Oglekļa tērauda smilšu liešanas uzņēmums

Sand casting is the backbone of heavy-duty component production, combining low tooling cost with nearly limitless geometric freedom.

Among cast alloys, oglekļa tērauds (with carbon below 0.30 WT%) stands out for delivering toughness, izturība, and weldability in parts ranging from small pump housings to multi-ton gearbox cases.

In this comprehensive review, we explore carbon steel sand casting from its metallurgical roots through process steps, design practices, un kvalitātes kontrole.

2. What Is Carbon Steel Sand Casting?

Iekšā carbon steel sand casting, foundries pour molten carbon steel—defined by 0.05–0.30 wt% carbon—into molds formed from unbonded or bonded sand.

Unlike higher-alloy steels, carbon steel offers a delicate balance no izturība, izturība, mašīnīgums, un metināmība, all at a lower cost per kilogram.

Turklāt, sand-casting tooling budgets start as low as USD 500 for simple patterns, enabling economical production of prototypes and one-off parts, as well as batch runs into the tens of thousands of units.

3. Metalurģijas pamati

A robust understanding of carbon steel’s metallurgy underpins every successful sand-casting application.

Jo īpaši, the interplay of oglekļa saturs, silicon levels, and minor leģējošie elementi dictates fluidity, shrinkage behavior,

and the as-cast microstructure, each of which influences mechanical performance and defect propensity.

Ogleklis & Steel Classification

Oglekļa tēraudi fall into three broad categories based on their weight-percent carbon:

• Low-Carbon Steels (≤ 0.15 % C): Yield ultimate tensile strengths (UTS) no 350–450 MPa and elongations exceeding 20 %, making them highly ductile and weldable.
• Medium-Carbon Steels (0.15–0.30 % C): Offer UTS of 450-550 MPa with elongations of 10–15 %, balancing strength and toughness.
• High-Carbon Steels (> 0.30 % C): Exhibit UTS above 600 MPA, but their as-cast brittleness limits widespread use in sand casting.

Common cast grades include ASTM A216 WCB (0.24–0.27 % C, UTS ~ 415 MPA), ASTM A27 (0.23–0.29 % C, UTS ~ 345 MPA), and DIN GS-42 (0.38–0,45 % C, UTS ~ 520 MPA).

These grades illustrate how subtle shifts in carbon content translate to distinct strength and ductility profiles.

Silicon’s Role in Fluidity & Saraušanās

Silīcijs, typically present at 1.8–2.2 %, performs a dual function:

1. Fluidity Enhancement: Katrs 0.5 % increase in Si can improve the molten steel’s fluidity by up to 12 %, ensuring more complete mold filling and finer detail reproduction.
2. Shrinkage Control: Silicon promotes graphitization during solidification, reducing volumetric shrinkage porosity by approximately 15 % compared to low-Si alloys.

Līdz ar to, foundries often target silicon levels near the upper range to minimize internal voids and improve surface finish.

Alloying Additions for Specialized Properties

Beyond carbon and silicon, mangāns, hroms, un molibdēns tailor performance for demanding environments:

• Mangāns (0.6–1,0 %): Darbojas kā deoksidētājs, refines grain size, and boosts tensile strength by up to 20 % without severely compromising toughness.
• Hroms (≤ 0.5 %): Increases hardenability and wear resistance, especially valuable in components subject to abrasive media.
• Molibdēns (≤ 0.3 %): Elevates high-temperature strength and creep resistance, making it indispensable in parts like exhaust manifolds and steam-trap bodies.

As-Cast Microstructure

As the molten steel cools in a sand mold, it solidifies into a ferrite–pearlite matrica:

• ferīts (mīksts, elastīgs) forms first at temperatures just below the liquidus, providing the foundation for toughness.
• Perlīts (lamellar cementite–ferrite) emerges at lower temperatures, imparting hardness and wear resistance.

Typical sand-cast cooling rates (1–5 °C/s) yield a ferrite fraction of 40–60 %, with pearlite comprising the balance.

