High-precision manufacturing process and quality control method of aluminum alloy guide rail for rail transit

Abstract

The invention relates to the technical field of aluminum alloy guide rail machining processes, in particular to a high-precision manufacturing process of an aluminum alloy guide rail for rail transit, and the high-precision manufacturing process of the aluminum alloy guide rail specifically comprises the following steps: step 1, designing and smelting an alloy material, and utilizing component optimization to design an alloy formula to inhibit grain coarsening; impurity control: Fe < = 0.25%, and Mn < = 0.15%; the tensile strength is greater than or equal to 275MPa, and the ductility is greater than or equal to 12%, which is superior to that of similar products (conventionally less than or equal to 10%); micron-order precision control: the cross section dimensional tolerance is less than or equal to + / -0.15 mm (improved by 50% compared with the traditional process); 12 key parameters from smelting to finished products are monitored in real time, and the yield is increased to 99.8% from 92%.

Description

Technical Field

[0001] This application relates to the technical field of aluminum alloy guide rail processing technology, specifically to a high-precision manufacturing process and quality control method for aluminum alloy guide rails used in rail transit. Background Art

[0002] The descriptions in this section only provide background information related to the present disclosure and do not constitute prior art.

[0003] It is mainly used to support, guide, or restrain an object to move precisely and smoothly along a specific path. Its core function is to provide stable guiding and load-bearing capabilities for linear motion systems, and it is commonly found in fields such as industrial automation, mechanical equipment, precision instruments, rail transit, and aerospace.

[0004] Among them, the "processing technology of an aluminum alloy guide rail for photovoltaic module installation" disclosed in the patent application with the application number "CN104846222A" is also an increasingly mature technology. Its "melting temperature is 880°C - 850°C, and after holding for 1 - 3 hours, the furnace temperature is raised to 910°C - 940°C, and appropriate amounts of B, Mg, Mn, Cr, Si, Ni, Fe, Cu, V, Mo, Ti, and Nb are added to obtain alloy liquid, and rare earth elements are added to the alloy liquid. Among the rare earth elements, the following components are included by weight percentage: Gd: 15% - 18%, Pr: 3% - 5%, Dy: 7% - 9%, Ac: 12.5% - 12.8%, Nd: 15% - 20%, Sm: 11% - 13%, and the balance is Er; the processing technology of the aluminum alloy guide rail for photovoltaic module installation designed in this application enables the molten aluminum alloy liquid to have good fluidity, can fill narrow slots and gaps; has good thermal conductivity, and the heat of the molten aluminum can be quickly transferred to the mold, resulting in a shorter casting cycle; hydrogen and other harmful gases in the melt can be effectively controlled through treatment, and at the same time, it is easy to perform surface treatment and has good processing performance.

[0005] The high-precision manufacturing of aluminum alloy guide rails needs to cover multiple links such as melting, casting, extrusion, and aging. Existing quality control technologies have the following problems: Detection lag: Traditional physical and chemical detection relies on laboratory spot checks and cannot provide real-time feedback on casting pores (Φ > 0.5 mm) or extrusion deformation defects; Data isolation: The detection data of composition, size, and performance are scattered, lacking multi-parameter correlation analysis, resulting in difficulties in tracing the root cause of abnormalities.

[0006] Therefore, it is necessary to provide a high-precision manufacturing process and quality control method for aluminum alloy guide rails used in rail transit to solve the above problems. Summary of the Invention

[0007] In view of the deficiencies of the prior art, this application provides a high-precision manufacturing process and quality control method for aluminum alloy guide rails used in rail transit, solving the problems raised in the background art.

[0008] To achieve the above object, the present application provides the following technical solutions: a high-precision manufacturing process for an aluminum alloy guide rail used in rail transit. The high-precision manufacturing process of the aluminum alloy guide rail specifically includes the following steps: Preferably, Step 1: Alloy material design and melting. Optimize the alloy formula (mass percentage) for composition: Main components: Al (92%-94%), Si (0.6%-1.0%), Mg (1.0%-1.4%), Cu (0.3%-0.5%); Micro-alloying elements: Ti (0.08%-0.12%), Zr (0.05%-0.1%), used to inhibit grain coarsening; Impurity control: Fe≤0.25%, Mn≤0.15%; Use a vacuum induction melting furnace (vacuum degree ≤10⁻³ Pa), melting temperature 740%-760°C; Remove the hydrogen content in the melt to ≤0.12 mL / 100g through a rotary degassing device (argon gas flow rate 20-30 L / min); Add a refining agent for degassing treatment, and control the hydrogen content to ≤0.15 mL / 100g. Before pouring, use a ceramic filter (pore diameter ≤0.5 mm) to filter inclusions.

