Recently, the necessity of designing and applying tool materials that perform machining of difficult-to-cut materials in a cryogenic treatment where demand is increasing. The objective of this study is to evaluate the performance of cryogenically treated WC-5 wt% NbC hard materials fabricated by a pulsed current activated sintering process. The densely consolidated specimens are cryogenically exposed to liquid nitrogen for 6, 12, and 24 h. All cryogenically treated samples exhibit compressive stress in the sintered body compared with the untreated sample. Furthermore, a change in the lattice constant leads to compressive stress in the specimens, which improves their mechanical performance. The cryogenically treated samples exhibit significant improvement in mechanical properties, with a 10.5 % increase in Vickers hardness and a 60 % decrease in the rupture strength compared with the untreated samples. However, deep cryogenic treatment of over 24 h deteriorates the mechanical properties indicating that excessive treatment causes tensile stress in the specimens. Therefore, the cryogenic treatment time should be controlled precisely to obtain mechanically enhanced hard materials.

The penetration depth, bead height, width, and internal porosity were analyzed to select the perfect penetration conditions for the STS316L tube material with an outer diameter of 38.1mm and a thickness of 3.4 mm. The welding conditions to secure a penetration depth of 3.4mm or more were selected. In addition, a welding range in which underfill does not occur was selected. The range of the selected conditions is the condition of a welding speed of 0.75 to 1.25m/min with an output of 2.0kW. The selected welding conditions were applied to STS316L tube orbital welding, and as a result of cross-sectional inspection after welding, a welded part of less than 4% of complete penetration and porosity was secured. The strength of the weld was measured to be more than 800kgf, and the hardness of the weld was found to decrease compared to the base material. The decrease in the hardness of the weld is judged by the annealing effect of the heat treated base material.

Safflower (Carthamus tinctorius L.) seeds have long been clinically used in Korea to promote bone formation and prevent osteoporosis. In addition, the safflower buds (SB) were found to have more useful functional ingredients than safflower seed. Thus, we investigated the preventive effects of SB diet in ovariectomized (OVX) rats. The rats were divided into five groups; sham operated group, OVX alone group, OVX plus 17β-estradiol (E2 10 ㎍/㎏, i.p.) and OVX plus SB diet feeding group (0.3% or 1%). Feeding of SB diet (0.3% or 3%) to OVX rats markedly increased trabecular formation in femur compared to OVX rats. Feeding of SB diet (0.3% or 3%) to OVX rats also decreased TRAP activity compared to OVX rats. These results suggest that SB diets have bone sparing effects by the decrease of osteoclast activity. We also observed that OVX rats fed with SB diet (0.3% or 3%) exhibited the decrease of calcium and phosphorus in serum compared to OVX-induced rats. Therefore, SB may be beneficial for the patients of osteoporosis, especially in postmenopausal women.