Abstract: An austenitic alloy based on nickel and having a high chromium content, intended to be used at a given operating temperature between 900° C. and 1150° C., comprises the following elements by mass percentage: chromium between 40% and 45%; iron between 10% and 14%; carbon between 0.4% and 0.6%; titanium between 0.05% and 0.2%; niobium between 0.5% and 1.5%; at least one reactive element, selected from rare earths or hafnium, between 0.002% and 0.1%; silicon between 0% and 1%; manganese between 0% and 0.5%; nickel to balance the alloy elements. In addition, the alloy has a molar fraction of more than 0.1% of secondary carbo-nitrides rich in niobium and/or titanium, after the operating temperature has been applied thereto. The disclosure also relates to a method for designing such an alloy and to a method for validating such an alloy.

Abstract: A process for manufacturing a process for manufacturing a part made of a magnesium alloy is disclosed. The process includes a step of forging a block of the alloy followed by a heat treatment. The alloy is a casting alloy based on 85% magnesium, and containing, by weight: 0.2 to 1.3% zinc; 2 to 4.5% neodymium; 0.2 to 7.0% rare-earth metal with an atomic number from 62 to 71; 0.2 to 1% zirconium. The forging is carried out at a temperature above 400° C. In particular the temperature is set between 420 and 430° C. and the forging step comprises a plastic deformation carried out at a slow rate. The process allows one to produce parts such as elements of casing for aeronautical machines, operating at a temperature of around 200° C. and having good aging properties.

Abstract: An improved centrifugally-cast tube is provided, along with a related method and apparatus of making the tube. The tube includes a plurality of grooves and bosses that are mechanically machined into an interior surface of the tube, such as by a broaching process. The profile of grooves and bosses may be defined by a plurality of intersecting concave and convex radii. The tube is resistant to creep, carburization and metal dusting. The tube also has an enhanced heat transfer rate, and a desirable surface roughness. A method of making the tube is also provided. The method essentially consists of mechanically deforming the interior surface of the tube by passing a series of cutting inserts on support rings having incrementally-differing dimensions over the interior surface.

Abstract: An improved centrifugally-cast tube is provided, along with a related method and apparatus of making the tube. The tube includes a plurality of grooves and bosses that are mechanically machined into an interior surface of the tube, such as by a broaching process. The profile of grooves and bosses may be defined by a plurality of intersecting concave and convex radii. The tube is resistant to creep, carburization and metal dusting. The tube also has an enhanced heat transfer rate, and a desirable surface roughness. A method of making the tube is also provided. The method essentially consists of mechanically deforming the interior surface of the tube by passing a series of cutting inserts on support rings having incrementally-differing dimensions over the interior surface.

Abstract: The present invention relates to a process for manufacturing a process for manufacturing a part made of a magnesium alloy, comprising a step of forging a block of said alloy followed by a heat treatment, characterized in that the alloy is a casting alloy based on 85% magnesium, and containing, by weight: 0.2 to 1.3% zinc; 2 to 4.5% neodymium; 0.2 to 7.0% rare-earth metal with an atomic weight from 62 to 71; 0.2 to 1% zirconium, and in that the forging is carried out at a temperature above 400° C. In particular the temperature is set between 420 and 430° C. and the forging step comprises a plastic deformation carried out at a slow rate. The process allows to produce parts such as elements of casing for aeronautical machines, operating at a temperature of around 200° C. and having good aging properties.

Abstract: An improved centrifugally-cast tube is provided, along with a related method and apparatus of making the tube. The tube includes a plurality of grooves and bosses that are mechanically machined into an interior surface of the tube, such as by a broaching process. The profile of grooves and bosses may be defined by a plurality of intersecting concave and convex radii. The tube is resistant to creep, carburization and metal dusting. The tube also has an enhanced heat transfer rate, and a desirable surface roughness. A method of making the tube is also provided. The method essentially consists of mechanically deforming the interior surface of the tube by passing a series of cutting inserts on support rings having incrementally-differing dimensions over the interior surface.

Abstract: An improved centrifugally-cast tube is provided, along with a related method and apparatus of making the tube. The tube includes a plurality of grooves and bosses that are mechanically machined into an interior surface of the tube, such as by a broaching process. The profile of grooves and bosses may be defined by a plurality of intersecting concave and convex radii. The tube is resistant to creep, carburization and metal dusting. The tube also has an enhanced heat transfer rate, and a desirable surface roughness. A method of making the tube is also provided. The method essentially consists of mechanically deforming the interior surface of the tube by passing a series of cutting inserts on support rings having incrementally-differing dimensions over the interior surface.

Abstract: An improved centrifugally-cast tube is provided, along with a related method and apparatus of making the tube. The tube includes a plurality of grooves and bosses that are mechanically machined into an interior surface of the tube, such as by a broaching process. The profile of grooves and bosses may be defined by a plurality of intersecting concave and convex radii. The tube is resistant to creep, carburization and metal dusting. The tube also has an enhanced heat transfer rate, and a desirable surface roughness. A method of making the tube is also provided. The method essentially consists of mechanically deforming the interior surface of the tube by passing a series of cutting inserts on support rings having incrementally-differing dimensions over the interior surface.

Abstract: A method of connecting a manganese steel part to another carbon steel part including the steps of depositing an austeno-ferritic stainless steel at the end of a carbon steel part and welding the latter provided at its end with the deposit to a manganese steel part, the method being applicable to assembling a rail to a common crossing railway track part.

Abstract: An insert for connecting a part made from a steel containing 12-14% by weight of manganese to at least one carbon steel part, said insert being made from an austenitic-ferritic alloy having the following chemical composition (in % by weight):______________________________________ Carbon 0.025-0.035% Manganese 6-11% Silicon 0.5-1.5% Nickel 5-8% Chromium 17.5-20% Molybdenum <0.5% Nitrogen 0.12-0.20% Phosphorus and sulfur .ltoreq.0.030% ______________________________________and the delta ferrite content of which (in percent by volume) as measured by micrographic counting ranges between about 5% and 15%.