Introducing clustering model for auto parts manufacturing companies

The index of development of every country is measured by the amount of its industrialization. The comparative statistics show that the level of industrial GDP in developed countries is much higher than in Iran. The influence of automotive industry on the redevelopment of satellite sectors such as steel, rubber, Polymer, petrol and petrochemicals, electrical and electronics, ceramics and etc. is very high. In view of the fact that the cluster system defines a collection of united small and medium enterprises which are distributed in a particular region, these companies do face with global and local threats, and opportunities in manufacturing of their products. In particular, the auto industry as one of the most important sector in the region qualifies for the application of clustering method, in order to unify efforts of the SME companies. A suitable cluster model if carefully applied, can result in increasing output and quality of parts, decreasing overhead costs, specialization of skills, increase of employment, equal opportunities and etc. This paper represents a thorough study of all SME’s for auto parts manufacturers in North West province of Azerbaijan. On the basis of these finding and the studies carried out, a suitable Cluster model within UNIDO requirements has been devised and developed, to suit the needs of all SME’s auto parts manufacturers in the region. The paper discusses and analysis the cluster model in details

Oxide Dispersion Strengthened Nickel Based Alloys via Spark Plasma Sintering

Oxide dispersion strengthened (ODS) nickel based alloys were developed via mechanical milling and spark plasma sintering (SPS) of Ni–20Cr powder with additional dispersion of 1.2 wt% Y2O3 powder. Furthermore, 5 wt% Al2O3 was added to Ni–20Cr–1.2Y2O3 to provide composite strengthening in the ODS alloy. The effects of milling times, sintering temperature, and sintering dwell time were investigated on both mechanical properties and microstructural evolution. A high number of annealing twins was observed in the sintered microstructure for all the milling times. However, longer milling time contributed to improved hardness and narrower twin width in the consolidated alloys. Higher sintering temperature led to higher fraction of recrystallized grains, improved density and hardness. Adding 1.2 wt% Y2O3 to Ni–20Cr matrix significantly reduced the grain size due to dispersion strengthening effect of Y2O3 particles in controlling the grain boundary mobility and recrystallization phenomena. The strengthening mechanisms at room temperature were quantified based on both experimental and analytical calculations with a good agreement. A high compression yield stress obtained at 800 °C for Ni–20Cr–1.2Y2O3–5Al2O3 alloy was attributed to a combined effect of dispersion and composite strengthening

Metal powder recyclability in binder jet additive manufacturing

The recyclability of 316L stainless steel powder in the binder jetting process has been determined. The powder characterization results demonstrated a 22% increase in the number of coarse particles (> 30 µm) and an 18.2% reduction in the number of small particles (< 10 µm) after recycling up to 16 times. A few elongated and irregular-shaped particles were found after recycling, possibly due to particle agglomeration during handling and sieving. A negligible increase in the oxygen content by 0.036% was detected in the recycled powder. The density of sintered parts produced using recycled powder was approximately 1.5% lower than when using fresh powder due to the changes in the particle size distribution and the flowability of the powder caused by the changes in morphology. Final parts built using fresh and recycled powder showed similar hardness (155 ± 3 HV and 165 ± 9 HV) and yield strength (206 ± 16 MPa and 192 ± 10 MPa), respectively

Additive Manufacturing of ODS Steels Using Powder Feedstock Atomized with Elemental Yttrium

This study investigates the microstructure and mechanical properties of an austenitic ODS steel produced by the Laser Directed Energy Deposition (LDED) process using powder feedstock atomized with elemental yttrium. The Microstructure of the samples was characterized by electron microscopy, and mechanical properties were measured using a tensile test and nanoindentation. Further, the thermal stability of the LDEDproduced ODS steels were evaluated. As-printed samples showed a cellular structure with Si-Mn-Y-Oenriched nanoparticles that were found to be amorphous. After 100 hours at 1000°C in an argon atmosphere, a partially recrystallized microstructure with a decrease in the number density of Y-O-enriched nanoparticles with crystalline structure was revealed. The as-printed (600 W, 600 mm/min) samples exhibited an ultimate tensile strength of 774 MPa and an elongation at a break of 22%. A lower ultimate tensile strength of 592 MPa and higher elongation of 42% was measured after 100 hours at 1000°C.Mechanical Engineerin

Selective laser melting and tempering of H13 tool steel for rapid toolingg applications

H13 components with a relative density of ∼99% were additively manufactured using the selective laser melting (SLM) process. The highest density part (relevant density 99%) with the lowest level of porosity (<0.01%) was made with a volumetric energy density of 760 J/mm3 (152 W laser power, 100 mm/s scanning speed, 40 μm hatch spacing, and 50 μm layer thickness). Wrought and additively manufactured samples underwent tempering at 550, 600, and 650 °C for 2 h followed by furnace cooling. Additively manufactured samples and wrought H13 samples that were austenitized followed by water quenching were martensitic with similar microhardness values of 708.4 ± 25.0 HV and 708.1 ± 12.6 HV, respectively. A tempered martensitic structure was observed in SLM-manufactured and tempered samples. Samples that were additively manufactured and tempered at 550 °C showed higher microhardness (728.5 ± 28.2 HV) than non-tempered SLM-manufactured samples due to an upward shift in the secondary hardening phase. Tempering at 600 and 650 °C resulted in coarsening of the carbides and martensite, which led to a reduction in microhardness. Additively manufactured samples maintained higher microhardness values than wrought H13 samples at all tempering temperatures, likely because of higher dislocation density, finer grains present, and higher volume fraction of carbide nanoparticles

