Phase Reactions During Sintering of M3/2 Based Composites with WC Additions

2013 ◽  
Vol 58 (3) ◽  
pp. 703-708 ◽  
Author(s):  
M. Madej
Keyword(s):  
Grain Boundary ◽  
Carbide Phase ◽  
High Speed ◽  
Brinell Hardness ◽  
High Speed Steel ◽  
Hardness Test ◽  
Edx Analysis ◽  
Boundary Film ◽  
Dilatometric Studies ◽  
Cold Pressed

Abstract Attempts have been made to describe the influence of WC additions on properties of M3/2 high speed steel (HSS) based composites. The powder compositions used to produce skeletons for further infiltration were M3/2, M3/2+10%WC and M3/2+30%WC. The powders were cold pressed at 800 MPa. The green compacts were subsequently sintered for 60 minutes at 1150°C in vacuum. These as-sintered specimens were used for copper infiltration. A qualitative EDX analysis revealed presence of both MC type vanadium-rich carbides and M6C type tungsten and iron rich carbides. In specimens containing 10 and 30% WC the carbide phase was uniformly distributed within copper-rich regions. The WC monocarbide reacts with the surrounding HSS matrix and forms a carbide grain boundary film. The microstructural observations of the as-sintered specimens was followed by Brinell hardness test and supplemented with dilatometric studies.

scholarly journals Some Aspects Of Infiltration Of High Speed Steel Based Composites With Iron Addition

2015 ◽  
Vol 60 (2) ◽  
pp. 1017-1021 ◽  
Author(s):  
M. Madej
Keyword(s):  
High Speed ◽  
Bending Strength ◽  
Brinell Hardness ◽  
High Speed Steel ◽  
Infiltration Process ◽  
Iron Powders ◽  
Wear Rates ◽  
Direct Infiltration ◽  
Cold Pressed ◽  
Wear Tests

AbstractAttempts have been made to describe the influence of the production process parameters and additions of iron powders on properties of copper infiltrated HSS based composites. The powder compositions used to produce skeletons for further infiltration were: M3/2, M3/2+20% Fe and M3/2+50% Fe. The powders were cold pressed at 800 MPa. The infiltration process was carried out in vacuum. Both green compacts and preforms sintered for 60 minutes at 1150°C in vacuum were contact infiltrated with copper to yield final densities exceeding 97% of the theoretical value.The as-infiltrated composites were tested for Brinell hardness and bending strength, and subjected to wear tests performed by block-on-ring wear tester. From the analysis of the obtained results it has been found that the mechanical properties are mainly affected by the manufacturing route and composition of porous skeletons used for infiltration. Considerable differences in hardness between materials obtained from the two infiltration routes have been observed, with lower wear rates achieved after direct infiltration of green compacts.

scholarly journals Internal Stresses in PVD Coated Tool Composites

2016 ◽  
Vol 61 (3) ◽  
pp. 1371-1378 ◽  
Author(s):  
A. Śliwa ◽  
J. Mikuła ◽  
K. Gołombek ◽  
W. Kwaśny ◽  
D. Pakuła
Keyword(s):  
Chemical Composition ◽  
Carbide Phase ◽  
High Speed ◽  
High Speed Steel ◽  
High Hardness ◽  
Functionally Graded ◽  
Internal Stresses ◽  
Surface Zone ◽  
The Core ◽  
The Matrix

Abstract The aim of work is the investigation of the internal stresses in PVD coated metal matrix composites (MMC). Sintered MMC substrate is composed of the matrix with the chemical composition corresponding to the high-speed steel, reinforced with the TiC type hard carbide phase. Functionally graded composition of MMC providing of high ductility characteristic of steel in the core zone as well as high hardness characteristic of cemented carbides in the surface zone. Internal stresses were determined with use of finite element method in ANSYS environment. The reason of undertaking the work is necessity of develop the research of internal stresses, occurring in the coating, as well as in the adhesion zone of coating and substrate, which makes it possible to draw valuable conclusions concerning engineering process of the advisable structure and chemical composition of coatings. The investigations were carried out on cutting tool’s models containing defined zones differing in chemical composition. Modelled materials were characteristic of chemical composition corresponding to the high-speed steel at the core, reinforced with the TiC type hard carbide phase with the growing fraction of these phases in the outward direction from the core to the surface, additionally coated with (Ti,Al)N or Ti(C,N) functionally graded PVD coatings. Results of determined internal stresses were compared with the results calculated using experimental X-ray sin2ψ method. It was demonstrated, that the presented model meets the initial criteria, which gives ground to the assumption about its utility for determining the stresses in coatings as well as in functionally graded sintered materials. The results of computer simulations correlate with the experimental results.

