One-heating-number forging forming process and die for piston rod forge piece with boss

Abstract

The invention provides a one-heating-number forging forming process for a piston rod forge piece with a boss, which comprises the following steps of: step 1, upsetting: selecting a 30CrMnSiA bar with the specification of phi 100 * 335, charging at the temperature, heating a cold material at the temperature of 1,160 + / -10 DEG C, preserving heat for 40-100 minutes, accurately placing a blank in a lower forming die of a forming die during upsetting, and positioning through 8MN fast forging and first hammer upsetting; upsetting the second hammer blank until H is approximately equal to 260 + / -10; then an upper forming die, a third hammer and a fourth hammer of the forming die are used for hitting and leaning, and a positioning groove is noticed in the downward pressing process; and secondly, the lower forming die is turned over by 180 degrees, the forge piece is taken out, then the upset forge piece is placed on a hammer anvil to be drawn out, drawing-out is conducted through an 8MN fast forging machine, and the diameter of a rod part is drawn out from 100 + / -5 to 80 + / -5. According to the method, the forging process is optimized, deformation and temperature parameters are accurately controlled, and the special forging die is combined, so that efficient and high-quality production of the piston rod forge piece with the boss is achieved.

Description

Technical Field

[0001] The invention relates to the technical field of metal processing, in particular to a one-time forging process for a piston rod forging with a boss and a die thereof. Background Art

[0002] The piston rod forging of the present invention is composed of three parts: a long handle, a square head and a circular positioning boss on the head. Figure 1 As shown in the figure, in the traditional piston rod forging design process, the square table cross-section is smaller than the head cross-section, and the free forging is used for drawing. The drawing material is too small, and the square table is easy to get stuck and cannot be pulled out. The forging process is as follows Figure 2 As shown; therefore, the free forging design is usually composed of a long-shank rod and a square head, and the round square table is wrapped by the square head. Since the cross-section of the square table is smaller than that of the head, a large part of the raw materials is wasted. Secondly, in the subsequent part machining process, the positioning square table must be milled out, and the cutting amount is large; using the die forging design, the blank needs to be placed vertically. Since the rod specification is φ80 and the bar diameter is ≤80, the bar is inserted into the die, and the length of the part exceeding the die is ≥3 of the upsetting ratio of the bar diameter, which makes the blank easy to bend and deform during the die forging process, affecting the forging quality; using the free forging + die forging design, it is necessary to increase the number of fires, increase labor costs and gas costs, and reduce production efficiency. Summary of the invention

[0003] The present invention provides a one-time forging process for a piston rod forging with a boss and a die thereof, which realizes efficient and high-quality production of the piston rod forging with a boss by optimizing the forging process, accurately controlling the deformation amount and temperature parameters, and combining a special forging die.

[0004] The technical solution of the present invention is as follows:

[0005] The present invention provides a single-fire forging process for a piston rod forging with a boss, comprising the following steps:

[0006] Step 1: Upsetting: Select φ100×335 30CrMnSiA bar, put it into warm charging furnace, heat and hold the cold material at 1160±10℃ for 40 to 100 minutes (Note 1: When heating, the holding time of cold material is calculated as 0.4min / mm~1.1min / mm, and the holding time of hot material is calculated as 0.2min / mm~0.8±0.1min / mm, and hot material refers to raw materials with temperature ≥750℃). When upsetting, place the blank accurately in the lower mold of the mold, and use 8MN fast forging to upset and position the blank with the first hammer; upset the blank to H≈260±10 with the second hammer; then use the upper mold of the mold to hit with the third and fourth hammers, and pay attention to the positioning groove during the pressing process;

[0007] Step 2: Turn the lower die 180°, take out the forging, and then put the upset forging on the hammer anvil for stretching. Use an 8MN fast forging machine to stretch the rod from a diameter of φ100±5 to a diameter of φ80±5.

