Atas 8 Kaedah pemutus aloi tembaga dan tembaga

1. Pengenalan

Copper and its alloys occupy a pivotal role in modern industry due to their outstanding electrical conductivity, Rintangan kakisan, dan prestasi terma.

Dari segi sejarah, civilizations dating back to 5000 BC mastered copper casting in simple stone molds, laying the groundwork for today’s sophisticated techniques.

Dalam artikel ini, we explore the full spectrum of copper‑based casting methods, examine their metallurgical principles, and guide engineers in selecting the optimal process for diverse applications.

2. Fundamental Principles of Metal Casting

Every casting method follows four core stages:

1. Penciptaan acuan – Technicians form a cavity in sand, logam, seramik, or plaster that mirrors the part geometry.
2. Mencurahkan – Furnaces melt copper (titik lebur 1 083 ° C.) or alloys up to 1 600 ° C., then pour the liquid into molds.
3. Pemejalan – Controlled cooling—guided by thermal conductivity (~ 400 W/m·K for copper) and mold material—drives microstructure development.
4. Shake‑Out – Once solid, castings exit the mold and undergo cleaning and post‐processing.

Copper’s high thermal conductivity demands higher mold preheat (200-400 ° C.) and precise pour control to maintain fluidity (viscosity ~ 6 mPa·s at 1 200 ° C.).

Di samping itu, copper’s pengembangan haba (16.5 μm/m · k) requires exact pattern offsets to achieve final dimensions.

3. Major Copper Alloy Casting Methods

Tembaga and its alloys—brasses, gangsa, copper-nickels, and others—are cast using a range of methods that suit different production volumes, keperluan mekanikal, and dimensional tolerances.

Each technique carries distinct advantages and limitations based on alloy characteristics and desired component outcomes.

This section explores the most prominent copper alloy casting methods in modern manufacturing, along with technical insights to guide process selection.

Pemutus pasir

Gambaran keseluruhan proses & Peralatan
Pemutus pasir remains one of the oldest and most widely used methods for casting copper alloys. It involves packing sand around a reusable pattern inside a mold box.

The sand is bonded with clay (pasir hijau) or hardened with chemicals (resin-bonded or CO₂-activated sands). After pattern removal, logam cair dituangkan ke dalam rongga.

 

Kelebihan

• Kos perkakas yang rendah, sesuai untuk rendah- Untuk berjalan lantang sederhana
• Flexible part sizes—from a few ounces to several tons
• Broad alloy compatibility

Batasan

• Coarse surface finishes (RA 6.3-25 μm)
• Loose tolerances (typically ±1.5–3 mm)
• Requires post-casting machining for most precision applications

Pelaburan (Hilang-Alat) Casting

Precision Shell Building
Pelaburan Pelaburan uses a wax model coated with ceramic slurry to build a thin, high-accuracy shell mold. After burnout, molten metal is poured into the preheated ceramic mold.

Faedah

• Cemerlang Ketepatan dimensi (± 0.1-0.3 mm)
• Sesuai untuk rumit, thin-walled geometries
• Superior kemasan permukaan (RA 1.6-3.2 μm)

Cabaran

• Higher tooling costs (due to the need for injection dies)
• Longer cycle times, especially for shell construction and burnout
• Typically economical only for medium-to-high volume pengeluaran

Shell Molded Casting

Process Details
Shell molding uses a heated metal pattern coated with resin-bonded sand. When exposed to heat, the resin sets to form a thin shell that acts as the mold.

The process produces more accurate and cleaner castings than traditional sand casting.

Kelebihan

• Improved surface quality and definition
• Tighter tolerances than green sand molds
• Reduced machining allowance due to near-net shape casting

Batasan

• Higher material costs (specialized resins and silica sands)
• Expensive pattern tooling (metal patterns required)

Pemutus Centrifugal

Mendatar vs. Vertical Setups
Dalam pemutus sentrifugal, logam cair dicurahkan ke dalam acuan berputar, either horizontally or vertically.

The centrifugal force distributes the metal against the mold wall, minimizing porosity and ensuring excellent material integrity.

Kelebihan utama

• High density and reduced porosity—ideal for pressure-retaining components
• Pengukuhan arah enhances mechanical properties
• Sesuai untuk bushings, cincin, tiub, and hollow parts
• Vertical casting often used for small parts; horizontal for large cylinders

Batasan

• Terhad kepada Bahagian simetri berputar
• Tooling setup is more complex and costly than static casting

Chill Casting

Kawalan pemejalan
Chill casting uses metal molds (often iron or steel) to rapidly extract heat from the molten metal. This rapid solidification refines the grain structure and enhances mechanical properties.

