Wyniki wyszukiwania - BazTech

1

Determinants of Quality of Life in Building the Green City Concept

Szołtysek J., Otręba J.

Logistyka

|

2016

|

nr 1

6--14

EN

Apart from a concept of logistics support, implementation of principles of a green city requires some social support. Insufficiency of financial means and necessity to select alternative methods of using such means call for good identification of social climate in order to obtain - apart from some environmental benefits - some improvement in the quality of life perceived. Therefore, in this research, authors decided to find out which components of the quality of life connected with the quality of environment facilitate decisions made to change places of residence and which of them did not have that kind of impact. The research was devoted to Polish cities only

PL

Wdrażanie zasad miasta zielonego, wymaga - poza koncepcją wsparcia logistycznego, pozyskania poparcia społecznego. Niedostatek środków finansowych oraz konieczność dokonywania wyborów pomiędzy alternatywnymi sposobami ich wykorzystania, wymaga dobrego rozpoznania nastrojów społecznych, by - poza korzyściami środowiskowymi, uzyskać poprawę odczuwanej jakości życia w mieście. Stąd w badaniu autorzy postanowili wykryć, które składniki jakości życia, powiązane z jakością środowiska, sprzyjają decyzjom o zmianie miasta jako miejsca zamieszkania, a które na taką decyzję nie mają wpływu. Badanie dotyczy polskich miast.

2

Mechanical properties and microstructural characteristic of sinter-hardened steels

Rosso M., Dobrzański L., Otręba J., Actis Grande M.

Archives of Materials Science and Engineering

|

2009

|

Vol. 35, nr 2

117-124

EN

Purpose: The main goal of this paper was the examination of the role of W addition on properties of two sinter-hardened alloys with two different carbon levels. Additionally the influence of sinter-hardening process has been evaluated. Microstructural characteristic and mechanical properties of Ni-Mo steels with increasing amount of tungsten (from 0 to 0.3% wt.) were taken under consideration. Design/methodology/approach: Powder mixes have been compacted at 700MPa and sintered in a vacuum furnace with argon backfilling at 1120 °C for 60 minutes. Rapid cooling has been applied with an average cooling rate of 2.5 °C/s. Obtained steels were analyzed by scanning microscopy with energy dispersive spectroscopy (EDS) for phase distribution and mapping and light optical microscopy for observations of the microstructure. Charpy impact test, three-point bending, microhardness, pin-on-disk and disk-on-disk tests were used. Findings: The outcome of implemented vacuum sintering with rapid cooling as well as chemical composition were studied in terms of mechanical properties, focusing in particular on impact energy, hardness and wear resistance. The results achieved after the investigation of Ni-Mo and Ni-Mo-W sinter-hardened steels with low and high carbon content proved that applied process of sintering under vacuum and rapid cooling brought expected outcome. Research limitations/implications: The characteristics of powders and the applied cooling rate were found be a good compromise for mechanical properties and microstructures, though further researches should be carried out in order to examine different cooling rates and parameters of tempering process. Originality/value: The effect of W and/or WC additions to highly alloyed steels is well known. In the work the effect of small additions of W and WC to low alloyed steels, especially in terms of hardenability and wear resistance, was investigated.

3

Utilisation of sinter-hardening treatment for various sintered steels

Dobrzański L. A., Otręba J., Brytan Z., Rosso M.

Journal of Achievements in Materials and Manufacturing Engineering

|

2007

|

Vol. 24, nr 2

187-190

EN

Purpose: Purpose of this paper was to present the benefits of powder metallurgy technology and development of sinter-hardening process applied to different steels including pre-alloyed Ni-Mo steels with W addition, Astaloy CrM and experimental sintered duplex stainless steels. The mechanical properties, focusing in particular on hardness and wear resistance, of two different sinter-hardened steels were described. Microstructure characteristic of produced sinter-hardened steels was taken under consideration. Design/methodology/approach: Different compositions have been tested in order to investigate the influence of sinter-hardening of steels under different cooling rates on microstructure and properties. As a first group of materials Ni-Mo pre-alloyed steel powders were used, differing with the addition of tungsten and amount of carbon. Green compacts were sintered at the temperature 1120 degrees centigrade for 1 hour. The next set of investigated materials was produced by mixing the Astaloy CrM powder with carbon amount of 0.6% and then compacted and sintered in the same conditions. Under sinter-hardened conditions, experimental sintered duplex stainless steels were also evaluated. After sintering, different cooling rates were applied. Findings: The applied sinter-hardening process resulted with achievement of material characterized by proper microstructure. The investigation of sinter-hardened steels proved that applied process of sintering under vacuum and rapid cooling brought expected outcome. Research limitations/implications: Considering the achieved outcome, it was revealed that chemical composition and applied process of steels preparation, sinter-hardening with rapid cooling, results in achievement of materials with relatively high apparent hardness and significant resistance to abrasion. Anyhow, further researches should be performed. Originality/value: The paper contributes to better understanding advantages of sinter-hardening process applicable to different sintered steels.

4

Sinter-hardening of Ni-Mo pre-alloyed powders with tungsten addition

Dobrzański L. A., Otręba J., Actis Grande M., Rosso M.

