Dökme çelik vs dökme demir: Anahtar farklılıklar, Özellikler & Başvuru

1. giriiş

Cast steel and cast iron are both ferrous metals produced through melting and casting processes.

Though they share a base element—iron—their properties, başvuru, and performance characteristics differ significantly due to variations in carbon content and alloying elements.

Choosing between cast steel and cast iron is crucial for engineers, üreticiler, and designers because it directly impacts the strength, işlenebilirlik, korozyon direnci, and overall lifecycle cost of a component.

This article explores the metallurgy, mekanik davranış, üretim yöntemleri, and end-use suitability of cast steel and cast iron in depth.

2. What Is Cast Iron?

Dökme demir bir grup demir-karbon alaşımı carbon content typically between 2.0% Ve 4.0%, along with varying levels of silicon (1.0–3.0%), manganez, sülfür, ve fosfor.

This high carbon content differentiates it from steel and gives cast iron its distinct physical and mechanical properties.

It is one of the oldest and most widely used ferrous metals in engineering and manufacturing, valued for its Mükemmel Dökülebilirlik, Titreşim sönümleme, Ve sıkıştırma mukavemeti.

Tarihsel bağlam

The use of cast iron dates back to 5th century BC in China, with widespread industrial adoption beginning in the 15th century.

It revolutionized construction, makine, ve ulaşım, making its way into everything from bridges and pipes to engines and cookware.

Key Types of Cast Iron

Key Characteristics of Cast Iron

• High Carbon Content: Enhances castability and wear resistance but reduces ductility.
• Mükemmel Dökülebilirlik: Düşük erime noktası (≈1150–1200 °C) and good fluidity allow intricate, büyük, and complex shapes to be cast easily.
• Good Damping Capacity: Particularly in gray iron, which absorbs vibration well, making it ideal for machinery bases.
• Kırmızlık: Most forms, especially gray and white cast iron, fracture under tensile or impact loads.
• Termal iletkenlik: Effective for heat distribution, making it a good material for engine parts and cookware.
• Korozyon direnci: Moderate without coatings, though improved with certain alloying elements or surface treatments.

3. What Is Cast Steel?

Çelik is a category of iron-carbon alloys with a carbon content typically ranging from 0.1% ile 0.5%, produced by melting and casting the molten steel into molds to form specific shapes.

Unlike cast iron, cast steel has a lower carbon content, which results in significantly daha yüksek süneklik, sertlik, ve kaynaklanabilirlik.

It is especially favored for applications involving dynamic loads, darbe direnci, Ve Direnç Giymek.

Tarihsel bağlam

While wrought steel dates back to antiquity, cast steel became widely available in the 19th century following advancements in steel-making processes such as the Bessemer and open-hearth methods.

Bugün, cast steel is a vital material in structural, otomotiv, madencilik, and pressure-containing applications due to its strength and versatility.

Key Types of Cast Steel

Key Characteristics of Cast Steel

• Lower Carbon Content: Typically 0.1–0.5%, resulting in superior ductility and weldability compared to cast iron.
• Yüksek güç & Sertlik: Cast steel offers Mükemmel mekanik özellikler, including high tensile strength and resistance to shock loading.
• Isıya göre tedavi edilebilir: Unlike cast iron, cast steel can be heat-treated (söndürülmüş, temkinli, normalleştirilmiş) to enhance hardness, sertlik, ve aşınma direnci.
• Kaynaklanabilirlik: Excellent for fabrication, repair, and joining—ideal for components that may need modification or maintenance.
• İşlenebilirlik: Genellikle iyi, though varies with alloy composition and heat treatment state.
• Korozyon direnci: Varies widely depending on alloying elements. Stainless grades are highly corrosion-resistant.

4. Karşılaştırma tablosu: Dökme çelik vs dökme demir

5. Common Casting Methods: Dökme çelik vs dökme demir

Casting method selection is pivotal for cost control, boyutsal hassasiyet, mekanik performans, and production scale.

Cast steel and cast iron share several casting techniques, but each material presents unique challenges due to differences in melting point, katılaşma davranışı, and alloy reactivity.

Casting Methods for Cast Steel

Cast Steel Sand Casting

Kum dökümü is the most widely used method for producing cast steel parts, especially for medium to large components.

Bir desen (odun, metal, or resin) is used to shape a cavity in sand—either green (clay-bound) or chemically bonded.

Because cast steel requires high pouring temperatures (1,450–1,600 ° C), mold materials and gating systems must be designed to handle thermal shock, erozyon, and shrinkage.

Common Parts: Dişli kutuları, valf gövdeleri, yapısal parantez.

Cast Steel Investment Casting (Kayıp balmumu)

Yatırım kadrosu excels at producing intricate shapes with thin walls and tight tolerances. A wax pattern is coated in ceramic slurry, forming a shell that is later dewaxed and fired.

