| Budget Amount *help |
¥1,500,000 (Direct Cost: ¥1,500,000)
Fiscal Year 1986: ¥300,000 (Direct Cost: ¥300,000)
Fiscal Year 1985: ¥1,200,000 (Direct Cost: ¥1,200,000)
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| Research Abstract |
Studies on the critical rupture stresses of heat-affected-zone of seven kinds of alloyed nodular graphite cast irons, containing (a)Ni 1%, (b)Ni 2%, (c)Ni 1%, Mo 0.5%, (d)Ni 1%, Mo 1%, (e)Ni 2%, Mo 1%, (f)Si 4% and (g)Si 5%, were made by means of the implant cracking test. Specimens (a) and (b) have pearlitic matrices, (c),(d) and (e) have bull's eye structures, (f) and (g) have ferritic matrices, respectively.
As the alloying elements of Ni and Mo increased the hardenability of steel, the critical rupture stresses of specimens (a)-(e) decreased; less than that of normal nodular graphite cast iron reported in the previous papers. Even in case of preheating at 300゜C, the implant specimens fractured about 250 MPa, (a) and (b), or 330-350 MPa, (c),(d) and (e).
On the other hand, specimens containing Si have very small range of HAZ, about 0.5mm. Therefore they showed the critical rupture stress about 320 MPa, and 400 MPa at without and with 300゜C preheating, respectivery.
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