Why choose shengrong foundry for grey cast iron casting parts?

We customize a wide variety of custom grey iron casting parts, grades HT200-HT350, according to customer drawings. Excellent mechanical properties and moderate hardness, typically ranging from 180-250 Brinell hardness (HB), Excellent vibration damping: The graphite structure in gray iron effectively absorbs vibration, surpassing steel.Wear resistance: The pearlite matrix (≥80%) provides high wear resistance, making it suitable for parts such as guide rails and cylinder liners.

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Why choose shengrong foundry for grey cast iron casting parts?

Why Choose Shengrong Grey Iron Casting Foundry?

Excellent mechanical properties.Uniform microstructure.Smooth surface.Excellent machinability.Long service life

Excellent mechanical properties

Tensile Strength: The actual tensile strength of grades HT250 and above consistently exceeds the standard.
Moderate Hardness: The Brinell hardness (HB) is typically between 180-250, ensuring machinability (e.g., HT200 hardness is approximately 180-220 HB).
Good Shock Absorption: The graphite structure in gray iron effectively absorbs vibration, surpassing that of steel.
Wear Resistance: The pearlite matrix (≥80%) provides high wear resistance, making it suitable for parts such as guide rails and cylinder liners.

Uniform microstructure

Graphite Morphology: Type A (uniform, non-directional) graphite predominates, with moderate length (grades 3-5, approximately 100-300 μm). Avoid Type D (overly fine) or Type E (directional) graphite.
Matrix Structure: High pearlite content (≥90% preferred), low ferrite content (<10%), and no free cementite (to avoid white cast iron tendency).
Free of harmful defects: No microshrinkage, slag inclusions, sulfur-phosphorus eutectics, etc.

Surface and dimensional quality

Smooth surface: Free from defects such as sand buildup, pores, cold shuts, cracks, and minimal casting burrs.
Dimensional precision: Conforms to drawing tolerances, with key areas (such as assembly surfaces) precision machined.
Cross-section color: The fracture surface is a uniform dark gray, free of bright white spots (cementite) or coarse grains.

Good process performance

Excellent machinability: Moderate hardness results in minimal tool wear and shavings.
Casting fluidity: Excellent mold filling during pouring, suitable for complex, thin-walled parts (e.g., 3-5mm wall thickness).

Low residual stress: After annealing, deformation is minimal (e.g., after aging treatment, deformation can be controlled within 0.1mm/m).

Reliable application performance

Long service life: Low wear in frictional and vibrating environments (such as engine blocks and brake discs).
No premature failure: No stress-concentration fractures caused by shrinkage or porosity.
Sealing: When used in hydraulic components, no leakage is observed after pressure testing (e.g., pressure ≥ 5 MPa).

Key production process control

Composition optimization: C (3.0-3.6%), Si (1.8-2.4%), carbon equivalent (CE ≈ 4.0-4.3) close to the eutectic point.
Inoculation: Use a 75Si-Fe inoculant for excellent instantaneous inoculation and graphite refinement.
Cooling rate: Avoid excessive cooling of the sand mold to prevent white cast. Use a sand-coated iron mold if necessary.

Best Use For Grey Iron Castings

Machine Tool Beds/Bases: Gray cast iron (such as HT200 and HT250) offers excellent shock absorption, absorbing machine vibration and ensuring machining accuracy.
Engine Cylinder Blocks/Cylinder Heads: Gray cast iron (such as HT150) leverages its heat resistance and casting properties, making it suitable for complex shapes and components subject to thermal cycling.
Gearbox/Reducer Housings: Gray cast iron's low cost and high wear resistance make it a preferred choice.
Brake Drums/Discs: Gray cast iron (HT250 and above) offers a high coefficient of friction and heat dissipation, making it suitable for braking systems.
Crankshafts/Flywheels: High-strength gray cast iron (such as HT300) is used for components subject to high dynamic loads.

Choosing Iron And Steel Casting Parts From Shengrong Foundry

More than 10 years of customized casting experience, stable casting process quality, professional casting engineer team, good worker training system, complete quality inspection equipment and good after-sales service. Send us the detailed drawing for quotation

Contact us today for a quote or more information.

