scholarly journals Sinteraustempering Of Two Mo-(Cu)-(Cr)-(Ni)-(Mn)-C Steels In A Semi-Closed Container In Flowing Nitrogen

2015 ◽  
Vol 60 (2) ◽  
pp. 783-788
Author(s):  
Ch. Fiał ◽  
E. Dudrova ◽  
M. Kabatova ◽  
M. Kupkova ◽  
M. Selecka ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Iron Powder ◽  
Graphite Powder ◽  
Nitrogen Atmosphere ◽  
Low Carbon ◽  
Sintering Atmosphere ◽  
Closed Container ◽  
Edx Analyses ◽  
Strength And Plasticity ◽  
Final Operation

Abstract Three types of heat treatment, sinteraustempering in 500°C, 400°C and 350°C; sinterhardening and sintering with cooling at the rate 10K/min) as the final operation, on steels sintered semi-closed container were investigated. Results of mechanical properties, microstructure investigations and fracture and EDX analyses are reported. The study involved two PM steels: DH-1 (Fe-2%Cu-1.5%Mo-0.5%C) and 34HNM (Fe-0.2%Mo-0.8%Mn-1.5%Cr-1.5Ni-0.4%C). Prealloyed Höganäs DH (Direct Hardening) iron powder and graphite powder (grade C-UF) were used to produce DH-1 steel. Prealloyed Astaloy CrL iron powder, low carbon ferromanganese, elemental nickel and graphite grade C-UF powder were the starting powders of 34HNM steel. Pressing was in rigid dies at 660MPa according to PN-EN ISO 2740 standard. After compaction, green compacts were sintered in a specially designed semi-closed container at 1120°C for 60 minutes in a nitrogen atmosphere. The chemical composition of the sintering atmosphere was modified by adding ferromanganese and/or activator into the container. All specimens were tested for tensile strength (UTS), elongation (A), yield offset strength (R0,2), TRS, apparent surface and cross section hardness (HV 30). The best combination of strength and plasticity for both steels was achieved after sinteraustempering at 500°C. The results show that, using the specially designed semi-closed container, sinteraustempering in N2 atmosphere offers the same or even better mechanical properties in comparison with sinteraustempering in vacuum. It means that sinteraustempering in N2 atmosphere is a very interesting process in terms of cost in comparison with vacuum sinteraustempering.

scholarly journals Mechanical Properties and Microstructure of PM Mn-Cr-Mo Steels With Low Carbon Concentration

2016 ◽  
Vol 61 (1) ◽  
pp. 109-114 ◽  
Author(s):  
E. Lichańska ◽  
M. Sułowski ◽  
A. Ciaś
Keyword(s):  
Mechanical Properties ◽  
Tensile Strength ◽  
Chemical Composition ◽  
Mechanical Tests ◽  
Carbon Steels ◽  
Low Carbon ◽  
Sintering Atmosphere ◽  
Low Carbon Steels ◽  
Closed Container ◽  
Offset Yield Strength

The effect of chemical composition of the sintering atmosphere on the microstructure and mechanical properties of PM structural low-carbon steels is presented. The base powders were Astaloy CrL, Astaloy CrM, low carbon ferromanganese and graphite C-UF. From the base powders two mixtures with compositions of Fe-3%Mn-(1.5/3%)Cr-(0.2/0.5)%Mo-0.2%C were prepared. Following pressing in a steel rigid die, compacts were sintered at 1250°C for 60 min in a semi-closed container. 5%H2-95%N2mixture and air were the sintering atmospheres. For sintering in air, lumps of ferromanganese were placed with the compacts in the container. After sintering, half of the samples were tempered at 200°C for 60 minutes in air. Mechanical tests (tensile, bend, toughness, hardness) and microstructural investigations were performed.The microstructures of the steels were inhomogeneous, mainly ferritic-bainic. Tempering of steel based on Astaloy CrM sintered in an atmosphere of 5% H2-95% N2slightly reduced tensile strength and toughness: from 748 to 734 MPa and from 7.15 to 6.83 J/cm2, respectively. Chemical composition had a greater effect; steels based on Astaloy CrL and Astaloy CrM had tensile strengths 526-665 and 672-748 MPa, hardness 280-325 and 388-421 HV, respectively. The best properties were obtained after sintering in air of Fe-3%Mn-3%Cr-0.5%Mo-0.2%C without heat treatment: tensile strength 672 MPa, toughness 6.93 J/cm2, hardness 421.1 HV, 0.2 % offset yield strength 395 MPa.

