Alloy composite pipe and preparation method thereof

Abstract

The invention discloses an alloy composite pipe and a preparation method thereof. The preparation method comprises the following steps: smelting prepared alloy into alloy mother liquor; the bar is cut, the two ends of the bar are punched, and the bar is put into a heat preservation furnace to be heated; the material pipe is placed on a centrifugal casting machine to be centrifuged at the gravitational acceleration of 2G, and the cosolvent is poured into the base pipe; alloy mother liquor is poured into the material pipe, the centrifugal force is pulled to the gravitational acceleration of 100 G, and the alloy mother liquor and the material pipe are subjected to mold filling and solidification to form a pipe; and the pipe is subjected to solution treatment and heat preservation, and the iron-based alloy pipe is obtained. The powder preparation process is completely canceled, intermediate links of alloy machine barrel manufacturing are reduced, only one smelting process is needed, the finished product manufacturing time is saved, and high-value elements in the alloy formula can be correspondingly reduced. And the prepared fluxing agent is used, so that the surface of the molten steel can be better protected, and the liquidity of the molten steel is improved. And the mechanical property of the charging barrel base material is not influenced. And the cost and the production period of the alloy machine barrel are reduced, and the use of the alloy machine barrel is greatly improved.

Description

Technical Field

[0001] The invention relates to the technical field of ferroalloy materials, and in particular to an alloy composite pipe and a preparation method thereof. Background Art

[0002] With the continuous improvement of plastic performance, the requirements for the wear and corrosion resistance of injection molding machine barrels are getting higher and higher. The barrels of injection molding machines are gradually being replaced by alloy barrels instead of the original nitrided barrels.

[0003] At present, the manufacturing process of alloy barrel (injection molding machine barrel bimetallic centrifugal casting process) is to pour low-melting-point alloy powder and flux into the material tube with the inner hole, weld the two ends to cover, and then put it on the heating equipment to heat it to about 1250℃, so that the alloy powder in the material tube is completely melted into molten steel, centrifuged after insulation, and then hung in the insulation furnace for insulation for about 4 hours before entering the subsequent machining. The existing process of alloy composite pipe is to first make the alloy powder of the material with alloy proportioning, add it to the ordinary iron pipe for overall heating and remelting again, and finally make it by centrifugation. Because the alloy material of the existing process needs to be made into powder and then remelted, there are 2 high-temperature heating processes (both exceeding 1000℃), and the corresponding material loss is large. The process equipment has huge investment and high energy consumption, and the powder preparation process and the subsequent heating process will inevitably produce certain losses. The most important thing is that after the substrate (steel) is heated at 1250℃, its own mechanical properties will be greatly reduced, affecting the service life of the alloy barrel. Summary of the invention

[0004] The object of the present invention is to provide an alloy composite tube and a preparation method thereof which integrates the powder making and remelting parts, greatly reduces the process, reduces energy consumption, reduces losses, reduces labor, and solves the above-mentioned defects in the prior art.

[0005] An alloy composite tube comprises a base tube and a composite layer, wherein the composite layer comprises, by mass percentage, C: 1.2%-1.8%, Cr: 7.0%-8.0%, Si: 1.2%-1.8%, Ni: 3.0%-4.0%, Mo: 2.5%-3.5%, B: 2.0%-3.0%, Cu: 0.6%-1.2%, and the remainder is Fe; the alloy material presents a dual-phase structural feature, and the base tube is austenite with a disordered face-centered structure.

[0006] A method for preparing an alloy composite tube, comprising the above alloy composite tube, comprises the following steps:

[0007] Step A, preparing raw materials, the alloy components by mass percentage include: C: 1.2%-1.8%, Cr: 7.0%-8.0%, Si: 1.2%-1.8%, Ni: 3.0%-4.0%, Mo: 2.5%-3.5%, B: 2.0%-3.0%, Cu: 0.6%-1.2%, and the balance is Fe;

[0008] Step B, smelting, smelting the prepared alloy into alloy mother liquid in a medium frequency vacuum induction arc furnace, and finally, taking out the alloy mother liquid when the temperature reaches 1600-1620°C;

[0009] Step C, heating the material tube, cutting the bar material and punching holes at both ends of the bar material, welding the two ends of the punched bar material with blanking caps and putting them into a heat preservation furnace for heating;

[0010] Step D, adding a solvent, when the material tube is placed from the holding furnace onto a centrifugal casting machine, the centrifugal casting machine is slowly centrifuged at a gravity acceleration of 2G, and the solvent is poured into the base tube, and the molten solvent is evenly covered on the inner wall of the material tube;

[0011] Step E, centrifugal casting, pouring alloy mother liquid at a temperature of 1600° C.-1620° C. directly into the material pipe from the end gate of the material pipe, the centrifugal casting machine pulls the centrifugal force to a gravity acceleration of 100G, and the alloy mother liquid and the material pipe are filled and solidified to form a pipe.

[0012] In one embodiment, the co-solvent in step D is a mixed material of potassium fluoroborate and sodium tetraborate, wherein the potassium fluoroborate is 10%-20% by mass, the sodium tetraborate is 80%-90% by mass, and the weight of the co-solvent is 1% of the alloy mother liquor.

