Cast Iron for Custom Industrial Components
LANJIAN manufactures custom cast iron components to customer drawings, supplied as casting blanks, rough-machined, or finish-machined parts. Cast iron type and grade, graphite structure, matrix condition, section thickness, hardness or mechanical properties, machining allowance, and test requirements are reviewed before production.
- Cast Iron Type, Grade & Condition Confirmed
- From Casting Blank to Finish-Machined Delivery
- Graphite Structure, Matrix & Section Thickness Reviewed
- Mechanical Properties & Test Requirements Agreed
Scope: Custom cast iron components produced to drawings or confirmed specifications.
What Cast Iron Can LANJIAN Work With?
LANJIAN produces custom gray cast iron and ductile iron castings according to customer drawings and specified material standards. Representative grades are listed below. The exact grade, casting section, heat-treatment condition, required properties and inspection requirements are confirmed for each project.
Cast Iron Type | Representative Grades | Suitable Conditions & Components | ||
Gray Cast Iron | GB/T 9439: HT200, HT250, HT300 | Graphite: Flake graphite. | Conditions: Static or mainly compressive loading where vibration damping and machinability are important. | |
ASTM A48/A48M: Class 30, Class 35, Class 40 | Key strengths: Good vibration damping, machinability and compressive-load performance. | Priority: Damping, machining performance and compressive strength. | ||
EN 1561: EN-GJL-200, EN-GJL-250, EN-GJL-300 | Limitations: Low tensile ductility and lower impact and fatigue resistance than ductile iron. | Components: Machine bases, equipment housings, covers, base plates and support bodies. | ||
Ductile Iron | GB/T 1348: QT400-18, QT500-7, QT600-3 | Graphite: Spheroidal or nodular graphite. | Conditions: Tensile, bending, impact or repeated loading requiring greater strength and ductility. | |
ASTM A536: 60-40-18, 80-55-06, 100-70-03 | Key strengths: Generally higher tensile and yield strength, ductility, impact resistance and fatigue performance than gray cast iron. | Priority: Strength, elongation, impact performance and fatigue resistance. | ||
EN 1563: EN-GJS-400-15, EN-GJS-500-7, EN-GJS-600-3 | Heat treatment: The required condition depends on the specified grade and mechanical properties. | Components: Load-bearing housings, hubs, brackets, supports, levers and power-transmission castings. |
Grades listed under different standards are representative references, not exact equivalents. Grade definitions, test specimens and mechanical-property requirements must be reviewed according to the governing standard.
Properties measured from test specimens may not represent every location in the finished casting. Critical-section hardness, microstructure or mechanical testing should be specified when required.
Cast Iron Characteristics at a Glance
Cast iron performance depends on graphite structure, matrix, hardness, section thickness and manufacturing condition. Buyers should consider how these factors affect damping, machining, wear, local properties, weld repair and corrosion protection.
01 — Vibration Damping
Gray cast iron generally provides higher internal damping than ductile iron. This helps reduce resonance and operational noise in machine bases, housings and support bodies. Actual performance also depends on graphite structure and matrix condition.
02 — Machinability
Machinability varies with graphite form, matrix, hardness and the presence of carbides or hard spots. Ferritic structures are generally easier to machine, while pearlite, chilled areas and carbides can increase cutting forces and tool wear.
03 — Wear Performance
Cast iron should not be described as wear-resistant without defining the wear condition. Sliding, rolling, abrasive and erosive wear require different combinations of matrix and hardness. Contact pressure, lubrication and abrasive material should also be considered.
04 — Section Sensitivity
Thin and thick sections cool at different rates, which can create local differences in graphite structure, matrix and hardness. Abrupt section changes may affect mechanical properties and machining consistency, so critical sections should be identified on the drawing.
05 — Welding and Repair
Cast iron welding requires different controls from low-carbon steel welding. Cast iron type, filler material, heat input and cooling method should be defined to reduce hard zones and cracking. Post-repair inspection may also be required.
06 — Corrosion Protection
Conventional unalloyed gray and ductile irons are not normally selected for inherent corrosion resistance. Painting, powder coating, plating or oil protection may be required according to the service environment. Coating suitability should be reviewed for salt or chemical exposure.
What Cast Iron Requirements Should Be Confirmed?
“Gray cast iron” or “ductile iron” alone is not a complete material specification. Before production, confirm the exact grade, governing standard, required properties, microstructure, critical sections, test method and delivery condition.
What Should Be Confirmed | What to Specify | Why It Matters | |||
Cast Iron Type, Grade and Standard | Gray cast iron or ductile iron; the exact grade under the applicable ASTM, EN, GB or customer specification; any mandatory chemical-composition limits. | Different standards may use different property and testing requirements. Grade-conversion tables do not establish exact equivalence. | |||
Service and Loading Conditions | Static, compressive, tensile, bending, impact or repeated loading; vibration, wear, operating temperature and corrosion exposure. | Operating conditions determine the appropriate cast iron type, grade, matrix, hardness and surface protection. | |||
Mechanical Properties and Hardness | Required tensile strength, yield strength and elongation where applicable; hardness range, impact requirement, test temperature and test location. | Properties measured from a standard test bar may not represent every local section of the finished casting. | |||
Graphite and Matrix Requirements | When required, specify graphite form and distribution for gray iron; nodularity or nodule count for ductile iron; and any ferrite, pearlite, carbide or chill limits. | Graphite and matrix structure directly affect strength, ductility, impact resistance, damping and machinability. | |||
Critical Sections and Test Samples | Critical wall sections, abrupt thickness transitions, test coupon type and sampling location. | Cooling rate changes with section thickness. Separately cast, cast-on and casting-cut samples may not represent the same local material condition. | |||
Heat Treatment and Delivery Condition | |||||
Material Verification and Documentation |
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The test method, sample location, sampling frequency, acceptance criteria, and report format for any additional verification should be agreed before production.
Cast Iron FAQ
LANJIAN works with gray cast iron and ductile iron for custom castings and machined components. The exact grade, governing standard, section thickness, required properties and inspection requirements are confirmed for each project.
Gray cast iron contains flake graphite and generally provides better vibration damping and machinability, making it suitable for machine bases and housings. Ductile iron contains spheroidal graphite and generally provides higher strength, elongation, impact resistance and fatigue performance.
No. ASTM A48/A48M and EN 1561 cover gray cast iron, while ASTM A536 and EN 1563 cover ductile iron, but their grade classifications, test specimens and property requirements are not identical. The governing standard and acceptance criteria should be specified.
Thin and thick sections cool at different rates, which can change graphite structure, matrix and hardness. Properties measured from a standard test bar may therefore differ from the local properties of a critical casting section.
Rapid cooling in thin sections, edges or local mold-contact areas can produce carbide-rich or chilled structures with high hardness. These areas may increase tool wear or prevent consistent machining. Hardness testing or metallographic examination can help identify the condition.
No. Stress relief may be specified for large or complex castings, components requiring substantial rough machining, or parts with tight final tolerances. When required, the treatment stage and procedure should be matched to the grade and casting section.
Yes, but repair suitability depends on the cast iron type, defect location and service requirements. Filler material, preheating, heat input, cooling method and post-repair inspection may need to be controlled to reduce hard zones and cracking.
Verification may include heat traceability, material certificates, chemical analysis, tensile testing, hardness testing and metallographic examination. For ductile iron, nodularity or nodule count may also be specified. A material certificate alone may not confirm the local properties of every casting section.
Need the Right Cast Iron for Your Component?
Send your drawing or available project details. LANJIAN will review the cast iron type, grade and standard, critical sections, machining condition, heat-treatment requirements and required material records before quotation.