Journal of Welding and Joining

: Journal of KWJS. 2007;25(5):53-58. Published online January 28, 2008.; A Study on Mechanical Properties and Friction Weldability of SKH51 and SM45C; Se-Gyoung Lee, Byung-Hoon Min, Su-Hyun Choi, Do-Ki Shim, Taeg-Ki Min

Abstract: The present study examined the mechanical properties of the friction welding of shaft made of SKH51 and SM45C, of which the diameter is 12㎜. Friction welding was done at welding conditions of 2,000rpm, friction pressure of 104㎫, upset pressure of 134㎫, friction time of 0.5sec to 2.5sec by increasing 0.5sec, upset time of 2 seconds. Under these conditions, a tensile test, a bending test, a shear test, a hardness test and a microstructure of weld interface were studied. When the friction time was 1.0 second under the conditions, the maximum tensile strength of the friction weld observed to be 963㎫, which is 89% the tensile strength of SKH51 base metal and 101% of the tensile strength of SM45C base metal. When the friction time was 1.0 seconds under the conditions, the maximum bending strength of the friction weld happened to be 1,647㎫, which is 78% the bending strength of SKH51 base meta l(2,113㎫) and 87% of the bending strength of SM45C base metal(1,889㎫). When the friction time was 1.0 seconds under conditions, the maximum shear strength of the friction weld was observed to be 755㎫, which is 92% the shear strength of SKH51 base metal and 122% of the shear strength of SM45C base metal. According to the hardness test, the hardness distribution of the weld interface varied from Hv282 to Hv327. HAZ was formed from the weld interface to 1.2㎜ of SKH51 and 1.6㎜ of SM45C. Upon examination it was found that the microstructure became finer along with increase of friction revolution radius.

Keywords :Friction welding;Friction time;Friction pressure;Tensile strength;SKH51;SM45C