[0009] Preferably, Step 2: Semi-continuous casting and homogenization treatment: Semi-continuous casting forming, casting temperature 690%-710°C, cooling water flow rate 3-5 m³ / h, ingot diameter Φ200-300 mm; Casting speed (80-100) mm / min, to avoid shrinkage cavities and cracks.

[0010] Preferably, Step 3: Hot extrusion forming and temperature-controlled cooling: Die preheating temperature (450-480)°C, blank heating temperature (490-510)°C, temperature difference ≤20°C; Extrusion ratio 10:1-15:1, extrusion speed (4-6) m / min, back pressure control (5-8) MPa, to reduce surface transverse cracks: After extrusion, cool in sections: The first stage: Air-cool to 300%-350°C (rate 8-10°C / s); The second stage: Water mist-cool to room temperature (rate 15-20°C / s), to avoid residual stress concentration.

[0011] Preferably, Step 4: Solution treatment: Heat in a salt bath furnace to 535%-545°C, hold for (2.5-3) h, and perform rapid water quenching (transfer time ≤8 s).

[0012] Preferably, Step Five: Rough Machining and Semi-Finishing: Rough Milling: Cemented Carbide Tool, Cutting Depth (2 - 3) mm, Feed Rate (0.1 - 0.2) mm / r; Semi-Finish Milling: Diamond Coated Tool, Cutting Depth (0.5 - 1) mm, Surface Roughness Ra ≤ 1.6 μm, Using a CNC Guideway Grinder (Resolution 0.1 μm): Grinding Wheel Grain Size #800 - #1200, Linear Velocity (25 - 30) m / s; Grinding Amount ≤ 0.02 mm / time, Final Dimension Tolerance ±0.005 mm.

[0013] Preferably, Step Six: Surface Strengthening and Protection: Electrolyte: Silicate System (Na 2 SiO 3 10 g / L - 15 g / L, KOH 2 g / L - 4 g / L); Voltage 400V - 500 V, Frequency 500Hz - 800 Hz, Oxide Film Thickness (20 - 30) μm, Hardness ≥ 1200 HV.

[0014] Preferably, the high-precision manufacturing quality control method for aluminum alloy guideways used in rail transit includes the following steps: Step One, Raw Material Pretreatment: The surface of the aluminum ingot is sandblasted to remove the oxide layer, preheated to (150 ± 10) °C, and held for 1 hour to reduce the melting energy consumption.

[0015] Step Two, Melting and Refining Control: Melting is carried out under inert gas protection, temperature (720 - 750) °C, melting time ≤ 40 minutes, stirring rate (200 - 300) rpm, avoiding local overheating, using electromagnetic stirring combined with bottom argon blowing to reduce inclusions; Online Refining: Adding a refining agent (Na2SiF6) for degassing, refining time (15 - 20) minutes, hydrogen content controlled at ≤ 0.15 ml / 100gAl, and using a rapid hydrogen detector for real-time monitoring.

[0016] Step Three, Continuous Casting and Homogenization Treatment: Casting temperature (680 - 700) °C, cooling rate ≥ 50 °C / s, billet cross-section dimension tolerance ±0.5 mm, using a two-stage cooling system, primary water cooling (flow rate 10 m³ / h), secondary fog cooling (pressure 0.3 MPa); Homogenization Treatment: Gradually heating to 590 °C and holding for 4 hours, then cooling to 300 °C at a rate of 30 °C / h to eliminate dendritic segregation.

[0017] Step Four, Extrusion Forming and Online Quenching: Die preheating temperature 450 °C, extrusion cylinder temperature 420 °C, extrusion ratio 20:1, speed (2 - 3) m / min; Control parameters: Dynamically adjust the extrusion speed through the PLC to ensure that the straightness of the profile is ≤0.1 mm / m. For water spray quenching, the water temperature is (20 - 30)°C, the quenching transfer time is ≤8 seconds, and the cooling rate is ≥200°C / min.

[0018] Step Five: Aging strengthening and surface treatment. First stage: 120°C × 6 h, second stage: 180°C × 2 h, air-cooled to room temperature; Anodic oxidation treatment: Electrolyte: Sulfuric acid concentration is 180 g / L, current density is 1.5 A / dm², time is 30 minutes, and the film thickness is (15 - 20) μm.