Contact interaction peculiarities at the boundary of layers of «structural steel–high-speed steel» hot-forged powder bimetal

2018 ◽  
pp. 11-22
Author(s):  
Yu. G. Dorofeyev ◽  
V. Yu. Dorofeyev ◽  
A. V. Babets ◽  
Eu. N. Bessarabov ◽  
O. N. Romanova ◽  
...  
Keyword(s):  
Structural Steel ◽  
High Speed ◽  
Hot Forging ◽  
Base Material ◽  
High Speed Steel ◽  
Contact Boundary ◽  
Adhesive Interaction ◽  
Layer Material ◽  
Working Layer ◽  
Cold Pressed

The main problem in the production of bimetals (BMs) is the need to ensure adhesive interaction at the contact boundary of layers to prevent their peeling during operation. Hot forging of porous preforms (HFPP) provides the possibility of obtaining high-density powder BMs with a minimum amount of pores both in the volume of the layer material and at the layer interface to increase adhesion strength. Production of hot-forged powder BMs may involve mixing of working layer and substrate charge materials, which can lead to uncontrolled interface «blurring». This study uses the previously proposed method for pre-pressing of hard-to-deform material powder to produce «structural steel – high-speed steel» porous BM preforms. Two-layer cylindrical ∅20×30 mm samples were obtained in order to determine mechanical properties and conduct structural analysis. The BM base material was PK40 steel, and the working layer was atomized powder of M2 high-speed steel featuring satisfactory compressibility properties. The porous preforms of BM samples were pressed in a specially designed mold at a hydraulic press enabling two-sided pressing of two-layer powder moldings with predetermined distribution of layer densities and strengths. Cold-pressed BM preforms were sintered in protective environment, and then subjected to hot repressing using a laboratory drop hammer. Some preforms were examined as sintered. In addition, hot repressing of cold-pressed green preforms was performed. Satisfactory process strength of the working layer material is observed at its porosity (Pwl) in the range from 34 to 45 %. When Pwl> 45 %, powder is not molded, and at Pwl< 34 % the working layer delaminates. The maximum layer bonding strength and thermal shock resistance of BM provides the use of a flow route that involves preliminary sintering of cold-pressed preforms and subsequent hot forging. The optimum pressure of working layer pre-pressing is 145 MPa.

Morphology of In Situ VC Ceramics in High Speed Steel with High Vanadium Content

2010 ◽  
Vol 105-106 ◽  
pp. 46-48
Author(s):  
Liu Jie Xu ◽  
Hui Min Chen ◽  
Shi Zhong Wei ◽  
Rui Long
Keyword(s):  
Chemical Composition ◽  
Grain Boundary ◽  
Grain Boundaries ◽  
High Speed ◽  
High Speed Steel ◽  
Vanadium Content ◽  
Obvious Effect ◽  
Eutectic Modification ◽  
Homogeneous Distributions

The morphology and distribution of in-situ VC ceramics in cast high speed steel with about 5-10wt.% vanadium and 1.7-3.2wt.% carbon were studied. The results show that the elementary morphology of in-situ VC ceramics has six kinds: spherical, lumpy, flower shaped, strip, short rod shaped, and vermicular. The in-situ VC in high-speed steel has three kinds of distributions: grain boundary, chrysanthemum-like and homogeneous distributions, depending on the chemical composition of high-speed steel. The in-situ VC ceramics grows up along grain boundaries if the high-speed steel is hypoeutectic, leading to grain boundary distribution of VC ceramics. On the contrary, it distributes homogeneously when the high-speed steel is hypereutectic. Whereas, the in-situ VC ceramics takes on chrysanthemum distribution if the high speed steel is just eutectic. Modification can improve the morphology of primary VC ceramics, but has not obvious effect on the morphology of eutectic VC.

