scholarly journals The Effect of Processing Parameters on Microstructure and Mechanical Properties of Sintered Structural Steels Based on Prealloyed Powders / Wpływ Parametrów Wytwarzania Na Strukturę I Własności Mechaniczne Spiekanych Stali Wykonanych Na Bazie Proszków Stopowych

2015 ◽  
Vol 60 (4) ◽  
pp. 2543-2548 ◽  
Author(s):  
P. Kulecki ◽  
E. Lichańska ◽  
M. Sułowski
Keyword(s):  
Mechanical Properties ◽  
Mechanical Testing ◽  
Graphite Powder ◽  
Processing Parameters ◽  
Structural Steels ◽  
Alloyed Powder ◽  
Production Parameters ◽  
Sintered Steels ◽  
Alternative Material ◽  
Horizontal Furnace

The object of the study was to evaluate the effect of production parameters on the structure and mechanical properties of Cr and Cr-Mo PM steels. The measurements were performed on sintered steels made from commercial Höganäs pre-alloyed powders: Astaloy CrA, Astaloy CrL and Astaloy CrM mixed with carbon, added in the form of graphite powder grade C-UF.Following mixing in a Turbula mixer for 30 minutes, green compacts were single pressed at 660 MPa according to PNEN ISO 2740 standard. Sintering was carried out in a laboratory horizontal furnace at 1120°C and 1250°C for 60 minutes, in 5%H2-95%N2atmosphere. After sintering, the samples were tempered at 200°C for 60 minutes in air. The steels are characterized by ferritic - pearlitic, bainitic - ferritic and bainitic structures.Following mechanical testing, it can be assumed that steel based on Astaloy CrA pre-alloyed powder could be an alternative material for steels based on Astaloy CrL powder. These steels sintered at 1250°C with 0.6% C had tensile strengths about 650 MPa, offset yield strengths about 300 MPa, elongations about 8.50 %, TRSs about 1100 MPa, hardnesses 220 HV.

scholarly journals Sintered Structural Pm Cr and Cr-Mo Steels/ Spiekane Stale Konstrukcyjne Chromowe I Chromowo-Molibdenowe

2014 ◽  
Vol 59 (4) ◽  
pp. 1507-1512 ◽  
Author(s):  
M. Sułowski ◽  
P. Kulecki ◽  
A. Radziszewska
Keyword(s):  
Mechanical Properties ◽  
Graphite Powder ◽  
Mechanical Tests ◽  
Nitrogen Atmosphere ◽  
Alloyed Powder ◽  
Production Parameters ◽  
Microstructure And Mechanical Properties ◽  
Alternative Material ◽  
Higher Temperature ◽  
Horizontal Furnace

Abstract The object of the study was the evaluation of the effect of production parameters on the microstructure and mechanical properties of Cr and Cr-Mo PM steels. The steels were processed from commercial Höganäs pre-alloyed powders: Astaloy CrA, Astaloy CrL and Astaloy CrM with carbon, added in the form of grade C-UF graphite powder in amounts of 0.4 and 0.8 wt. %. Following Turbula mixing for 30 minutes, green compacts were single pressed at 660 MPa according to PN-EN ISO 2740 standard. Sintering was carried out in a laboratory horizontal furnace at 1120°C and 1250°C for 60 minutes in a 5%-95% hydrogen-nitrogen atmosphere. After sintering, the samples were tempered at 200°C for 60 minutes in air. Mechanical tests indicate that the steel based on Astaloy CrA pre-alloyed powder could be an alternative material to steels based on Astaloy CrM. Steels sintered at the higher temperature revealed better mechanical properties.

scholarly journals Estimation of the Effect of Production Parameters on Mechanical Properties of Sintered Steels using ANOVA

2017 ◽  
Vol 62 (2) ◽  
pp. 571-576
Author(s):  
M. Sułowski ◽  
A. Jordan ◽  
A. Czarski ◽  
P. Matusiewicz
Keyword(s):  
Mechanical Properties ◽  
Sintering Temperature ◽  
Tensile Tests ◽  
Sintering Atmosphere ◽  
Production Parameters ◽  
Sintered Steels ◽  
Static Tensile ◽  
Large Level ◽  
Predictive Strength ◽  
Different Levels

