RU2344015C1 - Method of manufacturing bolt with profile head and flange - Google Patents

Abstract

FIELD: technological processes, metal processing.

SUBSTANCE: invention concerns metal processing by pressure and can be applied in cold upsetting of hardware. Method involves blank cutting, preliminary upsetting of cylindrical head part, head flange upsetting, head trimming, final shaping of profile bolt head, and threading. Bolt head is upset in advance at diametre equal to 0.98 of specified bolt head diametre, and simultaneously even part of blank rod is gaged. Bolt head flange is upset with hollow fillet on reference surface simultaneously with bolt head trimming and facet shaping. Head size obtained before is preserved; flange diametre is maintained during the next transitions.

EFFECT: improved quality of obtained item, enhanced durability of shaping tool.

1 dwg

Description

The invention relates to the processing of metals by pressure and can be used for cold heading fasteners.

A known method of manufacturing a bolt with a shaped head and a flange, including cutting a workpiece, pre-planting a bolt head in the form of a truncated cone, planting a cylindrical workpiece head with a diameter equal to 1.05-1.08 of the described diameter of the shaped head of the bolt, reducing the cylindrical head by a length equal to the height of the bolt head without a flange, and a diameter equal to the described diameter of the shaped bolt head, extruding the shaped profile of the head with a total extrusion angle of 60 ° with simultaneous upsetting of the flange and knurling (RF patent No. 2207931, class B21K 1/46).

The known method has several disadvantages:

- at the final position, fuzzy chamfering is detected during the transition from the side surfaces of the projections of the head to its end face;

- at the last forming position on the end of the head of the bolt, flows and folds are pressed in;

- in the manufacture of high-strength fasteners from low-plastic grades of steel, risks are formed on the surface of the bolt heads;

- when reducing the workpiece to the outer diameter of the TORX head at the 3rd position, partial removal of the phosphate coating on the metal surface occurs, which significantly affects the 4th position when extruding the shaped profile due to an increase in the friction force;

- when extruding the shaped profile and disembarking the flange in one technological transition to the 4th position, large specific loads arise on the working surfaces of the forming tool, as a result, the tool life decreases.

The closest in technical essence is a method of manufacturing a bolt with a shaped head and a flange, including a piece of workpiece, preliminary draft of the rod under the head and re-trimming, preliminary landing of the head, calibration of the end, preliminary formation of the flange, the design of the cylindrical part for the reduction of the outer profile, the final formation of the shaped heads with flange upsetting and thread rolling (article by E.N. Khokhlov, V.A. Makarov, V.V. Galkin. Progressive designs of heads of fasteners and technologies for their manufacture by cold forging. Forging and stamping, 2003, No. 2, p. 33-36).

This method also has several disadvantages:

- in the manufacture of high-strength fasteners from low-plastic grades of steel, risks are formed at the end of the bolt heads;

- at 2 and 3 transitions, the chamfers of the transition from the lateral surface of the protrusions of the shaped head to the end face of the head are not clearly defined;

- at the last forming position on the end of the head of the bolt, flows and folds are pressed in;

- at the final formation of the shaped head, the low resistance of the forming tool is manifested.

The invention solves the problem of improving the quality of the shaped bolt head with a flange and increasing the resistance of the forming tool.

The problem is achieved in that in the method of manufacturing a bolt with a shaped head and a flange, comprising a piece of workpiece and transitions performed by preliminary disembarkation of the bolt head, disembarkation of the flange of the head, trimming of the head, the final formation of the shaped head of the bolt and rolling of the thread on the bolt rod, according to the invention, preliminary head disembarkation is carried out at the first transition after cutting the workpiece, while the cylindrical part of the head is pre-planted with a diameter equal to 0.98 of the opioid diameter the circumference of the shaped head of the bolt, with the formation of a convex part in the form of a sphere on its end and simultaneous calibration of the workpiece rod, then the bolt head flange is planted with the formation of a chamfer and an undercut fillet on the supporting surface and simultaneous trimming of the bolt head, while retaining the previously obtained diameter the cylindrical part of the head, and at subsequent transitions save the previously obtained diameter of the bolt head flange.

The invention is illustrated in the drawing, which shows the technological process of manufacturing a bolt with a shaped head and a flange.

The method is as follows.

On the cold landing machine mod. MV-415 made of steel 30G1R cut a workpiece with a diameter (d _zag .) Of 11.7 mm, then at the same time a preliminary landing of the cylindrical part of the head with a diameter of d = 0.98 / D takes place, where D is the described diameter of the shaped head of the bolt, the formation of the head is convex parts in the form of a sphere and calibration of the smooth part of the workpiece core. Then, the bolt head flange with an undercut fillet is disembarked and at the same time the bolt head is trimmed to form a chamfer on it, while the previously obtained size of the cylindrical head is saved. Then, the bolt rod is reduced under the knurling of the thread at an average degree of deformation of 13%, while the previously obtained dimensions of the flange and head are retained. At the last stamping position, the extruded head profile is extruded with a total extrusion angle of 60 ° and the rod is calibrated for knurling.

Using the proposed method of manufacturing a bolt with a shaped head and flange allows to improve the quality of the resulting product and increase the durability of the forming tool.

Claims (1)

A method of manufacturing a bolt with a shaped head and a flange, comprising a preform segment and preliminary transitions of the bolt head, the landing of the head flange, the head trimming, the final formation of the shaped bolt head and thread rolling on the bolt shaft, characterized in that the preliminary head landing is carried out on the first the transition after pieces of the workpiece, while pre-planting the cylindrical part of the head with a diameter equal to 0.98 of the diameter of the described circumference of the shaped head of the bolt, with the formation of a convex part in the form of a sphere on its end and simultaneous calibration of the workpiece rod, then the bolt head flange is planted with the formation of a bevel on it and an undercut fillet on the supporting surface and at the same time the bolt head is trimmed, while the previously obtained diameter of the cylindrical part of the head is retained, and on subsequent transitions retain the previously obtained diameter of the bolt head flange.