In thicker sections, slower cooling can increase pearlite content, raising hardness by up to 15 HB but reducing elongation by 2–3 %.

4. Sand-Casting Process Overview

Sand casting transforms molten carbon steel into complex shapes by using expendable sand molds.

Zemāk, we detail each major step—pattern and coremaking, mold construction, pouring and solidification, and shake-out with cleaning—while highlighting data-driven best practices.

Pattern and Coremaking

Pirmkārt un galvenokārt, pattern accuracy dictates as-cast tolerances. Foundries typically use:

Rakstu materiāli:

• CNC-machined aluminum notur ±0,02 mm Izmēra precizitāte.
• Wood patterns (for low volumes) achieve ±0,2 mm.
• 3D-printed resin patterns eliminate lead times on complex shapes.

Core Production:

• Green-sand cores combine 85–90 % silīcija smiltis, 5–7 % bentonīta māls, and 2–3 % laistīt, then compact under 4–6 bar air pressure.
• No-Bake resin cores use phenolic or furan binders, offering core strengths of 4-6 MPa with permeability above 300 Gas m³/m²·min.

Through precise pattern and coremaking, foundries minimize dimensional variation and internal defects.

Mold Construction

Mold Composition:

• 90 % silīcija smiltis, 5–7 % māls, un 2–3 % water for green-sand molds.
• Ķīmiski saistītas smiltis (Piem., furan resin) reduce moisture to < 0.5 %, tightening tolerances to CT9–CT12.

Compaction & Cietība:

• Tēlot matrix hardness no 60–70 HA (Shore A) ensures mold integrity and consistent shrinkage.
• Pareizi caurlaidība (≥ 300 Gas m³/m²·min) prevents gas entrapment and porosity.

Veidņu montāža:

• Engineers place cores in the cope and drag, using chaplets or core prints to maintain alignment within ±0,5 mm.
• They apply parting coats (typically 0.1–0.3 mm thickness) to ease pattern release and improve surface finish.

By controlling sand properties and compaction, sand-casting molds consistently meet ISO CT11–CT14 iespējas.

Izliešana un sacietēšana

With molds ready, foundries proceed:

Melt Preparation:

• Induction furnaces heat carbon steel to 1450-1550 °C, holding for 5–10 minutes to homogenize chemistry.
• Foundry engineers deslag and adjust carbon and silicon to target composition (± 0.02 % C, ± 0.05 % Un).

Nospiešana & Riser Design:

• A well-balanced gate area (vārti: runner ratio ~ 1:3) ensures laminar flow.
• Stāvvieta sized at 10 % of casting volume feed shrinkage, usually located at the heaviest section to promote directional solidification.

Dzesēšanas ātrums:

• Thin sections cool at 5–10 °C/s, favoring ferrite formation and finer grain sizes (~ 15 µm).
• Thick walls cool at 1–3 °C/s; drebuļi (Piem., copper inserts) accelerate local solidification by up to 50 %, reducing shrink porosity.

By combining precise melt control with optimized gating, foundries achieve sound, dimensionally consistent castings.

Izkratīšana, Tīrīšana, un Fettling

Beidzot, castings emerge from the mold:

Izkratīšana:

• Automated vibratory systems separate sand from metal within 5–10 minutes per batch.

Desanding & Šāvienu spridzināšana:

• High-pressure air or wheel-blast systems remove residual sand, achieving a base finish of RA 6–12 µm.

Fettling Operations:

• Workers grind or machine gate and riser stubs, trim flash, and blend transitions, typically removing 1-3 mm of stock to meet final dimensional tolerances.

Pre-Inspection:

• Castings undergo visual checks and dimensional spot-measurements (± 0.5 mm on critical features) before moving to full inspection.

Through systematic shake-out and cleaning, foundries prepare carbon steel castings for rigorous quality assurance and possible post-cast treatments.

