No abstract

Type 304 austenitic stainless steel samples were implanted with nitrogen using plasma immersion ion implantation (PIII) at different temperatures between 350 and 500uC. Treated and untreated samples have been studied by wear-friction testing, microhardness measurement and scanning electron microscopy (SEM).The experimental results indicated that the hardness and wear resistance is improved by increasing the penetration depth of nitrogen, whereas the friction coefficient is significantly increased by PIII.

No abstract

The aim of this study is to investigate the effect of important process parameters and tool parameters on joint strength in fiction stir welding process of high density polyethylene (HDPE) using the Taguchi experimental design method. The tool rotation, feed rate and tool shoulder diameter were considered as varying parameter and used to fabricate the joints. The quality of the joint was evaluated by examining the characteristics of the joint as a result of ultimate tensile strength. For friction stir welding of the plates, the experiments were arranged by using Taguchi's L9 orthogonal array in randomized way. From the analysis of variance and the signal-to-noise response graphs, the significant parameters and the optimal combination level of the parameters were obtained. It was found that using a tool rotation of 1600 rpm, a feed rate of 20 mm·mm−1 and a shoulder diameter of 20 mm, an improved joint strength can be obtained. A confirmation run is also performed to prove the effectiveness of the Taguchi method. The results show that joint strength was improved by about 25% compared with the initial welding parameters.

In this study, AA 6063 (AlMgSi0.5) Aluminum alloy plates were welded by a solid state welding procedure, friction stir welding (FSW). The influence of pin structure on the microstructure of the weld region and the mechanical properties of the joints were studied. It has been seen that the helical structure on pinscrew has an effective role on the formation of a zigzag line in the weld region. While rather long and uninterrupted zigzag lines in the weld region are obtained when right helical pinscrew is used, left helical pinscrew gave rise to shorter zigzag lines. While the zigzag line has no effect on the mechanical properties of the as-welded joint, heat treatment after the welding (PWHT) procedure seriously affects the strength of the joint due to the zigzag line formed in the weld region. The mechanical strength decreases with right helical pinscrew in PWHT, whereas, left helical pinscrew causes an increase in mechanical strength.