INVESTIGATION OF THE MICROSTRUCTURE AND PROPERTIES OF THE AISI H13 TOOL STEEL TI-MODIFIED POWDER DURING LASER CLADDING PROCESS UNDER NITROGEN

Abstract

Laser cladding (LC) technology allows produce metal-matrix composites from discrete powder materials. Data analysis shows that use of such technology to obtain composite materials with enhanced functional properties is of heightened economical interest. The paper presents the results of research aimed at study the possibility synthesizing dispersion-strengthened steel by hard TiN particles formed during the interaction of elemental Ti powder with N 2 gas. It is added 5 % of VT1-0 titanium powder to the AISI H13 tool steel to form a mechanical mixture. Specimen was synthesized from this mixture on a substrate by laser cladding under nitrogen. Owing to the optical and electron microscopy, X-ray phase analysis as well as microhardness testing it was determined that as a result of synthesis, an alloy of steel with Ti with a lower hardness value is formed compared to the H13 steel deposited in pure form. Uniformly distributed nonmetallic inclusions were found, including titanium nitride in the form of dispersed particles. Thus, it can be concluded that before the titanium powder enters the melt pool, there is not enough temperature and time for diffusion processes with the formation of non-melting TiN particles in the steel matrix. Therefore, this phase is formed from the melt during crystallization. As a result, the high titanium in the form of an alloying element in steel does not lead to the targeted formation of a hardened metal-matrix composite but increases the plastic properties and reduces the quality of track formation during process.