Corrosion-resistant aluminum profile machining process

Abstract

The invention provides a corrosion-resistant aluminum profile machining process. The corrosion-resistant aluminum profile machining process comprises the steps that S1, an aluminum ingot and an alloy material are smelted to form an aluminum base material; wherein in the alloy material, the content of magnesium is 0.4-0.6 wt%, the content of silicon is 0.6-1.2 wt%, the content of iron is less than or equal to 0.35 wt%, the content of manganese is 0.2-0.5 wt%, and the content of copper is less than or equal to 0.1 wt%; s2, the aluminum base material is subjected to extrusion forming to form a profile with the required section shape; wherein the extrusion temperature is controlled to be 420-460 DEG C; s3, honing treatment is conducted on the profile; wherein the depth of the honing lines is 5-50 micrometers, the cross angle is 20-45 degrees, and the surface roughness Ra after honing is smaller than or equal to 0.8 micrometer; s4, surface treatment is conducted on the surface of the profile; the method specifically comprises the steps that epoxy resin-based corrosion-resistant paint is electrostatically sprayed to the surface of the profile, nano-silica with the particle size being 5-20 microns and an organic silicon modification additive are added into the paint, and the total thickness of the coating is 100-400 microns; s5, the sectional material is subjected to curing treatment; and specifically, baking at 180-200 DEG C for 10-30 minutes. Through the machining process, the corrosion resistance, the surface quality and the process sustainability of the aluminum profile are remarkably improved.

Description

Technical Field

[0001] The present invention belongs to the technical field of aluminum profile processing, and particularly relates to a processing technology for corrosion-resistant aluminum profiles. Background Art

[0002] Due to its light weight, high strength and easy processability, aluminum profiles are widely used in fields such as construction, transportation, and electronics. However, under corrosive conditions such as marine environments, industrial pollution or high humidity, traditional aluminum profiles are prone to problems such as pitting corrosion and intergranular corrosion, resulting in structural failure. In the prior art, the corrosion resistance is mainly improved through alloy composition optimization and surface coating, but there are the following problems: for example, the control of alloy composition is inaccurate, resulting in a decrease in the toughness of the material; during surface treatment, the thickness of the anodic oxidation film is uneven and the micropores are prone to adsorb corrosive media; the adhesion of the conventional epoxy coating is poor, and the dispersion of nano-fillers is insufficient, resulting in easy peeling of the coating. Summary of the Invention

[0003] The main purpose of the present invention is to provide a processing technology for corrosion-resistant aluminum profiles, which can significantly improve the corrosion resistance, surface quality and process sustainability of aluminum profiles through this processing technology.

[0004] To achieve the above object, the present invention provides a processing technology for corrosion-resistant aluminum profiles, which includes step S1: melting aluminum ingots and alloy materials to form an aluminum substrate; wherein, the magnesium content in the alloy material is 0.4-0.6 wt%, the silicon content is 0.6-1.2 wt%, the iron content ≤ 0.35 wt%, the manganese content is 0.2-0.5 wt%, and the copper content ≤ 0.1 wt%; step S2: extruding the aluminum substrate into a profile with a required cross-sectional shape; wherein, the extrusion temperature is controlled at 420-460 °C; step S3: performing honing treatment on the profile; wherein, the honing groove depth is 5-50 μm, the cross angle is 20-45°, and the surface roughness Ra ≤ 0.8 μm after honing; step S4: performing surface treatment on the surface of the profile; specifically, electrostatically spraying an epoxy resin-based corrosion-resistant coating on the surface of the profile, adding nano-silica with a particle size of 5-20 μm and an organosilicon-modified additive to the coating, and the total thickness of the coating is 100-400 μm; step S5: performing curing treatment on the profile; specifically, baking at 180-200 °C for 10-30 minutes.

