Creep feed profile grinding of Ni-based superalloys with ultrafine-polycrystalline cBN abrasive grits

This paper presents the grinding characteristics of a newly developed ultrafine-polycrystalline cBN abrasive grit in creep feed profile grinding of Nickel-based superalloys. Experiments for producing a rectangular-shaped groove on a flat surface in one pass by creep feed grinding have been carried out using the new polycrystalline cBN (PcBN-U) grit and a representative conventional monocrystalline cBN (McBN-B1) grit. The grinding forces in grinding with PcBN-U grits are reduced by 20 30% compared with McBN-B1 grits. When grinding with PcBN-U grits, both radial wear and profile wear are less, and hence the grinding ratio is around 4 times higher than that with McBN-B1 grits. The size of grit fracture during the grinding process with PcBN-U grits is smaller than that with McBN-B1 grits. It gives lower wheel wear rate and longer wheel life in grinding with PcBN-U than with McBN-B1.     

Development of Chloride Electrode Coated Wire and Composite Systems for Determination Chloride Ion in Gunungkidul Spring Water

The purpose of this research was to fmd out effectiveness of chloride solid membrane electrode of coated wire system compared to solid membrane electrode of composite system, the Nernstian response and character＇s potential response （detection limit, selectivity and response time）. The chloride ISEs （ion selective electrodes） in this research were the solid membrane chloride ISEs based AgC1. There were two types of chloride ISEs that were developed, namely the chloride ISEs of coated wire and composite systems. Both types of electrodes were characterized. The selectivity was done by comparing Esel of the chloride standard solutions and Esel of the interference ions （Br- and I-）. The measurement of chloride ions in water samples was done by using the coated wire chloride ISE, the composite chloride ISE and the Mohr method. We compared the result of the two chloride ISE methods to that of standard method for chloride determination （Mohr） by using F-test and Post Hoc Test LSD （least significant difference） and Duncan. Analysis by using F-test and Post Hoc Test （LSD and Duncan） and characterization results of both the methods showed that coated wire chloride ISE was more effective compared to composite chloride ISE. Nemstian response was 59.83 mV/decade, linier range measurement was 10-1-10-5 M, limit detection was 1.23 × 10-5 M, response time along was 25 s and interfering ion was 10-4 M Br-.     

用超细CBN磨料磨削超耐热合金

本文描述了用新开发的超细多晶CBN磨料成型缓进给磨削镍基超耐热合金的磨削特点。用新型聚晶CBN(CBN—U)磨粒和一种有代表性的传统单晶CBN(CBN—B1)磨粒以缓进给方法一次在平面上磨出一个矩型槽进行了试验。用CBN—U磨料与用CBN—B1相比，磨削力降低了20—30％。用CBN—U磨料进行磨削时，径向和轮廓磨损都较小，磨削比要比CBN—B1磨粒高约4倍。CBN—U磨料在磨削过程中的微破碎尺寸比CBN—B1磨料小。用CBN—U比用CBN—B1砂轮磨损率低而寿命长。