This high-precision process is ideal for cast steel due to its ability to minimize machining, especially for complex aerospace, tıbbi, or energy components.

Common Parts: Türbinli bıçaklar, tıbbi aletler, military components.

Cast Steel Shell Mold Casting

Kabuk kalıplama uses a heated metal pattern to cure a resin-coated sand shell. It provides superior surface finish and dimensional consistency compared to traditional sand casting.

For steel, the process is particularly effective when medium-complexity components with high repeatability are needed.

Common Parts: Engine mounts, hydraulic brackets, bearing caps.

Cast Steel Centrifugal Casting

İçinde savurma döküm, molten steel is poured into a rotating mold.

The high-speed spinning distributes the metal outward against the mold wall, increasing density and reducing defects like inclusions or gas porosity.

Particularly useful for cylindrical or tubular parts, this method produces components with a fine-grained, highly uniform structure.

Common Parts: Çelik borular, kollar, and rings for oil & gas or rail applications.

Cast Steel Continuous Casting (for Semi-Finished Products)

Although not used for near-net or finished parts, continuous casting is essential in the steel industry to produce billets, blooms, and slabs.

Molten steel is poured into a water-cooled mold, solidifying as it is drawn out. These forms are later processed via forging, işleme, veya yuvarlanan.

Ürünler: Bar stock, yapısal kirişler, sheet steel.

Casting Methods for Cast Iron

Cast Iron Green Sand Casting

Green sand casting remains the dominant method for cast iron due to its low cost, Geri dönüşüm, ve uyarlanabilirlik.

The “green” refers to the moisture content in the sand, which is bonded with bentonite clay.

Cast iron’s excellent fluidity and lower melting point (1,100–1,250°C) make it perfectly suited for this process.

Common Parts: Rögar kapakları, motor blokları, kompresör muhafazaları.

Cast Iron No-Bake (Reçine bağlı) Kum dökümü

In no-bake molding, sand is mixed with a resin and catalyst that cures at room temperature, forming strong, rigid molds.

This process is preferred for large cast iron parts that require better dimensional accuracy and smoother surfaces than green sand can provide.

Common Parts: Large machine bases, industrial housings, pervane.

Cast Iron Shell Mold Casting

Shell mold casting is used less often in iron but remains beneficial when tighter tolerances or smoother finishes are needed. Resin-coated sand forms a thin, semi-rigid shell around the pattern.

Because cast iron flows well, this process ensures minimal flashing and fine edge definition.

Common Parts: Dişli Konutları, valf gövdeleri, decorative ironwork.

Cast Iron Centrifugal Casting

Widely used for ductile iron pipe and cylinder liners, centrifugal casting leverages rotational force to distribute molten metal within a mold.

For cast iron, this enhances nodule formation (in ductile grades), gözenekliliği azaltır, and promotes grain refinement.

Common Parts: Boru bölümleri, vodifikler, and brake drums.

Cast Iron Lost Foam Casting

Kayıp köpük döküm uses a polystyrene pattern embedded in unbonded sand. When molten cast iron is poured in, the foam evaporates, forming the shape with minimal gas entrapment due to iron’s lower reactivity.

This method excels for complex geometries without parting lines or cores.

Common Parts: Engine manifolds, pompa gövdeleri, ornamental castings.

Key Differences in Casting Characteristics

6. Heat Treatment and Weldability: Dökme çelik vs dökme demir

Isıl işlem and weldability are critical factors influencing the performance, hizmet ömrü, and repairability of cast components.

The fundamental metallurgical differences between cast steel and cast iron directly impact how each material responds to thermal processing and welding.

Çelik

Isıl işlem:

Cast steel generally contains lower carbon (0.1–0.5) and is more amenable to a variety of heat treatments to tailor its mechanical properties. Common heat treatments include:

• Tavlama: Softens the steel, reduces residual stresses, and improves machinability.
• Normalleştirme: Refines grain structure by heating above critical temperature (~870–950°C) ardından hava soğutması; enhances strength and toughness.
• Söndürme ve temperleme: Hızlı Soğutma (söndürme) from the austenitizing temperature (~900–1,000°C) to form martensite, followed by tempering to balance hardness and ductility.
  This process is essential for wear-resistant or high-strength cast steel parts.

These heat treatments allow cast steel to achieve a wide range of mechanical properties, including high tensile strength (400–800 MPa), improved impact toughness, and controlled hardness.