Abstract The object of the study was to assess the influence of selected production parameters of sintered Fe-Mn-Cr-Mo-C steels i.e. chemical composition, sintering temperature, sintering atmosphere and heat treatment on the following mechanical properties: impact toughness, hardness of the surface, tensile strength, bend strength after static tensile tests. In the investigations, the general linear model (GLM) of the multivariate analysis of variance ANOVA was used. All assumptions of ANOVA, i.e. randomization of the experiment, the normality of the residuals, equality of variance at different levels have been fulfilled and verified. The predictive strength of the constructed models expressed by the adjusted determination coefficient (R2adj) is at medium or large level – R2adj is in the range from 41.46% to 76.97%. This work is focused mainly on the ANOVA methodology. A wide physical interpretation of the results will be possible after the optimization of the ANOVA models used.

scholarly journals The Effect of Powder Ball Milling on the Microstructure and Mechanical Properties of Sintered Fe-Cr-Mo-Mn-(Cu) Steel

2017 ◽  
Vol 17 (2) ◽  
pp. 82-92
Author(s):  
P. Kulecki ◽  
E. Lichańska
Keyword(s):  
Mechanical Properties ◽  
Cooling Rate ◽  
Ball Milling ◽  
Heating Rate ◽  
Mechanical Testing ◽  
Low Carbon ◽  
Powder Mixtures ◽  
Alloyed Iron ◽  
Horizontal Furnace ◽  
Frequency Inverter

Abstract The effect of ball milling powder mixtures of Höganäs pre-alloyed iron Astaloy CrM, low-carbon ferromanganese Elkem, elemental electrolytic Cu and C-UF graphite on the sintered structure and mechanical properties was evaluated. The mixing was conducted using Turbula mixer for 30 minutes and CDI-EM60 frequency inverter for 1 and 2 hours. Milling was performed on 150 g mixtures with (in weight %) CrM + 1% Mn, CrM + 2% Mn, CrM + 1% Mn + 1% Cu and CrM + 2% Mn + 1% Cu, all with 0.6%C. The green compacts were single pressed at 660 MPa according to PN-EN ISO 2740. Sintering was carried out in a laboratory horizontal furnace Carbolite STF 15/450 at 1250°C for 60 minutes in 5%H2 – 95%N2 atmosphere with a heating rate of 75°C/min, followed by sintering hardening at 60°C/min cooling rate. All the steels were characterized by martensitic structures. Mechanical testing revealed that steels based on milled powders have slightly higher mechanical properties compared to those only mixed and sintered. The best combination of mechanical properties, for ball milled CrM + 1% Mn + 1% Cu was UTS 1046 MPa, TRS 1336 MPa and A 1.94%.

scholarly journals Sintered Structural Steels Containing Mn, Cr And Mo – The Summary of the Investigations

2016 ◽  
Vol 16 (2) ◽  
pp. 59-85
Author(s):  
Maciej Sulowski
Keyword(s):  
Mechanical Properties ◽  
Chemical Composition ◽  
Sintered Material ◽  
Structural Steels ◽  
Processing Conditions ◽  
Alloying Element ◽  
Sintering Atmosphere ◽  
Sintered Steels ◽  
Method Of Production ◽  
Better Than

AbstractThe paper is presented the development and method of production of modern, Ni-free sintered structural steels which contain carbide forming alloying elements (Cr) with high affinity for oxygen (Cr, Mn) and the much smaller additive of an expensive alloying element (Mo), enabling the production of structural sintered steels in commercial belt furnaces, using safe sintering atmospheres. The investigations reported deal with the analysis of microstructure and mechanical properties of these sintered structural steels produced in different processing conditions, especially modification of chemical composition of sintering atmosphere and also the connections between the microstructure of sintered material and its mechanical properties. This analysis was done to propose the appropriate chemical composition of sintered Ni-free steels with properties which are comparable or even better than those of sintered structural steels containing rich and carcinogenic nickel. The investigations of PM Mn- Cr-Mo steels were preceded by those on Mn steels.

scholarly journals Fractography and Porosity Analysis of Cr and Cr-Mo PM Steels

2016 ◽  
Vol 61 (3) ◽  
pp. 1613-1622 ◽  
Author(s):  
P. Kulecki ◽  
E. Lichańska ◽  
A. Radziszewska ◽  
M. Sułowski
Keyword(s):  
Computer Software ◽  
Horizontal Tube ◽  
Graphite Powder ◽  
Alloyed Powder ◽  
Single Action ◽  
Sintered Steels ◽  
Ductile Fractures ◽  
Porosity Analysis ◽  
Carbon Concentrations ◽  
Horizontal Tube Furnace

