阅读说明：本技术 一种薄壁杯形件的旋转拉深成形方法 (Rotary deep-drawing forming method of thin-wall cup-shaped piece ) 是由 薛勇 樊洪智 张治民 王强 徐健 李旭斌 赵熹 李国俊 方敏 于 2020-06-29 设计创作，主要内容包括：本发明公开一种薄壁杯形件的旋转拉深成形方法,包括①下料,②均匀化热处理,③坯料和模具加热并保温,④坯料放入V形型腔中,冲头在上旋转液压机的带动下向下运动,先接触到坯料上表面,冲头匀速向下运动,使得接触面金属陆续流入冲头端面的型槽内,与冲头合为一体,冲头带动坯料开始扭转和下压,同时坯料外围部分金属陆续受挤压流入到多道次圆弧凸面台,首先外围金属的一侧接触到第一道次圆弧凸面台,与另一侧形成高度差,然后使得在接下来向下的扭挤变形过程中,两边形成速度差,最后挤入长方形型腔,直至运动到规定位置。本案能改善钢铁材料的成形性、提高成形构件的综合力学性能、克服传统变薄拉深成形的薄壁杯形构件各向强度差异大的缺点。(The invention discloses a rotary deep-drawing forming method of a thin-wall cup-shaped piece, which comprises the steps of blanking, homogenizing heat treatment, heating and heat preservation of a blank and a die, placing the blank into a V-shaped cavity, driving a punch to move downwards under the driving of an upper rotary hydraulic press, firstly contacting the upper surface of the blank, enabling a punch to move downwards at a constant speed, enabling a contact surface metal to continuously flow into a groove on the end surface of the punch and be integrated with the punch, driving the blank to start torsion and pressing by the punch, simultaneously enabling a part of the metal on the periphery of the blank to continuously flow into a multi-pass arc convex surface table by extrusion, firstly contacting one side of the peripheral metal with a first pass arc convex surface table to form a height difference with the other side, then enabling two sides to form a speed difference in the subsequent downward twisting and extrusion deformation process, and finally extruding the peripheral metal into a rectangular cavity until the thin-wall cup. The forming method can improve the formability of steel materials, improve the comprehensive mechanical property of formed components, and overcome the defect that the strength difference of the traditional thin-wall cup-shaped components formed by thinning and drawing is large.)

1. A rotary deep drawing forming method of a thin-wall cup-shaped piece is characterized in that: comprises the following steps:

(1) blanking a blank;

(2) carrying out homogenization heat treatment, and preparing a blank for forging and forming;

(3) preparation before forming: heating the blank subjected to the homogenization heat treatment to a forming temperature, preserving heat, and preheating a rotary deep-drawing forming die to the forming temperature of more than 30 ℃, wherein the die comprises a punch, a forming female die and a lower template which are connected with an upper rotary hydraulic press, the punch is coaxially arranged above the forming female die, and the forming female die is connected to the lower template; the forming female die is coaxially provided with a composite cavity for placing a blank, the end surface of the punch, which is in contact with the blank, is a conical boss die surface, and the conical boss die surface is provided with a groove; the composite cavity is formed by compounding a V-shaped cavity at the upper part and a rectangular cavity at the lower part, multiple passes of arc convex surface platforms which are contacted with a blank are respectively arranged on two sides of the joint of the V-shaped cavity and the rectangular cavity, and the multiple passes of arc convex surface platforms are composed of a plurality of convex surface platforms which are sequentially arranged from the top to the bottom and have sequentially increased arc radiuses, so that the inner diameter of the cavity at the position of the multiple passes of arc convex surface platforms is sequentially reduced from the top to the bottom; the number of the arc convex surface platforms on one side is one more than that on the other side, so that the forming female die is an asymmetric annular revolving body, the more arc convex surface platforms are arranged at the highest position of the side to form a first-pass arc convex surface platform, the arc convex surface platforms on the other two sides are mutually symmetrical, and the preheated and heat-insulated die is arranged on a hydraulic machine; uniformly spraying a water-based graphite lubricant on a composite cavity of the punch and the forming female die, putting the heated blank into a V-shaped cavity of the composite cavity, and waiting for extrusion deformation;