The Effects of Post-Sintering Treatments on Microstructure and Mechanical Properties of Mn-Mo Steel

2017 ◽  
Vol 17 (2) ◽  
pp. 104-111
Author(s):  
Ch. Fiał
Keyword(s):  
Mechanical Properties ◽  
Heat Treatment ◽  
Tensile Strength ◽  
Sintered Steel ◽  
Sintering Atmosphere ◽  
Closed Container ◽  
Single Action ◽  
Different Types ◽  
Strength And Plasticity ◽  
Additional Tempering

Abstract The effect of heat treatment on density, hardness, microstructure and tensile properties of Fe-0.85Mo-1.3Mn-0.6C sintered steel were investigated. Pre-alloyed Astaloy 85Mo, ferromanganese and UF4 graphite powders were mixed for 60 minutes in a Turbula mixer and then pressed in single-action die at 660MPa to produce green compacts (according to PN EN ISO 2740).The compacts were sintered in a specially designed semi-closed container at 1120 or 1250°C for 60 minutes in N2. The chemical composition of the sintering atmosphere was modified by adding getter and/or activator into the container. Two different types of heat treatment in nitrogen were carried out: sinteraustempering at 525°C for 60 minutes; and sinterhardening with additional tempering at 200°C for 60 minutes. The slightly better combination of strength and plasticity of steel for both sintering temperatures were achieved after sinterhardening+tempering variant. Average values of 0.2% offset yield stress, ultimate tensile strength and elongation after sintering in 1250°C, were 415MPa, 700MPa, and 2.0%, respectively.

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.

Effect of Pressure of Nitrogen Atmosphere on Microstructure and Mechanical Properties of Ti(C, N)–12WC–16Ni–4Mo2C Cermet

2012 ◽  
Vol 602-604 ◽  
pp. 540-543
Author(s):  
Teng Biao Zheng ◽  
Ping Feng ◽  
Hai Yan Lei
Keyword(s):  
Electron Microscopy ◽  
Mechanical Properties ◽  
Scanning Electron Microscopy ◽  
Rupture Strength ◽  
Nitrogen Pressure ◽  
Nitrogen Atmosphere ◽  
Vacuum Sintering ◽  
Sintering Atmosphere ◽  
Grain Sizes ◽  
Scanning Electron

The effect of sintering atmosphere and nitrogen pressure on microstructure of Ti(C, N)–12WC–16Ni–4Mo2C cermet were investigated by scanning electron microscopy (SEM) and optical microscopy (OM), the transverse rupture strength (TRS), porosities, volume fractions of phases and grain sizes were determined. Results show that nitrogen pressure has a significant impact on TRS, appropriate nitrogen pressure could improve TRS. Vacuum sintering promotes the densification of sintered body, however, nitrogen atmosphere sintering could gain maximal TRS. Nitrogen atmosphere sintering facilitates the formation of inner rim phase and reduces the dissolution of TiC and TiN, small grain size is gained.

scholarly journals The Effect of Mn Content on the Structure and Properties of PM Mn Steels

2017 ◽  
Vol 62 (4) ◽  
pp. 2153-2163
Author(s):  
M. Tenerowicz ◽  
M. Sułowski
Keyword(s):  
Heat Treatment ◽  
Cooling Rate ◽  
Graphite Powder ◽  
Strength Properties ◽  
Structure And Properties ◽  
Low Carbon ◽  
Plastic Properties ◽  
Closed Container ◽  
Dog Bone ◽  
Mn Content