[0005] The present invention provides a corrosion-resistant aluminum profile processing technology, which forms a fine Mg2Si strengthening phase through precise control of alloy ratio, taking into account both strength and corrosion resistance; limits Fe≤0.35wt% and Cu≤0.1wt% to reduce the corrosion activity of impurity phase, controls the extrusion temperature at 420-460℃, avoids grain coarsening caused by overheating, ensures material fluidity, improves molding quality, forms a micro-textured surface through honing, increases the contact area of the coating, and enhances mechanical bite force; adds nano-SiO2 and organosilicon modifiers to the epoxy resin-based coating, wherein nano-SiO2 improves the hardness and permeability resistance of the coating, organosilicon enhances hydrophobicity, synergistically inhibits the diffusion of corrosive media, and curing treatment promotes full cross-linking of epoxy resin to form a dense corrosion-resistant film layer. The processing technology significantly improves the corrosion resistance, surface quality and process sustainability of aluminum profiles.

[0006] As a further preferred technical solution of the above technical solution, in step S1, argon gas is used for smelting, the smelting temperature is 730-750°C, and the refining time is ≥15 minutes. Argon gas isolates oxidation and reduces slag inclusions; sufficient refining time ensures uniformity of alloy composition and reduces porosity.

[0007] As a further preferred technical solution of the above technical solution, in step S2, the extrusion die adopts a porous diverter die, the extrusion speed is 5-15m / min, and the traction force is controlled at 1.2-1.5 times the tensile strength of the profile. The porous diverter die improves the uniformity of metal flow and reduces surface wrinkles; the traction force matches the material strength to prevent the profile from deforming.

[0008] As a further preferred technical solution of the above technical solution, in the step S4, the profile is degreased and cleaned before surface treatment, and a phosphate-based environmentally friendly cleaning agent is used as the cleaning agent, the cleaning temperature is 50-60°C, and the cleaning time is 8-12 minutes. Phosphate esters are highly efficient in degreasing and have good biodegradability; temperature and time work together to ensure that oil stains are completely removed to avoid residues that affect the bonding of the coating.

[0009] As a further preferred technical solution of the above technical solution, in step S3, a diamond honing oilstone is used for honing, with an oilstone speed of 800-1200r / min and a reciprocating stroke of 0.5-1.0mm. The high hardness of diamond enables precise honing and uniform cross grain; parameter matching avoids surface overheating or over-cutting.

[0010] As a further preferred technical solution of the above technical solution, 0.5-1.5wt% of isophorone diisocyanate IPDI curing agent is added to the epoxy resin-based coating, and the curing agent particle size is ≤5μm. IPDI has high low-temperature curing activity, and its small particle size ensures uniform dispersion, thereby improving the crosslinking density and chemical resistance of the coating.

[0011] As a further preferred technical solution of the above technical solution, after the step S5, the profile is subjected to plasma treatment after curing. The treatment power is 5 - 10 kW, the treatment time is 5 - 10 seconds, and the surface energy ≥ 40 mN / m. Plasma etching removes surface organic matter, activates the substrate, and the high surface energy promotes coating wetting and chemical bonding.

[0012] As a further preferred technical solution of the above technical solution, after the profile is subjected to plasma treatment, the profile is sprayed. The spraying distance is 150 - 200 mm, the spraying pressure is 0.3 - 0.5 MPa, and the spraying environment adopts a three-stage filtration and purification system with filtration precisions of 5 μm, 1 μm, and 0.1 μm respectively. Multi-stage filtration eliminates environmental particle pollution; the spraying distance and pressure are optimized to ensure the coating uniformity and avoid orange peel or sagging. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] Figure 1 is a schematic diagram of the processing technological process of a corrosion-resistant aluminum profile provided by this application. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0014] The following description is used to disclose the present invention so that those skilled in the art can implement the present invention. The preferred embodiments described below are only examples, and those skilled in the art can think of other obvious variations. The basic principles defined in the following description can be applied to other embodiments, variants, improvements, equivalent solutions, and other technical solutions without departing from the spirit and scope of the present invention.

