Manufacturing method of cylinder with annular inner reinforcing ribs
Technical Field
The invention belongs to the technical field of accurate plastic processing, and particularly relates to a manufacturing method of a cylinder body with annular inner reinforcing ribs.
Background
As an important resource metal, the titanium alloy is expensive, has the characteristics of high specific strength, wide use temperature range (-269-600 ℃), corrosion resistance, no magnetism, low damping, good high-low temperature performance and the like, can meet the structural lightweight requirements of thin-wall shell parts such as aviation, aerospace, weapons and the like, and the demand of China on the titanium alloy is increased at the speed of 20-30% per year along with the continuous and rapid development of national economy.
At present, the manufacturing method of the titanium alloy thin-wall cylinder with one end provided with the annular inner rib mainly comprises two methods of 'forge piece integral machining' and 'annular inner rib section integral machining + thin-wall cylinder section spinning', and has the following process defects: 1. the main process defects of obtaining the titanium alloy thin-wall cylinder part with the annular inner rib at one end by using the method of 'integral machining of forgings' are as follows: (a) a large amount of titanium materials are hollowed during processing, and the material utilization rate is low; (b) for thin-wall long-cylinder parts, the overall machining process difficulty is higher, the product precision is not easy to guarantee, and the machining period is longer; (c) the streamline of the material fiber is cut off, and the fatigue impact resistance is weaker. 2. The main process defects of obtaining the titanium alloy thin-wall cylinder part with the annular inner rib at one end by using the method of 'annular inner rib section integral machine adding + thin-wall cylinder section spinning': (a) although the length of the forge piece can be saved by spinning the thin-wall cylinder section, the thickness of the forge piece cannot be saved due to the existence of the annular inner ribs, more titanium materials are still hollowed during processing, and the material utilization rate is relatively low; (b) the material fiber streamline is cut off by the annular inner rib section obtained by machining, the material fiber streamline is not strengthened by spinning, and the fatigue impact resistance is weaker.
Disclosure of Invention
Based on the problems, the invention aims to overcome the defects of the prior art and provide the manufacturing method of the cylinder with the inward reinforcing ribs, which has the advantages of high material utilization rate, high production efficiency and good product quality.
In order to achieve the above purpose, the invention adopts the technical scheme that: a manufacturing method of a cylinder body with annular inner reinforcing ribs comprises the following steps:
step 1, sleeving and fixing a limiting device on a core mold connected with a main shaft, arranging an annular groove matched with a reinforcing inner rib on a cylinder body to be manufactured at the end part of the core mold, preheating the core mold and keeping the temperature of the core mold at 500-550 ℃;
step 2, sleeving the blank part on the end part of the core mold, arranging a tail top at the rear end of the blank, and arranging a rotary wheel on the side surface of the blank, wherein the rotary wheel can feed in the axial direction and the radial direction relative to the blank;
step 3, driving the main shaft to rotate and driving the core mold, the limiting device and the blank to rotate, heating the blank and keeping the temperature of the blank within a range of 630-680 ℃, pushing the tail top to be close to the core mold axially, shortening the axial length of the blank, increasing the radial thickness, then controlling the spinning wheel to radially feed and extrude the blank relative to the port at the rear end of the blank, and under the limiting action of the annular groove at the end part of the core mold and the thrust action of the tail top, radially thickening and filling the port at the rear end of the blank along with the radial feeding of the spinning wheel and forming a radially inward-protruding annular inner reinforcing rib, thereby obtaining a primary cylinder body with the annular inward reinforcing rib;
step 4, controlling the limiting device to move along the mold core and to be far away from the initial cylinder body, controlling the rotary wheel to move axially relative to the initial cylinder body, enabling the initial cylinder body to flow along the outer wall of the mold core while rotating along with the mold core, increasing the axial length of the initial cylinder body and reducing the radial thickness of the initial cylinder body; when the spinning wheel is close to the wall thickness of the initial cylinder body to reach the preset value, the spinning wheel stops radial approaching and keeps axial movement so that the wall thickness of the initial cylinder body is uniform, and therefore the cylinder body with the inward reinforcing ribs is obtained.
In particular, the blank is a tube, usually of a diameter of
The wall thickness is 6-12 mm, the length is 200-1000 mm, and a gap which can be freely installed is reserved between the inner diameter and the outer diameter of the core mold, and is usually 0.20-0.30 mm; the tail jack is driven by an equipment oil cylinder and can provide a constant jacking force of 6 t-10 t; the rotary wheel is arranged on a rotary wheel shaft of the equipment, can do driven rotary motion along with the main shaft around the rotary wheel shaft and can also do radial and axial feed motion along with the rotary wheel shaft,the invention mainly adopts axial feeding motion, and the feeding speed is 100-300 mm/min.
Optimally, in order to avoid the defects of oxidation and the like of the outer surface of the core mold caused by overlong flame heating time, the core mold is preheated by adopting a medium-frequency induction heating coil in the step 1.
Optimally, a hollow inner cavity is formed in the core mold in the step 1, and a heating medium is filled in the hollow inner cavity to keep the temperature of the core mold at 500-550 ℃; the heating medium is preferably red-burned charcoal.