AbstractThe aim of the study was to examine how a reduction of Mn content in PM steels will affect their plastic and strength properties. The results of mechanical, metallographic and fractography tests of sintered (PM) steels containing 1% and 2% Mn are reported and compared with those for 3% Mn PM steel. Höganäs iron powder grade NC 100.24, low-carbon ferromanganese Elkem and graphite powder grade C-UF were used as the starting powders. Powder mixes Fe-(1-2)%Mn-0.8%C were prepared in a Turbula mixer for 30 minutes. Following mixing, “dog bone” compacts were single pressed at 660 MPa, according to PN-EN ISO 2740 standard. Sintering of compacts was carried out in a laboratory tube furnace at 1120°C and 1250°C for 60 minutes in a mixture of 95%N2– 5%H2in a semi-closed container. Three types of heat treatment were then used: sinterhardening (cooling rate – 66°C/min), slow furnace cooling (cooling rate 3.5°C/min) and tempering at 200°C. The studies have shown a beneficial effect of the reduction of manganese on plastic properties (up to 7.96%), while maintaining fracture strengths (UTSs) comparable to those of steel with higher contents of manganese. Currently detailed studies of steel containing 1%Mn are conducted.

Effects of Hydrogen Content in Nitrogen-Based Sintering Atmosphere on Microstructure and Mechanical Properties of Fe-0.3%C-0.1%B Alloy

2014 ◽  
Vol 802 ◽  
pp. 477-482
Author(s):  
Amauri Loberto ◽  
Maria do Carmo Amorim da Silva ◽  
Francisco Ambrozio Filho ◽  
Daniel Zanetti de Florio ◽  
Humberto Naoyuki Yoshimura
Keyword(s):  
Mechanical Properties ◽  
Liquid Phase ◽  
Rupture Strength ◽  
Substantial Reduction ◽  
Hydrogen Atmosphere ◽  
Nitrogen Atmosphere ◽  
Ferrous Alloys ◽  
Sintering Atmosphere ◽  
Microstructure And Mechanical Properties ◽  
Sintered Materials

For the sintered materials, the mechanical properties are strongly dependent on the density of the final product. A substantial reduction of the porosity can be achieved using additives in the powder mixture which promote the formation of a liquid phase during sintering. Boron is a potential liquid phase promoter in ferrous alloys, when sintering is carried out using hydrogen or argon atmospheres. These atmospheres, however, are costly, and the use of nitrogen containing low content of hydrogen could be beneficial. In this study the effects of 10 to 50% hydrogen in nitrogen atmosphere on the microstructure and mechanical properties of a Fe-0.3%C-0.1%B alloy sintered at 1120 and 1250°C were investigated. Boron addition increased the sintered densities, but lowered the transverse rupture strength and hardness in relation to the control alloy (Fe-0.3%C). No significant differences were observed among the samples sintered in different atmospheres for each alloy. Nitrogen containing up to 50% hydrogen atmosphere is not suitable to sinter Fe-C alloy containing boron since it lowers the mechanical properties with the formation of fragile boron nitride precipitates at the grain boundaries and lower perlite fraction.

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 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.

REMANIT 4439

Alloy Digest ◽  
1993 ◽  
Vol 42 (11) ◽  
Keyword(s):  
Mechanical Properties ◽  
Corrosion Resistance ◽  
Stainless Steels ◽  
Crevice Corrosion ◽  
Heat Treating ◽  
Corrosion Resistant Steel ◽  
Resistant Steel ◽  
Low Carbon ◽  
Corrosion Resistant ◽  
Mechanical Properties And Corrosion

Abstract REMANIT 4439 is a highly corrosion resistant steel with low carbon content, an addition of nitrogen to enhance both mechanical properties and corrosion resistance, and higher molybdenum than most stainless steels to resist pitting and crevice corrosion in chloride media. This datasheet provides information on composition, physical properties, and elasticity. It also includes information on corrosion resistance as well as forming, heat treating, machining, and joining. Filing Code: SS-556. Producer or source: Thyssen Stahl AG.

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