Abstract: A piston ring being planar, having a dished section and a planform giving desired radial pressure distribution on a co-operating cylinder wall and which ring is made form a steel resistant to stress relieving at the piston ring operating temperature. The dishing may be either positive or negative and may lie in the range from 0.025 to 0.75 mm. A method and apparatus are also described for the manufacture of such rings.

Abstract: A method for the manufacture of piston rings, includes the steps of producing a tube and machining the desired ring free shapes on the inner and outer diameters of the tube providing desired cross sectional profiles by grinding, for example, and then cutting the individual rings from the tube. The ring gaps are preferably formed after cutting the ring from the tube. Coatings on the ring outer surface may be applied and shaped while in tube form.

Abstract: A porous body is formed and joined to the component by sintering a metal powder to the component. The porous body and component are placed into a piston casting die. Molten metal is poured into the die such that the porous body becomes infiltrated with the molten metal and the molten metal is allowed to solidify. The porous body may be formed by sintering loose metal powder to the component, or by forming a separate body by die pressing of metal powder and which body may be subsequently sintered and joined to the component.

Abstract: Pistons and a method for their manufacture are described. The piston has at least one piston ring groove reinforcing member being annular in form and having, in cross-section, upper and lower, generally radially extending face portions and a radially inner, generally axially extending face portion between the two generally radially extending face portions, the generally axially extending face portion being coated with particulate material by a physical vapor deposition technique, to provide a porous adhesion assisting layer.

Abstract: A method for the manufacture of salt cores is described. The cores are used for the production of cavities in articles which have been made by a pressure casting technique. The cores are resistant to impregnation and fracture during, for example, the application of pressure during squeeze casting. In particular, the method comprises mixing coarse and fine particle salt powders in the ratio from 50/50 to 70/30 coarse/fine, the coarse powder having a maximum particle size of 250 micrometers, the fine powder having a maximum particle size of 25 micrometers. A lubricant, for example, oleic acid is added, possibly the quantity thereof being in the range 0. 1 to 1.0 wt %. A surfactant, such as a silane, also may be added, possibly the quantity thereof being in the range 0.1 to 1.0 wt %. The mixture is pressed to form a core having a density of at least 1.90 g/cm.sup.3 ; and is sintered at a temperature between 650.degree. C. and 775.degree. C., for a time in the range 15 minutes to 1 hour.

Abstract: The die for the production of piston blanks having high dimensional accuracy comprises an integral body and crown forming part with separate internal and pin boss bore cores and a single runner and feeder. Metal utilisation is greatly increased and fettling costs are greatly reduced.

Abstract: Pistons and a method for making them are described. The pistons have reinforcing components, such as piston ring groove inserts, incorporated therein. The reinforcements have one or more porous bodies joined thereto, for example, by brazing and which are infiltrated during casting of the piston.