RU2412777C1 - Method of forging reactor bottom (cover) from cake - Google Patents

Abstract

FIELD: process engineering.

SUBSTANCE: invention relates to metal forming and may be used in power engineering, chemical, metallurgical and other industries for production housings of reactors and steam-gas-generators. Proposed method comprises cake upsetting and piercing. Prior to upsetting, the cake is pierced to crop its bottom part. After upsetting, ingot is partly pierced by solid puncheon from its bottom part. Note here that barrel billet is produced with bottom thickness equal to that of forging. Solid forging of barrel wall is performed to upsetting of 50% to thickness equal to that of forging. Then, barrel wall is expanded to taper and billet if molded to final sizes of forging.

EFFECT: optimum physical and mechanical properties of forging.

4 cl, 4 dwg

Description

The invention relates to the processing of metals by pressure and can be used in the energy, chemical, metallurgical and other industries in the manufacture of reactor vessels and steam and gas generators.

A known method of manufacturing the bottom (cover) of the reactor, which includes forming a round plate in a stamp on the final forgings (see, for example, E.N. Moshnin. Technology of stamping large parts. - M .: Engineering. "240 p.).

The disadvantage of this method is that with this manufacture the optimal level of physical and mechanical properties (fracture toughness) and the structure of the processed material in the direction of the maximum working stresses in the finished part are not achieved.

A known method of manufacturing a forgings of the bottom (cover) of the reactor from an ingot, including draft, piercing, rolling the workpiece into a ring, cutting the ring along the generatrix of the cylinder and its reamer into a flat workpiece, cutting from a flat workpiece of a round workpiece and molding the latter in a stamp on the final dimensions of the forgings ( see Romashko N.I., Tokarev A.G., Kobelev O.A. Technology of manufacturing large-sized thick plates and drawing seamless bottoms of large diameter // Forging and stamping - Metal forming. - 2008. - No. 7. - S.22-26).

The disadvantages of the method are the high complexity of manufacturing and significant anisotropy of the mechanical properties in the flat initial (for stamping) billet, which, when molded to the final forgings, does not allow for the coincidence of the maximum (longitudinal) properties of the reamer blank with the direction of maximum working stresses (radial) in the part.

The technical result, the achievement of which the claimed solution is directed, is to ensure the optimal level of physico-mechanical properties (including fracture toughness) in the forging.

The specified technical result is achieved by the fact that in the method of manufacturing a forgings of the type bottom or reactor cover from an ingot, including the draft and piercing of the ingot, while the ingot is pulled and the bottom part is removed before the draft, after the draft is completed, the billet is incompletely pierced with continuous piercing from the bottom parts of the ingot with the formation of a glass blank with a bottom thickness equal to the thickness of the forging, broaches on the mandrel of the wall of the glass with a degree of deformation of at least 50% to a thickness equal to the thickness of the forging, with subsequent distribution her glass wall on the cone and forming in the die to the final dimensions.

The method produces a draft of the workpiece with a pin from the profitable part of the ingot.

In the method, the draft of the workpiece with the pin is carried out on the lower spherically concave plate with a central hole.

In the method, after broaching on the mandrel of the glass wall, the trunnion is removed from the profitable part of the ingot.

Draft in this method is an auxiliary operation, which serves to reduce the height of the workpiece for firmware. Because the firmware of high workpieces (with a height to diameter ratio of more than 1) on universal forging presses is associated with great technical difficulties, and sometimes it is simply impossible due to insufficient open press height.

Cutting (gas cutting) into the waste of the bottom of the ingot allows you to remove the seed and part of the body of the ingot corresponding to the zone of negative segregation of the alloy.

Incomplete flashing of the workpiece with continuous flashing on a plate with a central hole allows you to remove the defective profitable part of the ingot into waste and get a glass blank with a bottom, the thickness of which is equal to the thickness of the forging of the bottom.

With a broach on a mandrel with a degree of deformation of at least 50%, the thickness of the wall of the glass is brought to the thickness of the forgings of the bottom and the axis of the first-order dendrites of the ingot is oriented along the generatrix of the glass.

Precipitation of the workpiece with a pin from the profitable part of the ingot on a plate with a central hole and a spherical concavity ensures rigorous alignment of the workpiece in a vertical position and sufficient accuracy of the firmware. The spherical concavity of the plate during upsetting and piercing allows you to give the bottom of the glass blank an oval shape close to the shape of the finished bottom.

Subsequent distribution of the glass blank in the die, first with a conical and then spherical punch, allows forging the bottom (cover) of the reactor with a radially directed fiber in the entire volume of the latter and coinciding with the direction of action of the maximum working stresses in the product.

