Abstract: In a method for producing a cast aluminum wheel, a cast aluminum wheel is produced, and then all of three strengthening processes are applied to the cast aluminum wheel. The three strengthening processes include forging a portion of the cast wheel between adjacent boltholes, burnishing a nut seat of the cast wheel, and shot blasting a hub coupling surface of the cast wheel.

Abstract: A hinge pin couples a first hinge receiver mounted on a vehicle body and a second hinge receiver mounted on a door to be installed on the vehicle body. The hinge pin is removed from the vehicle body and the door to separate the vehicle body and the door from each other after the vehicle body and the door have been coated, and the removed pin engages in a hinge pin engaging member. The hinge pin is fed to a position where the vehicle body and the door are to be assembled together, and the hinge pin is removed from the hinge pin engaging member. Then, the removed hinge pin is pressed into the first and second hinge receivers which are aligned with each other, thereby coupling the vehicle body and the door to each other.

Abstract: A method for processing a nut seat formed around a bolthole on a wheel including the steps of drilling the nut seat and the bolthole substantially simultaneously with a step drill and performing roller burnishing on at least edge portions of the nut seat wherein the roller is rolled on the nut seat in the circumferential direction of the nut while the roller is pressed onto the nut seat. By roller burnishing, at least the edge portions of the nut seat are finished to a specular grade. The strength of the nut seat itself can be increased by the roller burnishing, thereby decreasing the required thickness of a light alloy wheel and the total weight of the wheel. In addition, the manhours for processing the wheel can be reduced.

Abstract: A paint priming method which forms, on the surface part of a ferrous material to be treated, a nitride layer with an adequate depth and preferably .epsilon. phase as a main phase thereof, and with no carbon adhesion to the surface thereof, by carrying out a gas soft nitriding treatment with gas components which generate no free carbon. The nitride layer formed on the surface part of the material is used as a presubstrate on which direct painting is possible, thereby providing a simplified and improved presubstrate treatment for painting.

Abstract: A method for continuously treating an iron member wherein the iron member is first subjected to furnace-brazing in a controlled gas environment and subsequently to a soft-nitriding treatment by addition of ammonia gas (NH.sub.3) to the controlled gas for the brazing. An apparatus for carrying out the method is also provided, and includes three partitioned chambers for brazing, annealing and soft-nitriding the iron member, each chamber being partitioned by a member such as a stainless steel film curtain at opposite sides thereof. A controlled gas feed system communicates with each of the chambers, and an ammonia gas feed system is connected to the soft-nitriding chamber.

Abstract: A gas soft-nitriding method which comprises a step of subjecting iron parts to a gas soft-nitriding treatment in a heat treating furnace at a temperature of approximately 550.degree. C.-620.degree. C. in a mixed atmosphere which comprises, when introduced into the furnace, 10%-30% ammonia gas, 2.5%-4.5% total carbon monoxide, and a balance of N.sub.2 gas or an exothermic gas on a volume basis. Thereby, the iron parts are provided with superior fatigue and wear resistance qualities, while production costs and the cost of the treated parts are substantially reduced.

Abstract: A method for continuously treating an iron member wherein the iron member is first subjected to furnace-brazing in a controlled gas environment and subsequently to a soft-nitriding treatment by addition of ammonia gas (NH.sub.3) to the controlled gas for the brazing. An apparatus for carrying out the method is also provided, and includes three partitioned chambers for brazing, annealing and soft-nitriding the iron member, each chamber being partitioned by a member such as a stainless steel film curtain at opposite sides thereof. A controlled gas feed system communicates with each of the chambers, and an ammonia gas feed system is connected to the soft-nitriding chamber.