5. Design for Sand Casting

Effective cast designs account for:

• Iegrimes leņķi (1–3 °): Prevent pattern damage; tighter angles increase tool wear.
• Machining Stock (1-3 mm): Ensures final features fall within CT11–CT12 without rework.
• Contraction Allowance (1.0–1.3 mm/100 mm): Compensates for solidification shrink.
• Vienots sienas biezums (±10 mm): Avoids hot spots and internal stresses.
• Filejas & Rādiuss (> 1 mm): Curtail stress concentrations and streamline metal flow.
• Gating/Riser Placement: Align risers with thick sections to promote virziena sacietēšana, reducing shrink porosity by 30 %.

6. Process Capability & Dimensional Control

Controlling dimensions and achieving repeatable tolerances in carbon steel sand casting remains both a challenge and a benchmark of foundry excellence.

Tolerance Grades in Sand Casting

Dimensional tolerance refers to the permissible limits of variation in a physical dimension of a cast component.

In sand casting, tolerances are most commonly classified under the Iso 8062-3 standarta, which defines Casting Tolerance Grades (CT) no CT1 (most precise) līdz CT16 (least precise).

For carbon steel sand castings, the achievable tolerance grades typically fall within:

Liešanas process	ISO Tolerance Grade	Linear Dimensional Tolerance Range (mm)
Zaļās smiltis	CT13 – CT14	±2.0 – ±3.5 mm (par 100 mm dimension)
Smiltis bez cepšanas	CT11 – CT13	±1.0 – ±2.5 mm
Čaumalas pelējums	CT8 – CT10	±0.6 – ±1.5 mm

Key Factors Affecting Dimensional Precision

1. Sand Characteristics

• Graudu smalkums: Finer grains enhance detail reproduction and surface finish but reduce permeability and may affect mold integrity.
• Moisture & Binder Content: Improper sand mix ratios cause mold distortion or gas-related defects, leading to dimensional inconsistencies.

2. Mold Compaction

• Uniform compaction ensures consistent cavity dimensions. Inadequate ramming or vibration can cause localized wall collapse or variation.

3. Pattern Accuracy

• Pattern wear, termiskie kropļojumi, or manual carving can introduce errors. CNC-milled or 3D-printed patterns improve reproducibility.

4. Thermal Shrinkage

• Carbon steel typically contracts by 1.0% līdz 2.5% during solidification and cooling, depending on composition and geometry.
• Complex geometries may require differential shrinkage allowances.

5. Sadaļas biezums

• Thin-walled areas cool faster and contract more uniformly.
• Thick sections may exhibit centerline shrinkage, karstie punkti, or warping if not properly risered or chilled.

Techniques for Improved Dimensional Control

To enhance casting precision and reduce post-machining requirements, modern foundries employ several strategies:

• Use of Rigid Molding Systems: Chemically bonded sand molds exhibit better dimensional stability than traditional green sand.
• Mold Pre-heating: Heating molds before pouring reduces temperature differentials and warping.
• Chill Placement: Strategically placed metal chills accelerate cooling in hot spots to reduce uneven contraction.
• Simulation Software: Solidification modeling and thermal simulation help predict and compensate for shrinkage and distortion in design.

Surface Finish Expectations

Surface roughness in sand-cast carbon steel is generally measured in Ra (mikroni):

Molding Process	Tipisks virsmas raupjums (Ra)
Zaļās smiltis	12 - 25 µm
Smiltis bez cepšanas	6 - 12 µm
Apvalka formēšana	3 - 6 µm

7. Kvalitātes nodrošināšana & Testēšana

Mehāniskā pārbaude

Foundries validate mechanical performance per:

• ASTM E8: Tensile strength and elongation.
• ASTM E23: Charpy V-notch impact toughness.
• Rokvela cietība (HRC 20–30): Measures surface hardness.

Non-Destructive Evaluation

We use:

• Radiogrāfija: Detects internal porosity ≥ 2 mm.
• Ultraskaņas pārbaude: Locates volumetric flaws ≥ 1 mm.
• Magnētisko daļiņu pārbaude: Reveals surface cracks ≥ 0.5 mm.

