Preparation of wear-resistant powder materials based on iron by hot stamping in the presence of a liquid phase

The interaction of components and structure formation were studied in liquid phase sintering of Co-Sn and Co-Sn-Cu powder materials. The powders of commercially pure metals were mixed with an organic binder and applied on the steel substrate. Sintering was performed under vacuum at temperatures of 820 and 1100 °C. The structure of sintered alloys was investigated by X-ray diffractometry and electron probe microanalysis, and microhardness (HV0.01) of the structural components was measured. It has been found that the nature of interaction of the liquid tin with the solid phase at the initial stage of sintering affects the formation of structure and porosity of Co-Sn and Co-Sn-Cu alloys considerably. In Co-Sn alloys, diffusion of tin into cobalt particles leads to the formation of intermetallic compounds, which hinders spreading of the liquid phase. This results in a porous defect structure formed in Co-Sn alloys. In Co-Sn-Cu alloys, at the initial stage of sintering the liquid phase enriched with copper is formed that wets the cobalt particles and contributes to their regrouping. As a result of this, materials with minor porosity are formed.

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Development of low-friction and wear-resistant surfaces for low-cost Al hot stamping tools

MATEC Web of Conferences ◽

10.1051/matecconf/20152105009 ◽

2015 ◽

Vol 21 ◽

pp. 05009 ◽

Cited By ~ 1

Author(s):

Y. Dong ◽

D. Formosa ◽

J. Fernandez ◽

X. Li ◽

G. Fuentes ◽

...

Keyword(s):

Friction And Wear ◽

Low Cost ◽

Hot Stamping ◽

Low Friction ◽

Wear Resistant

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Liquid phase sintering of hard and wear resistant stellites

Metal Powder Report ◽

10.1016/s0026-0657(96)94145-4 ◽

1996 ◽

Vol 51 (7) ◽

pp. 45

Keyword(s):

Liquid Phase ◽

Liquid Phase Sintering ◽

Wear Resistant

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Technology for producing wear-resistant bimetal bearing based on cast aluminum

E3S Web of Conferences ◽

10.1051/e3sconf/202016403045 ◽

2020 ◽

Vol 164 ◽

pp. 03045

Author(s):

Ruslan Kuznetsov ◽

Evgeniy Ol’khovik ◽

Mikhail Radkevich ◽

Pavel Kuznetsov

Keyword(s):

Liquid Metal ◽

Cast Alloy ◽

Applied Pressure ◽

Base Material ◽

Outer Radius ◽

Powder Materials ◽

Pressing Pressure ◽

Cast Aluminum ◽

Sintered Iron ◽

Wear Resistant

The paper presents the results of research the new technological process for producing bimetallic materials in the composition of “aluminum cast alloy - sintered iron powder” by the method of joint stamping of liquid metal. The purpose of this research is obtain parts with high wear-resistant properties, special sintered powder materials are used, which have an internal porosity to retain lubricant. However, such materials do not fit well with traditional aluminum alloys. This problem is may be solved by creating new bimetallic alloys, part of which is an outer casing, and the other materials is the functional bearing. To accomplish this task, we conducted a study of a new technology for joint stamping of liquid metal. In order to optimize and increase the reliability of the experiment, the pressing pressure, the pressure holding time, and the tooling temperature of the matrix were taken as quantitative factors. The effect of the applied pressure on the mechanical properties of the base material and the facing layer was determined on a longitudinal section of the obtained samples by the Vickers method. It was revealed that the gradient of increasing hardness is directed to the outer radius of the workpiece, that is, to the opposite crystallization front. The high level of bimetal adhesion is explained by the presence of a uniform moderate zone of mutual solubility, including due to the violation of the porous surface layer of the powder billet.

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Wear Resistant In Situ MMC Sintered with FeBC Liquid Phase

Materials Science Forum ◽

10.4028/www.scientific.net/msf.672.91 ◽

2011 ◽

Vol 672 ◽

pp. 91-98 ◽

Cited By ~ 2

Author(s):

Anastasia Saltykova ◽

Hans Berns

Keyword(s):

Liquid Phase ◽

Mesh Size ◽

Steel Powder ◽

Liquid Phase Sintering ◽

Full Density ◽

Steel Matrix ◽

Tungsten Carbides ◽

Component Mixture ◽

Wear Resistant

Powder metallurgy represents a good alternative to a conventional casting process to produce wear resistant materials. MMC (metal matrix composite) of a hardenable steel matrix and hard phases compacted by hot isostatic pressing (HIP) are highly wear resistant but high in price. In the present study liquid phase sintering was preferred to HIP and expensive hard phases as tungsten carbides were replaced by ferrotitanium particles (FeTi) to reduce costs. A mixture of gas atomized hot work steel powder of < 150 µm in size, hypereutectic FeBC powder of < 36 µm in size as liquid phase donor (LPD) and ferrotitanium particles (100-150 µm in size) with about 70 mass% of Ti was sintered in vacuum to give a wear resistant MMC of full density. However, the elements B and C from LPD diffused to the steel powder before the liquid phase appeared. Therefore these two powders merged into a near-eutectic or hypoeutectic constitution. The LPD was diluted by the steel. During sintering the ferrotitanium particles are transformed in situ into hard phases (in situ HP) with a Fe-rich core surrounded by a hard TiC case to withstand abrasive wear. Numerous investigations by LOM, SEM with EDX, WDX and DTA were realized step by step for a deeper understanding of what happens in the initial three-component mixture during liquid phase sintering and how the in situ MMC forms. The resistance to wear was measured by pin-on-plate tests against abrasive paper of different hardness and mesh size and compared with HIP-MMC and SLPS-MMC.

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Application of ultrasonic testing method for determining defects of hot-deformed powder materials

MATEC Web of Conferences ◽

10.1051/matecconf/201929800146 ◽

2019 ◽

Vol 298 ◽

pp. 00146

Author(s):

Maxim S. Egorov ◽

Andrey A. Atrokhov ◽

Evgeniy A. Nedostup ◽

Ekaterina V. Vasilyeva

Keyword(s):

Hot Stamping ◽

Side Surface ◽

Powder Materials ◽

Friction Forces ◽

Testing Method ◽

Peripheral Surface ◽

Deformed State ◽

Hot Plasticity ◽

Elastic Characteristics

The article is devoted to the analysis of elastic and plastic characteristics of composite materials during hot stamping. The purpose of this work is to offer optimal conditions for hot plasticity of composite porous material with determination of temperature conditions of hot stamping excluding the appearance of defects in the structure. Production of details of the difficult form by method of hot stamping from preparations of the cylindrical form is followed by development of barrel on a peripheral surface. Sludge sintered porous blanks, and sediment compact material, accompanied by a nonuniform height lateral deformation. In connection with the action of friction forces on the contact surfaces, this leads to the formation of a “barrel”. The heterogeneity of the deformed state is associated with the appearance of tangential tensile stresses on the free surface of the workpiece. If they exceed some critical degree of transverse deformation, cracks appear on the side surface, which leads to gas saturation (oxidation) of the inner layers of the forging, to the ingress of grease into them and its pressing into the volume of the part during hot stamping. In the end, this significantly reduces the properties of hot-stamped parts. Conclusion: the methods of determining the elastic characteristics depending on the geometric parameters of the workpieces, the applied strain energy, body density and temperature dependence of the plasticity characteristics of the hot deformation of the powder material are сonsidered.

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