阅读说明：本技术 一种整体锻造三拐曲轴锻件制造方法 (Manufacturing method for integrally forging three-crank-pin crankshaft forging piece ) 是由 贾俊林 蒋伟斌 刘鹏宇 赵艳荣 雷玉臣 李庆斌 姚凤祥 杨云志 牛震 王英丽 于 2019-10-25 设计创作，主要内容包括：本发明公开了一种整体锻造三拐曲轴锻件制造方法,设计了一种新型锻造成型工艺,变形采用拔圆下料分段,锻出三个曲拐,用特制角度尺配合锻造,本发明的三拐曲轴的锻造方法包括：将钢锭装入加热炉中加热,使钢锭温度均匀、透烧；第一火钢锭压钳口、倒棱、去锭尾,返炉加热；第二火镦粗,采用上平、下V型砧拔长外圆,坯料返炉加热；第三火用三角刻将圆形坯料压刻,采用专用窄平砧,拔长轴径Ⅰ、Ⅱ、Ⅳ、Ⅵ、Ⅷ部位,坯料返炉加热；第四火采用上平砧、下宽平砧压Ⅶ部位成扁方,配合特制角度尺测量角度,Ⅴ部位压扁方,Ⅲ部位压扁方,精整各部位至成品尺寸。本发明通过改变锻造成形工艺、制作特殊工具,使曲轴锻件一次合格率达到95%以上,实现批量生产。(The invention discloses a method for manufacturing a forged piece by integrally forging a three-throw crankshaft, which designs a novel forging and forming process, adopts drawing circle blanking segmentation to deform, forges three throws, and uses a special angle ruler to cooperate with forging, and the method for forging the three-throw crankshaft comprises the following steps: putting the steel ingot into a heating furnace for heating, so that the steel ingot is uniform in temperature and is thoroughly burnt; pressing a jaw, chamfering, removing a tail of the ingot, and returning to the furnace for heating; second hot upsetting, drawing the excircle by adopting an upper flat V-shaped anvil and a lower V-shaped anvil, and returning the blank to the furnace for heating; thirdly, pressing and carving the round blank by using triangular carving, drawing the parts with the shaft diameters of I, II, IV, VI and VIII by using a special narrow flat anvil, and returning the blank to the furnace for heating; and fourthly, pressing the VII part into a flat square by adopting an upper flat anvil and a lower wide flat anvil, measuring an angle by matching with a special angle ruler, pressing the V part into the flat square, pressing the III part into the flat square, and finishing each part to the size of a finished product. The invention changes the forging forming process and the manufacturing special tools, so that the one-time qualification rate of the crankshaft forge piece reaches more than 95 percent, and the batch production is realized.)

1. The manufacturing method of the integrally forged piece of the three-crank crankshaft is characterized by comprising the following steps of: the method comprises the following specific steps:

1) putting the steel ingot into a gas heating furnace for heating, wherein the heating temperature is 1200-1220 ℃, and the heat preservation time is 8.5-9 hours;

2) a first fire: pressing a jaw, chamfering, removing a tail of the ingot, and returning to the furnace for heating;

3) and (3) second fire: upsetting is carried out by using an upsetting platform, upsetting is carried out to the required size, an upper flat V-shaped anvil and a lower V-shaped anvil are adopted, the upset steel ingot is drawn to the required size, the single reduction is more than or equal to 120mm, and the blank is returned to a furnace and heated for 1.5-2 hours;

4) and (3) third fire: pressing and carving the round blank by using triangular carving according to the process requirements, drawing long shaft diameter I, II, IV, VI and VIII parts by adopting a special narrow flat anvil designed according to the size of a finished crankshaft, returning the blank to a furnace, heating at the temperature of 1160-1180 ℃, and heating for 1.5-2 hours;

5) and (4) fourth fire: pressing the VII part into a flat square by adopting an upper flat anvil and a lower wide flat anvil; the manipulator rotates 60 degrees clockwise, the angle is measured by matching with a special angle ruler, and the V part is pressed into a flat square; the manipulator rotates 120 degrees anticlockwise, the angle is measured by matching with a special angle ruler, the part III is flattened, during the process, the three crank throws are required to be 120 degrees, and all parts are finished to the size of a finished product.

