Steel Binder Research Articles

The reciprocating wear behaviour of TiC–304L stainless steel composites prepared by melt infiltration

TiC-based ceramic–metal composites, or cermets, are widely used in applications requiring wear and corrosion resistance. In the present work, a family of novel TiC–stainless steel (grade 304L) cermets has been developed using vacuum melt infiltration (1500°C/1h), with steel binder contents varied from 5 to 30vol%. Microstructural analysis showed a homogenous distribution of TiC within the steel binder, with mean TiC grain sizes of ∼6μm. Increasing the steel content resulted in an increase in the indentation fracture resistance and a decrease in the hardness. The reciprocating wear resistance of the cermets was assessed using a ball-on-flat geometry, using a WC–Co sphere dry sliding on the polished cermet surface. It was shown that there is an increase in the specific wear rate with both increasing load and binder content. Similarly, a higher coefficient of friction was observed with higher steel binder contents. The morphology of the worn surface was investigated using scanning electron microscopy, and associated energy dispersive X-ray spectroscopy, to more fully understand the operative wear mechanisms. Evidence of a transition from two- to three-body abrasive wear was observed, together with the formation of a tribolayer, indicating that adhesive wear was also occurring.

Effects of Sintering Temperature and Cooling Rate on Mechanical Properties of Powder Injection Molded 316L Stainless Steel

This research presents the effects of temperature and cooling rate on mechanical properties of powder injection molded 316L Stainless steel. Steel powder and binder were mixed together to produce the feedstock. The green samples were produced by injection molding and debinded. Brown test samples were sintered in vacuum at 1325°C, 1360°C and 1380°C for 2h with two heating and cooling rates 5°C/min and 10°C/ min. The test samples sintered at 1325°C achieved maximum sintered density. The higher cooling rate improved the strength of the sintered test samples. The maximum sintered density of 96% and tensile strength of 503MPa was achieved and these results are comparable to the wrought 316L stainless steel (according to ASTM standard).

Diamond tools with metastable steel binder for natural stone cutting

The structure and properties of diamond tools with steel powder matrices are studied. It is shown that the physical-mechanical and performance characteristics of the metallic matrices depend on the volume of the deformation phase transformation of austenite to martensite. The tools are tested under industrial conditions for cutting of various rocks. The optimal composition of the matrix is selected, possessing the highest volume of the phase transformation in cutting of all of the tested rocks.

Stainless steel binder for the development of novel TiC-reinforced steel cermets

Steel reinforced TiC composites are an attractive choice for wear resistance and corrosion resistance applications. TiC-reinforced 17-4PH maraging stainless matrix composites were processed by conventional powder metallurgy (P/M). TiC-reinforced maraging stainless steel composites with >97% of theoretical density were fabricated. The microstructure, mechanical and wear properties of the composites were evaluated. The microstructure of these composites consisted of spherical and semi-spherical TiC particles. A few microcracks appeared in the composites, showing the presence of tensile stress in the composites produced during sintering. Typical properties, namely, hardness and bend strength were reported for the sintered composites. After heat treatment and aging, the increase of hardness was observed. The increase of hardness was attributed to the aging reaction in the 17-4PH stainless steel. The precipitates appeared in the microstructure and were responsible for the increase in hardness. The specific wear behavior of the composites was strongly dependent on the content of TiC particles, the interparticle spacing, and the presence of hard precipitates in the binder phase.

TiC-maraging stainless steel composite: microstructure, mechanical and wear properties

Particulate TiC reinforced 17-4PH and 465 maraging stainless steel matrix composites were processed by conventional powder metallurgy (P/M). TiC-maraging stainless steel composites with theoretical density >97% were produced using conventional P/M. The microstructure, and mechanical and wear properties of the composites were evaluated. The microstructure of the composites consisted of (core-rim structure) spherical and semi-spherical TiC particles depending on the wettability of the matrix with TiC particles. In TiC-maraging stainless steel composites, 465 stainless steel binder phase showed good wettability with TiC particles. Some microcracks appeared in the composites, indicating the presence of tensile stresses in the composites produced during sintering. The typical properties, hardness, and bend strength were reported for the composites. After heat treatment and aging, an increase in hardness was observed. The increase in hardness was attributed to the aging reaction in maraging stainless steel. The specific wear behavior of the composites strongly depends on the content of TiC particles and their interparticle spacing, and on the heat treatment of the maraging stainless steel.

