---
publication_id: "OT-2026-000000561"
title: "Laser welding method and laser weld joint"
published_at: "2026-09-15T19:03:04.856092Z"
canonical_url: "https://opentechnical.org/p/OT-2026-000000561"
categories:
  - "manufacturing-assembly-equipment/joining-and-welding"
keywords:
  - "b23k26/21"
  - "c22c38/001"
  - "c22c38/002"
  - "c22c38/005"
  - "c22c38/02"
  - "c22c38/04"
---

# Laser welding method and laser weld joint

## Abstract

A laser welding method for preventing cracking and obtaining a weld joint of a weld metal with excellent toughness, and a laser weld joint. The laser welding method includes butting steel material members, the steel material having a chemical composition including, in mass %, C: 0.04 to 0.15%, Si: 0.05 to 1.00%, Mn: 0.50 to 2.50%, P: 0.030% or less, S: 0.020% or less, Al: 0.050% or less, Ti: 0.050% or less, O: 0.010% or less, and N: 0.008% or less, and having a carbon equivalent Ceq, represented by the following Expression (1), of 0.30 to 0.45, with the balance being Fe and unavoidable impurities, covering a portion on the surfaces of the steel material members including a weld line with flux having a predetermined composition, and performing laser welding thereon to produce a weld joint. Ceq=[C]+[Mn]/6+[Si]/24+[Cu]/20+[Ni]/40+[Cr]/5+[Mo]/4 (1)