[0015] Referring to the attached drawings Figure 1 , Figure 1 is a schematic diagram of the processing technological process of a corrosion-resistant aluminum profile provided by this application. As Figure 1 shown, a processing technology of a corrosion-resistant aluminum profile provided by the present invention includes step S1: melting aluminum ingots and alloy materials to form an aluminum substrate; wherein, the magnesium content in the alloy material is 0.4 - 0.6 wt%, the silicon content is 0.6 - 1.2 wt%, the iron content ≤ 0.35 wt%, the manganese content is 0.2 - 0.5 wt%, and the copper content ≤ 0.1 wt%.

[0016] Step S2: extruding the aluminum substrate into a profile with a desired cross-sectional shape; wherein, the extrusion temperature is controlled at 420 - 460 °C.

[0017] Step S3: performing honing treatment on the profile; wherein, the honing groove depth is 5 - 50 μm, the cross angle is 20 - 45°, and the surface roughness Ra ≤ 0.8 μm after honing.

[0018] Step S4: performing surface treatment on the surface of the profile; specifically, electrostatically spraying an epoxy resin-based corrosion-resistant coating on the surface of the profile, adding nano-silicon dioxide with a particle size of 5-20 μm and an organosilicon modification additive to the coating, and the total coating thickness is 100-400 μm; Step S5: performing curing treatment on the profile; specifically, baking at 180-200°C for 10-30 minutes.

[0019] The present invention provides a corrosion-resistant aluminum profile processing technology, which forms a fine Mg2Si strengthening phase through precise control of alloy ratio, taking into account both strength and corrosion resistance; limits Fe≤0.35wt% and Cu≤0.1wt% to reduce the corrosion activity of impurity phase, controls the extrusion temperature at 420-460℃, avoids grain coarsening caused by overheating, ensures material fluidity, improves molding quality, forms a micro-textured surface through honing, increases the contact area of the coating, and enhances mechanical bite force; adds nano-SiO2 and organosilicon modifiers to the epoxy resin-based coating, wherein nano-SiO2 improves the hardness and permeability resistance of the coating, organosilicon enhances hydrophobicity, synergistically inhibits the diffusion of corrosive media, and curing treatment promotes full cross-linking of epoxy resin to form a dense corrosion-resistant film layer. The processing technology significantly improves the corrosion resistance, surface quality and process sustainability of aluminum profiles.

[0020] As a further preferred technical solution of the above technical solution, in step S1, argon gas is used for smelting, the smelting temperature is 730-750°C, and the refining time is ≥15 minutes. Argon gas isolates oxidation and reduces slag inclusions; sufficient refining time ensures uniformity of alloy composition and reduces porosity.

[0021] As a further preferred technical solution of the above technical solution, in step S2, the extrusion die adopts a porous diverter die, the extrusion speed is 5-15m / min, and the traction force is controlled at 1.2-1.5 times the tensile strength of the profile. The porous diverter die improves the uniformity of metal flow and reduces surface wrinkles; the traction force matches the material strength to prevent the profile from deforming.

[0022] As a further preferred technical solution of the above technical solution, in the step S4, the profile is degreased and cleaned before surface treatment, and a phosphate-based environmentally friendly cleaning agent is used as the cleaning agent, the cleaning temperature is 50-60°C, and the cleaning time is 8-12 minutes. Phosphate esters are highly efficient in degreasing and have good biodegradability; temperature and time work together to ensure that oil stains are completely removed to avoid residues that affect the bonding of the coating.

[0023] As a further preferred technical solution of the above technical solution, in step S3, a diamond honing oilstone is used for honing, with an oilstone speed of 800-1200r / min and a reciprocating stroke of 0.5-1.0mm. The high hardness of diamond enables precise honing and uniform cross grain; parameter matching avoids surface overheating or over-cutting.

[0024] As a further preferred technical solution of the above technical solution, 0.5 - 1.5 wt% of isophorone diisocyanate (IPDI) curing agent is added to the epoxy resin-based coating, and the particle size of the curing agent is ≤5 μm. IPDI has high curing activity at low temperature, and the small particle size ensures uniform dispersion, improving the crosslinking density and chemical resistance of the coating.

