SK282085B6 - Method for free hammering of the pair of rods - Google Patents

Abstract

When loosely forging the connecting rods, the connecting rods bear together with the heads with the largest rectangular cross-sections. A blank is extruded from the forging ingot, the axis of which is the same as the ingot axis. The rectangular cross-section corresponds to the largest rectangular cross-section of the connecting rod blank. In the central part of the blank, it punches the hole (O) upstream with straight pins. Further, a pair of shafts (D) is further extruded from the blank by a conventional method, each ending with a head with a smaller rectangular cross section along with the conical passages between the shanks and the heads.

Description

Technical field

The invention relates to a method of free forging a pair of connecting rods from a forging ingot, in which the connecting rod blanks are adjacent to each other by heads with the largest rectangular cross-sections.

BACKGROUND OF THE INVENTION

Until now, the connecting rods were forged as well in pairs, but from the forging ingot, which, after heating to the forging temperature, compacted in the direction of the longitudinal axis of the ingot. Subsequently, a blank was forged from the forged blank, the axis of which was parallel to the ingot axis. The blank had a rectangular cross-section corresponding to the largest rectangular cross-section of the heads. Subsequently, both pairs of heads terminated symmetrically along the transverse axis. The whole forging had sufficient forging in each part. The pair of forgings was either smithically divided into two forgings of separate connecting rods or divided into a cutting machine. Semicircular holes in the heads at both ends were also fired on the cutting machines. Said method of manufacture is characterized by a greater number of heats and an increased weight of the input ingot, which must also cover burn losses at a greater number of heats and the addition to the material removed from the larger heads by firing. Also, a greater number of operations place higher demands on handling the forging. The final operation is the cold-burning of semicircular holes in the heads, and therefore the final operation cannot be a forging operation. During burning, non-standard changes in the material structure occur near the flame cut in the forging. Therefore, the product is subsequently needed in some of its weight, e.g. after roughing, still heat treated to the final value of material strength.

SUMMARY OF THE INVENTION

The method of free forging of a pair of connecting rods from a forging ingot according to the invention is also based on a connecting rod blank which bears on each other the heads with the largest rectangular cross-sections. The forging ingot is first forged with a blank whose longitudinal axis coincides with the ingot axis and the rectangular cross-section corresponds to the largest rectangular cross-section of the rods of the connecting rod blank. In the central part, in the forged blank, the opening is punched through the counter-mandrel mandrels. Furthermore, a pair of shafts, each of which is terminated by a head with a smaller cross-section, is forged from the blank. There are conical passages between the nipples and the stem. The entire billet forged from the ingot has a longitudinal axis coinciding with the ingot axis. The blank has a relatively low degree of folding that would not be sufficient for the final product. Subsequent forging, in which the shafts are formed with the heads, the necessary forging is achieved in these parts. The central part, however, achieves the necessary parameters only when counter-punching with straight mandrels. This process provides the necessary forging of the entire forging with an optimum number of heating and forging operations while maximizing the use of the ingot material.

In order to reduce the deformation of the blank, it is desirable to define a central portion forming the blank of adjacent heads by forging, preferably by a jam.

After counter-punching, the central portion is cut to the original size of the blank in the presence of the mandrels in the perforated hole. This not only returns the blank to its original size, but also increases the degree of forging in this part.

When punching the recesses in the heads with smaller rectangular cross-sections of the hollow mandrels, possible deformations are minimized. Here, the material is already sufficiently overlapped and there is no need to further increase the degree of overlapping. Since an ingot with an optimum weight is chosen, there is not enough material on these heads to surround the future hole sufficiently to allow straight mandrels to be used for punching.

BRIEF DESCRIPTION OF THE DRAWINGS

An overall view of a blank with a longitudinal axis coinciding with the ingot axis is shown in FIG. 1, the blank after punching with the indicated play is shown in FIG. 2 and FIG. 3 shows the final shape of the forging before splitting.

DETAILED DESCRIPTION OF THE INVENTION

In a conventional manner, after heating to the forging temperature, a rectangular cross section blank which corresponds to the largest rectangular cross section of the rod ends of the connecting rod blank is forged from the ingot. The central part of the blank forming a pair of adjacent heads with the largest rectangular cross-sections is defined by a forging Z-shaped notch. This defines the location of the permissible deformation that occurs when the hole 0 is subsequently punched with straight mandrels. The deformation of the workpiece is manifested in this operation, in particular, by the swelling of the sides of the workpiece of the rectangular cross-section, and only in the central part defined by the Z-engagement. Subsequently, a pair of shafts D terminated by heads having a smaller rectangular cross section together with conical passages between the shafts D and heads are wrought in a conventional manner. In the heads with smaller rectangular cross-sections, recesses in the hollow mandrels are punched. Subsequently, the outer parts of the heads are cut, while maintaining the necessary addition. The double blank is also forged in the cutting plane R. Since this is the last forging operation, the forging temperature can advantageously be used as a starting temperature for the subsequent heat treatment of the final forging.

Claims (4)

PATENT CLAIMS A method of free forging a pair of connecting rods from a forging ingot, wherein the connecting rod blanks are adjacent to each other by heads having the largest rectangular cross-section, characterized in that the forging billet is forged with a blank For this purpose, in the middle part of the blank, the hole is punched out with straight mandrels and a pair of stems are forged, each of which is terminated with a smaller rectangular head, together with conical transitions between the stems and heads. Method according to claim 1, characterized in that the central part of the workpiece is defined by forging before the counter-punching. Method according to claim 1 or 2, characterized in that after counter-punching SK 282085 Β6, the central part is forged to the original size of the blank in the presence of the mandrels in the perforated hole. Method according to one of Claims 1, 2 or 3, characterized in that recesses in hollow mandrels are punched in heads with smaller rectangular cross-sections.