[0019] Step Six: Quality inspection and data feedback: Use an X-ray diffractometer to detect the residual stress (≤50 MPa), and a laser rangefinder to detect the straightness of the guide rail (≤0.05 mm / m).

[0020] Data closed-loop control: Feed the detected data back to the melting and extrusion process parameter database, and automatically optimize the production parameters (such as adjusting the melting temperature by ±5°C).

[0021] Compared with the prior art, the beneficial effects of this application are: This application provides a high-precision manufacturing process and quality control method for aluminum alloy guide rails used in rail transit: Synergy of high strength and high toughness: The tensile strength is ≥275 MPa while the elongation rate is ≥12%, which is better than similar products (conventional ≤10%); Micron-level precision control: The cross-sectional dimension tolerance is ≤±0.15 mm (a 50% improvement compared to traditional processes); Full-life cycle quality control: 12 key parameters from melting to finished products are monitored in real time, and the yield rate is increased from 92% to 99.8%. Brief Description of the Drawings

[0022] Figure 1 It is a flow diagram of this application. Detailed Description of the Embodiments

[0023] Next, the technical solutions in the embodiments of this application will be clearly and completely described in conjunction with the drawings in the embodiments of this application. Obviously, the described embodiments are only a part of the embodiments of this application, rather than all of the embodiments. Based on the embodiments in this application, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of this application.

[0024] As Figure 1 shown, the high-precision manufacturing process of the aluminum alloy guide rail for rail transit proposed in this application specifically includes the following steps: Step One: Alloy material configuration and melting; Step Two: Semi-continuous casting and uniform processing; Step 3: Hot extrusion forming and temperature-controlled cooling; Step 4: Solution treatment; Step 5: Rough machining and semi-finishing machining; Step 6: Material strengthening and protection.

[0025] According to the alloy material configuration and melting in Step 1, the mass percentage of the alloy formula is optimized by composition design: Main components: Al (80% - 88%), Si (0.5% - 1.3%), Mg (1.1% - 1.3%), Cu (0.4% - 0.7%), Ti (0.06% - 0.15%), Zr (0.07% - 0.4%), Fe ≤ 0.25%, Mn ≤ 0.15%; Using a vacuum induction melting furnace (vacuum degree ≤ 10³ Pa), the melting temperature is 700% - 760 °C; removing the hydrogen content in the melt to ≤ 0.12 mL / 100 g through a rotary degassing device (argon flow rate 20 L / min - 30 L / min), adding a refining agent for degassing treatment, controlling the hydrogen content at ≤ 0.15 mL / 100 g, and filtering inclusions with a ceramic filter (pore diameter ≤ 0.5 mm) before pouring for high-temperature processing and melting.

[0026] According to Step 2, for semi-continuous casting and uniform processing, semi-continuous casting is carried out, the casting temperature is 690 - 710 °C, the cooling water flow rate is 3 - 5 m³ / h, the casting speed is (80 - 100) mm / min, to avoid shrinkage cavities and cracks.

[0027] Step 3: Hot extrusion forming and temperature-controlled cooling: The preheating temperature of the mold is (450 - 480) °C, the heating temperature of the blank is (490 - 510) °C, and the temperature difference ≤ 20 °C; the extrusion ratio is 10:1 - 15:1, the extrusion speed is (4 - 6) m / min, the back pressure is controlled at (5 - 8) MPa, reducing the transverse cracks on the surface of the aluminum alloy rail for rail transit. After extrusion, the aluminum alloy rail for rail transit after melting is cooled in segments by air cooling to (300 - 350) °C, and then water mist cooled to room temperature (rate 15 °C / s - 20 °C / s) to avoid residual stress concentration.

[0028] According to Step 4: Solution treatment of the aluminum alloy rail for rail transit, heat it in a salt bath furnace to (500 - 530) °C, hold for (3.5 - 5) h, and perform rapid water quenching.

[0029] According to Step 5, rough milling is carried out on the aluminum alloy rail for rail transit with a carbide tool, the cutting depth is (2 - 3) mm, the feed rate is (0.1 - 0.2) mm / r, a numerical control rail grinding machine (resolution 0.1 μm) is used, and the grinding wheel grit size is #800 - #1200 for grinding, the linear speed is (25 - 30) m / s; the grinding amount ≤ 0.04 mm / time, and the final dimensional tolerance is ±0.008 mm.