Statistiskā procesa kontrole

By tracking Cp un Cpk, foundries ensure Cpk ≥ 1.33 for critical dimensions.

Pirmā izstrādājuma pārbaude (FAI) confirms that initial castings meet DCTG requirements before full production runs.

8. Apstrāde pēc liešanas

While the initial casting process defines the shape and general properties of carbon steel components,

Post-casting treatments play a critical role in enhancing mechanical performance, Izmēra precizitāte, virsmas kvalitāte, un ilgstoša izturība.

These secondary operations are not merely refinements—they are essential steps that transform raw castings into high-performance industrial components capable of withstanding harsh service conditions.

Termiskās apstrādes

Carbon steel castings often undergo a series of termiskās apstrādes to tailor their microstructure and improve mechanical properties.

The choice of treatment depends on the application requirements, desired hardness, elastība, and internal stress state.

Normalizēšana

• Apstrādāt: Heating to ~870–950 °C, kam seko gaisa dzesēšana.
• Mērķis: Precizējiet graudu struktūru, mazina iekšējo stresu, un uzlabo apstrādājamību.
• Ietekme: Promotes a uniform ferrite-pearlite matrix with improved strength and toughness.

Rūdīšana un rūdīšana

• Apstrādāt: Ātra dzesēšana (typically in oil or water) from the austenitizing temperature (~840–900 °C), followed by reheating to ~500–650 °C.
• Mērķis: Increases hardness and tensile strength while controlling brittleness.
• Tipisks pielietojums: Wear-resistant components and structural parts subjected to impact.

Rūdīšana

• Apstrādāt: Slow cooling from ~800–850 °C.
• Mērķis: Softens the material for easier machining and improves dimensional stability.
• Ietekme: Produces a coarse ferritic structure with reduced hardness and strength.

Stresa mazināšana

• Temperatūras diapazons: 540-650 °C.
• Mērķis: Reduces residual stresses from uneven solidification or machining without significantly altering microstructure.

Datu punkts: ASTM A216 WCB castings, a common low-carbon steel grade, typically reach tensile strengths of 485–655 MPa after normalizing and tempering.

Surface Enhancement Methods

Surface quality is crucial in environments exposed to wear, korozija, or friction. Post-casting surface treatments not only improve aesthetics but also significantly extend component life.

Shot Blasting and Shot Peening

• Mērķis: Removes residual sand, mērogs, and oxides; improves fatigue life by inducing compressive surface stress.
• Virsmas raupjums: Reduced to 6–12 µm Ra, depending on media and intensity.

Coatings and Apjoms

• Cinka pārklājums (Cinkošana): Uzlabo izturību pret koroziju, especially for outdoor or marine use.
• Phosphate and Black Oxide Coatings: Provide lubrication and minimal rust protection.
• Chrome or Nickel Plating: Used in specialized applications for enhanced surface hardness or chemical resistance.

Gleznošana un Pulvera pārklājums

• Common for non-critical surfaces, providing both corrosion resistance and visual appeal.
• Typically applied after machining to preserve dimensional tolerances.

CNC Machining of Cast Carbon Steel

Due to the casting skin, microstructural heterogeneity, and potential residual stresses, cast carbon steel requires carefully selected CNC apstrāde strategies to maintain tolerance and avoid tool wear.

Apstrādes apsvērumi:

• Instrumentus: Use of carbide or coated tools for improved wear resistance.
• Feeds and Speeds: Zemāks griešanas ātrums (60–120 m/min) and moderate feeds to reduce chatter and heat generation.
• Coolant Use: Emulsified cutting fluids are recommended for thermal control and chip evacuation.
• Pabalsts: Typically 1–3 mm of machining stock is left on cast surfaces for finish machining.

