# Microstructural Characteristics and Properties of Laser-Welded Diamond Saw Blade with 30CrMo Steel

## TL;DR

This paper explores how laser-welding parameters affect the strength and microstructure of diamond saw blades made with 30CrMo steel.

## Contribution

The study introduces a novel Cu-Co-Fe and Ni-Cr-Cu transition layer for laser welding diamond composites to metal substrates.

## Key findings

- Optimal welding performance was achieved at 1600 W laser power and 1400 mm/min speed, yielding a tooth engagement strength of 819 MPa.
- The fusion zone microstructure consists of Cu-rich and Fe-rich regions with coarse grains and no preferred orientation.
- Fracture occurred at the fusion zone boundary due to stress concentration, with the heat-affected zone showing high microhardness.

## Abstract

In order to enhance the quality of diamond composite materials, this work employs a Cu-Co-Fe and Ni-Cr-Cu pre-alloyed powder mixture as a transition layer, and utilizes laser-welding technology for saw blade fabrication. By adjusting the laser-welding process parameters, including welding speed and welding power, well-formed welded joints were achieved, and the microstructure and mechanical properties of the welded joints were investigated. The results demonstrate that the best welding performance was achieved at a laser power of 1600 W and a welding speed of 1400 mm/min, with a remarkable tooth engagement strength of up to 819 MPa. The fusion zone can be divided into rich Cu phase and rich Fe phase regions, characterized by coarse grains without apparent preferred orientation. The microstructure of the heat-affected zone primarily consists of high-hardness brittle quenched needle-like martensite, exhibiting a sharp increase in microhardness up to 550 HV. Fracture occurred at the boundary between the fusion zone and the heat-affected zone of the base material, where stress concentration was observed. By adjusting the welding parameters and transition layer materials, the mechanical properties of the joints were improved, thereby achieving a reliable connection between diamond composite materials and the metal substrate.