Claims Analysis
Total Claims: 9
Claim 1
Independent Claim
265 words
A method of manufacturing an extruded steel component, including the steps of: a. producing a steel preform which defines a shank part of a required component and which includes a hollow head portion tapering inwardly to the shank part, the external diameter of the head portion being substantially equal to the external diameter of the head part of the required component, but the bore in the head portion having a diameter less than that required for said head part, and b. positioning the preform in a die cavity of the shape of the required component, and performing an extrusion operation on the head portion of the preform using a punch including inner and outer, relatively movable punch members, the inner punch member defining the shape of the wide portion of said bore in the required component and the head part of the outer punch member defining the shape of the free end of the required component, the extrusion operation comprising moving the inner punch member relative to the outer punch member and the die cavity so as to enter said head portion and produce said wide bore portion and a cam surface on the wall of the bore in the head part, and urging the outer punch member against the free end of the head portion to apply a predetermined load to the head portion of the preform so as to restrict the flow of material extruded from the preform by said inner punch member, said material thereby being constrained to fill the region of the die cavity defining the head part of the component.
Claim 2
Independent Claim
265 words
A method of manufacturing an extruded steel component, including the steps of: a. producing a steel preform which defines a shank part of a required component and which includes a hollow head portion tapering inwardly to the shank part, the external diameter of the head portion being substantially equal to the external diameter of the head part of the required component, but the bore in the head portion having a diameter less than that required for said head part, and b. positioning the preform in a die cavity of the shape of the required component, and performing an extrusion operation on the head portion of the preform using a punch including inner and outer, relatively movable punch members, the inner punch member defining the shape of the wide portion of said bore in the required component and the head part of the outer punch member defining the shape of the free end of the required component, the extrusion operation comprising moving the inner punch member relative to the outer punch member and the die cavity so as to enter said head portion and produce said wide bore portion and a cam surface on the wall of the bore in the head part, and urging the outer punch member against the free end of the head portion to apply a predetermined load to the head portion of the preform so as to restrict the flow of material extruded from the preform by said inner punch member, said material thereby being constrained to fill the region of the die cavity defining the head part of the component.
Claim 3
Dependent Claim
38 words
The method as claimed in claim 1, wherein step (b) is arranged to produce a plurality of angularly spaced ribs integral witn the head part and extending inwardly from the wall of said wide portion of the bore.
Claim 4
Dependent Claim
24 words
The method as claimed in claim 1, wherein the tapering head portion of the preform defines an included angle of between 80° and 100°.
Claim 5
Dependent Claim
130 words
The method as claimed in claim 1, wherein the preform is produced by effecting the following steps in order: c. cropping a steel bar to produce a slug having a length to diameter ratio of not less than 0.75, d. deforming the slug into a substantially cylindrical billet having a diameter substantially equal to the diameter of the head part of the required component, e. heat treating the billet to remove work hardening, f. forming an axially extending, centrally disposed bore in the billet, and g. positioning the billet in a further die cavity defining the external shape of the preform and using a further punch to perform an extrusion process on the billet such that metal flows in the direction of movement of the punch and produces said preform.
Claim 6
Dependent Claim
27 words
The method as claimed in claim 4, wherein the preform produced after step (g) is heat treated to remove work hardening before being subjected to step (b).
Claim 7
Dependent Claim
21 words
The method as claimed in claim 4 5, wherein the minimum length to diameter ratio of the cropped slug is 1.
Claim 8
Dependent Claim
24 words
The method as claimed in claim 4, wherein the length of the slug is reduced by at least 30% during the deforming step (d).
Claim 9
Dependent Claim
21 words
The method as claimed in claim 4, wherein step (f) is effected by an extrusion operation followed by a piercing operation.