[0030] Strengthen and protect the silicate system (KOH 2 - 4 g / L) according to the materials described in Step Six; voltage (400 - 500) V, frequency (300 - 500) Hz, oxide film thickness (40 - 70) μm, hardness ≥ 1600 HV.

[0031] A high-precision manufacturing quality control method for aluminum alloy guide rails used in rail transit, comprising the following steps: Step One, raw material pretreatment: The surface of the aluminum alloy guide rail is sandblasted to remove the oxide layer, preheated to 120 ± 10 °C, and kept warm for 2 hours to reduce the melting energy consumption; Step Two, melting and refining control: Melting is carried out under the protection of inert gas, temperature (700 - 750) °C, melting time ≤ 20 minutes, stirring rate (100 - 200) rpm, avoiding local overheating, using electromagnetic stirring combined with bottom argon blowing to reduce inclusions; Online refining: Adding a refining agent (Na2SiF6) for degassing, refining time (10 - 15) minutes, hydrogen content controlled at ≤ 0.17 ml / 200 g Al, and using a rapid hydrogen detector for real-time monitoring; Step Three, continuous casting and homogenization treatment: Casting temperature (690 - 700) °C, cooling rate ≥ 30 °C / s, cross-sectional dimension tolerance of the billet ± 0.4 mm, using a two-stage cooling system, primary water cooling (flow rate 10 m³ / h), secondary fog cooling (pressure 0.3 MPa); Homogenization treatment: Gradually heat up to 590 °C and keep warm for 2 hours, then cool down to 200 °C at a rate of 50 °C / h to eliminate dendritic segregation.

[0032] Step Four, extrusion forming and online quenching: Die preheating temperature 480 °C, extrusion cylinder temperature 400 °C, extrusion ratio 10:1, speed (3 - 6) m / min; Control parameters: Dynamically adjust the extrusion speed through PLC to ensure that the straightness of the profile ≤ 0.2 mm / m, water mist quenching, water temperature (40 - 70) °C, quenching transfer time ≤ 6 seconds, cooling rate ≥ 100 °C / min.

[0033] Step Five, aging strengthening and surface treatment, the first stage: 150 °C × 3 h, the second stage: 160 °C × 1 h, air-cooled to room temperature; Anodic oxidation treatment: Sulfuric acid concentration 180 g / L, current density 1.5 A / dm², time 20 minutes, film thickness 13 - 19 μm.

[0034] Step Six, quality inspection and data feedback: Use an X-ray diffractometer to detect the residual stress (≤ 50 MPa), and a laser rangefinder to detect the straightness of the guide rail (≤ 0.05 mm / m).

[0035] Data closed-loop control: Feed the detected data back to the melting and extrusion process parameter database, and automatically optimize the production parameters (such as adjusting the melting temperature by ±5°C).

[0036] The above are all preferred embodiments of this application. The protection scope of this application is not limited thereby. Therefore, all equivalent changes made according to the structure, shape, and principle of this application shall be covered within the protection scope of this application.

Claims

1. High-precision manufacturing process of aluminum alloy guide rails for rail transit, characterized in that: The high-precision manufacturing process of the aluminum alloy guide rail specifically includes the following steps: Step 1: alloy material preparation and smelting; Step 2: semi-continuous casting and uniform processing; Step 3: hot extrusion molding and temperature controlled cooling; Step 4: solution treatment; Step 5: Rough machining and semi-finishing; Step 6: Material reinforcement and protection.

2. The high-precision manufacturing process of aluminum alloy guide rails for rail transit according to claim 1 is characterized in that: According to the alloy material configuration and smelting described in step 1, the composition is optimized and designed, and the alloy formula is as follows: main components: Al (80%-88%), Si (0.5%-1.3%), Mg (1.1%-1.3%), Cu (0.4%-0.7%), Ti (0.06%-0.15%), Zr (0.07%-0.4%), Fe≤0.25%, Mn≤0.15%; A vacuum induction melting furnace (vacuum degree ≤10³Pa) is used, and the melting temperature is 700%-760℃; the hydrogen content of the melt is removed to ≤0.12mL / 100g by a rotary degassing device (argon flow rate 20-30L / min), and a refining agent is added for degassing treatment, and the hydrogen content is controlled at ≤0.15mL / 100g. Before pouring, a ceramic filter (pore size ≤0.5mm) is used to filter inclusions, and high-temperature processing and melting are performed.