Kaynaklanabilirlik:

Cast steel’s relatively low carbon content and homogeneous microstructure make it highly weldable. It can be welded using conventional techniques such as:

• Korumalı metal ark kaynağı (Susmak)
• Gaz tungsten ark kaynağı (GTAW)
• Flux-Cored Arc Welding (FCAW)

Fakat, care must be taken to control preheat and post-weld heat treatment to avoid cracking, especially in alloyed cast steels or thick sections.

The weld metal can closely match the base material properties, allowing effective repair and joining.

Dökme demir

Isıl işlem:

Dökme demir, with its high carbon content (2.0–4.0%) and presence of graphite flakes or nodules, reacts differently to heat treatment:

• Tavlama: Often applied to malleable iron to reduce hardness and improve ductility.
• Normalleştirme: Sınırlı kullanım, primarily to modify microstructure in white cast iron.
• Stres rahatlatıcı: Reduces residual stresses but does not significantly alter hardness or strength.

Unlike cast steel, cast iron cannot be effectively hardened through quenching due to the presence of graphite, which inhibits martensitic transformation.

Öyleyse, its mechanical properties are largely fixed after casting and cooling.

Kaynaklanabilirlik:

Welding cast iron poses significant challenges:

• The presence of graphite flakes (Özellikle gri dökme demirde) promotes crack initiation and propagation during welding.
• High carbon equivalent leads to brittleness and risk of hot cracking.
• Thermal expansion mismatch between weld and base metal causes residual stresses.

Welding cast iron often requires:

• Specialized techniques such as preheating (200–400 ° C), Yavaş soğutma, and use of nickel-based filler metals.
• Peening or stress relief after welding to minimize cracking.

8. Korozyon direnci ve yüzey kaplaması: Dökme çelik vs dökme demir

Material behavior in corrosive environments and the achievable surface quality after casting or machining are crucial factors in component durability, performans, ve estetik.

Cast steel and cast iron, though both ferrous materials, differ notably in corrosion resistance and post-casting finish characteristics due to their composition, mikroyapı, and carbon content.

Korozyon direnci

Çelik

Cast steel generally has lower intrinsic corrosion resistance than cast iron due to its more reactive, homogeneous microstructure and lower carbon content.

Fakat, BT teklifleri greater versatility in corrosion control through alloying and surface treatments.

Özellikler:

• Unalloyed carbon steel castings are prone to uniform rusting when exposed to moisture or oxygen.
• Alloyed cast steels (Örn., with chromium, nikel, veya molibden) can resist various environments:

• • Stainless steel castings (≥10.5% Cr) exhibit strong corrosion resistance, even in acidic or marine settings.

• Uyumlu kaplamalar (galvanizleme, tablo, epoksi) for enhanced protection.

Dökme demir

Despite being more brittle, cast iron often shows better corrosion resistance in stagnant or mildly corrosive environments, largely due to the koruyucu oksit tabakası formed by graphite content and surface texture.

Özellikler:

• Gri dökme demir forms a stabil, passivating oxide layer that slows corrosion—a self-limiting process.
• The graphite matrix acts as a cathode, making cast iron less prone to deep pitting but more susceptible to uniform surface oxidation.
• Sünek demir offers better corrosion performance than gray iron, especially with coatings or epoxy linings.

Surface Finish After Casting and Machining

Çelik

• Çünkü dense and homogeneous grain structure, cast steel can achieve a smoother surface finish post-machining and polishing.
• As-cast surfaces tend to be rougher than cast iron but can be improved using investment or permanent mold casting.
• Ideal for components requiring tight tolerances or critical sealing surfaces.

Typical finish (asi):

• Kum dökümü: RA 12.5-25 um
• Yatırım kadrosu: RA 1.6-6.3 µm

Dökme demir

• Cast iron has Mükemmel Dökülebilirlik, which often results in better surface replication from molds.
• Fakat, . presence of graphite can create a slightly porous surface texture, especially in gray iron.
• Machinability is superior due to graphite acting as a chip breaker and lubricant, leading to good post-machining finish.

Typical finish (asi):

• Green sand casting: RA 6.3-12.5 um
• Kabuk Kalıp Dökümü: RA 3.2-6.3 µm

9. Advantages and Limitations of Cast Steel vs Cast Iron

Aralarında Seçim cast steel VS dökme demir depends on a balance of mechanical performance, maliyet, üretim, korozyon direnci, and application-specific demands.

Both materials offer distinct strengths and trade-offs that influence design and procurement decisions.

Çelik

Avantajlar

1. High Ductility & Sertlik
   Cast steel exhibits excellent impact resistance and tensile strength, making it suitable for dynamic and high-load applications.
2. Üstün Kaynaklanabilirlik
   Its low carbon content and homogeneous structure allow for easy welding and repair.
3. Wide Alloy Selection
   Can be alloyed with chromium, nikel, molibden, vesaire., korozyon direncini arttırmak için, sertlik, veya ısı direnci.
4. Heat Treatability
   Mechanical properties can be customized through heat treatment (Örn., söndürme, temkinli, tavlama).
5. İyi yorgunluk direnci
   Ideal for cyclic loading and shock conditions (Örn., structural or automotive parts).