[0025] As a further preferred technical solution of the above technical solution, after the step S5, the profile is subjected to plasma treatment after curing. The treatment power is 5 - 10 kW, the treatment time is 5 - 10 seconds, and the surface energy is ≥40 mN / m. Plasma etching removes surface organic substances and activates the substrate, and the high surface energy promotes coating wetting and chemical bonding.

[0026] As a further preferred technical solution of the above technical solution, after the profile is subjected to plasma treatment, the profile is sprayed. The spraying distance is 150 - 200 mm, the spraying pressure is 0.3 - 0.5 MPa, and the spraying environment adopts a three-stage filtration and purification system with filtration accuracies of 5 μm, 1 μm, and 0.1 μm respectively. Multi-stage filtration eliminates environmental particle pollution; the optimized spraying distance and pressure ensure coating uniformity and avoid orange peel or sagging.

[0027] It is worth mentioning that for those skilled in the art, the technical solutions described in the foregoing embodiments can still be modified, or some of the technical features can be equivalently replaced. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A processing technology for corrosion-resistant aluminum profiles, characterized in that, Including: Step S1: Melting aluminum ingots and alloy materials to form an aluminum base material; wherein, the magnesium content in the alloy material is 0.4 - 0.6 wt%, the silicon content is 0.6 - 1.2 wt%, the iron content ≤ 0.35 wt%, the manganese content is 0.2 - 0.5 wt%, and the copper content ≤ 0.1 wt%. Step S2: Extruding the aluminum base material into a profile with a desired cross-sectional shape; wherein, the extrusion temperature is controlled at 420 - 460 °C. Step S3: Honing the profile; wherein, the honing groove depth is 5 - 50 μm, the crossing angle is 20 - 45°, and the surface roughness Ra after honing ≤ 0.8 μm. Step S4: Surface-treating the surface of the profile; specifically, electrostatically spraying an epoxy resin-based corrosion-resistant coating on the surface of the profile, adding nano-silica with a particle size of 5 - 20 μm and an organosilicon-modified additive to the coating, and the total thickness of the coating is 100 - 400 μm. Step S5: Curing the profile; specifically, baking at 180 - 200 °C for 10 - 30 minutes.

2. The corrosion-resistant aluminum profile processing technology according to claim 1, characterized in that In the step S1, argon protection is adopted during the melting process, the melting temperature is 730 - 750 °C, and the refining time ≥ 15 minutes.

3. The corrosion-resistant aluminum profile processing technology according to claim 2, characterized in that In the step S2, a multi-hole split die is used for the extrusion die, the extrusion speed is 5 - 15 m / min, and the traction force is controlled at 1.2 - 1.5 times the tensile strength of the profile.

4. The corrosion-resistant aluminum profile processing technology according to claim 3, characterized in that, In the step S4, before surface treatment, the profile is degreased and cleaned, the cleaning agent uses a phosphate-based environmentally friendly cleaning agent, the cleaning temperature is 50 - 60 °C, and the cleaning time is 8 - 12 minutes.

5. The corrosion-resistant aluminum profile processing process according to claim 4, characterized in that, In the step S3, diamond honing oilstones are used during honing treatment, the rotational speed of the oilstones is 800 - 1200 r / min, and the reciprocating stroke is 0.5 - 1.0 mm.

6. The corrosion-resistant aluminum profile processing technology according to claim 5, characterized in that, 0.5 - 1.5 wt% of isophorone diisocyanate IPDI curing agent is added to the epoxy resin-based coating, and the particle size of the curing agent ≤ 5 μm.

7. The corrosion-resistant aluminum profile processing technology according to claim 6, characterized in that, After the step S5, after curing treatment, the profile is subjected to plasma treatment, the treatment power is 5 - 10 kW, the treatment time is 5 - 10 seconds, and the surface energy ≥ 40 mN / m.

8. The corrosion-resistant aluminum profile processing technology according to claim 7, characterized in that, After the profile is subjected to plasma treatment, the profile is sprayed, the spraying distance is 150 - 200 mm, the spraying pressure is 0.3 - 0.5 MPa, and the spraying environment adopts a three-stage filtration and purification system with filtration precisions of 5 μm, 1 μm, and 0.1 μm respectively.

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