An upset pipe bending machine to control automatically a bending radius by means of high-frequency induction heating was developed by us. By using this machine and by varying the bending radius R/D (R : bending radius; D : nominal outside diameter) and offset e (eccentric distance), an experiment was conducted with respect to a condition to accept eccentric axial compression load of the pipe. Concurrently with this, thickness of the bending outside of the pipe was controlled. Furthermore strain measurement of the experiment where offset was changed under the condition that the bending radius R/D =1.5 and R/D =3.0 (respectively constant). This resulted in slight increase in the thickness of bending outside at e =11mm. In the meantime, a small amount of decrease was noticed likewise at e =13mm. Thus it is explained from the above that controlling the bending outside thickness is possible by changing the offset. In the experiments, carbon steel pipe for pressure service (STPG 370, JIS G 3454) of nominal number 2B×Sch80 is used.
The mixtures of machined cast iron (FC300) chips and graphite (Gr.) powder with 3∼10mass% Gr contents were mechanically alloyed (MA) up to 36ks. The obtained MA powder was mixed with polypropylene (PP) and paraffin wax (WAX) as the binder. Then it was stacked on a cast iron (FC300) plate as the substratum and hot-pressed at 893K at various pressures to realize debinding and preforming. Subsequently, it was sintered at 973∼1273K for 1.8ks, for the bonding of the MA alloy and FC300 plate. For the estimation of bonding characteristics, the structural change due to the sintering of the bonded MA alloy layer and the hardness distribution near the bonding interface were investigated. Rupture strength in a three-point-bending test was also investigated. The structure of the sintered MA alloy layer consists of a fine ferrite phase and graphite of nanometer-order size. The structure is the same as the MA powder. However, the hardness of the MA alloy layer decreases after sintering. The rupture strength of the cast-iron-bonded MA alloy is higher than that of cast iron without the MA alloy layer. Shot peening treatment was carried out on the surface of the MA alloy layer. The surface hardness of the MA alloy layer increases with the shot peening treatment.
In this paper, we describe the three-dimensional effect of a blade line end on the pushing shear of paperboard. In order to reveal the deviation of cutting line force caused by the strain constraint of the unseparated zone, the relationship between the cutting line force and the indentation depth of a blade was experimentally investigated by varying the tip thickness of the blade, the length of the blade, and the length of the unseparated zone of paperboard. The following results were obtained. (1) The first peak (or inflection) of line force fC1tends to decrease in a certain range of unseparated-zone length a and a certain range of blade-tip thickness w, while fC1 is almost constant with a in the case of a sharp blade. (2) The second peak of line force fC2 is increased in a certain range of a. (3) A formula of the approximate relationship of fC2 with respect to the blade length was experimentally derived.