Protective Coatings on Steel Dies for Wax Injection Process

Protective coatings are used today in many applications for reducing friction and wear of tools in hot-working process e.g. metal die casting, hot forging, metal die plastics injection. The main goal of undertaken investigation was to evaluate usability of those coatings for improving wear resistance of metal die applied in investment casting process for wax injection. The (Ti,Al)N and (Al,Cr)N PVD coatings were deposited onto X37CrMoV5-1 hot-work tool steel and their mechanical and tribological properties are characterized in the paper. Based on the results of microscope examinations, scratch test, hardness measurement the similar properties of (Ti,Al)N and (Al,Cr)N coatings were found. Moreover it was established that type of steel surface machining before coating deposition, i.e. grinding, electrical discharge machining (EDM) and milling, did not affect coating properties. Thin coatings replicate steel base roughness parameters as Ra, Rz and Rmax with over 95% of correlation. Based on tensile test results of wax/coated steel samples and wax/uncoated steel samples the lowest wax adhesion to (Ti,Al)N coating was confirmed.

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The Influence of Injection Processing on the Shrinkage Variation and Dimensional Stability of Wax Pattern in Investment Casting

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.538-541.1217 ◽

2012 ◽

Vol 538-541 ◽

pp. 1217-1221

Author(s):

Dong Hong Wang ◽

Bo He ◽

Fei Li ◽

Bao De Sun

Keyword(s):

Dimensional Stability ◽

Investment Casting ◽

Flow Direction ◽

Dimensional Accuracy ◽

Casting Process ◽

Cast Part ◽

Injection Process ◽

Wax Pattern ◽

Dimensional Variation ◽

Wax Injection

The accuracy of the wax patterns used in the investment casting process has a direct bearing on the accuracy of the final cast part. Wax injection process plays a key role in production of nearly net shape wax pattern. Dimension shrinkage is one of the most significant problems of a wax pattern in terms of dimensional stability in the wax injection molding. This study aimed to determine the effects of injection parameters on the dimensional accuracy of the wax patterns. Linear contractions normal to flow direction and weight of wax patterns were measured and dimensional variations were evaluated. The results highlight it is important that when dealing with thick gates, short packing time appears to be the best way to avoid gate area over packing and dimensional variations, high packing pressure appears to increase expansion and dimensional variation of wax pattern.

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Optimisation of Mechanical Properties of Gradient Zr–C Coatings

Materials ◽

10.3390/ma14020296 ◽

2021 ◽

Vol 14 (2) ◽

pp. 296

Author(s):

Łukasz Szparaga ◽

Przemysław Bartosik ◽

Adam Gilewicz ◽

Katarzyna Mydłowska ◽

Jerzy Ratajski

Keyword(s):

Adhesive Layer ◽

Scratch Test ◽

Deposition Process ◽

Functionally Graded ◽

Wear Properties ◽

Mechanical And Tribological Properties ◽

High Adhesion ◽

Graded Material ◽

Residual Stresses And Strains ◽

Optimisation Procedure

One of the key components of the designing procedure of a structure of hard anti-wear coatings deposited via Physical Vapour Deposition (PVD) is the analysis of the stress and strain distributions in the substrate/coating systems, initiated during the deposition process and by external mechanical loads. Knowledge of residual stress development is crucial due to their significant influence on the mechanical and tribological properties of such layer systems. The main goal of the work is to find the optimal functionally graded material (FGM) coating’s structure, composed of three functional layers: (1) adhesive layer, providing high adhesion of the coating to the substrate, (2) gradient load support and crack deflection layer, improving hardness and enhancing fracture toughness, (3) wear-resistant top layer, reducing wear. In the optimisation procedure of the coating’s structure, seven decision criteria basing on the state of residual stresses and strains in the substrate/coating system were proposed. Using finite element simulations and postulated criteria, the thickness and composition gradients of the transition layer in FGM coating were determined. In order to verify the proposed optimisation procedure, Zr-C coatings with different spatial distribution of carbon concentration were produced by the Reactive Magnetron Sputtering PVD (RMS PVD) method and their anti-wear properties were assessed by scratch test and ball-on-disc tribological test.

