• Journal of Korea Foundry Society
• /
• v.28 no.5
• /
• pp.237-241
• /
• 2008

This study has been carried out to investigate the wear and heat resistant properties of durable moldwash agent for Al gravity casting according to mold washing process conditions. The wear properties of coated specimen were performed by sliding wear testing machine and heat resistance were evaluated by measuring the loss of coated moldwash agent during emerging of coated specimen in Al melts. During testing, experimental variables were mold surface temperature, moldwash agent/distilled wear, and additive concentrations. The lower additive concentration and mold temperature caused the smooth surface roughness of coated specimen, It was found that the specimen coated with moldwash/water ratio 1:3, additive concentration 9wt% and mold temperature higher than $200^{\circ}C$ showed superior wear and heat treatment. Also, these results were supported by fluidity test.

• Journal of the Korean Society for Heat Treatment
• /
• v.19 no.1
• /
• pp.20-29
• /
• 2006

Wear behaviour of B.390 aluminum alloy with different particle sizes of primary Si against a SM45C counterface was studied as a function of wear load and sliding velocity, using pin-on-disk apparatus under dry condition. The wear rate of specimen with fine primary Si particles showed increased wear resistance at high wear load, on the other side wear resistance of coarse primary Si particle size was improved at low wear load. As the compressive residual stress in the matrix increased remarkably by liquid nitrogen(LN) treatment, wear resistance of the LN treated specimen was more excellent than that of T6 treated specimen.

• Corrosion Science and Technology
• /
• v.11 no.6
• /
• pp.280-285
• /
• 2012

Aluminum is on active metal, but it is well known that its oxide film plays a role as protective barrier which is comparatively stable in air and neutral aqueous solution. Thus, aluminum alloys have been widely applied in architectural trim, cold & hot-water storage vessels and piping etc., furthermore, the aluminum alloy of AC8A have been widely used in mold casting material of engine piston because of its properties of temperature and wear resistance. In recent years, the oil price is getting higher and higher, thus the using of low quality oil has been significantly increased in engines of ship and vehicle. Therefore it is considered that evaluation of corrosion resistance as well as wear resistance of AC8A material is also important to improve its property and prolong its lifetime. In this study, the effect of solution and tempering heat treatment to corrosion and wear resistance is investigated with electrochemical method and measurement of hardness. The hardness decreased with solution heat treatment compared to mold casting condition, but its value increased with tempering heat treatment and exhibited the highest value of hardness with tempering heat treatment temperature at $190^{\circ}C$ for 24hrs. Furthermore, corrosion resistance increased with decreasing of the hardness, and decreased with increasing of the hardness reversely. As a result, it is suggested that the optimum heat treatment to improve both corrosion and wear resistance is tempering heat treatment temperature at $190^{\circ}C$ for 16hrs.

• Journal of the Korean Society of Manufacturing Process Engineers
• /
• v.9 no.6
• /
• pp.7-15
• /
• 2010

Recently, with the high performance and efficiency of machine, there have been required the multi-functions in various machine parts, such as the heat resistance, the abrasion resistance and the stress resistance as well as the strength. Fatigue crack growth tests were carried out to investigate the fatigue characteristics of high carbon steel (SM53C) experienced by high-frequency induction treatment. The Cam nose part of the Automobile's Cam shaft is strongly bumped with rocker arm or valve-lift. Therefore abnormal wear such as unfair wear and early wear occur in the surface. This abnormal wear causes a defect that bad timing open and close actions of the engine valve happen in the combustion chamber so the fuel gas will be combustion imperfect. Therefore, the cam shaft demands high hardness and wear resistance. In this study, high frequency heat treatment has been accomplished while wear test for material SM53C.

• Journal of Welding and Joining
• /
• v.17 no.6
• /
• pp.62-69
• /
• 1999

The advantages of Thermal sprayed coatings as a replacement for cast iron liners are reduced weight, better heat transfer and reduced cost. One of the most important performance attributes of a cylinder bore coating is its wear resistance, since it must survive the abrasive sliding of both the piston rings and the piston skirt. In this study, composite powders were prepared by ball milling of Al-13Si-3Mg(wt%) alloy with SiC particles. The concentrations of SiC were 40 and 60wt%. The composite powders were sprayed using Metco-9MB plasma torch. Plasma sprayed coatings were heat-treated at 500℃ for 3 hours. The wear resistances of the plasma sprayed coatings were found to improve with heat treatment and superior to the commercially available G.C.I.(gray cast iron). AlSiMg-40SiC heat-treated coatings showed the best wear resistance in this study.

