Cast Steel vs Cast Iron: Mga Pangunahing Pagkakaiba, Mga Katangian & Mga Aplikasyon

1. Panimula

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

Though they share a base element—iron—their properties, mga aplikasyon, 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, mga tagagawa, and designers because it directly impacts the strength, machinability, paglaban sa kaagnasan, and overall lifecycle cost of a component.

This article explores the metallurgy, mekanikal na pag-uugali, production methods, and end-use suitability of cast steel and cast iron in depth.

2. What Is Cast Iron?

Email Address * is a group of iron-carbon alloys with a carbon content typically between 2.0% at 4.0%, along with varying levels of silicon (1.0–3.0%), mangganeso, asupre, and phosphorus.

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 mahusay na castability, panginginig ng boses damping, at lakas ng compressive.

Kontekstong Pangkasaysayan

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, Makinarya, at transportasyon, making its way into everything from bridges and pipes to engines and cookware.

Key Types of Cast Iron

Key Characteristics of Cast Iron

• Mataas na Nilalaman ng Carbon: Enhances castability and wear resistance but reduces ductility.
• Napakahusay na katatagan: Mababang punto ng pagtunaw (≈1150–1200 °C) and good fluidity allow intricate, malaki ang, and complex shapes to be cast easily.
• Good Damping Capacity: Particularly in gray iron, which absorbs vibration well, making it ideal for machinery bases.
• Brittleness: Most forms, especially gray and white cast iron, fracture under tensile or impact loads.
• Thermal kondaktibiti: Effective for heat distribution, making it a good material for engine parts and cookware.
• Paglaban sa kaagnasan: Moderate without coatings, though improved with certain alloying elements or surface treatments.

3. What Is Cast Steel?

Email Address * is a category of iron-carbon alloys with a carbon content typically ranging from 0.1% sa 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 mas mataas na ductility, tigas na tigas, at weldability.

It is especially favored for applications involving dynamic loads, epekto ng paglaban, at Paglaban sa Pagsusuot.

Kontekstong Pangkasaysayan

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.

Ngayong araw, cast steel is a vital material in structural, automotive, mining, and pressure-containing applications due to its strength and versatility.

Key Types of Cast Steel

Key Characteristics of Cast Steel

• Mas mababang Nilalaman ng Carbon: Typically 0.1–0.5%, resulting in superior ductility and weldability compared to cast iron.
• Mataas na Lakas & Tigas na tigas: Cast steel offers Mahusay na mga katangian ng mekanikal, including high tensile strength and resistance to shock loading.
• Heat Treatable: Unlike cast iron, cast steel can be heat-treated (pinatay, Tempered, Normalized) to enhance hardness, tigas na tigas, at magsuot ng resistensya.
• Weldability: Excellent for fabrication, repair, and joining—ideal for components that may need modification or maintenance.
• Machinability: Generally good, though varies with alloy composition and heat treatment state.
• Paglaban sa kaagnasan: Varies widely depending on alloying elements. Stainless grades are highly corrosion-resistant.

4. Talahanayan ng Paghahambing: Cast Steel vs Cast Iron

5. Common Casting Methods: Cast Steel vs Cast Iron

Casting method selection is pivotal for cost control, dimensional katumpakan, mekanikal na pagganap, and production scale.

Cast steel and cast iron share several casting techniques, but each material presents unique challenges due to differences in melting point, pag-uugali ng solidification, and alloy reactivity.

Casting Methods for Cast Steel

Cast Steel Sand Casting

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

A pattern (kahoy na kahoy, 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, erosion, and shrinkage.

Common Parts: Gearboxes, mga katawan ng balbula, structural brackets.

Cast Steel Investment Casting (Nawala ang wax)

Pamumuhunan sa paghahagis 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, medikal na, or energy components.

Common Parts: Mga blades ng turbine, mga instrumentong medikal, military components.

Cast Steel Shell Mold Casting

Shell molding 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

Sa sentripugal paghahagis, 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: Mga tubo ng bakal, Mga manggas, 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, machining, o gumugulong.

Mga Produkto: Bar stock, mga estruktural na beam, 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, recyclability, and adaptability.

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: Manhole covers, mga bloke ng engine, compressor housings.

Cast Iron No-Bake (Resin-Bonded) buhangin paghahagis

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, mga impeller.

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: Mga pabahay ng gear, mga katawan ng balbula, 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), reduces porosity, and promotes grain refinement.

Common Parts: Pipe sections, mga flywheel, and brake drums.

Cast Iron Lost Foam Casting

Nawala ang foam casting 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, Mga pabahay ng pump, ornamental castings.

Key Differences in Casting Characteristics

6. Heat Treatment and Weldability: Cast Steel vs Cast Iron

Lunas sa init and weldability are critical factors influencing the performance, Buhay ng Serbisyo, 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.

Cast Steel

Paggamot ng Heat:

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:

• Annealing: Softens the steel, reduces residual stresses, and improves machinability.
• Normalizing: Refines grain structure by heating above critical temperature (~870–950°C) Sinundan ng Paglamig ng Hangin; enhances strength and toughness.
• Pagpapawi at Pagtitimpi: Mabilis na paglamig (pagpapawi ng) 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.