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Micro Electrical Discharge Machining Thermal Effect on Micro-Cracks Generation on Silicon Material

Materials Science Forum ◽

10.4028/www.scientific.net/msf.1047.41 ◽

2021 ◽

Vol 1047 ◽

pp. 41-49

Author(s):

Xiao Zhong Song

Keyword(s):

Electrical Discharge Machining ◽

Crystalline Silicon ◽

Local Area ◽

Silicon Wafers ◽

Adverse Side Effect ◽

Micro Edm ◽

Crystalline Orientation ◽

Surface Machining ◽

Crack Generation ◽

Micro Cracks

Various novel 3D micro machining technologies were researched and developed for silicon micro mechanical system fabrication. Micro EDM is one of them. The material removal mechanism is thermal sparking erosion and is completely independent with regards to the crystalline orientation of silicon, therefore there is no orientation constraint in processing the complex 3D geometry of silicon wafers. As thermal sparking implied, the process features local area high temperature melting and evaporating, and this characteristic has an adverse side-effect on the sparked surface integrity. One important concern is the generation of micro cracks, which would provide an adverse effect on the fatigue life of the micro feature element made of silicon. For this consideration, in this paper, with the experiment and SEM picture analysis approach, the author explored the micro crack generation characteristics on mono crystalline silicon wafers under micro EDM with available sparking energies and on the different crystal orientation surface machining. The generation of micro cracking is not only related with the sparking energy but also related with the crystalline orientation. The {100} orientation is the strongest surface to resist crack generation. For a strong-doped P type silicon wafer, there exists a maximum crack energy threshold. If single sparking energy is over this threshold, micro cracks unavoidably would be generated on any orientation surface. Two types of chemical etching post processes that can remove cracks on sparked surfaces are also tested and discussed.

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Simulation of die filling for the wax injection process: Part II. Numerical simulation

Metallurgical and Materials Transactions B ◽

10.1007/s11663-004-0016-6 ◽

2004 ◽

Vol 35 (4) ◽

pp. 761-768 ◽

Cited By ~ 3

Author(s):

J. -C. Gebelin ◽

M. R. Jolly ◽

A. M. Cendrowicz ◽

S. Blackburn ◽

J. Cirre

Keyword(s):

Numerical Simulation ◽

Injection Process ◽

Die Filling ◽

Wax Injection

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Structure, Oxidation Resistance, Mechanical, and Tribological Properties of N- and C-Doped Ta-Zr-Si-B Hard Protective Coatings Obtained by Reactive D.C. Magnetron Sputtering of TaZrSiB Ceramic Cathode

Coatings ◽

10.3390/coatings10100946 ◽

2020 ◽

Vol 10 (10) ◽

pp. 946

Author(s):

Ph. V. Kiryukhantsev-Korneev ◽

A. D. Sytchenko ◽

S. A. Vorotilo ◽

V. V. Klechkovskaya ◽

V. Yu. Lopatin ◽

...

Keyword(s):

Magnetron Sputtering ◽

Oxidation Resistance ◽

Tribological Properties ◽

Protective Coatings ◽

Elastic Recovery ◽

Protective Film ◽

X Ray Diffraction ◽

Energy Dispersion Spectroscopy ◽

X Ray ◽

Mechanical And Tribological Properties

Coatings in the Ta-Zr-Si-B-C-N system were produced by magnetron sputtering of a TaSi2-Ta3B4-(Ta,Zr)B2 ceramic target in the Ar medium and Ar-N2 and Ar-C2H4 gas mixtures. The structure and composition of coatings were studied using scanning electron microscopy, glow discharge optical emission spectroscopy, energy-dispersion spectroscopy, and X-ray diffraction. Mechanical and tribological properties of coatings were determined using nanoindentation and pin-on-disk tests using 100Cr6 and Al2O3 balls. The oxidation resistance of coatings was evaluated by microscopy and X-ray diffraction after annealing in air at temperatures up to 1200 °C. The reactively-deposited coatings containing from 30% to 40% nitrogen or carbon have the highest hardness up to 29 GPa and elastic recovery up to 78%. Additionally, coatings with a high carbon content demonstrated a low coefficient of friction of 0.2 and no visible signs of wear when tested against 100Cr6 ball. All coatings except for the non-reactive ones can resist oxidation up to a temperature of 1200 °C thanks to the formation of a protective film based on Ta2O5 and SiO2 on their surface. Coatings deposited in Ar-N2 and Ar-C2H4 demonstrated superior resistance to thermal cycling in conditions 20-T−20 °C (where T = 200–1000 °C). The present article compares the structure and properties of reactive and “standard-inert atmosphere” deposited coatings to develop recommendations for optimizing the composition.