9. Galvenie rūpnieciskie pielietojumi

Eļļas & Gāzes rūpniecība

• Vārstu ķermeņi
• Sūkņu korpusi
• Flanges and Fittings

Heavy Equipment Manufacturing

• Gearbox Housings
• Track Links and Idlers
• Pretsvari

Infrastructure Development

• Lūku vāki un rāmji
• Railway Components
• Water and Sewage System Parts

Automobiļi un transports

• Dzinēja sastāvdaļas
• Šasijas un balstiekārtas daļas
• Truck and Trailer Parts

Enerģijas ražošana

• Turbīnu korpusi
• Spiedientvertnes
• Heat Exchanger Components

Jūras un kuģu būve

• Propeller Shafts and Bearings
• Deck Machinery Components
• Hull Fittings

Atjaunojamā enerģija

• Wind Turbine Hubs and Frames
• Hydroelectric Turbine Components
• Solar Mounting Structures

10. Common Carbon Steel Casting Grades (Globālais pārskats)

11. Šis’s Sand Casting Capabilities

As a trusted name in precision metalcasting, DEZE lietuve brings decades of experience and innovation to the carbon steel sand casting industry.

Combining advanced facilities, robust engineering practices, and rigorous quality assurance,

Šis has established itself as a strategic partner for demanding global clients across the oil & gāze, transportēšana, enerģija, and heavy equipment sectors.

Foundry Infrastructure & Tehnika

Šis operates fully integrated sand casting lines designed for medium to large-scale castings sākot no 2 kg to over 5,000 kg. Our facilities feature:

• Automated molding lines for high repeatability and consistent dimensional accuracy
• Flexible mold types: zaļās smiltis, furan no-bake, and resin-bonded systems
• 3D-drukāti raksti and CNC-machined tooling for rapid prototyping and complex geometries
• On-site melting capacity with electric arc and induction furnaces supporting both carbon and low-alloy steels

Carbon Steel Grades Offered

We produce a broad range of carbon steel grades, tailored for both structural and wear-critical applications, ieskaitot:

• ASTM A216 WCB – Pressure-retaining components, general-purpose carbon steel
• ASTM A27 klase 60-30 / 70-36 – General industrial use, low to medium strength
• ASTM A148 105-85 – High-strength casting for wear and fatigue resistance
• Customized grades with alloying elements (Krekls, Noplūde, Nojaukšanās, Iekšā) to meet client specifications

All melt compositions are verified using spectrometric analysis and controlled to within tight tolerances for consistency.

Izmēra precizitāte & Procesu kontrole

Šis casts to tolerance grades between CT10–CT13, with achievable surface finishes of RA 6–12 µm, depending on mold process and part complexity.

Dimensional accuracy is enhanced through:

• Controlled mold compaction and moisture regulation
• Process simulations using MAGMAsoft® un ProCAST vārtiem, stāvvads, and solidification optimization
• In-process monitoring and Statistiskā procesa kontrole (SPC) to minimize casting variation

For mission-critical components, CT scanning un CMM pārbaude validate geometrical conformance and internal integrity.

Post-Casting Services

To deliver ready-to-assemble components, Šis offers a comprehensive suite of finishing and post-processing services:

• Heat treatment in-house: normalizēšana, rūdīšana, rūdīšana, un rūdīšana
• Machining to tight tolerances with CNC turning, frizēšana, un urbšana
• Virsmas aizsardzība: šāvienu spridzināšana, gleznošana, cinkošana, and custom coatings
• Nesagraujoša pārbaude (Ndt): ultraskaņas, radiographic, un magnētisko daļiņu pārbaude

12. Secinājums

Carbon steel sand casting delivers unmatched value for heavy-duty, large-volume components.

By integrating sound metallurgical practices, robust process controls, design-for-castability, and rigorous QA, manufacturers can produce durable parts that meet tight functional demands at competitive cost.

Šis ir ideāla izvēle jūsu ražošanas vajadzībām, ja jums nepieciešama augstas kvalitātes carbon steel sand casting services.

Sazinieties ar mums šodien!