Material characterization of tribological effects in HSS hacksaw blade

2017 ◽  
Vol 69 (3) ◽  
pp. 355-362
Author(s):  
Nor Amirah binti Mohd Amran ◽  
Mohd Sayuti bin Ab Karim ◽  
Rusdi bin Abd Rashid ◽  
Waleed Alghani ◽  
Nur Aqilah binti Derahman
Keyword(s):  
Mechanical Properties ◽  
High Speed ◽  
High Speed Steel ◽  
Hardness Test ◽  
Vital Role ◽  
Von Mises Stress ◽  
Content Type ◽  
Cultural Aspects ◽  
Von Mises

Purpose This study aims to present a direct repurposing activity of consumed high-speed steel (HSS) hacksaw blade into fine-looking handmade knives to increase the awareness about sustainability by evaluating the relationship between the quality of material alloys and heat treatment as well as cultural aspects such as the treatment on the HSS hacksaw blade that will affect the material hardness. Design/methodology/approach The quality of HSS hacksaw blade samples was analyzed by using scanning electron microscope/energy dispersive X-Ray spectroscopy (SEM/EDX) through the identification of material element’s properties. Besides, finite element structural analysis was performed by using SolidWorks Simulation to evaluate the material performance by determining the Von Mises stress to find the factor of safety of the knife designs. Then, the effect of tribology implementation toward mechanical properties of the handmade knives was determined by using a Rockwell C hardness test. Findings It is found that the material composition of carbon plays a vital role in increasing and improving the hardness and wear resistance of the HSS hacksaw blade. The Von Mises stress obtained is lower than the yield strength of 3,250 MPa by 71.44 per cent with the safety factor of 3.58,which means the design will not be subjected to failure. The mechanical properties of the HSS hacksaw blade such as hardness were determined averagely by 5 per cent of hardness increase. Originality/value It has been validated that the tribological effect toward the material characteristic leads to hardness changes which contributed to the enhancement of tool life of the HSS hacksaw blade, thus producing better quality knives.

scholarly journals Comparison Of Oxidation Resistance of TiAlN Monolayer Coating And Its NaCo3 Nanostructured Version

2013 ◽  
Vol 21 (Special-Issue) ◽  
pp. 67-72
Author(s):  
Martin Sahul ◽  
Paulína Zacková ◽  
Ľubomír Čaplovič ◽  
Kristián Šalgó ◽  
Jana Bohovičová ◽  
...  
Keyword(s):  
Oxidation Resistance ◽  
High Speed ◽  
Elevated Temperatures ◽  
High Speed Steel ◽  
Phase Detection ◽  
X Ray Diffraction ◽  
Oxide Layers ◽  
Edx Analysis

Abstract The contribution deals with comparison of oxidation resistance of classical TiAlN monolayer coating and its advanced high hard nanostructured and multilayered nACo3 version at elevated temperatures. Both coatings were deposited onto AISI M36 high speed steel using unique LAteral Rotating Cathodes process (LARC®). “In - situ” X-Ray diffraction analysis was employed for determination of the beginning of oxides creation and phase detection at different heating temperatures. Scanning electron microscopy fitted with EDX analysis was used for observation of fracture areas and measurements of coatings and oxide layers thicknesses as well. Determination of chemical composition of coatings surfaces and elemental linescans through the coatings and oxide layers were performed using EDX analysis. All measurements of these coatings were carried out not only before but also after the thermal annealing.

The Properties and Structure of Infiltrated High Speed Steel-Tungsten Carbide-Copper Composites

2010 ◽  
Vol 636-637 ◽  
pp. 184-191
Author(s):  
Marcin Madej
Keyword(s):  
Tungsten Carbide ◽  
High Speed ◽  
Sintered Density ◽  
Bending Strength ◽  
High Speed Steel ◽  
Pendulum Motion ◽  
Infiltration Process ◽  
Cold Pressed ◽  
Sintering Condition ◽  
Better Than

The aim of the present study was to produce high speed steel – tungsten carbide – copper composites, which should have acceptable density, wear resistance and good sliding prosperities. Various amounts of WC powder were added to the HSS powder prior to compaction. The following compositions were investigated: 100% M3/2, M3/2 + 10% WC and M3/2 + 30%WC. The mixtures were prepared by mixing for 30 minutes in the 3-D pendulum motion Turbula® T2C mixer. Then the powders were cold pressed in a rigid cylindrical die at 800 MPa. Both green compacts and pre-sintered compacts (pre-sintering condition: 1150°C in vacuum for 60 minutes) were infiltrated with copper. The whole infiltration process was carried out in vacuum better than 10-3 Pa. Pre-weighed preforms of copper were carefully placed on top of the rigid skeletons in which porosity were predetermined, heated up to 1150°C, subsequently held at temperature for 15 minutes, and cooled down with the furnace to the room temperature. The dilatometer was used to detect some reaction in the sintering. The changes in as pressed and as sintered density, hardness, bending strength and tribological properties are discussed in this work.

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