Friction-Joining Steel Plate and Friction-Joining Structure

Abstract

Since a portion of projected streaks on a friction-joining steel plate 10 is provided with a Vickers hardness which is at least 3 times greater than that on the surface of steel plates IA and IB, the projected streaks are allowed to more easily enter into the steel plates IA and IB, and since a frictional resistance derived from a mechanical slip resistance of the thus entered projected streaks acts between the steel plates IA and IB, a marked increase is obtained in the friction coefficient between the steel plates IA and IB via the friction-joining steel plate 10 . Consequently, a friction-joining structure is constituted by a slip resistance mechanism which can be easily validated from a theoretical or an experimental point of view and is also small in variance of the friction coefficient. Therefore, a friction coefficient used in design can be set at a high value with high accuracy to realize a rational design.

1 . A friction-joining steel plate inserted between steel products to be joined which are mutually friction-joined by a compressive force derived from a fastening device,
 the friction-joining steel plate being provided on both faces with a plurality of projected streaks continuously formed mutually parallel or mutually in a concentric manner and also provided with at least one insertion hole for allowing the fastening device to be inserted, wherein   a portion of the projected streaks is designed to be higher in Vickers hardness than the surface of the steel product to be joined.   
   
   
       2 . A friction-joining steel plate according to  claim 1 , wherein
 a portion of the projected streaks is designed to be at least three times higher in Vickers hardness than the surface of the steel product to be joined.   
   
   
       3 . A friction-joining steel plate according to  claim 1 , wherein
 a tip angle (θ) of the projected streak is set in a range from 50° to 100°.   
   
   
       4 . A friction-joining steel plate according to  claim 1 , wherein
 a stress intensity ratio (σ/σ mb ) obtained by dividing a compressive stress (σ) acting on the steel product to be joined due to a compressive force of the fastening device by a tensile strength (σ mb ) of the steel product to be joined is set to be 0.5 or less.   
   
   
       5 . A function-joining steel plate according to  claim 1 , wherein
 a space (S) between the projected streaks is set in a range from 0.8 mm to 2.0 mm.   
   
   
       6 . A friction-joining steel plate according to  claim 1 , wherein
 a radius (R 1 ) of the tip end portion of the projected streak is set to be 0.1 mm or less.   
   
   
       7 . A friction-joining steel plate according to  claim 1 , wherein
 a radius (R 2 ) of a recess between the projected streaks is set to be 0.4 mm or greater.   
   
   
       8 . A friction-joining steel plate according to  claim 1 , wherein
 a width dimension (B) of apart at which the projected streaks enter into the surface of the steel product to be joined is set to be about ⅓ of the space (S) between the projected streaks.   
   
   
       9 . A friction-joining steel plate according to  claim 1 , wherein
 the friction-joining steel plate is formed in a planar shape to include a circle centering at the shaft of the fastening device, and   the diameter of friction-joining steel plate is 2.5 times the shaft diameter of the fastening device.   
   
   
       10 . A friction-joining steel plate according to  claim 1 , wherein
 a distance (H) between the tip end of the projected streak on one surface of the friction-joining steel plate and the tip end of the projected streak on the other surface of the friction-joining steel plate is set in a range from 1.5 mm to 2.5 mm.   
   
   
       11 . A friction-joining steel plate according to  claim 1 , wherein
 the projected streaks are formed by any processing method such as rolling, cutting or casting.   
   
   
       12 . A friction-joining steel plate according to  claim 1 , wherein
 the friction-joining steel plate is quenched after formation of the projected streaks.   
   
   
       13 . A friction-joining steel plate according to  claim 1 , wherein
 the friction-joining steel plate is tacked to one of the steel products to be joined by using tack tape or applying rust preventive paint.   
   
   
       14 . A friction-joining steel plate according to  claim 13  wherein
 the tack tape is aluminum tape adhered on one of the steel products to be joined so as to cover the friction-joining steel plate, and   when one and the other of the steel products to be joined are fastened by using the fastening device in a state that a face covered by the aluminum tape is kept in contact with the other of the steel product to be joined, projected streaks on the side of the other of the steel product to be joined break the aluminum tape, thereby entering into the other of the steel product to be joined, and the projected streaks on the side of one of the steel products to be joined enter into one of the steel products to be joined.   
   
   
       15 . A friction-joining steel plate according to  claim 1 , wherein
 the friction-joining steel plate is formed by having a plurality of insertion holes for allowing the shaft of the fastening device to pass through, and   a recess between the projected streaks at an intermediate position between the insertion holes is formed deeper than a recess at other positions.   
   
   
       16 . A friction-joining structure in which a friction-joining steel plate according to  claim 1  is inserted between steel products to be joined, wherein
 black scale or red rust is formed on the surface of the steel product to be joined, or abrasive blasting, sanding or rust preventive painting is applied thereto.   
   
   
       17 . A friction-joining structure according to  claim 16 , wherein two or more of the friction-joining steel plates are superimposed and inserted between the steel products to be joined.