All issues
Volume 45, Issue 2
Displaying 1-5 of 5 articles from this issue
- |<
- <
- 1
- >
- >|
Research Article
-
Toshiaki TANAKA1973 Volume 45 Issue 2 Pages 90-97
Published: February 25, 1973
Released on J-STAGE: September 21, 2012
JOURNAL FREE ACCESSCasting dilation is often measured during solidification to study the mechanism of shrinkage. In previous papers, the author reported on the casting dilation during solidification in rigid molds, but this paper is a report on the casting dilation in softer molds. The experiments were conducted to study the correlation between the casting dilation during solidification and shrinkage in softer molds at various carbon equivalents of Mg-treated hyper-eutectic spheroidal graphite iron. The results obtained are summarized as follows :
(1) The behavior of casting dilation during so1idification in softer molds was opposite to that in rigid molds, the casting dilation increasing with decreasing carbon equivalent.
(2) Casting dilation curves clearly showed that the casting dilation observed from the start of pouring to the start of eutectic solidification was larger than that observed during eutectic solidification.
(3) The volume of shrinkage became larger at lower carbon equivalents and lesser rigid mold.View full abstractDownload PDF (781K) -
Masataka SUGIYAMA, Yatarō TAKATA1973 Volume 45 Issue 2 Pages 98-104
Published: February 25, 1973
Released on J-STAGE: September 21, 2012
JOURNAL FREE ACCESSCast iron becomes porous after repeated heating and cooling above and below the A1 transformation point, and when oil is impregnated into the pores, it can be used as quality of oil-less bearing. The oil content of grown cast iron is almost proportional to the growth rate. As it is considered that the bearing performance is influenced by oil content, a series of bearing performance tests were carried out.
The results of the thrust journal bearing tests showed that the bearing performance rose rectilinealy up to 14 repeated heating and cooling treatments, 4% of growth rate, and about 1% of oil content. The Load capacity of thus treated cast iron was 10 times superior than that of nontreated cast iron. The bearing performance of the grown cast iron were constant in the oil content from 1 to 2%, but the load capacity decreased when oil content was more than 2%. It is considered that the fall of the load capacity is due to the deterioration of the material strength.
The bearing performances at higher sliding speeds improved by making the surface roughness of the mating material fine, whereas at lower sliding speeds, better results were obtained when the surface roughness was rather rough. It was observed that the friction surface was coated by the graphite in the grown cast iron.View full abstractDownload PDF (756K) -
Toshio MIYATE1973 Volume 45 Issue 2 Pages 105-111
Published: February 25, 1973
Released on J-STAGE: September 21, 2012
JOURNAL FREE ACCESSEffect of arsenic added to hyper-eutectic Al-Si, Sn-Si and Ag-Si alloys on the microstructure and line scanning analysis by X-ray microanalyser were studied.
The results of experiment are summarized as follows :
(1) When arsenic was added to molten aluminum and Al-Si alloy, a compound was formed which has been identified with AlAs. When As and Al were added to molten Sn-Si alloy or Ag-Si alloy, a compound identified with AlAs was formed in these alloys.
(2) With the addition of As or As and Al, the grain size of primary silicon in hyper-eutectic Al-Si alloy or Sn-Si and Ag-Si alloys was refined.
(3) The excess AlAs were retained in the matrix of alloy, free from the primary and eutectic silicon crystals, but the greater part of AlAs was included in the refined primary silicon crystals.
(4) The grain size of primary silicon and the size of AlAs in the silicon particles of the specimen cast into a metal mold were smaller than those in the specimen of the sand mold, and the number of grians in the metal mold specimen was larger than the number in the sand mold.
The results of the experiment seem to suport the ‘foreign neucleus theory’ which has been believed to be an appropriate explanation of the refining mechanism of AlAs.View full abstractDownload PDF (963K) -
Itsuo OHNAKA, Shōichi ŌYAMA, Kenji CHIJIIWA1973 Volume 45 Issue 2 Pages 112-120
Published: February 25, 1973
Released on J-STAGE: September 21, 2012
JOURNAL FREE ACCESSThe 2-pole-double-sided-flat-type electromagnetic pump is a most practical type of automatic pouring machine for casting. In this paper, the effect of the width of the stator core and channel on the output and the starting characteristics of the pump have been examined both theoretically and experimentally. In the experiment, mercury and molten aluminum were used. The results were as follows:
(1) When the width of the channel was larger than that of the stator core, the output was larger compared to the pump with the same width, because of the magnetic flux leakage and finite width effect of the channel.
(2) Smaller channel width decreased the output of the pump considerably.
(3) The output of the pump could be calculated theoretically using the experimental data of the magnetic flux.
(4) When the time constant of the pump electric circuit or fluid inertia was large, it took considerable time for the flow velocity to reach the appointed value. This should be noted in the design of high speed automatic pouring machines.
(5) The starting characteristics of the pump could be caluculated theoretically using the experimental data of the time constant.
(6) A 2-pole electromagnetic pump for molten aluminum was produced by way of trial. When the magnetizing current was 100A and pumping head was 100mm, the pouring capacity was about 18 kg/min. The net efficiency was 0.014% and power factor was about 0.2 to 0.5.
(7) Velocity of the molten aluminum were measured successfully by the electromagnetic flow meter.
(8) Flow resistance was very large contrary to expectations. This should be considered in the design of the pump.
(9) When molten aluminum is pumped out through a channel of about 100×6mm2 of cross-sectional area, a heating device to prevent solidification is necessary.
(10) Great care is needed to prevent thermal crack of the channel connection.View full abstractDownload PDF (847K) -
Kazuo MIYAKE, Kiyoshi KITA1973 Volume 45 Issue 2 Pages 121-131
Published: February 25, 1973
Released on J-STAGE: September 21, 2012
JOURNAL FREE ACCESSIn previous papers, authors studied the difference in value of tension test on the test specimens taken from the standard Y-block and the actual body of castings and, especially, the large difference in elongation in as-cast iron. This was due to the manner of solidification of iron. Hence, authors conducted to find out the difference in the value between specimens taken from the bottom and center of Y-block. The experiments were made on ordinary or stainless steel castings and spheroidal graphite and ordinary cast iron (Table 1), using the Y-block in Fig. 1 (as a reference, the plate-like specimens in Fig. 2 and the ordinary cast iron specimen in Fig. 3 were tested as well.). These results are given in Tables 2-8 and they can be summarized as follows :
(1) In the as-cast ordinary or stainless steel castings, the strength of the test specimens taken from the center of the Y-block was 95-99.5% of that from the bottom, while the elongation of the former was 77.5-82% of that of the latter. In the spheroidal graphite cast iron, these ratios were about 90.5% on the strength and about 50% on the elongation.
(2) This was caused by the difference in the freezing manner indicated by the comparison of cooling curves in Figs. 4-7. Also, it seems from the observation of the microstructure that intricate crystal-configurations may be a factor causing the drop in the value of strength and elongation.View full abstractDownload PDF (1025K)
- |<
- <
- 1
- >
- >|