Journal of Achievements in Materials and Manufacturing Engineering

|

2007

|

Vol. 20, nr 1-2

427-430

EN

Purpose: Purpose of this paper was to present the benefits of powder metallurgy technology and development of sinter-hardening process. The mechanical properties, focusing in particular on hardness and wear resistance, of two different carbon levels pre-alloyed steel powders processed with sinter-hardening method, were described. Microstructure characteristic of produced sinter-hardened Ni-Mo steels with increasing amount of tungsten (from 0 to 0.3% wt.) was taken under consideration. Design/methodology/approach: Different compositions have been tested in order to investigate the influence of various tungsten additions into low (0.4%) and high (0.6%) carbon content of pre-alloyed steel powders. Powders, with addition of 0.7% lubricant, were pressed in a 2000 kN hydraulic press. De-waxing process at 550 degrees centigrade for 60 minutes in a fully nitrogen atmosphere was performed before the sintering. Sinering was carried out in vacuum furnace with argon backfilling. The furnace was equipped with a cooling zone to provide accelerated cooling from the sintering temperature. Green compacts were sintered at the temperature 1120 degrees centigrade for 1 hour and rapidly cooled with a rate 2.5 degrees centigrade/s. Findings: The applied sinter-hardening process with achievement of material characterized by good wear resistance. The investigation of Ni-Mo and Ni-Mo-W sinter-hardened steels with low and high carbon content proved that applied process of sintering under vacuum and rapid cooling brought expected outcome. Research limitations/implications: Considering the achieved outcome, it was revealed that chemical composition and applied process of steels preparation, sinter-hardening with the cooling rate 2.5 degree centigrade/s, results in achieving materials with relatively high hardness and significant resistance to abrasion. Anyhow, further research should be performed. Originality/value: Sinter-hardening of Ni-Mo pre-alloyed powders with the addition of different additions of tungsten, especially in terms of hardenability and wear resistance, was investigated.

5

Sintering of Ni-Mo-W steels and their properties

Dobrzański L. A., Otręba J., Actis Grande M., Rosso M.

Archives of Materials Science and Engineering

|

2007

|

Vol. 28, nr 2

77-82

EN

Purpose: The paper focuses on microstructural and mechanical characteristics of Ni-Mo and Ni-Mo-W sintered steels with increasing amount of tungsten, low and high addition of carbon. Design/methodology/approach: Prepared mixes of powders have been compacted at 700 MPa and sintered in a vacuum furnace with argon backfilling at 1120°C for 60 minutes; after sintering rapid cooling has been applied with an average cooling rate of 2,5°C/s. Produced sets of samples have been studied by scanning electron microscopy (SEM) with EDS for phase distribution and mapping and light optical microscopy (LOM) for microstructure observations. Mechanical properties such as impact energy, microhardness and wear rates were evaluated depending on chemical composition and the effect of applied sintering process with rapid cooling. Wear resistance was investigated using both pin on disk and disk on disk tests. Findings: The highest value of impact energy was achieved for set of steels with smaller amount of carbon. It was noticed that the presence of tungsten didn't differ much the results. The situation was opposite in the case of microhardness, where the best results were obtained for set with addition of 0.6%C and reached 452 HV0.1. The microstructure of all investigated alloys was mainly martensitic with minor presence of bainite in the set of steels containing low addition of carbon. Research limitations/implications: According to the powders characteristic, the applied cooling rate seems to be a good compromise for mechanical properties and microstructures, nevertheless further tests should be carried out in order to examine different cooling rates and parameters of tempering process. Originality/value: The effect of small additions of W and WC to low alloyed steels, especially in terms of hardenability and wear resistance, was investigated.

6

Microstructural characteristic and mechanical properties of Ni-Mo-(W) steels

Dobrzański L. A., Otręba J., Actis Grande M., Rosso M.

Journal of Achievements in Materials and Manufacturing Engineering

|

2006

|

Vol. 18, nr 1-2

347--350

EN

Purpose: Purpose of this paper was to examine the role of tungsten on properties of two different carbon levels pre-alloyed steel powders. Microstructural characteristic and mechanical properties of sinter-hardened Ni-Mo steels with increasing amount of tungsten (from 0 to 0.3% wt.) were taken under consideration. Design/methodology/approach: Powder mixes (Ni-Mo, Ni-Mo-W) have been compacted at 700MPa and sintered in a vacuum furnace with argon backfilling at 1120°C for 60 minutes. Rapid cooling has been applied with an average cooling rate of 2.5°C/s. Obtained samples were analyzed by scanning microscopy with Energy dispersive spectroscopy (EDS) for phase distribution and mapping and light optical microscopy for observations of the microstructure. Charpy impact test, three-point bending, microhardness and pin-on-disk tests were used. Findings: The effect of chemical composition and applied vacuum sintering with rapid cooling were studied in terms of mechanical properties, focusing in particular on impact energy, hardness and wear resistance. The results achieved after the investigation of Ni-Mo and Ni-Mo-W sinter-hardened steels with low and high carbon content proved that applied process of sintering under vacuum and rapid cooling brought expected outcome. Research limitations/implications: According to the powders characteristic, the applied cooling rate seems to be a good compromise for mechanical properties and microstructures, nevertheless further tests should be carried out in order to examine different cooling rates and parameters of tempering process. Originality/value: The effect of small additions of W and WC to low alloyed steels, especially in terms of hardenability and wear resistance, was investigated.