AbstractThe aim of the study was to evaluate the effect of processing variables on the porosity and fractography of Cr and Cr-Mo PM steels. The measurements were performed on sintered steels made from commercial Höganäs pre-alloyed powders: Astaloy CrA, Astaloy CrL and Astaloy CrM with two different carbon concentrations (0.2% and 0.6%) added in the form of ultra fine graphite powder grade C-UF. Following mixing in Turbula mixer for 30 minutes, green compacts were single-action pressed at 660 MPa according to PN-EN ISO 2740 standard. Sintering was carried out in a laboratory horizontal tube furnace at 1120°C and 1250°C for 60 minutes, in an atmosphere containing 5%H2and 95%N2. After sintering, the samples were tempered at 200°C for 60 minutes in air. For porosity evaluation computer software was employed. Hitachi S-3500M SEM equipped with EDS (made by Noran) was employed for fracture analysis. The steel based on Astaloy CrM pre-alloyed powder is characterized by fine pores and good mechanical properties. When sintered at 1250°C, it had area of pores approx. 7.12 μm2, ultimate tensile strength (UTS) about 679 MPa and elongation about 4%. The steels were characterized by ductile/cleavage and ductile fractures.

scholarly journals Fractography of Sinteraustempered and Sinterhardened Fe-3Mn-0.8C PM Steels

2016 ◽  
Vol 61 (4) ◽  
pp. 1909-1918
Author(s):  
M. Tenerowicz ◽  
M. Sułowski
Keyword(s):  
Mechanical Properties ◽  
Steel Production ◽  
Graphite Powder ◽  
Mechanical Tests ◽  
Low Carbon ◽  
Pure Nitrogen ◽  
Sintering Atmosphere ◽  
Sintered Steels ◽  
Dog Bone ◽  
Higher Temperature

Abstract Sintered steels with the addition of manganese are widely used in industry because of their attractive mechanical properties. The main problem of using manganese in powder metallurgy steel production is its high affinity for oxygen. The choice of proper sintering parameters can significantly improve the properties of the final product. For the present investigations Höganäs iron powder grade NC 100.24, low-carbon (1.3%C) ferromanganese Elkem (Eramet Norway Sauda – formerly Elkem Manganese Sauda) and graphite powder grade C-UF were used as the starting powders. Mixture of powders, containing 3% Mn and 0.8% C, was prepared in Turbula mixer for 30 minutes. Following mixing, “dog bone” compacts were pressed at 660 MPa according to PN-EN ISO 2740 standard. Sintering of compacts was carried out in the laboratory tube furnace at 1120 and 1250°C for 60 minutes in air or pure nitrogen (99.999%N2). The present investigation deals with the comparison of two heat treatment routes: sinterhardening (SH) and sinteraustempering (SAT), carried out both in air and pure nitrogen. Mechanically tested steels were investigated using JEOL JSM 700F completed with EDS. Metallography tests were carried out on 3% Nital etched samples. In this paper the results of mechanical tests and metallography and fractography investigations are shown. According to the results obtained, it can be assumed that for sinteraustempering higher temperature does not influence mechanical properties of sintered steels. For both methods using pure nitrogen as sintering atmosphere gave better results.

scholarly journals A comparison of mechanical properties and microstructures of PM steels with chemical compositions Fe-(1-3)%Mn-0.8%C

2018 ◽  
Vol 50 (4) ◽  
pp. 457-466
Author(s):  
Monika Tenerowicz-Zaba ◽  
Maciej Sulowski
Keyword(s):  
Mechanical Properties ◽  
Graphite Powder ◽  
Chemical Compositions ◽  
Low Carbon ◽  
Sintered Steels ◽  
Dog Bone ◽  
Mn Content ◽  
Point Bend ◽  
Structural Parts ◽  
Mn Steel