2. The method for manufacturing the integrally forged three-crank shaft piece according to claim 1, wherein the method comprises the following steps: the method adopts a specially-made angle ruler, the angle ruler is a right-angled triangle, three angles are respectively 30 degrees, 60 degrees and 90 degrees, the 60 degrees of the angle ruler is utilized, the angle ruler is used when the V part and the III part are flattened, after the VII part is flattened, the angle ruler is rotated by 60 degrees clockwise, the 60 degrees of the angle ruler is clung to the VII part which is flattened into the flat square on the left side, and the V part is flattened; and then, rotating 120 degrees anticlockwise, tightly pressing a 60-degree angle of the angle ruler at the right side to form a flat square VII part, and flattening a III part to enable the angles of the VII part, the V part and the III part to mutually form 120 degrees.

Technical Field

The invention relates to a method for manufacturing a three-crank-pin crankshaft forge piece through integral forging, and belongs to the technical field of forging.

Background

The crankshaft is a power transmission core component of the piston compressor, converts the rotary motion of the motor into reciprocating motion, bears the whole driving power of the piston compressor, and bears alternating composite actions of tension, compression, shearing, bending, torsion and the like, so that the crankshaft is a key component of the compressor, and the quality of a crankshaft forging plays a crucial role in the performance of a product. Because the three corners form 120 degrees, the forging forming difficulty is high, the size and the angle of a forged piece are not easy to be qualified, the forging allowance is large, the requirement on the technical level of an operator is high, rework or scrapping of the forged piece is often caused due to improper torsion angles, sometimes, the size of a blank of each corner part needs to be increased in order to solve the problem that the size of each crank angle is unqualified, a steel ingot with a larger tonnage needs to be selected, and the problems of high raw material cost and excessive processing amount of a subsequent process are caused. According to the characteristics of the structure of the crankshaft, the technical scheme of the production of the domestic three-throw crankshaft forging at present is to adopt steel ingots → heating, forging → normalizing and annealing, and the crankshaft forging mainly comprises the following two forming modes:

the method comprises the following steps: forging a steel ingot, namely, pressing a jaw by a first fire, removing an ingot bottom and upsetting; drawing out the blank to a flat square by a second fire; pressing and carving with a triangle (note: material is left at the I and II parts, and flat square is not pulled out); drawing the shaft diameters of the IV, VI and VIII parts to the required size by using a narrow flat anvil for the third fire; and the fourth fire hammer head presses the position V, the operating machine clamps the overflow end and twists the position VII clockwise for 60 degrees, the hammer head presses the position V, the operating machine clamps the water end and twists the position III counterclockwise for 60 degrees, the positions I and II are drawn out to the required size, and the rest parts are finished to the required size to obtain the finished product.

The forming method has the main problem that the fourth torsion procedure when the heating temperature is higher is easy to cause unqualified dimension and discard due to mutual superposition of deformation generated when the crankshaft bends and twists under the action of gravity. Secondly, when the operating machine is used for clamping the crank, pits are easy to clamp, a jaw hydraulic system is easy to damage, the damage to equipment is large, the operation difficulty is large, the technical requirement on operators is high, the forging allowance at the crank is large, and the qualification rate is low.

The second method comprises the steps of forging a steel ingot, pressing a jaw by a first fire, removing an ingot bottom and upsetting, drawing and growing into a regular hexagon by a second fire, blanking, sequentially pressing VI, VII and VIII parts into flat squares by a third fire, clockwise rotating an operating machine by 60 degrees, pressing IV and V parts into flat squares, anticlockwise rotating the operating machine by 120 degrees, pressing III parts into flat squares, drawing I and II shaft diameter parts, drawing IV, VI and VIII parts by a fourth fire by a narrow flat anvil, and finally finishing to a finished product size.

The invention aims to improve the primary qualification rate and quality of the crankshaft forge piece, reduce the forging allowance of the crank throw part of the crankshaft by changing the forging forming process, manufacturing special tools and changing the forging method, ensure that the primary qualification rate of the crankshaft reaches more than 95 percent, ensure that the metal streamline of the forge piece is better, reduce the forging operation difficulty of the three-throw crankshaft, improve the production environment and realize batch production. Looking up documents, the manufacturing method for integrally forging the three-crank crankshaft forge piece does not exist in the market at present.

