Mo 0.5Cwt%. Standard internal lubrication vs DWL
In figure 03 an example of DWL green cylinder samples is shown.
Figure 03: DWL green cylinder – Astaloy Mo 0.5Cwt%
In order evaluate the effect of the DWL on dimensional stability, three material have been considered and investigated.
- Astaloy Mo: 5%Mo – 0.6%C
- Astaloy CrA: 8%Cr – 0.6%C
- Astaloy CrM: 0%Cr – 0.5%Mo – 0.6%C
Transverse Rupture Strength samples have been compacted and sintered in order to evaluate the density evolution and also the dimensional change/stability (respect to the width direction).
In figure 04 the effect of DWL respect to Internal Lubrication is reported for the three materials:
Figure 04: Green density Internal Lubrication vs DWL
The graph shows the green density evolution of low-alloy steels (commercial pre-alloyed steels with chromium and molybdenum). The trend of lower compressibility of chromium pre-alloyed powders is observed both in internal lubrication and in DWL. This trend also rise with the increasing of the alloy elements. It is possible to note that for all three material the DWL compaction means a benefit effect more than 3% in density.
Figure 05 shows the sinter density after vacuum sinterhardening at 1250°C, cooling at 2-3 °C/s followed by tempering in air at 200°C.
Figure 05: Sintered density Internal Lubrication vs DWL
Figure 06 shows the effect of DWL in term of dimensional stability after vacuum sinterhardening.
Figure 06: Dimensional change Internal Lubrication vs DWL
The dimensional change has been measured in the transverse direction (width direction) respect to the pressing direction. It is clear the benefit of DWL compaction on dimensional stability.
Figure 07: Dimensional stability benefit of DWL compared to Internal Lubrication after sinterhardening
From figure 07 it is possible to note the benefit of DWL compared to the Internal Lubrication in term of dimensional stability. The dimensional change is reduced more than 50% for all the three materials investigated adopting DWL compaction instead of the standard Internal Lubrication.
The main tasks of the 2019 activities regarded:
- Press prototype with DWL system installation and testing
- Compaction and Sintering of PM for mechanical testing characterization
The expected results for 2019 have been targeted and the results are shown below
Figure 08: Press Prototype SACMI MPH 2002 Die Wall Lubrication
Figure 08 shows the press Prototype SACMI MPH 2002 Die Wall Lubrication. During January 2019 the press prototype installation has been completed and now it is fully operative and both standard and DWL samples can be compacted. Complex geometry samples for material characterization and mechanical test have been produced.
Transverse Rupture Strength – an overview
Mechanical properties have been evaluated in term of Transverse Rupture Strength (also TRS) as three point bending test in accordance to the ASTM B528, measured after vacuum sinterhardening at 1250°C and forced cooling at 2-3 °C/s followed by tempering in air at 200°C. The results for the pre-alloyed chromium and molybdenum steels are shown in the following figures.
- Astaloy Mo: 5%Mo – 0.6%C
- Astaloy CrA: 8%Cr – 0.6%C
- Astaloy CrM: 0%Cr – 0.5%Mo – 0.6%C
Figure 09: TRS pre alloyed steel DWL compared to Internal Lubrication
Figure 09 highlights the benefit of DWL in term of improved strength respect to the internal lubricated compacted sample. The benefit is mainly due to the improved density since the final microstructure is the same.
Figure 10 shows the percentage improvements of TRS from internal lubrication to DWL compaction.
While the detected TRS strength provides an assessment of the mechanical strength of the material, the area subtended by the stress/strain curve gives an indication of toughness. Results on specific energy detected are following reported.
Figure 10: TRS pre alloyed steel DWL compared to Internal Lubrication
As reported in figure 11, a density improvements due to DWL compaction reflects an increase in toughness that can be related to the specific energy absorbed from the sample up to break point.
Figure 11: Specific Energy pre alloyed steel DWL compared to Internal Lubrication
Mechanical properties have been evaluated in term of Green strength after compaction stage and Tensile strength after sintering and heat treatment. This investigation have been focused on Astaloy Mo 0.5Cwt%.
Disks Ø45 mm have been compacted for tensile green strength test (Brazilian test). The main results are following reported in figure 12 where a comparison between standard PM (internal Lubrication) and DWL is presented.
It is possible to note the benefit of DWL; the green strength is more than double and open the interesting possibility to perform some dry machining operation before sintering.
Figure 12: Green strength – Brazilian test – Internal lubrication vs DWL
Dog bone sample have been compacted , vacuum sintered at 1250 °C and heat treated for tensile strength evaluations.
Figure 13 shows the mechanical properties in term of tensile strength of Astaloy Mo: internal lubrication and DWL are compared respect to sintering condition and thermal treatment (Quench and Tempering). Mechanical test highlights the benefits of DWL
Figure 13: Tensile sthength – Inernal Lubrication vs DWL
Comparing the sintered conditions (SH) no noticeable difference are noted in term of Ultimate Tensile Strength (UTS) or Yield Strength (YS) while a very noticeable increase of elongation at fracture (Ef) about the DWL is noted. This aspect is related to the DWL benefits in term of increased density and therefore reduced residual porosity.
After thermal treatment (quench and tempering – QT) also the benefits in term of UTS and YS can be observed. More than 1700 MPa (UTS) combined to elongation higher than 2% can be considered a very good results.
Figure 14 highlights the mechanical properties improvements from Internal Lubrication to DWL process of same material after same thermal treatments.
Figure 15 and figure 16 show the microstructure of DWL Astaloy Mo 0.5C, after sintering and after quench and tempering respectively.
Figure 15 shows the bainitic micostructure with a detected microhardness of 273 HV05. Figure 16 shows a stronger martensitic microstructure with a detected microhardness of 487 HV05 that define the higher mechanical properties as above reported.
Figure 15: LOM DWL Astaloy Mo 0.5C sintered 1250 – Bainitic microstructure
Figure 16: LOM DWL AstaloyMo-0.5C Quench&Tempered – Martensitic microstructure
The LIFE 4GreenSteel project was born from a group of companies and universities involved in the field of powder metallurgy with the aim of finding innovative solutions to mitigate and reduce the environmental impact of industrial activities.
The companies and university involved are:
◊ TFM Automotive & Industry S.p.A.
◊ SACMI Cooperativa Meccanici Imola S.C.
◊ K4Sint S.r.l.
◊ Università degli Studi di Trento
The Powder Metallurgy technology is a sustainable manufacturing process recognized as a green technology. The aim of the project is to demonstrate the feasibility to replace the traditional energy-intensive and materialconsuming machining of wrought metals with a new and innovative High Density Powder Metallurgy (HDPM) technology for the manufacturing of high-performance steel components. The project has received the financial support of the European Union through the LIFE programme, thanks to the environmental importance of the project and to the possibility of transferring it to other companies.