(4) in the forming process: the punch moves downwards under the driving of the upper rotating hydraulic machine, and the upper rotating hydraulic machine does not rotate at the moment and only moves downwards; the punch moves downwards along with the punch, the punch contacts with the upper surface of a blank to be extruded in the V-shaped cavity firstly, the punch moves downwards at a constant speed, so that metal on a contact surface flows into a groove on the end surface of the punch sequentially and is integrated with the punch, the upper rotating hydraulic machine drives the punch to rotate, and the punch drives the blank to rotate; the punch rotates at a constant speed, presses down at a constant speed, simultaneously, metal on the periphery of the blank is extruded to flow into the multi-pass arc convex surface table, one side of the peripheral metal is contacted with the first pass arc convex surface table, a height difference is formed between the peripheral metal and the other side of the peripheral metal, then a speed difference is formed between the two sides of the peripheral metal in the process of downward twisting and extruding deformation, and finally the peripheral metal is extruded into the rectangular cavity until the upper rotating hydraulic machine moves downwards to a specified position;

(5) and (4) finishing forming: and after the upper rotating hydraulic machine stops rotating and moves downwards, the upper rotating hydraulic machine reversely rises until the stroke of the upper rotating hydraulic machine is reset, and a working cycle is completed.

2. The rotary deep drawing method of a thin-walled cup-shaped member according to claim 1, wherein: the die further comprises an ejection mechanism for ejecting the blank upwardly out of the forming groove after step (5).

Technical Field

The invention belongs to the technical field of metal plastic processing technology and forming, in particular to a technology for drawing and forming steel materials, and particularly relates to a rotary drawing and forming method of a thin-wall cup-shaped piece.

Background

With the rapid development in the fields of aerospace, national defense and military industry, transportation and the like, the adoption of a high-strength and high-toughness light member to realize light weight is urgently needed, wherein a cup-shaped member is one of the most representative structural forms. The drawing is essentially the process of gradually transferring the flange part material of the blank to the cylinder wall, in the transferring process, the flange part material generates tensile stress in the radial direction due to the action of drawing force, the flange part material generates extrusion action due to the gradual reduction of the diameter of the flange part, and generates compressive stress in the tangential direction, and under the combined action of the tensile stress and the compressive stress, the metal of the flange part generates plastic deformation, radial extension, tangential compression and size reduction, and is continuously drawn into the opening of the female die to be changed into a cylindrical hollow part. Ironing is a process for obtaining a cup-shaped member by changing the wall thickness of a hollow cylindrical cup-shaped member having a bottom wall, and there are many processes for ironing a semi-finished blank in the prior art. The thinning and drawing process is widely applied to the fields of aerospace, transportation, national defense and military industry and the like. The difference in the strength in each direction of a cup-shaped member formed by conventional ironing is more remarkable, and a press-and-twist deformation process is one of them. The press-twist deformation process is originated from the improvement of the flat anvil upsetting process defect of the soviet union scholars at the end of the 50 th century, namely the axial linear motion of the upper flat anvil is compounded with the rotation motion around the axial direction, the harmful friction is changed into the beneficial shearing action, and the adverse effect caused by the friction during the upsetting deformation is solved. The high-pressure torsion applied to the current practical production is a special case of a pressure-torsion deformation process, and the preparation process comprises the following steps: the deformation body bears the pressure action of about several thousand megapascals between the flat pressing head and the female die, and meanwhile, the flat pressing head or the female die rotates, and the deformation body is also subjected to strong shearing force action, so that great plastic deformation is obtained. The violent plastic deformation generated by the high-pressure and torsion combined loading mode can effectively refine the material grains to a micro-nano order, so that the material without loose holes is obtained, and the adverse effect of residual holes on the material is avoided. At present, forming hydraulic machines with upper/lower working tables rotating are successfully developed at home and abroad, but the pressing and twisting forming process of the hydraulic machines is usually used for preparing round flat and thin workpieces with smaller size, can not form parts with certain shape requirements, and has certain limitation in industrial production.

Disclosure of Invention

The invention mainly aims to provide a rotary drawing forming method of a thin-wall cup-shaped member aiming at the forming of the thin-wall cup-shaped member, which can effectively improve the formability of steel materials, improve the comprehensive mechanical property of the formed member and overcome the defect of large strength difference of the thin-wall cup-shaped member formed by traditional thinning drawing.

