Method for extruding powder alloy bar with high utilization rate

Abstract

The invention relates to a method for extruding a powder alloy bar with a high utilization rate. An end cover, a powder high-temperature alloy ingot and a base are sequentially assembled into a blank to be extruded from top to bottom; the structures of the end cover and the base are optimized, so that the end cover is directly separated from the bar after being extruded, and a wrapping phenomenon is avoided; the depth of the base penetrating into the bar is smaller than or equal to 100 mm, the penetrating shape is in a round head shape, waste of powder alloy materials is reduced, and the material utilization rate of the bar is increased. The high-temperature-resistant fiber blanket is used for wrapping the welding seam of the end cover and the powder high-temperature alloy ingot, the temperature drop of the high-temperature alloy ingot in the transferring process after heating is reduced, the cracking degree of the head of the bar is reduced by 80% or above, even the crack-free level is achieved, and the material utilization rate of the alloy bar is further increased. According to the method, large-specification bars with the diameter of 250-400 mm can be extruded, and the material utilization rate is increased by 20% or above compared with a traditional method.

Description

Technical Field

[0001] This invention belongs to the field of metal extrusion, and specifically relates to a method for extruding powder alloy rods with high utilization rate. Background Technology

[0002] The nickel-based powder metallurgy superalloy turbine disks used in aircraft engines operate under harsh conditions, have high quality requirements, and are complex and difficult to manufacture. They require high-ratio extrusion deformation to break down metallurgical defects such as the original particle boundaries and inclusions in the powder, resulting in alloy rods with ultrafine grains. Powder metallurgy superalloys are typical difficult-to-deform materials with high deformation resistance, poor process plasticity, and their microstructure and properties are sensitive to processing parameters. While hot extrusion forming of large-size powder metallurgy superalloy rods can be achieved using an upper and lower pad (upper end cap and lower base) encapsulation extrusion process, defects such as cracking at the ends of the extruded rods exist. Furthermore, the upper and lower pads are embedded in the powder metallurgy superalloy rod matrix after extrusion. Severe cracking at the rod head can reach a depth of approximately 50mm and a length of about 500mm; the upper and lower pads are embedded in the powder metallurgy superalloy rod matrix for about 2000mm, rendering the rod unusable and resulting in very low material utilization and significantly increased costs. Summary of the Invention

[0003] This invention addresses the problem of low utilization rate of powdered high-temperature alloy rods by providing a method for extruding powdered alloy rods with high utilization rate. By designing end caps and base structures for extruding powdered alloy ingots, and wrapping them with high-temperature resistant fiber blankets, the method solves the problems of surface cracking and end cap covering of the rods, thereby improving the material utilization rate.

[0004] To address the above technical problems, this invention provides a method for extruding powder alloy rods with high utilization rate, characterized by comprising the following steps:

[0005] S1: The end cap, powder high-temperature alloy ingot and base are assembled in sequence from top to bottom to form the billet to be extruded;

[0006] S2: Sandblasting treatment of the billet to be extruded;

[0007] S3: After the surface of the extruded billet is preheated to 80-150℃, spray it with an anti-oxidation and lubricating coating.

[0008] S4: The extrusion blank is heated to 1050℃-1180℃ and held for ≥1.5h / 100mm;

[0009] S5: A layer of glass powder lubricant is fused onto the surface of the billet to be extruded;

[0010] S6: Place the billet to be extruded into the extrusion cylinder of the vertical extruder. The extrusion cylinder and extrusion die have been preheated to 250℃-350℃.

[0011] S7: Place a glass pad on the top of the billet to be extruded for lubrication, extrusion speed 18-22mm / s, extrusion ratio (4-8):1, and diameter of the extruded bar 250-400mm.

[0012] Beneficial effects:

[0013] 1. The extrusion device for powder alloy rods of the present invention optimizes the end cap and base structure, so that the end cap can be directly separated from the rod after extrusion without any wrapping phenomenon; the base penetrates the rod to a depth of ≤100mm and has a rounded shape, which reduces the waste of powder alloy material and improves the material utilization rate of the rod.

[0014] 2. This invention uses high-temperature resistant fiber blankets to wrap the end caps and the weld seams of the powder high-temperature alloy ingots, reducing the temperature drop of the high-temperature alloy ingots during transportation after heating, reducing the degree of cracking at the head of the rod by more than 80%, and even reaching the level of no cracks, further improving the material utilization rate of the alloy rods.