[0013] In one embodiment, the method further comprises step F, wherein the tube is solution treated and then kept at 700-760° C. for 16-24 hours, and then air-cooled to room temperature to obtain an iron-based alloy tube.

[0014] The above technical solution has the following advantages or beneficial effects:

[0015] The alloy composite tube and preparation method of the present invention integrate the powder making and remelting parts, greatly reducing the process, energy consumption, loss, and labor, completely eliminating the powder making process, and no need to purchase powder making equipment. The intermediate links in the production of alloy barrels are greatly reduced, and only one smelting process is required, which saves the production time of finished products, and the high-value elements in the alloy formula can be reduced accordingly. The use of self-configured flux can better protect the surface of the molten steel and increase the fluidity of the molten steel. The overall heating does not need to be heated to a high temperature of 1250°C, but only needs to be heated to 600°C, which does not affect the mechanical properties of the barrel substrate (steel). The cost and production cycle of the alloy barrel are reduced, and the service life of the alloy barrel is greatly improved. DETAILED DESCRIPTION

[0016] The technical solutions of various embodiments of the present invention are described clearly and completely below. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of them. Based on the embodiments described in the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0017] An alloy composite pipe comprises a base pipe and a composite layer, wherein the composite layer comprises, by mass percentage: C: 1.2%-1.8%, Cr: 7.0%-8.0%, Si: 1.2%-1.8%, Ni: 3.0%-4.0%, Mo:

[0018] 2.5%-3.5%, B: 2.0%-3.0%, Cu: 0.6%-1.2%, and the balance is Fe; the alloy material has a dual-phase structure, and the base tube is a disordered face-centered austenite.

[0019] Because the original process alloy materials need to be made into powder and then remelted, there are two high-temperature heating processes (both exceeding 1000℃), and the corresponding material loss is relatively large. According to the test, 30% of the alloy components will be diluted into the substrate tube. The new process only needs one melting process, and the dilution is only 10%. The high-value elements in the alloy formula can be reduced accordingly. The original formula is a highly wear-resistant and corrosion-resistant iron-based alloy powder, with a mass percentage of components: C

[0020] 1.5%-2.2%, Cr 8.0%-10.0%, Si 1.5%-2.5%, Ni 4.5%-6.5%, Mo 3.0%-5.0%, B2.5%-4.0%, Cu 0.8%-1.8%, and the rest is iron. The corresponding material cost of the new formula can be reduced by 20%.

[0021] The equipment of the present invention has low investment cost and less material loss; it reduces energy consumption and is expected to save more than 50% of electricity; it does not use traditional processes but adopts a new centrifugal casting process; and the mechanical properties of the barrel base material (steel) will not be reduced substantially.

[0022] A method for preparing an alloy composite tube, comprising the above alloy composite tube, comprises the following steps:

[0023] Step A, raw material preparation, alloy components by mass percentage, including: C: 1.2%-1.8%, Cr: 7.0%-8.0%, Si: 1.2%-1.8%, Ni: 3.0%-4.0%, Mo: 2.5%-3.5%, B:

[0024] 2.0%-3.0%, Cu: 0.6%-1.2%, the balance is Fe

[0025] Step B, smelting, smelting the prepared alloy into alloy mother liquid in a medium frequency vacuum induction arc furnace, and finally, taking out the alloy mother liquid when the temperature reaches 1600-1620°C;

[0026] Step C, heating the material tube, cutting the bar material and punching holes at both ends of the bar material, welding the two ends of the punched bar material with blanking caps and putting them into a heat preservation furnace for heating;

[0027] Step D, adding a solvent, when the material tube is placed from the holding furnace onto a centrifugal casting machine, the centrifugal casting machine is slowly centrifuged at a gravity acceleration of 2G, and the solvent is poured into the base tube, and the molten solvent is evenly covered on the inner wall of the material tube;

[0028] Step E, centrifugal casting, pouring alloy mother liquid at a temperature of 1600° C.-1620° C. directly into the material pipe from the end gate of the material pipe, the centrifugal casting machine pulls the centrifugal force to a gravity acceleration of 100G, and the alloy mother liquid and the material pipe are filled and solidified to form a pipe.

[0029] Furthermore, in a preferred embodiment of a method for preparing an alloy composite tube of the present invention, the co-solvent in step D is a mixed material of potassium fluoroborate and sodium tetraborate, the potassium fluoroborate is 10%-20% by mass, the sodium tetraborate is 80%-90% by mass, and the weight of the co-solvent is 1% of the alloy mother liquor.