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Global Standard Grey Cast Iron Material Grade Comparison

Precisely Matching Your Project Requirements

Gray Iron Material Grades
CountryStandardEquivalent Grades of Grey Iron (Gray Cast Iron)
ISOISO 185100150200250300350–
ChinaGB 9439HT100HT150HT200HT250HT300HT350–
USAASTM A48–NO.20NO.30NO.35NO.40NO.50NO.55
NO.25NO.45NO.60
GermanyDIN 1691GG10GG15GG20GG25GG30GG35GG40
EuropeanEN 1561EN-GJL-100EN-GJL-150EN-GJL-200EN-GJL-250EN-GJL-300EN-GJL-350
JapanJIS G5501FC100FC150FC200FC250FC300FC350–
ItalyUNI 5007G10G15G20G25G30G35–
FranceNF A32-101–FGL150FGL200FGL250FGL300FGL350FGL400
UKBS 1452100150200250300350–
IndiaIS 210–FG150FG200FG260FG300FG350FG400
SpainUNF–FG15FG20FG25FG30FG35–
BelgiumNBN 830-01FGG10FGG15FGG20FGG25FGG30FGG35FGG40
AustraliaAS 1830–T150T220T260T300T350T400
SwedenSS 14 01O110O115O120O125O130O135O140
NorwayNS11 100SJG100SJG150SJG200SJG250SJG300SJG350–
Min. Tensile Strength (Mpa)100150200250300350–

Complete Grey Iron Sand Casting Production Line

Advanced Equipment for High-Quality Custom Grey Iron Casting Parts Manufacturing

01
Professional Grey Iron Casting Equipment

Cast Star Horizontal Molding Line/Microcrystalline automatic pouring machine/New Donger Molding Machine/Sand mixing system and sand separator/Coremaking machine/40T automatic sand treatment line/1T intermediate frequency furnace 3 sets

02
Professional Machining Equipment

We have 1set 1005 horizontal machining center, 6sets 630 horizontal machining centers, 1set 500 horizontal machining center, 7sets 850 vertical machining centers, 3sets 1160 vertical machining centers, and 1set CMM Main Machining: robot joints, reducer boxes, aluminum alloy high-voltage housings, textile machinery accessories, etc.

03
Autonomous detection equipment

2 spectrometers, 2universal material testing machines, C-S analyzer, Si-Mn-P high-speed analyzer, 2 metallographic microscopes, 2 Brinell hardness meters, impact testing machines, molding sand permeability detectors, and an independent physical and chemical testing

04
Quality assurance

Casting Inspection
1.Visual Inspections
2.Dimensional Inspections
3.Chemical Inspections
4.Mechanical Properties Inspections

05
Technology and R&D

We have materials R&D center,In line with the CAD and UG three-dimensional mold creation capabilities equipped with independent R&D

How Shengrong Ensure Product Quality

1. Design Stage Control
Rational structural design: Avoid sudden changes in wall thickness and sharp corners, and use rounded corner transitions to reduce stress concentration.
Processability Review: Ensure that the casting design meets casting process requirements (e.g., draft angle, shrinkage allowance).
2. Raw Material Control
Metal materials: Strictly control chemical composition (e.g., carbon equivalent, impurities) to ensure the purity of the smelted material.
Smelting Process: Control the melting temperature and deoxidize and degas (e.g., use argon refining) to avoid inclusions and residual gases.
3. Process Control
Mold/Mold Shell Quality: Ensure mold accuracy and surface finish, and uniform sand compaction.
Gating System Design: Properly arrange the gate, riser, and chiller to ensure sequential or simultaneous solidification.
Gating Temperature (too high can cause sand sticking, too low can cause cold shutoff).
Gating Speed (avoid turbulence that causes air entrainment).
Cooling Rate (control grain size and microstructure uniformity). Special Processes: Advanced processes such as low-pressure casting and lost foam casting are used for complex parts.
4. Production Process Monitoring Real-time Testing: Thermocouples are used to monitor the melting temperature, and spectrometers are used for rapid composition analysis.
Environmental Control: Humidity and temperature affect the properties of the molding sand and must be maintained stable.
Operational Specifications: Standardized operations are implemented (e.g., cleaning loose sand before assembly and ensuring proper heat preservation after pouring).
5. Inspection and Defect Analysis
X-ray/ultrasonic testing for internal defects (porosity, shrinkage).
Penetrant testing for surface cracks.
Destructive Testing: Mechanical testing (tensile strength, hardness) and metallographic analysis are performed on random samples.
Defect Traceability: A defect classification database (e.g., slag inclusions, pinholes) is established to analyze the root causes and provide feedback for improvements.

foundry checking machine spectrometer

Spectrometer

grey cast iron carbon sulfur analyzer

Carbon sulfur analyzer

impact tester

Impact tester

China foundry machine metallurgical microscope

Metallurgical microscope

green sand casting parts radial inspection machine

Radial inspection machine

Hydraulic universal testing machine

Certificates

Our Commitment To Quality, Safety & Sustainability

ISO9001

ISO 9001:2015Certification

IATF 16949 Certification

Business License

Benefits of Working With ShengRong Grey Iron Casting Foundry

Customize various grades of gray iron castings HT200-HT350 and provide machining services. Casting parts with stable quality, competitive prices, short delivery times. Developing new project with customer pay half mold cost and samples free of charge

High quality custom grey iron casting partss

High-quality custom grey iron casting parts with precise dimensions and good surface finish

OEM small order available and fast delivery

We no requirem MOQ and for new project, the lead time with mold no more than 40 days

Good price of casting parts

Competitve casting parts in china, the more oreder, the better price.