In order to achieve the above purpose, the solution of the invention is: a rotary deep drawing forming method of a thin-wall cup-shaped piece comprises the following steps:

(1) blanking a blank;

(2) carrying out homogenization heat treatment, and preparing a blank for forging and forming;

(3) preparation before forming: heating the blank subjected to the homogenization heat treatment to a forming temperature, preserving heat, and preheating a rotary deep-drawing forming die to the forming temperature of more than 30 ℃, wherein the rotary deep-drawing forming die comprises a punch, a forming female die and a lower template which are connected with an upper rotary hydraulic press, the punch is coaxially arranged above the forming female die, and the forming female die is connected to the lower template; the forming female die is coaxially provided with a composite cavity for placing a blank, the end surface of the punch, which is in contact with the blank, is a conical boss die surface, and the conical boss die surface is provided with a groove; the composite cavity is formed by compounding a V-shaped cavity at the upper part and a rectangular cavity at the lower part, multiple passes of arc convex surface platforms which are contacted with a blank are respectively arranged on two sides of the joint of the V-shaped cavity and the rectangular cavity, and the multiple passes of arc convex surface platforms are composed of a plurality of convex surface platforms which are sequentially arranged from the top to the bottom and have sequentially increased arc radiuses, so that the inner diameter of the cavity at the position of the multiple passes of arc convex surface platforms is sequentially reduced from the top to the bottom; the number of the arc convex surface platforms on one side is one more than that on the other side, so that the forming female die is an asymmetric annular revolving body, the more arc convex surface platforms are arranged at the highest position of the side to form a first-pass arc convex surface platform, the arc convex surface platforms on the other two sides are mutually symmetrical, and the preheated and heat-insulated die is arranged on a hydraulic machine; uniformly spraying a water-based graphite lubricant on a composite cavity of the punch and the forming female die, putting the heated blank into a V-shaped cavity of the composite cavity, and waiting for extrusion deformation;

(4) in the forming process: the punch moves downwards under the driving of the upper rotating hydraulic machine, and the upper rotating hydraulic machine does not rotate at the moment and only moves downwards; the punch moves downwards along with the punch, the punch contacts with the upper surface of a blank to be extruded in the V-shaped cavity firstly, the punch moves downwards at a constant speed, so that metal on a contact surface flows into a groove on the end surface of the punch sequentially and is integrated with the punch, the upper rotating hydraulic machine drives the punch to rotate, and the punch drives the blank to rotate; the punch rotates at a constant speed, presses down at a constant speed, simultaneously, metal on the periphery of the blank is extruded to flow into the multi-pass arc convex surface table, one side of the peripheral metal is contacted with the first pass arc convex surface table, a height difference is formed between the peripheral metal and the other side of the peripheral metal, then a speed difference is formed between the two sides of the peripheral metal in the process of downward twisting and extruding deformation, and finally the peripheral metal is extruded into the rectangular cavity until the upper rotating hydraulic machine moves downwards to a specified position;

(5) and (4) finishing forming: and after the upper rotating hydraulic machine stops rotating and moves downwards, the upper rotating hydraulic machine reversely rises until the stroke of the upper rotating hydraulic machine is reset, and a working cycle is completed.

Preferably, the die further comprises an ejection mechanism for ejecting the blank upwardly out of the forming recess after step (5).

After the scheme is adopted, the invention has the beneficial effects that:

the end face of the punch head, which is contacted with the blank, adopts a conical boss die face, so that the metal flow is facilitated during rotary extrusion, and the forming uniformity is improved. The upper rotating hydraulic press controls the punch to rotate and feed up and down, the rotating punch changes passive friction into active friction promoting metal flow, and torque action is exerted on the blank through active friction force, so that the blank is subjected to larger torque force, the blank is forced to generate compression deformation in the height direction and shear deformation on the cross section in the pressing and twisting process, the harmful effect of friction in extrusion forming is eliminated, forming force is reduced, hydrostatic pressure of metal below the punch is increased, high-temperature deformation is added, and plasticity of the metal is improved. The forming concave die is an asymmetric annular revolving body, the arc convex surface table with gradually changed diameter is arranged below the arc convex surface table at the first pass, and the height difference is formed, so that the asymmetric deformation revolving body introduces shear deformation in the deformation process, the shear deformation is introduced in the forming process, larger strain is accumulated in the deformation process, the grain refinement can be effectively realized, and the material texture is improved. The invention obtains rapid multi-pass continuous deformation in the subsequent two-pass and three-pass deformation processes, so that the deformation is more uniform, the formability of steel materials is improved, and the defect of large strength difference in all directions of the traditional thin-wall cup-shaped member formed by thinning and drawing is overcome.

Drawings

FIG. 1 is a schematic view of the blank of one embodiment of the present invention in an operating condition when the blank is to be extruded;

FIG. 2 is a schematic view of the blank of one embodiment of the present invention in an operating condition during extrusion;

FIG. 3 is a schematic view of the blank of one embodiment of the present invention in an operating condition after extrusion is completed;

FIG. 4 is a cross-sectional view of a straight-grooved structured boss die face punch according to one embodiment of the present invention;

FIG. 5 is a bottom view of a straight slot configuration boss die face punch according to one embodiment of the present invention;

FIG. 6 is a bottom view of a cross-slot configuration boss die face punch according to one embodiment of the present invention;

FIG. 7 is a bottom view of a punch with a hexagonal groove configuration and a raised boss face according to an embodiment of the present invention;

FIG. 8 is a bottom view of a forming die according to one embodiment of the present invention;

FIG. 9 is a cross-sectional view of a forming die according to one embodiment of the present invention;

FIG. 10 is a cross-sectional view of a blank according to one embodiment of the invention;

fig. 11 is an enlarged view at B in fig. 9.