[0030] The homemade flux formula is potassium fluoroborate, sodium tetraborate and other fluxes. The melting point of potassium fluoroborate is 530℃, and the melting point of sodium tetraborate is 741℃. The mixing ratio is: 10%-20% potassium fluoroborate, 80%-90% sodium tetraborate. Before starting centrifugal casting, when the base tube is placed on the centrifuge from the insulation furnace, the centrifuge is slowly centrifuged at a speed of 2G gravity acceleration. The fluxes are mixed evenly in proportion, with a weight of 1% of the alloy liquid, and poured into the base tube. At this time, they will melt into liquid. Due to the existence of centrifugal force, the molten state flux will evenly cover the inner wall of the tube, protecting the inner hole of the base tube and avoiding oxidation of the inner hole to cause product quality problems. Then the centrifugal force is pulled to 100G gravity acceleration, at which time the alloy melt at a temperature of 1600℃-1620℃ is directly poured into the base tube from the end gate. Due to the centrifugal force of up to 100G, the alloy liquid quickly fills the entire cavity and evenly adheres to the tube wall. The tube wall protected by the flux will be metallurgically combined with the high-temperature alloy liquid to form a composite layer to achieve an overall effect. The flux will use centrifugal force to bring impurities and pores to the surface of the alloy liquid, protect the entire alloy composite layer, and ensure the quality of the composite layer after processing.

[0031] Furthermore, in a preferred embodiment of the method for preparing an alloy composite tube of the present invention, the method further comprises step F, wherein the tube is solution treated and then kept at 700-760° C. for 16-24 hours, and then air-cooled to room temperature to obtain an iron-based alloy tube.

[0032] In summary, the alloy composite tube and preparation method of the present invention will integrate the powder making and remelting parts, greatly reduce the process, reduce energy consumption, reduce losses, reduce labor, completely cancel the powder making process, and do not need to purchase powder making equipment. The intermediate links in the production of alloy barrels are greatly reduced, and only one smelting process is required, which saves the production time of finished products, and the high-value elements in the alloy formula can be reduced accordingly. Using a self-configured flux can better protect the surface of the molten steel and increase the fluidity of the molten steel. The overall heating does not need to be heated to a high temperature of 1250°C, but only needs to be heated to 600°C, which does not affect the mechanical properties of the barrel substrate (steel). The cost and production cycle of the alloy barrel are reduced, and the service life of the alloy barrel is greatly improved.

[0033] The above are only preferred embodiments of the present invention, and are not intended to limit the implementation methods and protection scope of the present invention. Those skilled in the art should be aware that all solutions obtained by equivalent substitutions and obvious changes made using the contents of the specification of the present invention should be included in the protection scope of the present invention.

[0034] In the description of the present invention, it is necessary to understand that the directions or positional relationships indicated by the terms "upper", "lower", "front" and "rear" are directions or positional relationships, which are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific direction, be constructed and operated in a specific direction, and therefore cannot be understood as a limitation on the present invention.

Claims

1. An alloy composite tube, characterized in that: The invention comprises a base tube and a composite layer, wherein the composite layer comprises, by mass percentage, C: 1.2%-1.8%, Cr: 7.0%-8.0%, Si: 1.2%-1.8%, Ni: 3.0%-4.0%, Mo: 2.5%-3.5%, B: 2.0%-3.0%, Cu: 0.6%-1.2%, and the remainder is Fe; the alloy material presents a dual-phase structure feature, and the base tube is austenite with a disordered face-centered structure.

2. A method for preparing an alloy composite tube, comprising the alloy composite tube according to claim 1, characterized in that: The following steps are involved: Step A, preparing raw materials, the alloy components, calculated by mass percentage, include: C: 1.2%-1.8%, Cr: 7.0%-8.0%, Si: 1.2%-1.8%, Ni: 3.0%-4.0%, Mo: 2.5%-3.5%, B: 2.0%-3.0%, Cu: 0.6%-1.2%, the balance is Fe; Step B, smelting, smelting the prepared alloy into alloy mother liquid in a medium frequency vacuum induction arc furnace, and finally, taking the alloy mother liquid out of the furnace when the temperature reaches 1600-1620°C; Step C, heating the material tube, cutting the bar material and punching holes at both ends of the bar material, welding the two ends of the punched bar material with blind covers and putting them into a heat preservation furnace for heating; Step D, adding a solvent, when the material tube is placed from the holding furnace onto a centrifugal casting machine, the centrifugal casting machine is slowly centrifuged at a gravity acceleration of 2G, and the solvent is poured into the base tube, and the molten solvent is evenly covered on the inner wall of the material tube; Step E, centrifugal casting, pouring alloy mother liquid at a temperature of 1600° C.-1620° C. directly into the material pipe from the end gate of the material pipe, the centrifugal casting machine pulls the centrifugal force to a gravity acceleration of 100G, and the alloy mother liquid and the material pipe are filled and solidified to form a pipe.

3. The method for preparing an alloy composite tube according to claim 2, characterized in that: The auxiliary solvent in step D is a mixed material of potassium fluoroborate and sodium tetraborate, wherein the potassium fluoroborate accounts for 10%-20% by mass, the sodium tetraborate accounts for 80%-90% by mass, and the weight of the auxiliary solvent accounts for 1% of the alloy mother liquor.

4. The method for preparing an alloy composite tube according to claim 2, characterized in that: The method further comprises step F, wherein the tube is solution treated and then kept at 700-760° C. for 16-24 hours, and then air-cooled to room temperature to obtain an iron-based alloy tube.