Kekuatan

• Produces lebih sukar, denser castings (hingga 50% increase in hardness vs. Pemutus pasir)
• Excellent for phosphor bronze and gunmetal
• Cost-effective for repetitive casting of bars, batang, dan bahagian kecil

Batasan

• Less suited for geometri kompleks
• Limited size range due to mold constraints

Mati Casting (Hot-Chamber and Cold-Chamber)

Pressure Injection Process
Die casting involves injecting molten copper alloys into a high-strength steel mold under high pressure.

Cold-chamber machines are typically used due to the high melting points of copper alloys.

Kelebihan

• Fast production rates—ideal for mass production
• Superior surface finish and precision (Ra 1–2 µm, tolerances ±0.05 mm)
• Reduces or eliminates machining

Constraints

• Not all copper alloys are suitable (Mis., high zinc brasses can corrode dies)
• Die tooling is mahal (investment of $50,000 atau lebih)
• Terbaik untuk medium to high volumes

Pemutus berterusan

Gambaran keseluruhan proses
Molten metal is poured into a water-cooled mold that continuously forms and pulls solidified metal through a withdrawal system.

Common outputs include rods, bar, and billets for downstream machining or rolling.

Kelebihan

• Produktiviti yang tinggi with minimal human intervention
• Excellent mechanical properties due to controlled solidification
• Smooth surfaces and straightness suitable for automatic feed machining
• Low scrap rate and better yield (berakhir 90% penggunaan bahan)

Aloi biasa

• Tin bronzes, leaded bronzes, phosphor bronzes, and copper-nickels

Plaster Mould Casting

Penggunaan khusus
This process employs plaster or ceramic molds formed around a pattern to capture fine detail and tight tolerances.

The mold is removed after casting by breaking or dissolving the plaster.

Kelebihan

• Excellent for bentuk rumit dan Permukaan halus selesai
• Good for prototaip dan volum rendah pengeluaran

Kelemahan

• Kebolehtelapan yang rendah—limits to casting size
• Longer preparation time dan limited mold life

Jadual perbandingan ringkasan

4. Common Copper Alloys Used in Casting

Foundries cast a wide array of copper‑based alloys, each engineered to balance mechanical strength, Rintangan kakisan, thermal and electrical performance, dan kebolehan.

5. Kesimpulan

Copper and copper‑alloy foundries offer a rich toolbox of casting methods—each balancing kos, ketepatan, prestasi mekanikal, dan Jumlah pengeluaran.

By understanding process nuances—from mold materials and thermal management to alloy behavior—engineers can optimize part design, minimize scrap, and ensure reliable performance.

As technologies like additive mold fabrication dan real‑time simulation matang, copper casting will continue to evolve, sustaining its critical role in high‑performance manufacturing.

Pada Ini, Kami dengan senang hati membincangkan projek anda pada awal proses reka bentuk untuk memastikan bahawa apa sahaja aloi dipilih atau rawatan pasca-casting digunakan, Hasilnya akan memenuhi spesifikasi mekanikal dan prestasi anda.

Untuk membincangkan keperluan anda, e -mel [email protected].

Soalan Lazim

Can all copper alloys be die-cast?

Tidak. Only specific alloys like aluminum bronzes, high-tensile brasses, dan silicon brasses are suitable for Mati Casting due to the high pressures and rapid cooling involved.

Aloi seperti Gangsa fosfor atau gunmetal are better suited to sand or chill casting.

What’s the difference between centrifugal and chill casting?

• Pemutus Centrifugal uses rotational force to push molten metal into the mold, producing dense, defect-free components (ideal for pipes, bushings, dan lengan baju).
• Chill casting uses static metal molds to rapidly solidify the surface, improving mechanical properties and reducing grain size—especially effective for tin bronzes.

Why is continuous casting preferred for high-volume copper alloy bars?

Pemutus berterusan offers consistent quality, sifat mekanikal yang sangat baik, and low scrap rates.

It’s optimal for Gangsa fosfor, gunmetal, dan Gangsa yang dipimpin Billet, especially when integrated with rolling or extrusion processes.

What post-processing is required after casting copper alloys?

Depending on the casting method and alloy, post-processing may include:

• Heat treatment for stress relief or aging (especially for beryllium copper)
• Machining for critical surfaces or tight tolerances
• Surface finishing such as polishing or coating for corrosion protection or aesthetics