Selection guide of insert piece shape for steel joint by autocompleting friction welding method

Abstract

An autocompleting friction welding method, which was developed by the authors, is to weld with using a rotating insert piece set between fixed base metals. This paper describes the selection guide of the insert piece size for steel joints by the autocompleting friction welding method. The base metal was low carbon steel (LCS), and the weld faying surface of the fixed specimen had a 10 mm diameter. The effect of the thickness at the bottom of the grooves for the insert piece (groove bottom thickness) on the joining phenomena was investigated. When the joint was made at a friction pressure of 90 MPa with a friction speed of 27?5 s 21 , the insert piece had a shear fracture towards the circumferential direction (circumferential shear fracture) in the peripheral portion of the weld interfaces by the initial peak produced during the friction process. In this case, the insert piece had the following dimensions: the thickness was 4?0 mm, and the groove bottom thickness was 1?2 mm or over with an inner groove diameter of 11 mm. In particular, the joint with a groove bottom thickness of 1?2 mm had 100% joint efficiency and the LCS base metal fracture with no crack at the weld interface. The value of a circumferential shear fracture (CSF value) was defined and calculated by the ratio between the theoretical and the actual generated friction torques. When the CSF value nearly equalled 1, the joint had 100% joint efficiency and the LCS base metal fracture with no crack at the weld interface.

Strength enhancement of autocompleting medium and high carbon steels friction welded joints

“…2a. These dimensions were determined from the value of a circumferential shear fracture (referred to as CSF value), which was defined by the ratio between the theoretical friction torque and the actual generated friction torque, in a previous report (Kimura et al, 2009a). In this connection, CSF value is the dimensionless parameter.…”

“…In this connection, CSF value is the dimensionless parameter. In addition, the insert piece suffered a circumferential shear fracture before the friction torques reached the initial peak when the CSF value was smaller than 1 and that can obtain a circumferential shear fracture after the friction torques reached the initial peak when the CSF value was 1 or more (Kimura et al, 2009a the 16 mm rod was used for the fixed specimen and machined to 10 mm in diameter as the weld faying surface, as shown in Fig. 2b.…”

“…The joint was made using a rotating insert piece, and the fixed base metals were set between them. The detailed characteristics of the insert center drive friction welding machine were previously described (Kimura et al, 2007(Kimura et al, , 2008(Kimura et al, , 2009a.…”

“…In particular, it is possible to make a sound joint such as the base material fracture with no cracks. However, those results were obtained using a low carbon steel (referred to as LCS) that has good weldability (Kimura et al, 2008(Kimura et al, , 2009a. Further investigation is necessary to clarify the joint properties made by other steels for the adaptability of an autocompleting friction welding method due to the weldability of those steels differed with LCS.…”

Advances in friction welding process: A review

“…In another work, Kimura et al described the joining phenomena and mechanical properties of a joint made with an autocompleting friction welding method developed by authors. They welded with 88 or without 89 using a rotating insert piece set between fixed base metals. The material joined was LCS (the same material) with a 10 mm diameter faying surface and the effect of insert thickness on the joining phenomena was investigated.…”