GH4350 bolt high-speed extrusion forming method based on Mg-containing lubricating getter

Abstract

The high-speed extrusion forming method for the GH4350 bolt based on the Mg-containing lubricating getter comprises a forming method which meets the requirement that the appearance of a twelve-angle wrenching area of the GH4350 bolt is full through high-speed extrusion. The GH4350 bolt is subjected to high-speed extrusion forming by adopting the Mg-containing lubricating getter, in a high-temperature and high-pressure environment during high-speed forming, active elements such as Mg, Ca and Li in the lubricant can be stimulated to have a rapid chemical reaction with residual N2 and O2 in a hot upsetting mold cavity, oxides are generated in the reaction process, the chemical exhaust effect is achieved, instantaneous vacuum is formed, flowing filling of a metal material is facilitated, and the service life of the GH4350 bolt is prolonged. The full degree of the twelve-angle wrenching area can be effectively improved, the appearance of the formed twelve-angle wrenching area of the bolt is full, and the problem that the appearance of the formed twelve-angle wrenching area of the bolt is not full due to an existing technology is solved. Meanwhile, the generated oxide and the copper-containing substance play a role in lubricating the mold together.

Description

Technical Field

[0001] The invention relates to a high-speed extrusion molding method for a GH4350 bolt based on a lubricating and degassing agent containing Mg, and belongs to the technical field of bolt extrusion molding. Background Art

[0002] GH4350 bolts for aviation use. This grade of high-temperature alloy has a Co content of 23% to 27%, a Cr content of 14.5% to 18%, and a Ta content of 3.5% to 4.6%. It has a very high degree of alloying, low material plasticity, high deformation resistance, and a complex twelve-angle structure on the head.

[0003] The existing process (see Chinese patent announcement number CN110656286A) uses cold-drawn bars, which are cut and then hot-forged by a punch press, resulting in an incomplete appearance of the twelve-angle wrench area of ​​the bolt. Summary of the invention

[0004] In order to solve the above technical problems, the present invention provides a high-speed extrusion molding method of GH4350 bolts based on a Mg-containing lubricating and degassing agent.

[0005] The present invention is achieved through the following technical solutions.

[0006] The invention provides a high-speed extrusion molding method for GH4350 bolts based on a Mg-containing lubricating degassing agent, comprising: a molding method that satisfies the requirement of a full appearance of a twelve-angle wrench area of ​​the GH4350 bolt through high-speed extrusion.

[0007] The forming method comprises: spraying a hot upsetting die with a lubricant containing Mg, heating a blank of a GH4350 bolt, placing the blank in the hot upsetting die for high-speed extrusion and hot upsetting, taking the blank out for cooling, and forming a twelve-angle wrenching area of ​​the GH4350 bolt into a full shape.

[0008] The Mg-containing lubricant consists of Mg, Ca, Li and cold heading oil.

[0009] The Mg-containing lubricant comprises the following components: Mg (3% to 8%), Ca (0.05% to 1%), Li (0.09% to 6%), and the remainder is cold heading oil.

[0010] The hot upsetting die is made of PRV6N high Co and W hard alloy material, so that the hardness of the hot upsetting die is ≥HRA96.

[0011] The heating temperature of the GH4350 bolt blank is 860-1120° C., and the heating time is 0.8-16 seconds.

[0012] When the GH4350 bolt blank is extruded and hot-forged at a high speed in a hot-forging die, the forming rate is 300-500 mm / s and the heat shrinkage rate is 0.5%-3.5%.

[0013] The cooling rate of the cooling is 180-500°C / s.