3. The high-precision manufacturing process of aluminum alloy guide rails for rail transit according to claim 1, characterized in that: According to the semi-continuous casting and uniform processing described in step 2, the semi-continuous casting is formed, the casting temperature is 690-710°C, the cooling water flow rate is (3-5) m³ / h, and the casting speed is (80-100) mm / min to avoid shrinkage holes and cracks.

4. The high-precision manufacturing process of aluminum alloy guide rails for rail transit according to claim 1, characterized in that: Step 3: Hot extrusion molding and temperature-controlled cooling: mold preheating temperature (450-480)℃, billet heating temperature (490-510)℃, temperature difference ≤20℃; extrusion ratio 10:1-15:1, extrusion speed (4-6)m / min, back pressure control (5-8)MPa, reduce transverse cracks on the surface of aluminum alloy guide rails for rail transit, and cool in sections after extrusion. The smelted aluminum alloy guide rails for rail transit are air-cooled to 300-350℃, and then water-mist cooled to room temperature at a rate of (15-20)℃ / s to avoid residual stress concentration.

5. The high-precision manufacturing process of aluminum alloy guide rails for rail transit according to claim 1, characterized in that: According to step 4: solution treatment of aluminum alloy guide rails for rail transit, heat the salt bath furnace to (500-530) ° C, keep warm for (3.5-5) h, and quickly quench with water.

6. The high-precision manufacturing process of aluminum alloy guide rails for rail transportation according to claim 1, characterized in that: According to the rough milling carbide tool described in step five, the aluminum alloy guide rail for rail transit is processed with a cutting depth of (2-3) mm and a feed rate of (0.1-0.2) mm / r. A CNC guide rail grinder (resolution 0.1 μm) is used with a grinding wheel grit of #800-#1200 for grinding, and a linear speed of (25-30) m / s; the grinding amount is ≤0.04 mm / time, and the final dimensional tolerance is ±0.008 mm.

7. The high-precision manufacturing process of aluminum alloy guide rails for rail transportation according to claim 1, characterized in that: According to the material strengthening and protection silicate system (KOH2-4g / L) described in step six; voltage (400-500) V, frequency (300-500) Hz, oxide film thickness (40-70) μm, hardness ≥1600 HV.

8. A high-precision manufacturing quality control method for aluminum alloy guide rails for rail transit, comprising the high-precision manufacturing process for aluminum alloy guide rails for rail transit described in 1-7 above, characterized in that: The steps include: Step 1: Raw material pretreatment: The surface of the aluminum alloy guide rail is sandblasted to remove the oxide layer, preheated to (120±10)℃, and kept warm for 2 hours to reduce smelting energy consumption; Step 2: Melting and refining control: Melting under inert gas protection, temperature (600-7500)℃, melting time ≤20 minutes, stirring rate (100-200)rpm, avoid local overheating, use electromagnetic stirring combined with bottom argon blowing to reduce inclusions; Online refining: add refining agent (Na2SiF6) for degassing, refining time (10-15) minutes, hydrogen content is controlled at ≤0.15ml / 200gAl, and real-time monitoring is performed using a rapid hydrogen meter; Step 3: Continuous casting and homogenization treatment: casting temperature (690-700)℃, cooling rate ≥30℃ / s, billet cross-sectional dimension tolerance ±0.4mm, two-stage cooling system, first-stage water cooling (flow rate 10m³ / h), second-stage mist cooling (pressure 0.3MPa); Homogenization treatment: Gradient heating to 590℃ for 2 hours, then cooling to 200℃ at 50℃ / h to eliminate dendrite segregation; Step 4: Extrusion molding and online quenching: mold preheating temperature 400°C, extrusion barrel temperature 500°C, extrusion ratio 10:1, speed (3-6) m / min; Control parameters: Dynamically adjust the extrusion speed through PLC to ensure that the profile straightness is ≤0.2mm / m, water mist quenching, water temperature (40-70)℃, quenching transfer time ≤6 seconds, cooling rate ≥200℃ / min; Step 5: Aging strengthening and surface treatment, first stage: 150℃×3h, second stage: 160℃×1h, air cooling to room temperature; Anodizing treatment: sulfuric acid concentration 180g / L, current density 1.5A / dm², time 20 minutes, film thickness 13-19μm; Step 6: Quality inspection and data feedback: Use X-ray diffractometer to detect residual stress (≤50MPa) and laser rangefinder to detect guide rail straightness (≤0.05mm / m); Data closed-loop control: Feedback the detection data to the melting and extrusion process parameter database to automatically optimize the production parameters (such as adjusting the melting temperature by ±5°C).

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