Effect of CO2 Laser Fluence in Cladding Process on the Microstructure of Cold Rolled 0.2 % Carbon Steel

Suhair Hussein,Mahdi Hanon,Mohammed Kadhim

doi:10.30684/etj.v39i7.1475

Abstract

In this article a 1.8kW continuous wave of high power CO2 laser was used to clad of a titular composition of Ni – 10 wt% Al powder on cold rolled 0.2% carbon steel substrate. The feed rate was kept constant after many preliminary claddings at approximately 11 g/min. In order to produce clads with different specific energies and interaction times, different traverse speeds were used in the range of 1.5 to 12.5 mm/s. The microstructure of substrate was changed at the heat affected zones under the variety of specific energies. The cladded coatings showed the presence of ɣ solid solution and β (NiAlFe) phases. A strong metallurgical bonding produced between the substrate and the clad coat at fluence higher than 48 J/mm2. The changing in microstructure were observed using both microscope and SEM. The microhardness was evaluated using Vickerʼs microhardness test. The microstructure of the substrate was ferrite and pearlite transformed to martensite at the region adjacent to the clad interface. It followed by a three regions can be classified, a grain growth zone (large grains of austenite/ferrite and pearlite), recrystallization zone (fine grains of austenite/ferrite and pearlite) and recovery zone (the structure has a little changes from the structure of low carbon steel). The microhardness testing result showed higher values for the clad regions compared with substrate. This study emphasize the possibility to develop a temporary new graded material.

Highlights

Laser cladding can be defined as a melting process in which the laser beam induced to fuse an alloy addition on to a substrate producing a homogeneous surface with a strong metallurgical bonding on the substrate with very low dilution]1[
The microstructure of cold rolled 0.2wt% carbon steel was ferrite and pearlite transformed near the interface region to four distinct zones within the heat affected zone areas appeared in optical microscope and can be classified into martensite zone, grain growth zone, recrystallization zone and the recovery zone
1) Microhardness of cladding areas varies according to the laser cladding parameters that was used

Summary

INTRODUCTION

Laser cladding can be defined as a melting process in which the laser beam induced to fuse an alloy addition on to a substrate (base material) producing a homogeneous surface with a strong metallurgical bonding on the substrate with very low dilution]1[. Widespread of alloys for cladding are based on cobalt, iron and nickel Maybe, they include tungsten carbides, Ti and Si, ceramics like Zr that brews a reinforced particle composite metal matrix surface by solidification which giving more resistance for wear. In numerous mechanical applications, and the market interest for the fixing of such items is enormous Along these lines, it is direly important to locate a successful fix strategy to re-establish the geometry and give adequate solidarity to such parts taking into consideration their proceeded with the use [7]. It is direly important to locate a successful fix strategy to re-establish the geometry and give adequate solidarity to such parts taking into consideration their proceeded with the use [7] This method is utilized for depositing alloys on turbine sharp edges, motor valves, valve seats and boring parts. Study and analyze changing in the microstructure and how affecting it in the improvement of microhardness cladding areas

EXPERIMENTAL PROCEDURES

RESULTS AND DISCUSSION

CONCLUSIONS