[0014] The beneficial effect of the present invention is that the present invention uses a Mg-containing lubricating degassing agent to perform high-speed extrusion molding on GH4350 bolts. In the high-temperature and high-pressure environment during high-speed molding, the active elements Mg, Ca, and Li in the lubricant and the residual N in the hot upsetting mold cavity can be stimulated. 2 , O 2 A rapid chemical reaction occurs, and oxides are generated during the reaction process, which plays a role in chemical exhaust and forms an instantaneous vacuum, which is conducive to the flow and filling of metal materials. It can effectively improve the fullness of the twelve-angle wrench area, and make the appearance of the twelve-angle wrench area of ​​the bolt full after forming, thus solving the problem of the existing process causing the appearance of the twelve-angle wrench area of ​​the bolt to be not full after forming. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 It is a process flow chart of the present invention;

[0016] Figure 2 It is a schematic diagram of the hot upsetting die structure of the twelve-angle wrenching area of ​​the bolt of the present invention;

[0017] Figure 2 In the figure, 11 is a mold core, and 12 is a mold sleeve;

[0018] Figure 3 It is a schematic diagram comparing the shaping of the twelve-angle wrench area of ​​the existing bolt and the twelve-angle wrench area of ​​the bolt of the present invention;

[0019] Figure 3 In the figure, a is the twelve-angle tightening area of ​​the existing bolt, and b is the twelve-angle tightening area of ​​the bolt of the present invention. DETAILED DESCRIPTION

[0020] The technical solution of the present invention is further described below, but the scope of protection claimed is not limited to the description.

[0021] like Figures 1 to 3 shown.

[0022] A high-speed extrusion molding method of a GH4350 bolt based on a Mg-containing lubricating degassing agent of the present invention comprises the following steps:

[0023] Step 1: Material preparation: Purchase materials according to special requirements, improve the quality of material purchases, and strictly control the composition and surface status of incoming materials.

[0024] Step 2, cutting: the size and appearance are controlled according to the process, and the end face is required to be flat. This process fine-controls the chamfer size; the cutting process accurately controls the size of the blank corners, which is adjusted according to different blanks.

[0025] Step three, lubrication: The hot upsetting die cavity is automatically spray lubricated according to a special structure, using a Mg-containing lubricant. The hot upsetting die includes a die core 11 and a die sleeve 12 for embedding and installing the die core 11. The composition of the Mg lubricant is Mg (3% to 8%), Ca (0.05% to 1%), Li (0.09% to 6%), and the remainder is cold upsetting oil. The degree of lubrication is precisely controlled by the PLC program to ensure that the lubricating layer is evenly distributed in the cavity. In the high temperature and high pressure environment during high-speed forming of the product, the active elements such as Mg and Ca in the lubricant can be stimulated to react with the residual N in the mold cavity. 2 , O 2 A rapid chemical reaction occurs, and the reaction process generates oxides, which play a role in chemical exhaust, forming an instantaneous vacuum, which is conducive to the flow and filling of metal materials, and can effectively improve the fullness of the twelve-angle wrench area. At the same time, the generated oxides and copper-containing substances play a role in lubricating the mold. In addition, the Mg-containing lubricant can react with water (H 2 O) to form Mg(OH) 2 Weakly alkaline substances such as Mg are non-polluting to the environment and have low cleaning costs. The use of Mg-containing lubricants for lubrication of this alloy is the first time in the industry and is one of the key technologies for the successful application of this process technology. The hot upsetting die is processed with PRV6N material ≥HRA96, giving full play to the high hardness, wear resistance, high temperature resistance, impact resistance and thermal fatigue resistance of high-Co tungsten steel materials. The forming mold is processed with PRV6N high-Co and W cemented carbide to replace the tool steel or ST6 tungsten steel used in the industry. The hardness of this cemented carbide is ≥HRA96, which exceeds that of conventional cemented carbide (≈HRA86.3) and is close to that of ceramic materials. It can effectively improve the wear resistance of the mold and ensure that the mold life exceeds 5,000 pieces, meeting the needs of mass production. ≥HRA96 high-cobalt cemented carbide is used to process bolt molds, which is the first time in the industry and is one of the core conditions for the successful application of this process technology.