Mechanical properties of sintered steels containing 1, 1.5, 2, 2.5 and 3 %Mn and 0.8 %C, candidate materials for structural parts, are compared with actually used PM steels. H?gan?s iron powder grade NC 100.24, low-carbon ferromanganese Elkem and graphite powder grade C-UF were used as the starting powders. Powder mixtures were prepared in a Turbula mixer for 30 minutes and ?dog bone? compacts were single pressed at 660 MPa, according to PN-EN ISO 2740 standard. Sinterhardening was carried out in a semi-closed container in a laboratory tube furnace at 1120?C and 1250?C for 60 minutes in a mixture of 95%N2-5%H2. Microstructures consisted of pearlite and ferrite, sometimes bainite and martensite, depending on the Mn content. Yield, tensile and three point bend strengths and Vickers' microhardness were determined and metallographic observations carried out. The best combination of properties was for 2.5 %Mn steel: yield strength 620 MPa and 3.7 % elongation. The tensile properties of 2.5/3 %Mn-0.8 %C are not inferior to the best Ni-Cr-Mo-Cu type PM steels in MPIF Standard 35.

Surface Modification and its Influence on the Microstructure and Creep Resistance of Nickel Based Superalloy René 77 / Modyfikacja Powierzchniowa Oraz Jej Wpływ Na Mikrostrukture I Wytrzymałosc Na Pełzanie Odlewów Z Nadstopu Niklu Ren´E 77

2013 ◽  
Vol 58 (1) ◽  
pp. 95-98 ◽  
Author(s):  
M. Zielinska ◽  
J. Sieniawski
Keyword(s):  
Mechanical Properties ◽  
Grain Size ◽  
Surface Modification ◽  
Turbine Blades ◽  
Processing Parameters ◽  
Grain Structure ◽  
Creep Tests ◽  
Cobalt Aluminate ◽  
Nickel Based Superalloy ◽  
Average Grain Size

Superalloy René 77 is very wide used for turbine blades, turbine disks of aircraft engines which work up to 1050°C. These elements are generally produced by the investment casting method. Turbine blades produced by conventional precision casting methods have coarse and inhomogeneous grain structure. Such a material often does not fulfil basic requirements, which concern mechanical properties for the stuff used in aeronautical engineering. The incorporation of controlled grain size improved mechanical properties. This control of grain size in the casting operation was accomplished by the control of processing parameters such as casting temperature, mould preheating temperature, and the use of grain nucleates in the face of the mould. For nickel and cobalt based superalloys, it was found that cobalt aluminate (CoAl2O4) has the best nucleating effect. The objective of this work was to determine the influence of the inoculant’s content (cobalt aluminate) in the surface layer of the ceramic mould on the microstructure and mechanical properties at high temperature of nickel based superalloy René 77. For this purpose, the ceramic moulds were made with different concentration of cobalt aluminate in the primary slurry was from 0 to 10% mass. in zirconium flour. Stepped and cylindrical samples were casted for microstructure and mechanical examinations. The average grain size of the matrix ( phase), was determined on the stepped samples. The influence of surface modification on the grain size of up to section thickness was considered. The microstructure investigations with the use of light microscopy and scanning electron microscopy (SEM) enable to examine the influence of the surface modification on the morphology of ’ phase and carbides precipitations. Verification of the influence of CoAl2O4 on the mechanical properties of castings were investigated on the basis of results obtained form creep tests.

scholarly journals Effect of Moisture Content on the Processing and Mechanical Properties of a Biodegradable Polyester

Polymers ◽  
2021 ◽  
Vol 13 (10) ◽  
pp. 1616
Author(s):  
Vincenzo Titone ◽  
Antonio Correnti ◽  
Francesco Paolo La Mantia
Keyword(s):  
Mechanical Properties ◽  
Tensile Strength ◽  
Moisture Content ◽  
Mechanical Testing ◽  
Hydrolytic Degradation ◽  
Slight Reduction ◽  
Biodegradable Polyester ◽  
Molding Process ◽  
Elongation At Break ◽  
Effect Of Moisture

This work is focused on the influence of moisture content on the processing and mechanical properties of a biodegradable polyester used for applications in injection molding. The pellets of the biodegradable polyester were exposed under different relative humidity conditions at a constant temperature before being compression molded. The compression-molded specimens were again placed under the above conditions before the mechanical testing. With all these samples, it is possible to determine the effect of moisture content on the processing and mechanical properties separately, as well as the combined effect of moisture content on the mechanical properties. The results obtained showed that the amount of absorbed water—both before processing and before mechanical testing—causes an increase in elongation at break and a slight reduction of the elastic modulus and tensile strength. These changes have been associated with possible hydrolytic degradation during the compression molding process and, in particular, with the plasticizing action of the moisture absorbed by the specimens.

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