Showing papers on "Roller burnishing published in 2003"

Method for manufacturing a bearing raceway member

Abstract: At least a race ( 1 c ) of a blank (B) for forming a bearing raceway member is hardened by heating. The race ( 1 c ) thus hardened by heating is finished to predetermined precisions. Subsequently, the race ( 1 c ) is roller burnished for hardening the race ( 1 c ). The blank (B) is formed from a steel for bearing manufacture or a carbon steel for machine structural use. The blank (B) formed from the steel for bearing manufacture is subjected to the roller burnishing, thereby achieving a hardness of HRC65 or more at a surface of the race ( 1 c ), and a center-line average roughness Ra of 0.1 μm or less at the surface of the race ( 1 c ). The blank (B) formed from the carbon steel for machine structural use is hardened by the roller burnishing, thereby achieving a hardness of Hv800 or more at depth of at least 0.2 mm from a surface of the race ( 1 c ). Where cutting by turning is adopted as the finishing process, the surface of the race ( 1 c ) is finished to a center-line average roughness Ra of 0.35 μm or more and then the race ( 1 c ) is subjected to the roller burnishing, thereby achieving a center-line average roughness Ra of 0.25 μm or less and a compressive residual stress of 1000 MPa or more at depth of at least 0.2 mm from the surface thereof. Where cutting by turning or grinding is adopted as the finishing process, the race ( 1 c ) is subjected to the roller burnishing, thereby achieving a center-line average roughness Ra of 0.15 μm or less at the surface thereof and a compressive residual stress of 1000 MPa or more at depth of at least 0.2 mm form the surface thereof.

Method of producing bearing raceway member

Abstract: At least a raceway portion (1c) of a blank (B) for a bearing raceway member is hardened by heat treatment, finished at a predetermined accuracy, and then roller-burnished and work-hardened. The blank (B) made of bearing steel is processed by the roller burnishing work so that the hardness of the surface of the raceway portion (1c) is HRC 65 or more and centerline-average roughness Ra of the surface is 0.1 µm or less. The blank (B) made of carbon steel for use in machine structure is hardened by the roller burnishing work so that the hardness at a depth of at least 0.2 mm from the surface of the raceway portion (1c) is HV 800 or more. When turning is used as finish machining, centerline-average roughness Ra of the surface of the raceway portion (1c) is to be 0.35 µm or more, and the raceway portion (1c) is roller-burnished so that its centerline-average roughness Ra is 0.25 µm or less and residual compression stress at a depth at least 0.2 mm from the surface of the raceway portion (1c) is 1,000 Mpa or more. When turning or grinding is used as the finish machining, centerline-average roughness Ra of the raceway portion (1c) by the roller burnishing work is to be 0.15 µm or less.

Finite Element Simulation Of Roller Burnishing In Crankshafts

Abstract: Roller burnishing is a very commonly used industrial process. It involves a local plastic deformation on surfaces that permits the fatigue strength of structures to be increased. Crack propagation is indeed delayed by the introduction of compressive residual stresses. In th~s way, this process is particularly useful in the presence of stress concentrators like in the fillets of crankshafts or in notched shafts for instance. In the present work, a three-dimensional finite element analysis is carried out with the commercial software ABAQUS in order to model roller burnishng in the fillets of crankshafts. The contact between the workpiece and the tool is simulated and the latter is subjected to a pressure. Thus, all the residual stresses and strains can be calculated after unloading. The outputs are compared to experimental profiles of residual stresses measured by X-ray diffraction and a good agreement between experimental and three-dimensional numerical results is obtained. Unfortunately, this analysis is costly and the effects of roller burnishing can only be observed in the vicinity of the contact between the tool and the piece and not on the whole circumference of the shaft since neither the tool nor the piece rotates. However, our investigations show also that a simple axisymrnetric model may approach experiments, not considering residual stresses as unknown quantities but as inputs of the problem. The threedimensional field obtained by revolving the two-dimensional one will then make it possible to study, by the finite element method, crack propagation in such residual stress fields.

Review on the Fatigue Behavior of Magnesium Alloys

Abstract: This report provides some of the results of magnesium alloys studying, especially about its fatigue behavior , in recent years. The factors that influence the fatigue behavior of magnesium alloys can be given from several aspects of metallurgy, form factor, loading system, medium and temperature. The strengthening methods can be concluded in three aspects. One is heat treatment; the other two are roller burnishing and shot blasting. In addition, the prospect of fatigue behavior observation on magnesium alloys is discussed.

Method of manufacturing rotary shaft

Abstract: PROBLEM TO BE SOLVED: To provide a method of manufacturing a rotary shaft that can improve strength of a weld zone in which members are friction-welded to each other. SOLUTION: Three solid round bars are prepared as auger members, respectively as a main body member 41, an upper shaft member 42, and a lower shaft member 43. End surfaces of the members are coaxially joined together by friction welding. Turning machining is then performed by using a lathe, forming a helical blade 31a, a spline 33a, and the like. In addition, burnishing is performed on a corner portion 35 that includes an outer circumferential edge 34a of a joining surface 34 where friction welding is performed, and another corner portion 37 that includes an outer circumferential edge 36a of another joining surface 36 where friction welding is performed, The burnishing is performed by pressing a roller 55, which is freely rotatable around a roller support shaft center 54 of a Superoll (R) 50, in the direction of the arrow A, toward the corner portions 35, 37 of the rotating auger. Roller burnishing may also be performed two times on the same location, with a predetermined time interval therebetween. COPYRIGHT: (C)2005,JPO&NCIPI

Method and device for the production of coated bores

Abstract: The invention relates to a method and device for the production of coated bores, whereby the bore wall is plasma sprayed with a coating material after formation of the bore. According to the invention, an adequate resistance of the coating of the bore wall to mechanical loads may be achieved, whereby the bore wall is subjected to a roller burnishing.

Roller-burnishing tool for drawing work and drawing device using the same

Abstract: PROBLEM TO BE SOLVED: To provide a roller-burnishing tool for drawing work capable of drawing and a drawing device using the roller-burnishing tool for the drawing work. SOLUTION: The roller-burnishing tool for outer periphery, which performs rolling-compaction finishing by pressing the outer peripheral surface of a material to be processed by a parallel roller protruded from the inner peripheral surface of the cylindrical frame member, is characterized in that the drawing work and mirror finishing are executed by making the roller portion composed of a plurality of parallel rollers 6 to abut against the inner peripheral surface taper portion of the cylindrical head member 5 by providing a taper portion in the peripheral surface of the cylindrical head member 5.