Disclosure of Invention

In order to overcome the inconvenience of the prior art, the invention provides the method for manufacturing the three-crank crankshaft forge piece through integral forging, the method is simple to operate, the process weight of the forge piece blank is reduced, the manufacturing cost is reduced, and the batch production is realized.

The technical scheme adopted by the invention for solving the technical problems is as follows:

1) putting the steel ingot into a gas heating furnace for heating, wherein the heating temperature is 1200-1220 ℃, and the heat preservation time is 8.5-9 hours;

2) a first fire: pressing a jaw, chamfering and removing a tail of the ingot, and returning to a heating furnace for heating;

3) and (3) second fire: upsetting is carried out by using an upsetting platform, a steel ingot is upset to a required size, an upper flat V-shaped anvil and a lower V-shaped anvil are adopted for drawing the excircle size to the required size, the single rolling reduction is more than or equal to 120mm, and a blank returns to a heating furnace to be heated for 1.5-2 hours;

4) and (3) third fire: pressing and carving the round blank by using a triangular carving according to the process requirements, drawing long shaft diameters I, II, IV, VI and VIII by using a special narrow flat anvil, and returning the blank to a heating furnace for heating at the temperature of 1160-1180 ℃ for 1.5-2 hours;

5) and (4) fourth fire: pressing the VII part into a flat square by adopting an upper flat anvil and a lower wide flat anvil; the manipulator rotates 60 degrees clockwise, the angle is measured by matching with a special angle ruler, and the V part is pressed into a flat square; and rotating the manipulator by 120 degrees anticlockwise, measuring the angle by matching with a special angle ruler, flattening the part III to a square, and finishing each part to the finished product size.

The special angle ruler is a right-angled triangle, three angles are respectively 30 degrees, 60 degrees and 90 degrees, the angle ruler is used when the V part and the III part are flattened by utilizing the 60 degrees of the angle ruler, when the VII part is flattened, the angle ruler is rotated by 60 degrees clockwise, the 60 degrees of the angle ruler is clung to the VII part which is flattened into the flat square on the left side, and the V part is flattened; and then, rotating 120 degrees anticlockwise, tightly pressing a 60-degree angle of the angle ruler at the right side to form a flat square VII part, and flattening a III part to enable the angles of the VII part, the V part and the III part to mutually form 120 degrees.

The invention has the beneficial effects that: through the design of the forging deformation process, the process breakthrough is that the forging deformation adopts a direct circle-drawing blanking mode to replace the regular hexagonal blanking and the flat square blanking deformation, the forging forming mode is optimized from the forging regular hexagonal blanking and the flat square blanking deformation to the circle-drawing section blanking, and a special angle ruler is adopted to match with the forging forming, so that the one-time qualification rate of the three-throw crankshaft forging reaches more than 95 percent, the metal fiber streamline of the forging is better, the operation is simple, the process weight of the forging blank is reduced, the product quality requirement is met, the product manufacturing cost is reduced, the operation difficulty is reduced, the production environment is improved, and the batch production is realized.

Drawings

The invention is further described with reference to the following figures and detailed description.

FIG. 1 is a schematic illustration of a three-throw crankshaft of the present invention.

Fig. 2 is a side view of a three-throw crankshaft of the present invention.

Fig. 3 is a schematic diagram of a special angle ruler structure.

Fig. 4 is a schematic view of the use of a special angle ruler.

FIG. 5 is a flow chart of a forging deformation process.

Detailed Description

The invention is further described with reference to the following figures and detailed description.

Referring to fig. 1-4, taking 35CrMoA crankshaft machining as an example, the manufacturing method is as follows: forging by using a 30MN hydraulic press, wherein the weight of a steel ingot is 16.6 tons, and the specific process comprises the following steps: heating steel ingot → pressing jaw → chamfering → removing ingot bottom → upsetting → pulling long circular blank → triangular pressing carving → pressing shaft diameter → pressing three crank turns into flat square (the three crank turns mutually form 120 °) → finishing each part to finished size. The forging deformation process is shown in figure 5.