[0015] 3. The powder alloy rod extrusion method of the present invention can extrude large-diameter rods with a diameter of 250-400mm, and the material utilization rate is increased by more than 20% compared with the traditional method. Attached Figure Description

[0016] Figure 1 Schematic diagram of the billet to be extruded. Detailed Implementation

[0017] To make the objectives, contents, and advantages of the present invention clearer, the specific embodiments of the present invention will be described in further detail below.

[0018] The present invention proposes a method for extruding powder alloy rods with high utilization rate, the specific steps of which are as follows:

[0019] S1: The end cap, powder high-temperature alloy ingot and base are assembled in sequence from top to bottom to form the blank to be extruded. The coaxiality of the assembly is ≤2mm. The assembly is welded in sections in the circumferential direction, and the weld bead spacing is 100-150mm.

[0020] S2: Sandblasting treatment of the billet to be extruded.

[0021] S3: After the surface of the extruded billet is preheated to 80-150℃, spray it with an anti-oxidation and lubricating coating.

[0022] S4: The extrusion blank is heated to 1050℃-1180℃ and held for ≥1.5h / 100mm;

[0023] S5: A layer of glass powder lubricant is fused onto the surface of the billet to be extruded using a cover-type lubrication device.

[0024] S6: Place the billet to be extruded into the extrusion cylinder of the vertical extruder. The extrusion cylinder and extrusion die have been preheated to 250℃-350℃.

[0025] S7: Place a special glass pad on the top of the billet to be extruded for lubrication, the extrusion speed is 18-22mm / s, the extrusion ratio is (4-8):1, and the diameter of the extruded bar is 250-400mm.

[0026] Furthermore, the end cap has a rotating body structure, with a chamfered upper part and a cylindrical lower part. The rotating body has a through hole in the center, with a diameter of 50-120mm.

[0027] Furthermore, the upper part of the end cap is chamfered, with a chamfer angle of 60-120°, the same as the chamfer angle of the extrusion die, and the height of the chamfered part is 100-250mm. The flatness of the upper and lower end faces is 0.1.

[0028] Furthermore, the diameter of the lower cylindrical part of the end cap differs from the diameter of the powder high-temperature alloy ingot by ±10mm, and the height of the cylindrical section is 50-150mm.

[0029] Furthermore, the base is a cylindrical structure with a height of 80-160mm, and the diameter of the base differs from the diameter of the powder high-temperature alloy ingot by ±10mm.

[0030] Furthermore, the end caps and bases are made of austenitic stainless steel such as TP304, TP316, TP321, and TP347.

[0031] Furthermore, the high-temperature resistant fiber blanket 3, with a thickness of 5mm-15mm and a width of 50-150mm, wraps around the weld seam of the end cap and the powder high-temperature alloy ingot, and is heated together with the billet to be extruded.

[0032] Furthermore, a high-temperature glass powder lubricant is filled between the high-temperature resistant fiber blanket and the powdered high-temperature alloy ingot.

[0033] Example:

[0034] The specific steps for extruding an FGH96 powder superalloy rod with a diameter of Φ300mm are as follows:

[0035] S1: The end cap (1), powder high-temperature alloy ingot (4) and base (5) are assembled from top to bottom as the blank to be extruded. The coaxiality of the assembly is ≤2mm. The assembly is welded in sections in the circumferential direction. The welding rod is A507. Two layers are welded with a weld spacing of 120mm.

[0036] S2: Sandblasting treatment of the surface of the billet to be extruded.

[0037] S3: After the surface of the extruded billet is preheated to 80-150℃, spray it with an anti-oxidation and lubricating coating.

[0038] S4: The weld seam is wrapped with high-temperature resistant fiber blanket and high-temperature resistant glass powder.

[0039] S5: Heat the extruded billet to 1080℃ and hold for ≥10h.

[0040] S6: After the extruded billet is heated to the specified temperature, a layer of glass powder lubricant is fused onto its surface using a hood-type lubrication device after it is taken out of the furnace.

[0041] S7: Place the billet to be extruded into the extrusion cylinder of the vertical extruder. The extrusion cylinder and extrusion die have been preheated to 250℃-350℃.

[0042] S8: Place a special glass pad on the top of the billet to be extruded for lubrication, extrusion speed 18-22mm / s, extrusion ratio 5.4:1.

[0043] Furthermore, the end cap has a rotating body structure, with a chamfered upper part and a cylindrical lower part. The rotating body has a through hole in the center with a diameter of 100mm.

