Numerical modelling of heat and mass transfer in laser surface alloying: Non-equilibrium solidification effects

Author(s):  
Suman Chakraborty ◽  
Sankar Chowdhury
1997 ◽  
Vol 109-110 ◽  
pp. 143-149 ◽  
Author(s):  
A.G. Gnedovets ◽  
O.M. Portnov ◽  
I. Smurov ◽  
G. Flamant

2019 ◽  
Vol 16 (33) ◽  
pp. 498-504
Author(s):  
I. S. BELASHOVA ◽  
L. N. RABINSKI ◽  
O. V. TURSHAVINA

The modern stage of equipment development imposes increased requirements for the performance characteristics of parts. Different components and parts of machines, metal-cutting tools and metal structural elements work in the conditions of high friction, high specific loads, high temperatures, a wide range of speeds and impact of aggressive media, for instance. Therefore, improvement the quality, reliability, economical efficiency and productivity of machines, tools, equipment and other engineering products as well as reduction of their specific material consumption and energy consumption is achieved primarily by the use of materials and progressive strengthening technology that improve the hardening, wear resistance, corrosion resistance and other physical and mechanical properties of machine parts and tool. Therefore, the main objective of the paper was to evaluate the mass-transfer during laser surface alloying in the reflow mode. To evaluate the effectiveness of surface hardening technology, it was proposed to use two new parameters – reduced wear and reduced integrated micro hardness of the modified surface layer. Based on an analysis of the experimental data on the wear of a cutter made of HVG and U10 steel, processed by a laser with smears in the reflow mode, the existence of a correlation between the entered parameters is demonstrate and the regression equation is obtained. The proposed approach to evaluating the effectiveness of surface hardening can be used not only in the special case of laser modification but also for any other technology for creating gradient and functional coatings.


Author(s):  
P. A. Molian ◽  
K. H. Khan ◽  
W. E. Wood

In recent years, the effects of chromium on the transformation characteristics of pure iron and the structures produced thereby have been extensively studied as a function of cooling rate. In this paper, we present TEM observations made on specimens of Fe-10% Cr and Fe-20% Cr alloys produced through laser surface alloying process with an estimated cooling rate of 8.8 x 104°C/sec. These two chromium levels were selected in order to study their phase transformation characteristics which are dissimilar in the two cases as predicted by the constitution diagram. Pure iron (C<0.01%, Si<0.01%, Mn<0.01%, S=0.003%, P=0.008%) was electrodeposited with chromium to the thicknesses of 40 and 70μm and then vacuum degassed at 400°F to remove the hydrogen formed during electroplating. Laser surface alloying of chromium into the iron substrate was then performed employing a continuous wave CO2 laser operated at an incident power of 1200 watts. The laser beam, defocussed to a spot diameter of 0.25mm, scanned the material surface at a rate of 30mm/sec, (70 ipm).


Author(s):  
N. Pirch ◽  
G. Backes ◽  
E. W. Kreutz ◽  
X. He ◽  
A. Weisheit ◽  
...  

Sign in / Sign up

Export Citation Format

Share Document