---
publication_id: "OT-2026-000000833"
title: "Friction stir spot welded joint and production method therefor, and friction stir spot welding method"
published_at: "2026-09-15T19:03:27.877769Z"
canonical_url: "https://opentechnical.org/p/OT-2026-000000833"
categories:
  - "manufacturing-assembly-equipment/joining-and-welding"
keywords:
  - "b23k20/12"
  - "b23k2101/18"
  - "b23k2101/34"
  - "b23k2103/04"
---

# Friction stir spot welded joint and production method therefor, and friction stir spot welding method

## Abstract

Provided is a friction stir spot welded joint having high joint strength even in the case where a high strength steel sheet, particularly a steel sheet with a tensile strength (TS) of 980 MPa or more, is used as a material to be welded. An annular groove is formed on an upper surface of an upper sheet out of overlapping steel sheets, and a shape, microstructure, and hardness of a welded portion are appropriately controlled simultaneously.