Weldability:

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

• Shielded Metal Arc Welding (SMAW)
• Gas Tungsten Arc Welding (GTAW)
• Flux-Cored Arc Welding (FCAW)

Gayunpaman, 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.

Cast Iron

Paggamot ng Heat:

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

• Annealing: Often applied to malleable iron to reduce hardness and improve ductility.
• Normalizing: Limited use, primarily to modify microstructure in white cast iron.
• Nakakawala ng stress: 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.

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

Weldability:

Welding cast iron poses significant challenges:

• The presence of graphite flakes (especially in gray cast iron) 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), mabagal na paglamig, and use of nickel-based filler metals.
• Peening or stress relief after welding to minimize cracking.

8. Corrosion Resistance and Surface Finish: Cast Steel vs Cast Iron

Material behavior in corrosive environments and the achievable surface quality after casting or machining are crucial factors in component durability, pagganap, at mga estetika.

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

Paglaban sa kaagnasan

Cast Steel

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

Gayunpaman, ito ay nag aalok ng greater versatility in corrosion control through alloying and surface treatments.

Mga Katangian:

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

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

• Email Address * mga patong na patong (Pag-galvanize, pagpipinta, Epoxy) for enhanced protection.

Cast Iron

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

Mga Katangian:

• Kulay-abo na cast iron forms a stable, 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.
• Ductile na bakal offers better corrosion performance than gray iron, especially with coatings or epoxy linings.

Surface Finish After Casting and Machining

Cast Steel

• Dahil sa kanyang 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 (bilang cast):

• Buhangin paghahagis: Ra 12.5–25 μm
• Pamumuhunan sa paghahagis: Ra 1.6–6.3 μm

Cast Iron

• Cast iron has mahusay na castability, which often results in better surface replication from molds.
• Gayunpaman, ang 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 (bilang cast):

• Green sand casting: Ra 6.3–12.5 μm
• Paghahagis ng amag ng shell: Ra 3.2–6.3 μm

9. Advantages and Limitations of Cast Steel vs Cast Iron

Pagpili sa pagitan ng cast steel mga bes cast iron depends on a balance of mechanical performance, gastos, manufacturability, paglaban sa kaagnasan, and application-specific demands.

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

Cast Steel

Mga kalamangan

1. High Ductility & Tigas na tigas
   Cast steel exhibits excellent impact resistance and tensile strength, making it suitable for dynamic and high-load applications.
2. Superior Weldability
   Its low carbon content and homogeneous structure allow for easy welding and repair.
3. Wide Alloy Selection
   Can be alloyed with chromium, nikel, molibdenum, atbp., upang mapahusay ang paglaban sa kaagnasan, tigas na tigas, o paglaban sa init.
4. Heat Treatability
   Mechanical properties can be customized through heat treatment (hal., pagpapawi ng, paghina ng loob, annealing).
5. Good Fatigue Resistance
   Ideal for cyclic loading and shock conditions (hal., structural or automotive parts).

Mga Limitasyon

1. Lower Castability
   Higher shrinkage and poor fluidity make casting intricate or thin-walled shapes more difficult.
2. Mas Mataas na Gastos
   More expensive in terms of energy use, mold complexity, and alloying elements.
3. Tapos na sa ibabaw
   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.

Cast Iron

Mga kalamangan

1. Napakahusay na katatagan
   Flows easily in molds; ideal for complex, manipis na pader, or intricate shapes.
2. Superior Machinability
   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. Epektibo sa Gastos
   Lower melting point and less energy-intensive processing reduce overall costs.
5. Natural Corrosion Resistance (in stagnant conditions)
   Especially gray iron, which forms a protective oxide layer.

Mga Limitasyon

1. malutong na pagkabali
   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 at cast iron is often driven by performance demands, mga kondisyon ng kapaligiran, and economic constraints.

Mga Application ng Cast Iron

Cast iron’s excellent fluidity, pagiging castable, 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, epekto ng paglaban, at integridad ng istruktura, particularly under dynamic or extreme service conditions.

11. Pangwakas na Salita

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

Cast iron is ideal for applications requiring excellent castability, machinability, and vibration damping, whereas cast steel excels in high-impact, mataas na lakas, 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, kalidad, and cost-efficiency for every project.

Casting Methods We Provide:

• buhangin paghahagis
• Pamumuhunan sa Paghahagis (Nawala ang wax)
• Permanenteng amag paghahagis
• mamatay paghahagis
• Centrifugal Casting
• Nawala ang Foam Casting
• Gravity Casting

Materials We Work With:

• Cast Iron (kulay abo na bakal, Ductile Iron, puting bakal)
• Cast Steel (Carbon Steel, Bakal na may mababang haluang metal, Hindi kinakalawang na asero)
• Mga Alloys ng Aluminyo (AlSi10Mg, A356, atbp.)
• Mga haluang metal na nakabatay sa tanso (tanso, tanso)
• Zinc Alloys
• Specialty Alloys (Lumalaban sa init, corrosion-resistant grades)

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

Mga FAQ

Is cast iron stronger than cast steel?

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

Can cast iron be welded?

Ductile iron can be welded with preheating (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 (tubig dagat, mga kemikal) or high-purity applications (parmasyutiko, pagproseso ng pagkain) where rust or contamination is unacceptable.