Trw Limited

Battelle Memorial Institute

Roger R Wills

Mohan Kurup

William Neumann

Victor D Levin

Mark S Scherer

Edgel P Stambaugh

Beebhas C Mutsuddy

Ibrahim Sekercioglu

Marion Brockway

James H Adair

A work-hardened poppet exhaust valve for internal combustion engines is obtained from a solutioned work-hardenable austenitic stainless steel coil or bar stock in which chromium is present in the range of 13%-25% by weight, nickel is present in the range of 4%-16% by weight, manganese is present in the range of 0.25%-8% by weight, copper is present in the range of 0.5%-7% by weight, the interstitial elements carbon plus nitrogen are present in a total amount less than 0.45% by nitrogen are present in a total amount less than 0.45% by weight, and at least one refractory metal selected from the group consisting of molybdenum, niobium, vanadium, tungsten and tantalum is present in the range of 1%-5% by weight. The coil or bar stock is extruded to a poppet valve preform configuration at a temperature in the range of room temperature to 1,000&deg; F., and at a true strain of more than 0.8. The parameters of extrusion provide said work-hardened poppet valve with a stem hardness more than R &equals;25.

Work hardened poppet exhaust valve

The present invention resides in a method for making an internal combustion engine intake valve. An iron aluminum alloy, in the form of a coil or bar stock, is provided. The alloy comprises 76.05 to 90.15 weight percent iron, 9 to 13.3 weight percent aluminum, 0.05 to 0.35 weight percent carbon, and 0.5 to 3 weight percent of a refractory metal, and/or 0.3 to 1.5 weight percent of titanium in combination with, or in place of, the refractory metal. The coil or bar stock is extruded to a poppet valve preform configuration at a heading temperature in the range of 800.degree. to 2,000.degree. F. and a true strain of about 0.5 to 2.2. The preform configuration is then headed to a pre-machined configuration while maintaining the head of such preform at an effective heading temperature up to 2,200.degree. F. said heading being carried out at a true strain of about 1.4 to 2.3. The headed preform is then machined, to its machined configuration, without intermediate heat treatment, and then is coated by either nitriding or chrome plating. If desired, a hardenable steel tip can be welded to the valve stem, and then heat hardened.

Iron aluminum based engine intake valves and its manufacturing method

The present invention resides in a method for making an internal combustion engine intake valve. An iron aluminum alloy, in the form of a coil or bar stock, is provided. The alloy comprises 76.05 to 90.15 weight percent iron, 9 to 13.3 weight percent aluminum, 0.05 to 0.35 weight percent carbon, and 0.5 to 3 weight percent of a refractory metal, and/or 0.3 to 1.5 weight percent of titanium in combination with, or in place of, the refractory metal. The coil or bar stock is extruded to a poppet valve preform configuration at a heading temperature in the range of 800.degree. to 2,000.degree. F. and a true strain of about 0.5 to 2.2. The preform configuration is then headed to a pre-machined configuration while maintaining the head of such preform at an effective heading temperature up to 2,200.degree. F., said heading being carried out at a true strain of about 1.4 to 2.3. The headed preform is then machined, to its machined configuration, without intermediate heat treatment, and then is coated by either nitriding or chrome plating. If desired, a hardenable steel tip can be welded to the valve stem, and then heat hardened.

Iron aluminum based engine intake valves and method of making thereof

A method of making work-hardened poppet exhaust valves for internal combustion engines comprises the steps of: providing a solutioned work-hardenable austenitic stainless steel coil or bar stock in which chromium is present in the range of 13%-25% by weight, nickel is present in the range of 4%-16% by weight, manganese is present in the range of 0.25%-8% by weight, copper is present in the range of 0.5%-7% by weight, the interstitial elements carbon plus nitrogen are present in a total amount less than 0.45% by weight, and at least one refractory metal selected from the group consisting of molybdenum, niobium, vanadium, tungsten and tantalum is present in the range of 1%-5% by weight; extruding the coil stock to a poppet valve preform configuration at a speed in the range of 60 to 100 strokes per minute and at a temperature in the range of room temperature to 1,000.degree. F.; and heading the preform at the same speed while maintaining the head of the preform at a temperature in the range of room temperature to 2,200.degree.; the parameters of extrusion providing the work-hardened poppet valve with a stem hardness more than R.sub.c =25.

Process for making exhaust valves

A process for producing toughened ceramic composites from ceramic precursor materials by forming microcomposite particles from the ceramic precursor materials to produce microstructures that impart enhanced toughness to the particles. The microcomposite particles are consolidated at a pressure, a temperature and for a time sufficient to form bulk ceramic components that exhibit the general microstructure and toughness of the microcomposite particles while the temperature is maintained above that where particle consolidation occurs but below the eutectic or melting temperature of the matrix. The consolidated product retains the toughness of the microcomposite particles.

Process for producing ceramic composites from microcomposite particles

The invention is characterized by two main methods of producing stabilized or partially stabilized zirconia powders with controlled particle size by use of complexing agents and hydrothermal treatment. A further embodiment of the invention is characterized by a combination of the first two methods to produce powders containing more than one major particle size. The invention also allows use of low cost readily available starting material, controlled doping level and incorporation of dual constituents such as MgO, CaO; Y.sub.2 O.sub.3, MgO; or Y.sub.2 O.sub.3, CaO in the structure for production of stabilized zirconia. Triply stabilized zirconia containing Y.sub.2 O.sub.3, MgO and CaO may also be produced. A final embodiment of the invention allows the production of dually and triply stabilized zirconia by hydrothermal treatment without the use of complexing agents.

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Solon, OH, United States of America

Roger R Wills