The study of laser deep penetration processing on prefabricated cracks of high carbon steel

Dongwei Liu,Yan Shi,Jia Liu

doi:10.1016/j.optlastec.2021.107414

Abstract

This paper describes the testing of laser deep penetration processing on controlled fragmentation of high carbon steel (50SiMnVB). The objective of this research is to make use of defects in deep penetration zones and optimize the quality of prefabricated cracks. The research shows that a deeper central crack appear in the deep penetration zone when the heat input is 60 J/mm, and the appeared crack is affected by martensite in microstructure, high microhardness and a high magnitude of tensile stress. Furthermore, the fracture mode of the deep penetration zones is mixed-mode (ductile and brittle fracture).

Highlights

It is known that 50SiMnVB steel has many excellent properties such as higher fragment rate and superior hardness
It should be noted that the ratio of depth to width increases slowly when heat input (HI) jumps from 60 J/mm to 240 J/mm
The pattern of martensite is different from image (b) to (d) because the martensite existing in heat affected zone (HAZ) is smaller than the others

Summary

Introduction

It is known that 50SiMnVB steel has many excellent properties such as higher fragment rate and superior hardness. The processing methods include deep laser melting [4], laser transformation notching [6], laser cutting [8, 9], laser microdrilling [10, 11], and laser scribing [12]. They make the modified zones more brittle and micro-cracks tend to form macro cracks with the plastic deformation in the case of higher tensile stresses [4, 6, 13]

Objectives

Methods

Results

Conclusion