The method comprises the following specific steps:

and (3) putting the steel ingot into a gas heating furnace for heating, wherein the heating temperature is 1200-1220 ℃, and the heat preservation time is 8.5-9 hours, so that the steel ingot is uniform in temperature and is thoroughly burnt.

A first fire: the steel ingot pressing jaw forges the riser part of the steel ingot into a square or round shape with a certain length, so that the steel ingot is convenient to clamp during operation; chamfering, namely slightly chamfering the outer right angle or the inner right angle of the steel ingot to avoid stress concentration; removing the ingot tail, and returning to the heating furnace for heating.

And (3) second fire: upsetting is carried out by using an upsetting platform, the height of the steel ingot is reduced and the diameter of the steel ingot is increased by using pressure, upsetting is carried out to phi 1450mm, the upsetting ratio is larger than 1.9, an upper flat anvil and a lower V-shaped anvil are adopted, the outer circle size of the upset steel ingot is drawn to phi 770mm, the single reduction is larger than or equal to 120mm, a blank is returned to a heating furnace to be heated for 1.5-2 hours, the steel ingot deforms by upsetting, the forging ratio is increased, the drawing forging ratio of the process is required to reach more than 3.5, the defects of internal looseness and the like of the steel ingot can be effectively overcome, and the internal quality of a product is further improved.

And (3) third fire: and (3) pressing and carving the round blank by using a triangular carving according to the process requirements, and drawing the shaft diameter I part, the shaft diameter II part, the shaft diameter IV part, the shaft diameter VI part and the shaft diameter VIII part by using a special narrow flat anvil designed according to the size of a finished crankshaft. And returning the blank to the heating furnace for heating, wherein the heating temperature is 1160-1180 ℃, and the heating time is 1.5-2 hours.

And fourthly, applying pressure to VII parts by utilizing an upper flat anvil and a lower wide flat anvil to press the parts into flat squares, controlling the feeding amount of a blank in the forging process to be 0.7 ~ 0.9 times of the width of the anvil, ensuring that the widening amount of the width of the crank throw is large, and enabling the blank to generate plastic deformation to obtain a blank with certain mechanical property and size, clockwise rotating the operating machine by 60 degrees, measuring the angle by matching with a special angle ruler, flattening the V parts, anticlockwise rotating the operating machine by 120 degrees, measuring the angle by matching with a special angle ruler, flattening the III parts into the flat squares, paying attention to the fact that the three crank throws are required to be mutually 120 degrees, finishing each part to the finished size, and conveniently widening the crank throw parts by feeding amount which is 0.7-0.8 times of the wide anvil when flattening the square.

The special angle ruler is a right-angled triangle, three angles are respectively 30 degrees, 60 degrees and 90 degrees, the angle ruler is used when the V part and the III part are flattened by utilizing the 60 degrees of the angle ruler, when the VII part is flattened, the angle ruler is rotated by 60 degrees clockwise, the 60 degrees of the angle ruler is clung to the VII part which is flattened into the flat square on the left side, and the V part is flattened; and then, rotating 120 degrees anticlockwise, tightly pressing a 60-degree angle of the angle ruler at the right side to form a flat square VII part, and flattening a III part to enable the angles of the VII part, the V part and the III part to mutually form 120 degrees.

The forged blank forging is air-cooled to 600-650 ℃, and then is put into a heat treatment furnace for normalizing, wherein the normalizing temperature is 880 +/-10 ℃, the heat preservation time is 4-5 hours, the annealing temperature is 670 +/-10 ℃, the heat preservation time is 40 hours, crystal grains are refined, the structure is uniform, the forging stress is reduced, the forging hardness is reduced, the production efficiency is improved, the processing period is shortened, and the processing of subsequent procedures is facilitated.

The manufacturing method of the three-crank-shaft forge piece through integral forging is suitable for integral forging of the three-crank-shaft forge piece in a factory.

By designing the forging deformation process and utilizing a specially-made angle ruler to match with forging forming, the one-time qualified rate of the produced 35CrMoA three-throw crankshaft is up to more than 95% in inspection size, the metal fiber streamline is better, the operation is simple, the process weight of a forging blank is reduced, the manufacturing cost is reduced, and batch production is realized.