An Advanced Oscillation Mixing Method for Improving the Cooling Uniformity in Quenching

In quenching, the cooling uniformity is most important to diminish distortion occurring on work pieces. As a trial to accomplish uniform cooling, therefore, there exist various mixing methods of a quenchant and the quenchant circulation with an external pump has so far been the well accepted mixing method. However, this study proposes an advanced oscillation mixing method that can improve more the cooling uniformity in quenching. The proposed method includes a stirrer in oscillating motion, so that the simultaneous oscillating and mixing movements of the stirrer are considered to provide effectively the uniform cooling characteristics for the quenchant. In comparison with the case of the circulation pump mixing, the investigation using the oscillation mixing method has demonstrated the following two experimental facts: (1) the short vapor blanket stage caused by the quick breakage of the oil vapor blanket and (2) the reduced variation of the quenching distortion.

Development of New Sliver Probe for Cooling Power Test of Polymer Quenchants

Working group on cooling power test of quenchants of Japanese Heat Treatment Society has studied on the new method for testing cooling power of aqueous quenchants. This method employed the cooling curve test of a new sliver rod probe, which has a metal-sheathed thermocouple at its geometrical center. The experimental study has clarified that the new silver probe has more excellent durability than the JIS silver probe employed for cooling power test of heat treating oils (JIS K 2242) and an aluminum alloy probe. Good repeatability and reproducibility of the cooling curves during polymer quenching have been confirmed. This new method is useful especially for cooling power test of aqueous quenchants used for solution heat treatment of aluminum alloys. This new silver rod probe is expected to be adopted for the revised version of JIS K 2242 as the cooling power test method for aqueous quenchants.

Standardization of New Sliver Probe for Cooling Power Test of Polymer Quenchant

Technical committee for Japanese industrial standard of heat treating oils has studied on the new method for testing cooling power of aqueous quenchants. This method employed the cooling curve test of a new sliver rod probe, which has a metal-sheathed thermocouple at its geometrical center. The experimental study has clarified that this probe has the higher sensitivity and excellent durability. In order to standardize this probe for cooling power test of aqueous quenchants, the repeatability and reproducibility of test results etc. have been studied. D.O.P. (Di-2-ethylthexyl Phthalate) was used as reference quenching fluid for initial calibration and for periodic calibration verification of the probe and system. In addition, 10% brine was used to check the response capability of the probe and system to the sudden change of temperature. These procedures are established according to the experimental investigation. This new test method is going to be built in the revised version of JIS K 2242 "Heat treating oils" as the cooling power test method for aqueous quenchants.

Synchrotron Refraction Enhanced Tomography of an Intact Common Marmoset (<i>Callithrix jacchus</i>)

The common marmoset (Callithrix jacchus), a small new world monkey species, has been widely used in various scientific fields. It is necessary to understand connections between specific genotypes, their structure, and function;however, an anatomical atlas of the entire body of the common marmoset has not yet been reported. In addition to conventional absorption, refraction enhanced computed tomography (CT) based on synchrotron radiation can increase the contrast of boundaries between small absorption differences. In this study, to examine the potential of creating an anatomical atlas of the whole body of the common marmoset non-invasively, we visualized an intact marmoset using synchrotron refraction enhanced CT. The cryogenic marmoset was scanned using the medical imaging beamline at the SPring-8 synchrotron radiation research facility in JAPAN. The trabecular structure, articular cartilage, cruciate ligament in the knee joint, and small airways (diameter: > 400 μm) was clearly identified with 50 μm voxel size and 37 keV x-ray energy. The structure of the heart and branching vessels in the kidneys and liver were also identified without contrast agents, and the anatomical structure of the brain was slightly visible. These results show that synchrotron refraction enhanced CT is useful for creating an anatomical atlas non-invasively, and further studies are planned that will combine refraction enhanced CT and other imaging techniques to analyse the morphology and create a complete atlas of the whole body of the common marmoset.