• Journal of the Korean Society of Manufacturing Technology Engineers
• /
• v.20 no.2
• /
• pp.162-168
• /
• 2011

In this research, nitrogen plasma source ion implantation(PSII) of non-coated tungsten carbide endmill tools was conducted with low heat treatment for increasing wear resistance. After the low heat treatment of PSIIed tools to give a homogeneity of wear resistance, the surface modification of tools was analyzed by hardness test, surface roughness and cutting forces. As for the resultant cutting forces, low heat treatment in temperature of $400^{\circ}C$ and $500^{\circ}C$ is stable because of low cutting resistance. The 20-minutes heat treated tool at spindle speed 25000rpm has superiority of surface roughness, Ra of $0.420{\mu}m$ and was found to have good wear resistance. The higher hardness value was obtained by increasing temperature from $300^{\circ}C$ to $600^{\circ}C$ for PSIIed tools with low heat treatment. As the PSIIed tools under 10minutes at temperature of $600^{\circ}C$ have the highest hardness as Hv of 2349.8, It was analyzed that temperature processing give much influences on hardness.

• Journal of Korea Foundry Society
• /
• v.22 no.4
• /
• pp.184-191
• /
• 2002

This study aims to investigate on the effects of alloying elements and heat treatment on the microstructures, wear and heat resistance of Al-Si-Cu-Mg-(Ni)/SiCp prepared by the duplex process developed in previous study, which consists of squeeze infiltration (1st process) and squeeze casting (2nd process). The hardness of composite increased with decrease in SiCp size and Ni addition in both the heat exposured composite and the as-cast one. And the heat and wear resisting properties was improved by the SiCp reinforcement and the Ni addition. The wear amount of Al/SiCp composite decreased with decreasing in the size of silicon carbide particle.

• Proceedings of the Korean Society of Tribologists and Lubrication Engineers Conference
• /
• 2000.06a
• /
• pp.48-53
• /
• 2000

The effects of added elements, such as Co or Nb, on wear properties of high speed steel by powder metallurgy(PM-HSS) had been evaluated in previous paper. The wear properties of materials, in fact, have been a]so influenced by heat-treating conditions. In this paper, the effects of heat-treating conditions on wear properties of PM-HSS have been evaluated. The wear tests have been performed as same conditions as previous paper using PM-HSS(5%Co-1%Nb) heat-treated under different quenching and tempering temperature. The result of this paper shows that wear resistance of PM-HSS is improved with relatively high quenching temperature. However tempering temperature is not sensitve to the wear resistance in range of high quenching temperature. It may be deduced by the fact that the shear strength of matrix by strengthening mechanisms of quenching aging in addition to dispersion-hardening is improved.

• Journal of Welding and Joining
• /
• v.19 no.5
• /
• pp.506-511
• /
• 2001

Weld overlay has been developed to improve the property of material surface which is used in the severe environment. Weld overlay is the process which uses an arc heat and welds different composition of alloy on the substrate for the improvements of heat resistance and wear resistance. Weld overlay has a lot of advantages which are high hardness, good processing efficiency, easy controlling of layer thickness, good quality and low cost. In this study, weld overlay was performed by MAG welding on the base metal(SS400) with filler metal which contain composite powders(Cr+C+Mn+Mo+NbC) and solid wire(JIS-YGW11). Characterization of hardness and wear resistance were analyzed by EDS, EPMA, XRD and observations of microstructure were performed to investigate characteristics of overlays. The experimental results of overlaid specimens manufactured with Cr+C+Mn+Mo+NbC powders were obtained as fellows. ${\alpha}-phase$, M(Fe, Cr)3C and NbC of overlays were increased with decreasing the wire feed rates and increasing powder feed rates. Also the hardness of overlays were increased and the specific wear were decreased.

• Journal of the Korean Society for Heat Treatment
• /
• v.11 no.2
• /
• pp.82-91
• /
• 1998

The elastic modulus and wear resistance in austempered ductile cast iron(ADI) are two important mechanical properties for automobile parts. Therefore, the effect of Cu, Ni, Mo and special austempering treatment such as preheated, prequenched, and step austempering treatments on elastic modulus and wear resistance has been investigated systomatically. As a result, elastic modulus and wear resistance were increased by the addition of Mo-Cu and preheated austempering treatment.