[0026] Step 4, high-speed wrenching structure forming: heat the blank in the range of 860-1120℃, heating time 0.8-16s, strictly control the heating temperature and time to ensure that the thermoplasticity of the material is in the optimal forming range; use PRV6N high Co mold, mold hardness ≥HRA96, and there is almost no wear when the alloy contacts the mold; the forming rate is 300-500mm / s, and the heating temperature and other parameters must be strictly controlled to ensure that the thermoplasticity of the material is in the optimal forming range. The specific parameters are reflected in the special process documents. The forming process adopts one-time fine upsetting, and the cavity size is designed according to the middle and lower difference, which is conducive to improving the life of the mold. The thermal shrinkage rate is selected between 0.5% and 3.5%, and the specific requirements are reflected in the mold drawing. The high-speed forming process forms an instantaneous high temperature of 1600-2300℃ in the cavity, which is the key point to trigger the chemical reaction of the lubricant; controlled cooling, according to the material properties of GH4350, strictly controls the cooling rate, and the cooling rate is controlled at 180-500℃ / s, which is conducive to maintaining the wrenching morphology, and the size will not be deformed due to cooling stress. The rate of 300-500mm / s belongs to the category of high-speed forming, which exceeds the processing requirements of conventional products and is one of the conditions for the successful application of this technology. The reaction equation of lubricant degassing and subsequent cleaning at high temperature is as follows:

[0027] Mg+N 2 →Mg 3 N 2

[0028] Mg 3 N 2 +6H 2 O→3Mg(OH) 2 +2NH 3

[0029] Ca+N 2 →Ca 3 N 2

[0030] Ca 3 N 2 +6H 2 O→3Ca(OH) 2 +2NH

[0031] Li+N 2 →Li 3 N 2

[0032] Li 3 N 2 +6H 2 O→3Li(OH) 2 +2NH

[0033] from Figure 3It can be concluded that the edges of the twelve-angle wrench area a of the existing bolt have collapsed angles and the appearance is not full; the edges of the twelve-angle wrench area b of the bolt of the present invention do not have collapsed angles and the appearance is full. Therefore, the present invention uses a Mg-containing lubricating degassing agent to perform high-speed extrusion molding on the GH4350 bolt, which can make the twelve-angle wrench area of ​​the bolt have a full appearance after molding, solving the problem of the existing process causing the twelve-angle wrench area of ​​the bolt to have an incomplete appearance after molding.

Claims

1. A high-speed extrusion molding method for GH4350 bolts based on a Mg-containing lubricating degassing agent, characterized in that: include: A forming method that uses high-speed extrusion to achieve a full appearance in the twelve-angle wrench area of ​​the GH4350 bolt.

2. The high-speed extrusion molding method of GH4350 bolts based on Mg-containing lubricating and degassing agent according to claim 1, characterized in that: The forming method comprises: spraying a hot upsetting die with a lubricant containing Mg, heating a blank of a GH4350 bolt, placing the blank in the hot upsetting die for high-speed extrusion and hot upsetting, taking the blank out for cooling, and forming a twelve-angle wrenching area of ​​the GH4350 bolt into a full shape.

3. The high-speed extrusion molding method of GH4350 bolts based on Mg-containing lubricating and degassing agent according to claim 2, characterized in that: The Mg-containing lubricant consists of Mg, Ca, Li and cold heading oil.

4. The high-speed extrusion molding method of GH4350 bolts based on Mg-containing lubricating and degassing agent according to claim 3, characterized in that: The Mg-containing lubricant comprises 3% to 8% Mg, 0.05% to 1% Ca, 0.09% to 6% Li, and the remainder is cold heading oil.

5. The high-speed extrusion molding method of GH4350 bolts based on Mg-containing lubricating and degassing agent according to claim 2, characterized in that: The hot upsetting die is made of PRV6N high Co and W hard alloy material, so that the hardness of the hot upsetting die is ≥HRA96.

6. The high-speed extrusion molding method of GH4350 bolts based on Mg-containing lubricating and degassing agent according to claim 2, characterized in that: The heating temperature of the GH4350 bolt blank is 860-1120° C., and the heating time is 0.8-16 seconds.

7. The high-speed extrusion molding method of GH4350 bolts based on Mg-containing lubricating and degassing agent according to claim 2, characterized in that: When the GH4350 bolt blank is extruded and hot-forged at a high speed in a hot-forging die, the forming rate is 300-500 mm / s and the heat shrinkage rate is 0.5%-3.5%.

8. The high-speed extrusion molding method of GH4350 bolts based on Mg-containing lubricating and degassing agent according to claim 2, characterized in that: The cooling rate of the cooling is 180-500°C / s.

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