Sınırlamalar

1. Lower Castability
   Higher shrinkage and poor fluidity make casting intricate or thin-walled shapes more difficult.
2. Daha yüksek maliyet
   More expensive in terms of energy use, mold complexity, and alloying elements.
3. Yüzey İşlemi
   Generally rougher than cast iron in as-cast form and may require additional machining.
4. Corrosion Prone (if unalloyed)
   Requires coatings or alloying for applications in corrosive environments.

Dökme demir

Avantajlar

1. Mükemmel Dökülebilirlik
   Flows easily in molds; Karmaşık için ideal, ince duvarlı, or intricate shapes.
2. Üstün işlenebilirlik
   The graphite microstructure acts as a lubricant, improving machinability and tool life.
3. Good Vibration Damping
   Ideal for machine bases and engine blocks where noise and vibration control are critical.
4. Uygun maliyetli
   Lower melting point and less energy-intensive processing reduce overall costs.
5. Doğal korozyon direnci (in stagnant conditions)
   Especially gray iron, which forms a protective oxide layer.

Sınırlamalar

1. Kırılgan kırılma
   Low ductility and poor impact resistance make it unsuitable for dynamic loading or high-stress applications.
2. Poor Weldability
   Difficult to weld due to graphite flakes and high carbon content; repair is often impractical.
3. Lower Tensile Strength
   Cannot match cast steel in load-bearing or structural applications.
4. Limited Heat Treatment Options
   Mostly limited to stress relieving or annealing; mechanical properties are less tunable.

10. Common Applications of Cast Steel vs Cast Iron

The selection between cast steel Ve dökme demir is often driven by performance demands, çevre koşulları, ve ekonomik kısıtlamalar.

Dökme Demir Uygulamaları

Cast iron’s excellent fluidity, bozulabilirlik, and damping properties make it ideal for components with complex geometries, static loads, and noise/vibration sensitivity.

Cast Steel Applications

Cast steel is favored in industries requiring high strength, darbe direnci, ve yapısal bütünlük, particularly under dynamic or extreme service conditions.

11. Çözüm

Both cast iron vs cast steel play essential roles in modern engineering.

Cast iron is ideal for applications requiring excellent castability, işlenebilirlik, and vibration damping, whereas cast steel excels in high-impact, yüksek güçlü, and fatigue-prone environments.

Material choice should be based on performance requirements, operating conditions, and lifecycle costs to achieve optimal functionality and durability.

LANGHE’s Comprehensive Metal Casting Services

Langhe offers a wide range of professional casting services tailored to meet the diverse needs of industries worldwide.

Our capabilities span multiple casting techniques and metal materials to ensure optimal performance, kalite, and cost-efficiency for every project.

Casting Methods We Provide:

• Kum dökümü
• Hassas Döküm (Kayıp balmumu)
• Kalıcı kalıp dökümü
• Döküm
• Savurma döküm
• Kayıp Köpük Dökümü
• Yerçekimi dökümü

Materials We Work With:

• Dökme demir (Gri demir, Sünek demir, Beyaz demir)
• Çelik (Karbon Çelik, Alçak çelik, Paslanmaz çelik)
• Alüminyum alaşımları (Alsi10mg, A356, vesaire.)
• Bakır bazlı alaşımlar (Pirinç, Bronz)
• Çinko alaşımları
• Özel alaşımlar (Isıya dayanıklı, corrosion-resistant grades)

Whether you’re developing complex precision parts veya large structural castings, Langhe is your trusted partner for reliable, high-quality metal casting solutions.

SSS

Is cast iron stronger than cast steel?

HAYIR. Cast steel has higher tensile strength (400–1000 MPa) than ductile iron (400–800 MPa) and far exceeds gray iron (200–400 MPa).

Dökme demir kaynaklı olabilir mi?

Sünek demir ön ısıtma ile kaynaklanabilir (200–300 ° C) but loses 10–20% ductility. Gray iron is difficult to weld due to brittleness. Cast steel welds easily, matching base metal strength.

Which is more machinable?

Gray iron is most machinable (graphite acts as a lubricant), followed by ductile iron. Cast steel is harder to machine, requiring carbide tools.

Why is cast iron used for engine blocks?

Its vibration-damping reduces noise, low-cost suits mass production, and fluidity enables complex water jackets and oil galleries.

When is stainless cast steel necessary?

In corrosive environments (deniz suyu, kimyasallar) or high-purity applications (farmasötik, gıda işleme) where rust or contamination is unacceptable.