US 11,376,688 B2Granted

Friction stir welding tool

AssigneesNachi-Fujikoshi Corp., Honda Motor Co., Ltd.

InventorsNobuyuki Funahira, Takuya Miyamoto, Ryo Kawahara, Akiyoshi Miyawaki, Mitsuru Sayama, Keisuke Tsuta, Yasumasa Hyodo

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Abstract

The disclosure provides a friction stir welding tool which can inhibit chipping even if an adhesion matter having high hardness adheres to a tip thereof during friction stir welding of an iron-base alloy and an aluminum alloy. In the tool for friction stir welding made of high-speed tool steel that includes a minor diameter portion and a major diameter portion formed adjacently to the minor diameter portion, hardness of the tool decreases from the minor diameter portion toward the major diameter portion. The hardness of the minor diameter portion may be 65 HRC or more by Rockwell hardness C-scale, and the hardness of the major diameter portion may be 60 HRC or less by Rockwell hardness C-scale.

Claims2

Dependent claims

A friction stir welding tool made of high-speed tool steel comprising a minor diameter portion and a major diameter portion formed adjacently to the minor diameter portion, wherein

hardness of the tool continuously decreases from the minor diameter portion toward the major diameter portion,
the hardness of the minor diameter portion is 65 HRC or more by Rockwell hardness C-scale, and the hardness of the major diameter portion is 60 HRC or less on Rockwell hardness C-scale, and
an equivalent circular diameter of MC-type carbide in a structure of the high-speed tool steel is in the range of 4 to 20 μm in a cross-section perpendicular to a forging direction or a rolling direction of the high-speed tool steel, and the ratio of the MC-type carbide in the structure is in the range of 3 to 10%.

Dependencies are inferred from the claim text.