Okay,about stainless steel casting grades. Let me start by recalling what I know about stainless steel classifications. Stainless steels are typically categorized into different families like austenitic, ferritic, martensitic, duplex, and precipitation-hardening. Each has different properties and applications.
First, I need to list the common casting grades for each category. For austenitic grades, the 300 series comes to mind. Grades like CF8 (which is similar to 304) and CF8M (similar to 316) are commonly used. Then there's CF3 and CF3M, which have lower carbon content. Maybe also mention CN7M for more corrosive environments.
Next, ferritic stainless steels. Grades like CB30 (similar to 430) and CC50 might be relevant here. These are less common in casting but used where high corrosion resistance isn't as critical.
Martensitic grades include CA15 and CA6NM. CA15 is similar to 410, and CA6NM is used in applications requiring high strength and toughness, like turbines.
Duplex stainless steels combine austenitic and ferritic structures. CD4MCu and CD3MN are examples, offering good strength and corrosion resistance, used in chemical processing.
Precipitation-hardening grades like CB7Cu-1 (similar to 17-4 PH) are used when high strength and moderate corrosion resistance are needed. They can be heat treated for better properties.
I should also mention the standards organizations, like ASTM, ACI, and DIN, since grades can vary by standard. Including equivalent grades from different standards would be helpful.
Applications are important too. For example, CF8 in pumps and valves, CA15 in turbine parts, CD4MCu in chemical equipment. This gives context on where each grade is used.
I need to check if there are other grades or details I might be missing. Maybe the difference between cast and wrought grades? Like CF8 vs 304, where the cast version has a different composition. Also, note that cast grades often have a 'C' prefix in ASTM standards.
Also, considerations for selecting a grade: corrosion resistance, mechanical properties, temperature resistance, and cost. Maybe mention post-casting treatments like heat treatment or surface finishing.
Wait, did I cover all the categories? Austenitic, ferritic, martensitic, duplex, PH. Yes. Are there any other specific grades under these categories that are important? Maybe CK20 for high-temperature applications, though that's part of austenitic.
Make sure to structure the answer clearly, listing each category with grades, their properties, standards, and applications. Keep it organized so the user can easily find the information they need. Avoid jargon where possible, but include technical terms since the user is asking about grades specifically.
Double-check the equivalencies, like CF8 to 304, CF8M to 316. Also, note that cast grades may have slightly different compositions due to casting requirements. Maybe mention that cast grades are designed for better castability and may have higher carbon or other elements to prevent hot cracking.
Include examples of ASTM specifications, like ASTM A743, A744, A351, etc. ACI standards like ACI CF8M. DIN standards like GX2CrNiMo19-11-2.
Applications should tie each grade to real-world uses. For example, CA15 in pump shafts, CD4MCu in valves for corrosive environments.
I think that's a solid outline. Now, structure it in a clear, concise manner without being too verbose. Use bullet points or sections for each category. Ensure the user can quickly identify which grade is suitable for their needs based on properties and applications.
Stainless steel casting grades are categorized based on their microstructure and properties. Below is a structured overview of common grades, their standards, properties, and applications:
1. Austenitic Stainless Steels
Properties: Excellent corrosion resistance, good weldability, non-magnetic, ductile.
Common Grades:
CF8 (ASTM A351): Similar to wrought 304. Used in pumps, valves, and food processing.
CF8M (ASTM A351): Similar to 316. Higher Mo content for chloride resistance. Common in marine/chemical applications.
CF3/CF3M: Low-carbon versions (304L/316L equivalents). Ideal for welded parts.
CN7M (Alloy 20): Superior corrosion resistance in sulfuric acid. Used in chemical processing.
CK20 (ASTM A351): High-temperature resistance (similar to 310). For furnace parts.
2. Ferritic Stainless Steels
Properties: Magnetic, moderate corrosion resistance, lower ductility.
Common Grades:
CB30 (ASTM A743): Similar to 430. Used in automotive and low-stress environments.
CC50 (DIN 1.4509): Moderate heat resistance for automotive exhaust systems.
3. Martensitic Stainless Steels
Properties: High strength, hardness, and wear resistance. Magnetic.
Common Grades:
CA15 (ASTM A743): Similar to 410. For turbine blades, pump shafts.
CA6NM (ASTM A487): High toughness. Used in hydroelectric turbines and valves.
4. Duplex Stainless Steels
Properties: Mixed austenitic-ferritic structure. High strength and corrosion resistance.
Common Grades:
CD4MCu (ASTM A890): High chloride resistance. Used in chemical/petrochemical equipment.
CD3MN (ASTM A351, UNS J92205): Similar to 2205 duplex. For offshore and desalination systems.
5. Precipitation-Hardening (PH) Grades
Properties: High strength post-heat treatment, moderate corrosion resistance.
Common Grades:
CB7Cu-1 (ASTM A747, 17-4 PH): Aerospace, nuclear components. Combines strength and corrosion resistance.
Standards Organizations
ASTM: A351 (austenitic), A743/A744 (ferritic/martensitic), A890 (duplex).
ACI (Alloy Casting Institute): CF8M, CN7M.
DIN: GX2CrNiMo19-11-2 (CF8M equivalent), GX4CrNi13-4 (CA6NM).
Selection Considerations
Corrosion Resistance: Austenitic/duplex for harsh environments.
Mechanical Properties: Martensitic/PH for high strength.
Temperature: Austenitic (high-temp) vs. ferritic (moderate-temp).
Cost: Ferritic/martensitic are more economical than duplex/PH.
Applications
CF8/CF8M: Valves, pump housings.
CA15/CA6NM: Turbine components.
CD4MCu: Chemical processing valves.
CB7Cu-1: Aerospace fittings.
Note: Cast grades (e.g., CF8 vs. 304) may have adjusted compositions (e.g., higher carbon) for castability. Post-casting treatments (heat treatment, machining) are often required.