THE PROPERTIES OF CAST IRON SURFACE LAYERS MODIFIED BY LASER ABLATION MICROMACHINING

Tribologia ◽  
2017 ◽  
Vol 276 (6) ◽  
pp. 59-64
Author(s):  
Wojciech NAPADŁEK ◽  
Adam WOŹNIAK ◽  
Czesław PAKOWSKI
Keyword(s):  
Surface Layer ◽  
Cast Iron ◽  
Laser Micromachining ◽  
Grey Cast Iron ◽  
Linear Wear ◽  
Micro Channels ◽  
Iron Specimen ◽  
Friction Temperature ◽  
Grey Cast ◽  
Ablative Laser

The article presents the results of model laboratory tests, including the measurement of temperature, friction force, and linear wear of the surface layer of samples made of grey cast iron sliding against a steel counterpart. The surface layer of the cast iron specimen was modified using ablative laser micromachining in order to change its macro- and micro-geometry. To produce regular oil micro-reservoirs in a shape of micro-channels, an Nd: YAG laser (λ = 1064 nm, ƒ = 1 – 100 kHz, E = 50 J, P = 50W) with a special focusing system was used. Comparative studies included a grey cast iron specimen subjected to conventional mechanical machining and a specimen modified by ablative laser micromachining. 41Cr4 steel with a hardness of 50 HRC was used as a counterpart. Tribological tests were run in a pin-on-disk (T-11 tribometer) test set-up. The best results in the reduction of friction, temperature, and wear were obtained for samples with oil micro-reservoirs (made of ablative laser texturing) in a shape of micro-channels covering 5% of the entire tribological contact surface.

scholarly journals Possibilities of using 3D printing for surface layers

2018 ◽  
Vol 183 ◽  
pp. 02005
Author(s):  
Agnieszka Dulska
Keyword(s):  
Surface Layer ◽  
Cast Iron ◽  
3D Printing ◽  
Abrasive Wear ◽  
Composite Layer ◽  
Casting Process ◽  
Grey Cast Iron ◽  
Titanium Layer ◽  
Mould Cavity ◽  
Grey Cast

This article describes how to improve the tribological properties of cast iron by local strengthening by titanium layer, directly in the casting process. The research comprised test molds with a titanium (composite) layer. The insert with titanium was made basing on proprietary development of geometric assumptions. The innovation relies on application the 3D printing insert obtaining in SLM (selective laser melting) method. The tests included measurement of resistance to abrasive wear and carried out metallographic, microhardness measurements as the presents detailed geometry of the insert as well. On the basis of obtaining results was stated that there is a possibility of reinforcing surface layer of the grey cast iron casting by using 3D printing scaffold insert in the method of mould cavity preparation. Moreover there was a local increase in hardness and abrasive wear resistance in spite of the precipitation of titanium carbides in surface layer of grey cast iron.

scholarly journals Bimetallic Casting: Ferritic Stainless Steel – Grey Cast Iron

2015 ◽  
Vol 60 (3) ◽  
pp. 2361-2365 ◽  
Author(s):  
T. Wróbel ◽  
J. Szajnar
Keyword(s):  
Surface Layer ◽  
Cast Iron ◽  
Base Material ◽  
Grey Cast Iron ◽  
Low Carbon ◽  
High Carbon ◽  
Working Surface ◽  
Mould Cavity ◽  
Grey Cast ◽  
Layer Coating

Abstract The paper presents the problem of obtaining a permanent diffusional joint between the working surface layer and the base part in a bimetallic casting. The studied bimetallic casting was obtained as a result of using the founding method of layer coating directly in the cast process. The casting prepared using this method consists of two fundamental parts, i.e., the grey cast iron base and the working surface layer which constitutes of X6Cr 13 high-chromium stainless steels plate. Based on the obtained results it was confirmed that the decisive phenomena that are needed to create a permanent joint between the two components of the bimetallic casting are carbon and heat transport from the high-carbon and hot base material which was poured into the mould in the form of liquid metal to the low-carbon and cold material of the working layer which was placed in the mould cavity in the form of a monolithic insert.