Design, development and evaluation of 3D mold inserts using a rapid prototyping technique and powder-sintering process

In this research work, attempts have been made to design, develop and evaluate the performance of mould inserts for injection moulding by using a powder-sintering process. Maraging steel powder, sintering aid and binder are materials used in this proposed development process. Attempts have been made to perform in-depth studies and to apply the powder-sintering process, to eventually produce the final sintered components. In addition, an analysis of the dimensional accuracy of the respective stereolithography master models and an analysis of the sintered specimens during various stages of powder-sintering process have been carried out. The intelligent manufacturing systems (IMS) test part with minor modifications has been used in the evaluation of dimensional accuracy, tolerances, distortion and volumetric variations. The main reason for using this unique geometry is the suitability of its design for injection-moulding processes and tooling.

Performance of TiC base cermets sintered by different techniques

The performance and structure of some advanced TiC base cermets with Ni steel binder, sintered by different techniques (sintering atmosphere, vacuum level, etc.), prospective for metal forming, were investigated. It is shown that the influence of sintering technology on the performance characteristics of TiC cermets (strength, wear resistance) depends on the composition and structure of their binder. Regarding the performance characteristics (transverse rupture strength and adhesive wear resistance) TiC base cermets with martensitic–bainitic steel binder sintered by optimum techniques demonstrated a marked superiority over those with austenitic binder and particularly over those with Ni alloy.

Wear of advanced cemented carbides for metalforming tool materials

Wear behavior of some advanced cemented carbides (TiC-base cermets and some WC-hardmetals) in a series of functional wear experiments (including blanking of electrotechnical sheet steel in production conditions) was analyzed. Comparative laboratory trials of related materials in abrasive-erosion and adhesive-wear conditions were conducted, complemented by SEM. A good correlation between adhesive-wear resistance of the alloys investigated and their resistance to side wear (flank wear of blanking tool) as well as similarity in the morphology of surface failure in both cases was found. With regard to blanking performance, TiC-base cermet with a Ni–steel binder proved to have advantages over conventional WC-base hardmetals (used in metalforming).

Study of the Microstructure and Phase-Composition of a WC-Alloy with a Hadfield Steel Binder

The phase composition and structure of a tungsten carbide alloy with a Hadfield steel binder are studied using metallography, x-ray diffraction analysis, and transmission electron microscopy. It is found that tungsten carbide is dissolved in the binder during sintering. This gives rise to a nonuniform distribution of the alloying additions in the γ-solid solution, which results in precipitation of complex carbides of the (W, Fe)xC type having different crystal-lattice parameters. The volume fraction of these carbides is as high as 9–10%.

Oxidation resistance of two TiB 2-based cermets

The oxidation kinetics of two TiB 2 cermets containing Fe–Ni–Al-ferritic and stainless steel binder phases has been determined in air at temperatures in the range of 700–1000°C for up to 70 h. Mass gain records as a function of time and temperature showed two kinetic ranges, a parabolic one up to 775°C and a linear one above 800°C. Activation energies were observed to be 153–165 and 110–118 kJ·mol −1 for the parabolic and linear ranges, respectively. The oxidation products were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), and transmission electron microscopy (TEM). The results are compared to those reported for similar materials.

Laser treatment of sintered TiC-steel alloys

1. Laser treatment of TiC-5Kh6VM2 steel alloys leads to a significant increase in hardness in the zone of laser action. The maximum effect of laser hardening is obtained for alloys containing up to 30% TiC. 2. The addition of titanium carbide to the steel leads to an increase in the depth of the zone of laser action as the result of a change in the character of heat dissipation. 3. The increase in hardness of the alloy with 10% TiC is caused by the significant redistribution of the carbide phase, the increase in its degree of dispersion, and additional alloying of the steel binder. 4. After laser treatment of alloys containing 10% TiC their relative wear resistance e is four to five times higher than after through oil hardening. The e of the alloy with 10% TiC is also higher than the e of alloys with a higher TiC content. 5. The tendency toward crack formation of alloys with titanium carbide limits its content to 10%.

Effect of carbon concentration in binder on the mechanical properties of heat-treatable titanium carbide-steel alloys

The optimum amount of carbon in the binder of titanium carbide-steel alloys depends on the carbon content of the carbide employed. In the preparation of alloys from titanium carbide of composition close to stoichiometric and high free-carbon content, alloying with only small amounts of carbon is recommended. When a nonstoichiometric, “low-carbon” carbide is used, however, larger amounts of carbon can be added to the alloys. The strong influence exerted by the concentration of carbon (combined and free) in the carbide and steel binder is clearly one of the causes of discrepancies in literature data on the properties of titanium carbide-steel alloys.

Optimization of the process of manufacture of diamond-containing composite materials based on titanium carbide-steel alloys

A study was made of the conditions of production of tungsten-free composite materials by sintering in a high-pressure chamber and in vacuum. Good-quality nonporous specimens of titanium carbide-steel materials cannot be produced by hot pressing in graphite dies. The hardness of materials sintered in a HPC is higher (81–86 HRA) than that of materials sintered in vacuum (75–82 HRA.). Heat treatment slightly lowers it (to 77–85 HRA). The highest wear resistance is exhibited by vacuum-sintered materials. In alloys sintered in a HPC a directional orientation of the steel binder with titanium carbide grain inclusions was observed. In service tests the properties of composition diamond-containing materials based on titanium carbide-steel alloys were found to match those of Tvesal alloys-diamond-containing composites based on a tungsten-group hard metal.