[0008] Preferably, in the above-mentioned upsetting step, the tire mold includes upper and lower tire molds, the rod and the direction head are placed on the lower tire mold, the positioning boss is placed on the upper tire mold, and the upper tire mold is wrapped by the lower tire mold; a method similar to closed extrusion of die forging is adopted to squeeze and fill the positioning boss. At the same time, the rod of the lower tire mold is designed to be φ100, avoiding the use of φ80 for blanking, resulting in an upsetting ratio ≥3 during the upsetting process, and the blank is bent and deformed to produce forging defects.

[0009] Preferably, in the above-mentioned drawing step, the rod is drawn after upsetting by die forging. The upsetting and drawing can be combined, and the production can be completed using an 8MN fast forging machine. The rod can be drawn to φ80 required by the drawing after die forging, avoiding the need to replace the free forging equipment when drawing the rod after die forging, or a forging scheme of blank making + die forging. The two types of equipment, die forging and free forging, lead to multiple forming steps, while die forging upsetting + drawing can be formed in one step, saving labor costs and gas costs and improving production efficiency.

[0010] The invention also provides a die for single-fire forging of piston rod forgings with bosses, comprising an upper die and a lower die, wherein the lower die has a rod draft of 1-3° and a diameter of φ100 (0, +5) mm, and an upper die has a draft of 5-7°.

[0011] Preferably, both the upper and lower molds in the mold are designed with material blocking platforms with a width of 10±2mm and a height of 5±1mm, and a direction along the length contour of the forging head on the parting surface, so as to control the flow direction of the blank during the forging forming process and avoid defects such as the inability to fill the two sides of the head length direction and the positioning boss.

[0012] Preferably, the upper die is designed to be circular and is covered by the lower die to avoid the forging positioning boss and the rod being out of center during the forging process.

[0013] Preferably, the upper tire mold is provided with a positioning boss, the size of which is φ50±10mm×30±10mm. The lower tire mold is provided with a positioning groove, the width of which is 20±5mm, the depth is 15(0,+10)mm, and the chamfer R5-R10 can be achieved. The positioning boss and the positioning groove correspond to each other to ensure the positioning of the material blocking platform and the upper and lower tire molds.

[0014] The beneficial effects of the present invention are:

[0015] 1. The shape of the die and forgings has been optimized, the problem of one-time forging of the forging positioning boss has been solved, and the difficulty of forging production has been reduced.

[0016] 2. Through die forging upsetting + drawing, the loss of raw materials is significantly reduced, one-fire forming is achieved, and multi-fire forging is avoided.

[0017] 3. It combines the advantages of die forging and free forging, improves product quality and qualification rate, reduces production times, and ensures the quality of mass-produced forgings. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 It is a piston rod forging diagram involved in the present invention;

[0019] Figure 2 It is the free forging and drawing process in the prior art;

[0020] Figure 3 It is the overall cross-sectional view of the tire mold;

[0021] Figure 4 is a schematic diagram of the upper fetal membrane;

[0022] Figure 5 It is a schematic diagram of the lower tire mold;

[0023] Figure 6 Comparison of forging methods before and after optimization;

[0024] Figure 7 It is a comparison between open and closed die forging methods;

[0025] Figure 8 It is the comparison of the resistance platform and positioning slot before and after optimization;

[0026] Fig. 9 It is the comparison of the resistance platform and positioning boss before and after optimization;

[0027] Fig.10 This is a before and after comparison of the boss design. DETAILED DESCRIPTION

[0028] The present invention will be further described below in conjunction with the accompanying drawings. The following embodiments are only used to more clearly illustrate the technical solution of the present invention, and cannot be used to limit the protection scope of the present invention.