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Scratch Testing of AlSi12/SiCp Composite Layer with High Share of Reinforcing Phase Formed in the Centrifugal Casting Process

Materials ◽

10.3390/ma13071685 ◽

2020 ◽

Vol 13 (7) ◽

pp. 1685

Author(s):

Anna Janina Dolata ◽

Marek Mróz ◽

Maciej Dyzia ◽

Magdalena Jacek-Burek

Keyword(s):

Simple Model ◽

Abrasion Resistance ◽

Centrifugal Casting ◽

Composite Layer ◽

Casting Process ◽

Scratch Test ◽

Scratch Testing ◽

Scratch Depth ◽

Diamond Indenter ◽

High Share

The scratch test enables assessing the susceptibility of a material to the development of scratches and, being in some ways a measure of its abrasion resistance, allows extended knowledge in the field of material application usability, especially its machining capabilities. The aim of the study was to assess the resistance of a centrifugally formed AlSi12/SiCp composite layer with a high share of reinforcing phase (Vp > 40%) to scratching with a diamond indenter. The microstructure and effect of the load applied to the diamond indenter on the scratch depth and susceptibility of the composite layer to the nucleation and propagation of cracks in hard and brittle SiC particles were analyzed. A simple model of SiCp cracking depending on their size, shape (geometry), and orientation in relation to the direction of scratching has been proposed.

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Simulation Study on Wax Injection for Investment Casting

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.834-836.1575 ◽

2013 ◽

Vol 834-836 ◽

pp. 1575-1579

Author(s):

Bo He ◽

Dong Hong Wang ◽

Fei Li ◽

Bao De Sun

Keyword(s):

Numerical Simulation ◽

Mold Design ◽

Trial And Error ◽

Efficient Tool ◽

Injection Process ◽

Wax Pattern ◽

Filling Time ◽

Gate System ◽

The Cost ◽

Wax Injection

As investment castings grow in size and complexity, control of wax pattern dimensions becomes increasingly important and difficult. Conventionally, mold design and dimensions are re-worked by trial-and-error procedures until casting dimensions are produced within acceptable dimensional tolerances, increasing the cost of the castings.Nowadays, numerical simulation is an efficient tool for mold design. However, one of the critical difficulties in using computer models for the simulation of wax injection process is the lack of material properties of the wax. Material property measurements were conducted in this study that can be used as input in Moldflow. Then, 3D numerical simulation could be applied in analysis with mold design of thin-walled wax pattern, with high dependability. Simulation results of filling time and the location of the air traps were analyzed. Consequently, best gate location and reasonable gate system were determined. The paper highlighted the effectiveness of simulation in filling optimization and deformation of wax pattern.

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Effects of Heat Treatment on the Mechanical and Tribological Properties of Aluminium (LM6) Reinforced with Iron Oxide (Fe2O3)

International Journal of Vehicle Structures and Systems ◽

10.4273/ijvss.12.3.09 ◽

2020 ◽

Vol 12 (3) ◽

Author(s):

J. Arun Prakash ◽

P. Shanmughasundaram ◽

M. Vemburaj ◽

P. Gowtham

Keyword(s):

Mechanical Properties ◽

Heat Treatment ◽

Tensile Strength ◽

Iron Oxide ◽

Treatment Process ◽

Casting Process ◽

Stir Casting ◽

Heat Treatment Process ◽

Treatment Results ◽

Mechanical And Tribological Properties

This work deals with the examination of the mechanical properties of Aluminium (LM6) reinforced with iron oxide (Fe2O3). Stir casting process is used to formulate the composite sampling by varying iron oxide in 5% and 10% by weight. Three different heat treatment process of hardening, annealing and normalizing is carried out on samples of aluminium (LM6), aluminium (LM6) + 5% Fe2O3 and aluminium (LM6) + 10% Fe2O3. Composite specimens are tested to analyze the mechanical properties such as hardness, yield stress, tensile strength and elongation. Present reinforcement specks enabled the alloy to preserve higher hardness during the heat treatment. Results have shown substantial improvements in properties of the specimens with various compositions of reinforcement.

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