Effect of cover upon the stress–strain properties of concrete confined in steel binders

Synopsis Cover to the stirrups in reinforced concrete structures is one of the important parameters in the theory of confined concrete, On the basis of experimental results, a new term ‘effective confinement index’ is introduced. The expressions for increase in maximum stress and the corresponding strain in terms of effective confinement index are given. Theory is developed to obtain the stress–strain curve of total condtere with confined core and unconfined cover. The experimental and analytical stress–strain curves are compare. Also the maximum stresses and the corresponding strains of shell concrete are compared with the results obtained by the theory of sargin et al.

Nitriding of titanium carbide-steel materials

A study was made of the nitriding of TiC-Kh6V3M steel materials in ammonia; the variable parameters were titanium carbide content (0.40%), amount of combined carbon in the TiC (18.2 and 19.2%), and physicochemical treatment temperature (500, 750, and 1020°C) and time (30–60 min). Nitriding at temperatures of 500 and 1020°C with subsequent oil quenching increased the hardness of the materials, which was a result of diffusional impregnation of the steel binder with nitrogen. Increasing the duration of impregnation, lowering the amount of TiC in the alloys, and decreasing the deficiency of carbon in the TiC had a beneficial effect on nitriding. The thickness of the nitrided layer was determined by layer-by-layer phase analysis and measurements of the microhardness of the steel binder on transverse microsections. It is recommended that nitriding at 500°C should be the final operation, but when it is performed at about 1000°C it should be followed by quenching.

Sintering of titanium-carbide-steel materials in various environments

A study was made of the wetting of titanium carbide by 5Kh6VM2 and Kh6V3M steels in a vacuum, argon, and hydrogen. The optimum compositions of steel binders were established ensuring good wetting of TiC in hydrogen. An investigation was carried out into the production of TiC-5Kh6VM2 and TiC-Kh6V3M materials by sintering in a vacuum, argon, and hydrogen. The properties of the resultant sintered materials were determined. It was found that good-quality nonporous specimens cannot be produced by sintering in hydrogen.

Ductility of reinforced concrete sections with confined compression zones

AbstractConfinement of concrete in circular spiral steel binders imparts to it considerable ductility and also some increase in strength. This property can be utilized in designing concrete structures to withstand seismic forces where the members are required to possess not only strength but also energy absorbing capacity. Assuming the stress‐strain behaviour of confined concrete as elastic‐plastic, the ductility factor for strain and the strength factor (denoting increase in strength) have been determined for concrete confined to different degrees. Similarly, assuming the moment‐curvature behaviour of reinforced concrete sections with confined compression concrete to be elastic‐plastic, the ductility factor for curvature has been determined for such beams. The computed moment‐curvature plots have been found to compare satisfactorily with tests on 18 beams. Ductility factors for curvature of singly and doubly reinforced concrete sections with compression concrete confined to different degrees have been determined and presented for certain typical cases. Such plots would be of use in designing reinforced concrete beam sections for required ductility.

Dependence of the properties of titanium carbide-steel materials upon the composition of the titanium carbide

1. A study was made of conditions of preparation of titanium carbide-Kh12M steel (30 and 50 wt.%) alloys at various titanium carbide compositions (combined carbon contents ranging from 14.4 to 19.1 wt.%). 2. It was established that the sintering of alloys with a carbon-deficient titanium carbide brings about impregnation of the latter with carbon, which depletes the steel of carbon and limits the degree of hardening attainable in the steel binder during quenching. 3. The hardness after sintering and heat treatment and the compressive and transverse rupture strengths fall with increase in the degree of carbon deficiency of the titanium carbide. 4. To obtain titanium carbide-steel alloys of high hardness, strength, and wear resistance, the titanium carbide employed must be close to stoichiometric.

Confined concrete—Its application in R.C. beams and frames

Stress-strain characteristics of concrete confined in steel binders have been determined. A new factor “confinement index” has been introduced for a quantitative measure of the confinement and using these results a “stress-block” has been developed. Tests have been made on simply supported reinforced concrete beams with spiral binder confinement and analysed on the basis of the proposed stress-block. Tests have also been made oon reinforced concrete portal frames and continuous beams with spiral binder confinement at sections of possible plastic hinge formation. An analysis of these tests indicates that a full redistribution of moments has taken place at ultimate.

Discussion: Stress-strain characteristics of concrete confined in steel binders

Discussion: Stress-strain characteristics of concrete confined in steel binders