[0029] Embodiment 1:

[0030] The present invention provides a single-fire forging process for a piston rod forging with a boss, comprising the following steps:

[0031] Step 1: Upsetting: Select φ100×335 30CrMnSiA bar, put it into warm charging furnace, heat and hold the cold material at 1160±10℃ for 40 to 100 minutes (Note 1: When heating, the holding time of cold material is calculated as 0.4min / mm~1.1min / mm, and the holding time of hot material is calculated as 0.2min / mm~0.8±0.1min / mm, and hot material refers to raw materials with temperature ≥750℃). When upsetting, place the blank accurately in the lower mold of the mold, and use 8MN fast forging to upset and position the blank with the first hammer; upset the blank to H≈260±10 with the second hammer; then use the upper mold of the mold to hit with the third and fourth hammers, and pay attention to the positioning groove during the pressing process;

[0032] Step 2: Turn the lower die 180°, take out the forging, and then put the upset forging on the hammer anvil for stretching. Use an 8MN fast forging machine to stretch the rod from a diameter of φ100±5 to a diameter of φ80±5.

[0033] Preferably, in the above-mentioned upsetting step, the tire mold includes upper and lower tire molds, the rod and the direction head are placed on the lower tire mold, the positioning boss is placed on the upper tire mold, and the upper tire mold is wrapped by the lower tire mold; a method similar to closed extrusion of die forging is adopted to squeeze and fill the positioning boss. At the same time, the rod of the lower tire mold is designed to be φ100, avoiding the use of φ80 for blanking, resulting in an upsetting ratio ≥3 during the upsetting process, and the blank is bent and deformed to produce forging defects.

[0034] Preferably, in the above-mentioned drawing step, the rod is drawn after upsetting by die forging. The upsetting and drawing can be combined, and the production can be completed using an 8MN fast forging machine. The rod can be drawn to φ80 required by the drawing after die forging, avoiding the need to replace the free forging equipment when drawing the rod after die forging, or a forging scheme of blank making + die forging. The two types of equipment, die forging and free forging, lead to multiple forming steps, while die forging upsetting + drawing can be formed in one step, saving labor costs and gas costs and improving production efficiency.

[0035] Embodiment 2:

[0036] like Figure 3-5 As shown, the present invention also provides a die for single-fire forging of a piston rod forging with a boss, comprising an upper die 1 and a lower die 2, wherein the rod portion of the lower die 2 has a draft of 1-3° and a diameter of φ100 (0, +5) mm, and the upper die 1 has a draft of 5-7°.

[0037] Preferably, the upper mold 1 and the lower mold 2 in the mold are designed with a material blocking platform 3 with a width of 10±2mm and a height of 5±1mm, and a direction along the length contour of the forging head on the parting surface, so as to control the flow direction of the blank during the forging forming process and avoid defects that the two sides of the head length direction and the positioning boss cannot be filled.

[0038] Preferably, the upper die 1 is designed to be circular and is covered by the lower die 2 to avoid the forging positioning boss and the rod being out of center during the forging process.

[0039] Preferably, the upper tire mold 1 is provided with a positioning boss 1-1, and the size of the positioning boss 1-1 is φ50±10mm×30±10mm. The lower tire mold 2 is provided with a positioning groove 2-1, and the positioning groove 2-1 has a width of 20±5mm and a depth of 15(0,+10)mm, and can be chamfered R5-R10. The positioning boss 1-1 and the positioning groove 2-1 correspond to each other to ensure the positioning of the material blocking platform and the upper and lower tire molds.

[0040] Embodiment 3:

[0041] like Figure 6 As shown in the figure, the diameter of the forging rod is φ80. Before optimization, the corresponding position of the die is designed to be φ80, which may easily cause the billet (φ80 bar) to exceed the die part with a larger height-to-diameter ratio, and may cause bending and deformation during the pressing process, or even pinching. The free forging method of stretching one end and then inserting it into the die forging method may easily lead to more forging times. After optimization, the corresponding position of the die is changed to φ100, and the billet (φ100 bar) exceeds the die part with a height-to-diameter ratio of ≤2.5, which is easy to forge without defects. At the same time, the die forging method is selected to avoid the need to switch to the free forging equipment after die forging. The rod can be stretched directly after die forging to ensure one-fire forming.

[0042] Embodiment 4:

[0043] like Figure 7 As shown, in the traditional die design, the upper die is the hammer anvil. This time, the piston rod needs to be forged with a boss, so the upper die needs to be designed. In Scheme 1, since the forging process is open-type, the boss and the rod are easily misaligned and eccentric, affecting the tolerance of the forging. After changing to Scheme 2, the closed extrusion method is adopted to ensure the correct position of the upper and lower dies during the forging process, and to ensure the concentricity of the forging boss and the rod.