Specifically, in the step 2, a flame heating torch is adopted to heat the blank and keep the temperature of the blank within a range of 630-680 ℃, a large-diameter flame heating torch can be adopted, 2-3 flame heating torches are respectively arranged on two sides of the device, the heating uniformity is improved, and on the basis of the step 1, the blank and the core mold can be heated to 630-680 ℃ within a short time; in the whole manufacturing process, flame torch heat compensation is adopted on the outer surface of the blank all the time, and the heating and heat preservation combination of the flame torch heat compensation and the red charcoal firing in the hollow inner cavity of the core die in the optimized mode forms an isothermal spinning condition, effectively reduces the temperature gradient of the inner surface and the outer surface of the blank, and improves the alloy plasticity of the blank.
And coating graphite on the surface of the blank before heating the blank in the step 3 to prevent the blank from being oxidized.
The limiting device is an annular disc body, and further, the limiting device is fixed or moved through the servo oil cylinder.
The invention has the beneficial effects that:
1) the material utilization rate is high: according to the invention, by the technology of 'thickening filling and thinning increasing', the length and thickness of raw materials (pipes) are effectively saved, the precise forming of the annular inner rib section and the thin-wall cylinder section is realized, the machining size is limited to the length of two ends, the machining allowance is small, and the material utilization rate is high.
2) The production efficiency is high: the invention realizes the accurate forming of the whole part on one numerical control spinning machine, has no intermediate links such as secondary alignment, clamping and the like, and has the advantages of simple operation, greatly simplified production process, fast processing beat and high production efficiency.
3) The product quality is good: the product part obtained by the invention has continuous material fiber streamline, and the organization and the mechanical property are improved through the annular inner rib section filled by thickening and the thin-wall cylinder section increased by thinning, and compared with the traditional process, the product quality is greatly improved.
Drawings
FIG. 1 is a schematic view of steps 2 and 3;
FIG. 2 is a schematic view of step 4;
FIG. 3 is a sectional view of a cylinder with an inward reinforcing rib manufactured in the example;
wherein, 1 is the main shaft, 2 is the mandrel, 3 is stop device, 4 is the blank, 5 is the tail top, 6 is the spinning wheel, 7 is the barrel, 71 is the hoop internal strengthening rib.
Detailed Description
The present invention will be described in further detail with reference to the accompanying drawings.
Examples
The embodiment provides a manufacturing method of a cylinder body 7 with an inward reinforcing rib as shown in fig. 3, which comprises the following steps:
step 1, sleeving and fixing a ring-shaped limiting device 3 on a core mold 2 connected with a main shaft 1, wherein the limiting device 3 is connected with a servo oil cylinder, an annular groove matched with a reinforcing inner rib on a cylinder body to be manufactured in shape is formed in the end portion of the core mold 2, and the core mold 2 is preheated and the temperature of the core mold 2 is kept at 500-550 ℃;
step 2, as shown in fig. 1, partially sleeving a blank 4 on the end part of a core mold 2, arranging a tail top 5 at the rear end of the blank 4, connecting the tail top 5 with an oil cylinder and enabling the tail top 5 to be close to or far away from the rear end of the blank 4 under the driving of the oil cylinder, arranging a spinning wheel 6 on the side surface of the blank 4, wherein the spinning wheel 6 is arranged on a spinning wheel shaft of the equipment and can do driven rotary motion along with a main shaft 1 around the spinning wheel shaft and also can do radial and axial feeding motion along with the spinning wheel shaft;
step 3, driving the main shaft 1 to rotate and driving the core mold 2, the limiting device 3 and the blank 4 to rotate, coating graphite on the surface of the blank 4, heating the blank 4 by adopting a flame heating torch to keep the temperature of the blank 4 within a range of 630-680 ℃, pushing the tail top 5 to be close to the core mold 2 in the axial direction, shortening the axial length of the blank 4, increasing the radial thickness, controlling the spinning wheel 6 to feed in the radial direction relative to the port of the rear end of the blank 4 and extruding the blank 4, and filling the thickened port of the rear end of the blank 4 along with the radial feeding of the spinning wheel 6 under the limiting action of the annular groove at the end part of the core mold 2 and the thrust action of the tail top 5 to form an annular inner reinforcing rib 71 protruding inwards in the radial direction so as to obtain a primary cylinder body;
step 4, as shown in fig. 2, the servo oil cylinder controls the limiting device 3 to move along the axial direction of the core mold and to be far away from the initial cylinder body, the rotating wheel 6 is controlled to feed axially relative to the initial cylinder body, the initial cylinder body flows along the outer wall of the core mold 2 while rotating along with the core mold 2, the axial length of the initial cylinder body is increased, and the radial thickness is reduced to complete the manufacture of the cylinder body, so that the cylinder body 7 with the inward reinforcing ribs 71 is obtained;
in the embodiment, a hollow inner cavity is arranged in the core mold 2, the core mold 2 is preheated by adopting a medium-frequency induction heating coil in the step 1, and the core mold 2 is kept at the temperature of 500-550 ℃ by filling red charcoal serving as a heating medium in the hollow inner cavity;
in the embodiment, in the step 2, a flame heating torch is used for heating the blank 4, and the temperature of the blank 4 is kept within the range of 630-680 ℃.
The above examples of the present invention are merely illustrative of the present invention and are not intended to limit the embodiments of the present invention. Variations and modifications in other variations will occur to those skilled in the art upon reading the foregoing description. Not all embodiments are exhaustive. All obvious changes and modifications of the present invention are within the scope of the present invention.