In-situ manufacturing of ODS FeCrAlY alloy via laser powder bed fusion

Gas-atomized Fe–24Cr–8Al–0.5Y (wt.%) powder was used as a feedstock in a laser powder bed fusion process with nitrogen atmosphere. Formation of Al–Y–O-enriched nanoparticles with diameters of 10–100 nm implied in-situ precipitation of Al–Y–O-enriched nanoparticles within the ferritic matrix developing an oxide dispersion strengthened FeCrAl alloy without any mechanical alloying. Thermodynamics and kinetics of the internal oxidation during rapid solidification of laser powder bed fusion process are discussed

Effects of atomizing media and post processing on mechanical properties of 17-4 PH stainless steel manufactured via selective laser melting

Water-atomized and gas-atomized 17-4 PH stainless steel powder were used as feedstock in selective laser melting process. Gas atomized powder revealed single martensitic phase after printing and heat treatment independent of energy density. As-printed water atomized powder contained dual martensitic and austenitic phase regardless of energy density. The H900 heat treatment cycle was not effective in enhancing mechanical properties of the water-atomized powder after laser melting. However, after solutionizing at 1315 degrees C and aging at 482 degrees C fully martensitic structure was observed with hardness (40.2 HRC), yield strength (1000 MPa) and ultimate tensile strength (1261 MPa) comparable to those of gas atomized (42.7 HRC, 1254 MPa and 1300 MPa) and wrought alloy (39 HRC, 1170 MPa and 1310 MPa), respectively. Improved mechanical properties in water-atomized powder was found to be related to presence of finer martensite and higher volume fraction of fine Cu-enriched precipitates. Our results imply that water-atomized powder is a promising cheaper feedstock alternative to gas-atomized powder

Pulmonary arterial pressure detects functional mitral stenosis after annuloplasty for primary mitral regurgitation: An exercise stress echocardiographic study

Introduction: The restrictive mitral valve annuloplasty (RMA) is the treatment of choice for degenerative mitral regurgitation (MR), but postoperative functional mitral stenosis remains a matter of debate. In this study, we sought to determine the impact of mitral stenosis on the functional capacity of patients. Methods: In a cross-sectional study, 32 patients with degenerative MR who underwent RMA using a complete ring were evaluated. All participants performed treadmill exercise test and underwent echocardiographic examinations before and after exercise. Results: The patients� mean age was 50.1 ± 12.5 years. After a mean follow-up of 14.1 ± 5.9 months (6�32 months), the number of patients with a mitral valve peak gradient >7.5 mm Hg, a mitral valve mean gradient >3 mm Hg, and a pulmonary arterial pressure (PAP) �25 mm Hg at rest were 50, 40.6, and 62.5, respectively. 13 patients (40.6) had incomplete treadmill exercise test. All hemodynamic parameters were higher at peak exercise compared with at rest levels (all P <.05). The PAP at rest and at peak exercise as well as peak transmitral gradient at peak exercise were higher in patients with incomplete exercise compared with complete exercise test (all P <.05). The PAP at rest (a sensitivity and a specificity of 84.6 and 52.6, respectively; area under the curve AUC =.755) and at peak exercise (a sensitivity and a specificity of 100% and 47.4%, respectively; AUC =.755) discriminated incomplete exercise test. Conclusion: The RMA for degenerative MR was associated with a functional stenosis and the PAP at rest and at peak exercise discriminated low exercise capacity. © 2017, Wiley Periodicals, Inc

Pulmonary arterial pressure detects functional mitral stenosis after annuloplasty for primary mitral regurgitation: An exercise stress echocardiographic study

Introduction: The restrictive mitral valve annuloplasty (RMA) is the treatment of choice for degenerative mitral regurgitation (MR), but postoperative functional mitral stenosis remains a matter of debate. In this study, we sought to determine the impact of mitral stenosis on the functional capacity of patients. Methods: In a cross-sectional study, 32 patients with degenerative MR who underwent RMA using a complete ring were evaluated. All participants performed treadmill exercise test and underwent echocardiographic examinations before and after exercise. Results: The patients� mean age was 50.1 ± 12.5 years. After a mean follow-up of 14.1 ± 5.9 months (6�32 months), the number of patients with a mitral valve peak gradient >7.5 mm Hg, a mitral valve mean gradient >3 mm Hg, and a pulmonary arterial pressure (PAP) �25 mm Hg at rest were 50, 40.6, and 62.5, respectively. 13 patients (40.6) had incomplete treadmill exercise test. All hemodynamic parameters were higher at peak exercise compared with at rest levels (all P <.05). The PAP at rest and at peak exercise as well as peak transmitral gradient at peak exercise were higher in patients with incomplete exercise compared with complete exercise test (all P <.05). The PAP at rest (a sensitivity and a specificity of 84.6 and 52.6, respectively; area under the curve AUC =.755) and at peak exercise (a sensitivity and a specificity of 100% and 47.4%, respectively; AUC =.755) discriminated incomplete exercise test. Conclusion: The RMA for degenerative MR was associated with a functional stenosis and the PAP at rest and at peak exercise discriminated low exercise capacity. © 2017, Wiley Periodicals, Inc