THE EFFECT OF NANOCRYSTALLINE LAYERS ON THE WEAR RESISTANCE OF GREY CAST IRON DURING FRICTION IN AN OIL-ABRASIVE MEDIUM

Tribologia ◽  
2018 ◽  
Vol 282 (6) ◽  
pp. 37-42
Author(s):  
Ihor HUREY ◽  
Tetyana HUREY ◽  
Volodyr GUREY
Keyword(s):  
Surface Layer ◽  
Cast Iron ◽  
Sliding Friction ◽  
Friction Pair ◽  
Grey Cast Iron ◽  
High Rate ◽  
Unit Load ◽  
Abrasive Medium ◽  
Friction Hardening ◽  
Grey Cast

Friction hardening is one of the surface hardening methods with the use of highly concentrated energy sources. In the “tool-treated surface” contact area, the surface layer of a metal is heated at a very high rate to phase transition temperatures, and then it is cooled at a high rate, which results in the formation of hardened nanocrystalline layers. The studies carried out have shown that a hardened nanocrystalline layer is formed in the surface layer in the course of friction hardening of cast-iron (EN-GJL-200) components. The layer thickness is 90–120 μm, and the microhardness is 7–8 GPa. Grain size of the hardened surface layer was equal to 20–40 nm near the treated surface. It is shown that the hardened layer significantly increases the serviceability of the pair “grey cast iron-grey cast iron” during sliding friction in the lubricated-abrasive medium. When increasing the unit load from 2 to 6 MPa, the wear rate of the hardened pair decreased by 2.6–4.2 times in comparison with an unhardened pair. Only one component of the friction pair was hardened.

scholarly journals Hardness characterisation of grey cast iron and its tribological performance in a contact lubricated with soybean oil

2016 ◽  
Vol 232 (1) ◽  
pp. 190-203 ◽  
Author(s):  
Adli Bahari ◽  
Roger Lewis ◽  
Tom Slatter
Keyword(s):  
Cast Iron ◽  
Soybean Oil ◽  
Mass Loss ◽  
Friction And Wear ◽  
High Hardness ◽  
Grey Cast Iron ◽  
Hardness Distribution ◽  
Flat Specimen ◽  
Iron Specimen ◽  
Grey Cast

The effect of hardness of grey cast iron flat specimen on its wear and friction on the contact were characterised with the presence of vegetable oil as biolubricant. Prior to the tribological test, the as-received grey cast iron flat specimen hardness was characterised. Friction and wear tests were then conducted using a ball-on-flat reciprocating sliding contact. The one-way analysis of variance (ANOVA) was used to determine the significance of friction and wear data with a 95% significance level. The wear scars after the test were then characterised by surface roughness and wear mechanism. The microstructure and elemental analysis were also reported. The average value of hardness was 210 HV with a large difference between minimum (185 HV) and maximum (250 HV) values. The friction and wear performance of grey cast iron specimens with soybean oil varied with its hardness. The specimens with higher hardness gave lower friction coefficient and greater wear resistance than the lower hardness specimens. The difference in coefficient of friction produced between high hardness specimens (COF = 0.122) and low hardness specimens (COF = 0.140) was 17%. In terms of mass loss, the low hardness specimens (mass loss = 50.38 mg) and the high hardness specimens (mass loss = 12.90 mg) produced a difference of 74%. It is shown that, with soybean oil lubricant, the grey cast iron specimen can produce wide range of tribological data especially on mass loss due to its hardness distribution. The influence of soybean oil lubrication in this work is less in improving the wear resistance (about 7%), but greater for friction reduction (about 24%) compared to an unlubricated grey cast iron surface. The hardness of grey cast iron specimen is an important parameter that needs to be specifically measured and controlled on the contact due to wide hardness distribution of grey cast iron may produce variation in tribological data.

CHARACTERISTIC INTERNAL FRICTION SPECTRUM OF GREY CAST IRON

1981 ◽  
Vol 42 (C5) ◽  
pp. C5-929-C5-934 ◽  
Author(s):  
P. Millet ◽  
R. Schaller ◽  
W. Benoit
Keyword(s):  
Cast Iron ◽  
Internal Friction ◽  
Grey Cast Iron ◽  
Grey Cast ◽  
Internal Friction Spectrum
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