Description of reference numerals:

1. a punch; 2. a blank; 3. forming a female die; 31. a composite cavity; 311. a V-shaped cavity; 312. a rectangular cavity; 4. positioning pins; 5. a fastener; 6. a lower template; 61. a through hole; 7. a straight-shaped groove; 8. an outer hexagonal groove; 9. a cross-shaped groove; 10. a multi-pass arc convex platform; 101. a first-pass arc convex surface platform; 102. a second pass circular arc convex platform; 103. a third secondary arc convex surface platform; 104. a fourth pass of arc convex platform; 105. and (4) a groove.

Detailed Description

The invention is described in detail below with reference to the accompanying drawings and specific embodiments.

The invention provides a rotary deep-drawing forming die for a thin-wall cup-shaped piece, which comprises a punch 1, a forming female die 3, a lower template 6 and a lower template (not shown in the figure) which are connected with an upper rotary hydraulic machine (not shown in the figure), wherein the punch 1 is coaxially arranged above the forming female die 3, the lower template is arranged between the forming female die 3 and the lower template 6 and plays a role in buffering, and the forming female die 3 and the lower template are connected with the lower template 6 through a fastener 5 and a positioning pin 4.

The forming female die 3 is coaxially provided with a composite cavity 31 for placing the blank 2, the composite cavity 31 is formed by compounding a V-shaped cavity 311 at the upper part and a rectangular cavity 312 at the lower part, the V-shaped cavity 311 is connected with the rectangular cavity 312, the diameter of the blank 2 is larger than that of the rectangular cavity 312, and the rectangular cavity 312 is provided with a certain draft angle; the two sides of the joint of the V-shaped cavity 311 and the rectangular cavity 312 are respectively provided with a multi-pass arc convex surface platform 10 which is contacted with the blank 2, and with reference to fig. 9 and 11, the multi-pass arc convex surface platform 10 consists of a plurality of convex surface platforms which are sequentially arranged from the top to the bottom and the arc radiuses of which are sequentially increased, so that the inner diameters of the cavities of the forming grooves at the positions of the multi-pass arc convex surface platforms 10 are sequentially reduced from the top to the bottom; the number of the arc convex surface platforms on one side is one more than that of the arc convex surface platforms on the other side, so that the forming female die 3 is an asymmetric annular revolving body, the more arc convex surface platforms are arranged at the highest part of the side to form a first-pass arc convex surface platform 101, the highest part and the lowest part of the first-pass arc convex surface platform 101, which are in contact with the blank 2, have a certain height difference H, the arc convex surface platforms on the other two sides (respectively a second-pass arc convex surface platform 102, a third-pass arc convex surface platform 103 and a fourth-pass arc convex surface platform 104) are mutually symmetric, grooves 105 are formed among the arc convex surface platforms, and the blank 2 flows from the last arc convex surface platform to the next arc convex surface platform and undergoes an expansion process of filling the grooves 105 for one time, so that the blank 2 can be repeatedly reduced in diameter and then expanded during the whole multi-pass arc convex surface platform 10.

The blank 2 is placed between the punch 1 and the forming female die 3, the punch 1 is a rotary part, and the end surface of the punch 1, which is in contact with the blank 2, is a conical boss die surface, as shown in fig. 4.

As shown in fig. 5-6, a straight-line-shaped groove 7, a cross-shaped groove 9 or an outer hexagonal-shaped groove 8 is formed in the die surface of the conical boss, the straight-line-shaped groove 7 is a symmetrical structure in which the grooves are distributed in a straight line shape, the cross-shaped groove 9 is a symmetrical structure in which the grooves are distributed in a cross-shape, and the outer hexagonal-shaped groove 8 is a symmetrical structure in which the grooves are distributed in an outer hexagonal shape.

An embodiment:

the boss structure of the conical boss die surface is designed into a straight-line-shaped groove 7, and the blank 2 adopts a No. 45 steel cup-shaped piece with the inner diameter of 50mm and the outer diameter of 62mm as a specific example, so that the thin-wall cup-shaped piece rotary extrusion forming method is described in detail.