[0044] Embodiment 5:

[0045] like Figure 8 , 9 As shown in the figure, before optimization, the blank was poorly filled during forging, and the two sides of the head and the boss were not filled because the die was not designed with a material blocking platform. At the same time, the positioning groove was not designed, which made it inconvenient for workers to install the die. After optimization, the material blocking platform was added to provide resistance during the forming process, ensuring the filling of the forgings. At the same time, the positioning groove was added to facilitate the workers to install the die.

[0046] Embodiment 6:

[0047] like Fig.10As shown, in Scheme 1, since the boss is machined out after forging, the streamlines at the illustrated position are cut off, resulting in reduced mechanical properties at that local position. In Scheme 2, since the boss is forged from the billet, the overall streamlines of the forging are complete, and the mechanical properties of the forging are more stable than in Scheme 1.

[0048] According to the piston rod forging product with locating boss developed according to Example 1, the size of the locating boss of the product meets the nominal size of the forging ±1.5mm (forging size tolerance +3mm, -2mm), the forming effect is good, no scrap occurs, and the utilization rate of the forging raw materials reaches more than 90%.

[0049] The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the technical principles of the present invention. These improvements and modifications should also be regarded as the scope of protection of the present invention.

Claims

1. A one-time forging process for a piston rod forging with a boss, characterized in that: The steps include: Step 1: Upsetting, select 30CrMnSiA bars of φ100×335, heat to 1160±10℃ and keep warm for 40-100 minutes, then place the blank accurately in the lower die of the die mold, and upset it through an 8MN fast forging machine. First, position the blank, then upset it to a height of about 260±10mm, and use the upper die of the die mold for subsequent upsetting and beating; Step 2: Turn the lower die 180°, take out the forging, and then put the upset forging on the hammer anvil, and use the 8MN fast forging machine to stretch it, stretching the rod from a diameter of φ100±5mm to a diameter of φ80±5mm.

2. The one-time forging process for a piston rod forging with a boss according to claim 1, characterized in that: The tire mold in the upsetting step includes an upper and lower tire mold, the rod and the square head are placed in the lower tire mold, the positioning boss is placed in the upper tire mold, and the upper tire mold is wrapped by the lower tire mold, and the positioning boss is squeezed and filled by a die forging closed extrusion method.

3. The one-time forging process for a piston rod forging with a boss according to claim 1, characterized in that: The stretching step is performed immediately after the tire die forging and upsetting, without the need to replace equipment, thus achieving one-time forming.

4. A die for single-fire forging of a piston rod forging with a boss, characterized in that: It includes an upper tire mold and a lower tire mold. The draft angle of the lower tire mold rod is 1-3°, the diameter is φ100 (0, +5) mm, and the draft angle of the upper tire mold is 5-7°.

5. The die for single-stage forging of a piston rod forging with a boss according to claim 4, characterized in that: The upper tire mold is designed to be circular and is wrapped by the lower tire mold.

6. The die for single-stage forging of a piston rod forging with a boss according to claim 4, characterized in that: The upper and lower dies in the die are designed with material blocking platforms with a width of 10±2 mm and a height of 5±1 mm. The direction is along the length contour of the forging head on the parting surface to control the flow direction of the billet during the forging forming process and avoid defects on both sides of the head length direction and the positioning bosses that cannot be filled.

7. The die for single-stage forging of a piston rod forging with boss according to claim 4, characterized in that: The upper tire mold is provided with a positioning boss, the size of which is φ50±10mm×30±10mm. The lower tire mold is provided with a positioning groove, the width of which is 20±5mm, the depth is 15 (0, +10) mm, and the chamfer R5-R10 can be achieved. The positioning boss and the positioning groove correspond to each other to ensure the positioning of the material blocking platform and the upper and lower tire molds.

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