The method is as follows.

First, the ingot is heated to the forging temperature in the furnace and served under the press for forging. From the profit of the ingot, a pin is forged to capture the manipulator. Then, capturing the ingot by the manipulator, carry out the pulling of his body in strikers. Marking the workpiece and cutting into the waste of the bottom of the ingot, after which the workpiece is placed in a furnace for heating.

In the second discharge, an ingot with a trunnion is upset on the lower sedimentary plate with a hole, after which a continuous conical piercing produces incomplete piercing of the workpiece to a thickness of the bottom of the glass, equal to the thickness of the forging of the bottom (cover), and is again fed to the furnace for heating.

In the third run, first extend the glass wall on the mandrel to a thickness equal to the thickness of the forgings of the bottom (cover) with a degree of deformation of not less than 50%, and then trunnion is chopped and its remains cleaned “hot” at the bottom of the glass. The resulting billet is placed in a furnace for heating.

After heating, the glass blank is fed into the press die and, first, the glass wall is distributed into a cone with a conical punch, and then stamped into the final dimensions of the bottom (cover) of the reactor with a spherical punch.

The drawings show the main transitions for the manufacture of the bottom (cover) of the reactor.

Figure 1 - forging of the trunnion from the profit of the ingot, broaching his body with an uk 4-11, cutting the bottom of the ingot.

Figure 2 - draft and incomplete firmware blanks with a pin on the bottom plate with a hole.

Figure 3 - broach on the mandrel of the wall of the glass and the cabin of the axle.

Figure 4 - distribution of the billet of the glass on the cone and stamping on the final dimensions of the bottom (cover).

As an example, the manufacture of the bottom (cover) of the reactor vessel from an ingot weighing 235 tons of 15Kh2NMFAA steel is presented.

The ingot from the steel mill is transferred to the forging shop and placed in the furnace for heating. After heating and holding at a temperature of 1250 ° C, the ingot was transferred to a press of 120 MN. At first, a trunnion with a diameter of 1100 mm was forged from the profitable part of the ingot and, having grabbed into the pliers of the manipulator, they extended the body of the ingot in combined strikers to a diameter of 2360 mm, marking the workpiece with a length of 4800 mm and chopped off the bottom and part of the profitable part of the ingot with the trunnion to waste.

The obtained measured billet was again heated to a temperature of 1250 ° C and precipitated on flat plates to a diameter of 3400 mm. After that, the lower flat plate was changed to a plate with a hole and a solid piercing with a diameter of 900 mm, incomplete piercing of the preform was carried out with extrusion of a process into the hole of the plate with a part of the sub-profitable zone of positive segregation of the ingot and the formation of a glass preform with a bottom 500 mm thick and a wall - 1250 mm. After removing the firmware, the cup blank was transferred to the oven.

Again, the billet was heated at 1200 ° C and, grabbing the billet by the process in the bottom of the glass, the manipulator in the combined strikers on the mandrel extended the glass wall to a thickness of 500 mm. After that, the process was cut and placed in a furnace for heating.

Heating for distribution and stamping was carried out to 1070 ° C and after heating the billet, a lower spherical stamp and an upper conical stamp were installed on the press. The blank was installed in the lower die and the cup wall was distributed into a cone, after which the conical punch was replaced by a spherical one and the bottom was finally stamped with an outer diameter of 4750 mm and an inner 3750 mm.

The proposed manufacturing method allows to obtain a bottom blank not only with a given size and shape, but with a directed fiber in the forging, oriented in the direction of maximum stresses in the part and providing maximum mechanical properties in this direction. And therefore, this technical solution improves the reliability and durability of the product.

Claims (4)

1. A method of manufacturing a forgings of the type of bottom or reactor cover from an ingot, including sludge and piercing of the ingot, characterized in that the ingot is pulled and removed to the bottom of the ingot prior to upsetting; after the precipitation, the billet is incompletely pierced with continuous piercing from the bottom of the ingot to form cup blanks with a bottom having a thickness equal to the forging thickness, a broach on the mandrel of the cup wall with a degree of deformation of at least 50% to a thickness equal to the forging thickness, dispensing the cup wall into a cone and forming the blank in the stamp on the final forging dimensions. 2. The method according to claim 1, characterized in that they produce a draft of the workpiece with a pin from the profitable part of the ingot. 3. The method according to claim 1, characterized in that the draft of the workpiece with a pin is carried out on the lower spherically concave plate with a Central hole. 4. The method according to claim 2, characterized in that after broaching on the mandrel of the wall of the glass, the trunnion is removed from the profitable part of the ingot.

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