Analysis of Mechanical and Thermal Stresses in a Pressure Casting Machine Plunger

Abstract

The study discusses the thermo-mechanical stress distribution in the plunger of a cold chamber casting machine with a horizontal casting chamber in the stationary aspect. The main stresses as well as the reduced stresses were determined for four different strength hypotheses, two of which took into account different acceptable maximal tensile and compressive stresses. For comparative purposes, the calculations were performed for three different construction materials used for cold chamber pressure machine plungers: grey pearlitic cast iron, high silicon bronze and beryllium bronze, as well as one more type of bronze, which has not been used for plungers so far, i.e. aluminium-iron-nickel bronze, constituting the initial alloy for the newly-developed complex bronzes with high wear resistance and elevated strength.

Selection of the Technological Ceramic Layer Thickness in an HPDC Machine Plunger in the Aspect of its Strength

“…An analysis of the thermal stresses in an HPDC machine plunger made of the aluminiumiron-nickel bronze was carried out. According to the conclusions following from [5], a simplified axially symmetrical stress state [4] can be assumed with sufficient accuracy (up to 12%) in comparison to the flat stress state, which corresponds better to the actual stress state in the plunger. A simplified model considerably facilitates the solution and an analysis of the problem.…”

“…For the bronze sleeve as well as for the cylindrical ceramic ring, the same model, i.e., the equations for thick-walled sleeves, were assumed. The properties of the bronze sleeve and the Al 2 O 3 coating are listed in Table 1 [4,5].…”

“…In [4] devoted to the analysis of the mechanical and thermal stress state in a plunger of the cold-chamber HPDC machine with a horizontal shot sleeve, the temperature distributions in the shot sleeve were discussed based on [6,7]. The stress state was considered on the assumption of a homogenous temperature field in the plunger surroundings.…”

“…The tensile stresses occur on the outer surface of a one-layer plunger, whereas the compression stresses are present on the inner surface [4,5]. On both surfaces, the radial stresses are equal to zero.…”

“…The analysis of the plunger/sleeve operation presented here is based on a representation of the actual die casting process that takes place with a Buehler HPDC machine in the WIFAMA-PREX-ER company located in Lodz [4].…”