Good after service

If casting parts defects more than 5%, we will send you new one free of charge

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Frequently Asked Questions

Gray iron castings are manufactured very easily and have good machinability.They are typically used in the following applications where strength is important, but not the main required property:

We make the parts from 0.5kgs to 10000kgs, special size is available

For samples, it need about 30days(model develop time 15-20 days, samples production time 10 days)

Bulk order after mold finished, it need about 20 days

Our yearly production can reach to 4000 tons

Yes, please offer detailed 2D drawing

We promise the QC pass rate 95%, if lower than this, we will send you new part free of charge

Gray cast iron is a broad term used for a number of cast irons whose microstructures are characterized by the presence of flake graphite in the ferrous matrix. Such castings often contain 2.5% to 4% carbon, 1% to 3% silicon, and some additions of manganese ranging from 0.1% to 1.2%.

Grey Cast Iron - an overview | ScienceDirect Topics

 

Normally, grey iron will be cheaper than ductile iron, and ductile iron will be cheaper than malleable iron. As for the same type of cast iron, the low and middle grades will have the same prices, but high grades will cause higher production costs.

Physical PropertiesMetricEnglish
Hardness, Rockwell C2020
Hardness, Vickers246246
Tensile Strength, Ultimate>= 276 MPa>= 40000 psi
Ultimate Compressive Strength>= 1034 MPa>= 150000 psi
A cast iron skillet can turn grey due to a few reasons, most commonly because the seasoning (a layer of polymerized oil) has been worn away or burned off. This can happen from using high heat, acidic foods, or harsh cleaning methods. The grey color reveals the bare iron underneath, which is more prone to rust and sticking. 
 
Here’s a more detailed explanation:
  • Seasoning:
    Cast iron cookware relies on a layer of polymerized oil (seasoning) to create a non-stick surface and protect it from rust. 
     
  • Burning Off Seasoning:
    High heat, especially when cooking with certain oils, can degrade the seasoning, causing it to turn grey or even flake off. 
     
  • Stripping Seasoning:
    Harsh cleaning methods, like using abrasive cleaners or steel wool, can also strip away the seasoning. 
     
  • Exposure to Moisture:
    Bare cast iron will rust easily if exposed to moisture. 
     
To restore the grey skillet to its original black, seasoned state, you’ll need to re-season it. This involves cleaning the skillet, applying a thin layer of oil, and baking it to polymerize the oil. 
 
Here’s a simplified process for re-seasoning:
  1. 1. Clean the skillet:
    Remove any loose rust or carbon buildup with a scrub brush or steel wool if necessary, and then dry it thoroughly. 
     
  2. 2. Seasoning:
    Apply a thin, even layer of seasoning oil (like flaxseed, vegetable, or grapeseed oil) to the entire skillet. 
     
  3. 3. Bake:
    Place the skillet upside down on a baking sheet (to catch drips) in a 350-450°F (175-230°C) oven for an hour. 
     
  4. 4. Cool and repeat:
    Let the skillet cool down in the oven, then repeat the seasoning and baking process a few times for a more durable seasoning. 

The biggest disadvantage of gray cast iron is its low tensile strength. This results from the graphite flakes within the material – which also give it many of its benefits.

Class 25,30,35,40 tensile and heat resistant irons. Gray Iron has a dense gray structure and offers excellent machinability. Grades 25, 30, 35 and 40 can fill specific requirements for hardness and wear, and heat treatments can yield even higher mechanical properties.

The defect appears preferably on horizontal or convex surfaces and at the surface of parts of reduced thickness having solidified at high cooling rates. In grey cast irons with high carbon contents, the defect can be formed in thick sections in which C-type graphite (hypoeutectic alloys) is commonly present.

Casting Defects in Sand-Mold Cast Irons—An Illustrated Review ...

Like gray cast iron, white cast iron features many small fractures. The difference is that white cast iron features cementite below its surface, whereas gray cast iron features graphite below its surface. The graphite creates the appearance of a gray color, while the cementite creates the appearance of a white color.

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The more carbon present in a material, the more brittle it is. Grey cast iron is further impacted by its graphical microstructure. It has tiny cracks and graphite flakes inherent within the material and these also contribute to its brittleness.

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