[0044] Furthermore, the upper part of the end cap is chamfered with a chamfer angle of 100°, which is the same as the chamfer angle of the extrusion die. The height of the chamfered part is 150mm, and the flatness of the upper and lower end faces is 0.1.

[0045] Furthermore, the diameter of the lower cylindrical part of the end cap differs from the diameter of the powder high-temperature alloy ingot by ±10mm, and the height of the cylindrical section is 80mm.

[0046] Furthermore, the base is a cylindrical structure with a height of 120mm, and the diameter of the base differs from the diameter of the powder high-temperature alloy ingot by ±10mm.

[0047] Furthermore, the end caps and base are made of TP304 austenitic stainless steel.

[0048] Furthermore, a high-temperature glass powder lubricant is filled between the high-temperature resistant fiber blanket and the powdered high-temperature alloy ingot.

[0049] Furthermore, a high-temperature resistant fiber blanket with a thickness of 10mm and a width of 100mm is used to wrap around the weld seam of the end cap and the powder high-temperature alloy ingot, and is heated together with the billet to be extruded.

[0050] The surface of the extruded bar is free of defects, the head of the bar is not covered, the bottom stainless steel base extends 90mm into the bar, and the material utilization rate of the bar is as high as 93%.

[0051] The above description is only a preferred embodiment of the present invention. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the technical principles of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A method for extruding powder alloy rods with high utilization rate, characterized in that, Includes the following steps: S1: The end cap, powder high-temperature alloy ingot and base are assembled in sequence from top to bottom to form the billet to be extruded; S2: Sandblasting treatment of the billet to be extruded; S3: After the surface of the extruded billet is preheated to 80-150℃, spray it with an anti-oxidation and lubricating coating. S4: The extrusion blank is heated to 1050℃-1180℃ and held for ≥1.5h / 100mm; S5: A layer of glass powder lubricant is fused onto the surface of the billet to be extruded; S6: Place the billet to be extruded into the extrusion cylinder of the vertical extruder. The extrusion cylinder and extrusion die have been preheated to 250℃-350℃. S7: Place a glass pad on the top of the billet to be extruded for lubrication, extrusion speed 18-22mm / s, extrusion ratio (4-8):1, and diameter of the extruded bar 250-400mm.

2. The method for producing high-utilization extruded powder alloy rods according to claim 1, characterized in that, The end cap has a rotating body structure. The upper part of the rotating body has a chamfered structure, and the lower part has a cylindrical structure. There is a through hole in the center of the rotating body, with a diameter of 50-120mm.

3. The method for producing high-utilization extruded powder alloy rods according to claim 1, characterized in that, The upper part of the end cap is chamfered, with a chamfer angle of 60-120°. The chamfer angle is the same as the chamfer angle of the extrusion die. The height of the chamfered part is 100-250mm, and the flatness of the upper and lower end faces is 0.

1.

4. The method for producing high-utilization extruded powder alloy rods according to claim 1, characterized in that, The diameter of the lower cylindrical part of the end cap differs from the diameter of the powder high-temperature alloy ingot by ±10mm, and the height of the cylindrical section is 50-150mm.

5. The method for producing high-utilization extruded powder alloy rods according to claim 1, characterized in that, The base is a cylindrical structure with a height of 80-160mm. The diameter of the base differs from the diameter of the powder high-temperature alloy ingot by ±10mm.

6. The method for producing high-utilization extruded powder alloy rods according to claim 1, characterized in that, The end caps and bases are made of austenitic stainless steel such as TP304, TP316, TP321, and TP347.

7. A method for producing high-utilization extruded powder alloy rods according to any one of claims 1-6, characterized in that, The weld seams of the end caps and powder high-temperature alloy ingots are wrapped with high-temperature resistant fiber blankets.

8. The method for producing high-utilization extruded powder alloy rods according to claim 7, characterized in that, High-temperature glass powder lubricant is filled between the high-temperature resistant fiber blanket and the powder high-temperature alloy ingot.

9. The method for producing high-utilization extruded powder alloy rods according to claim 7, characterized in that, The high-temperature resistant fiber blanket is 5mm-15mm thick and 50-150mm wide, and is heated together with the blank to be extruded.

10. A method for producing high-utilization extruded powder alloy rods according to any one of claims 1-6, characterized in that, In S1, the coaxiality of the assembly is ≤2mm, and the assembly is welded in sections in the circumferential direction with a weld spacing of 100-150mm.

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