SS 316L vs CF3M Steel: What’s the Difference?

When it comes to selecting the right stainless steel for your project, understanding the differences between SS 316L and CF3M Steel can be critical. These two materials, while both within the austenitic stainless steel category, offer distinct properties that can significantly impact their suitability for various applications. SS 316L is renowned for its excellent corrosion resistance, making it a top choice in marine and medical environments. In contrast, CF3M Steel, with its robust mechanical properties, excels in high-stress applications such as valve components and pump parts.

In this article, we will delve into the nuances of their chemical compositions, mechanical properties, and real-world applications. How does SS 316L’s corrosion resistance stack up against CF3M Steel? Which one should you choose for high-strength, complex shapes? Read on as we unravel these questions and more, helping you make an informed decision for your next project.

Introduction to Stainless Steel Grades

Overview of Stainless Steel and Its Significance

Stainless steel is a fundamental material in many industries, valued for its excellent resistance to corrosion and its durability. These properties make it indispensable in applications where materials are exposed to harsh environments or corrosive substances. The diversity of stainless steel grades allows for tailored solutions to a wide array of industrial challenges.

Classification of Stainless Steel Grades

Stainless steel is categorized into several families based on its crystalline structure, including austenitic, ferritic, martensitic, and duplex stainless steels. Austenitic stainless steels, such as the 300 series, are particularly prominent due to their high corrosion resistance and excellent ductility, typically containing 18-30% chromium and 6-20% nickel.

SS 316L and CF3M Steel: An Introduction

SS 316L and CF3M steel are two notable grades within the austenitic family. SS 316L is a wrought stainless steel known for its enhanced performance in various applications, while CF3M is a cast austenitic stainless steel with unique characteristics.

Comparison of General Characteristics

SS 316L is renowned for its excellent corrosion resistance, especially in marine environments, and its high yield and tensile strength make it suitable for structural applications. In contrast, CF3M is prized for its casting properties, which allow it to form complex shapes ideal for components like valves and pumps.

Impact on Industry Applications

The distinct features of SS 316L and CF3M lead to their varied industrial uses. SS 316L is commonly used in chemical processing, medical device manufacturing, and marine equipment due to its corrosion resistance and strength. CF3M is preferred for high-pressure and corrosion-resistant cast components in industrial machinery.

Chemical Composition

SS 316L is an austenitic stainless steel known for its low carbon content and high corrosion resistance, with a specific chemical composition that includes chromium, nickel, and molybdenum.

Chemical Composition of SS 316L

• Chromium (Cr): 16.00 – 18.00%
• Nickel (Ni): 10.00 – 14.00%
• Molybdenum (Mo): 2.00 – 3.00%
• Carbon (C): Maximum 0.03%
• Manganese (Mn): Up to 2.00%
• Silicon (Si): Up to 1.00%
• Phosphorous (P): Maximum 0.045%
• Sulfur (S): Maximum 0.030%
• Nitrogen (N): Up to 0.10%
• Iron (Fe): Balance

Chemical Composition of CF3M Steel

• Chromium (Cr): 17.00 – 21.00%
• Nickel (Ni): 9.00 – 13.00%
• Molybdenum (Mo): Similar to SS 316L (2-3%)
• Carbon (C): Maximum 0.03%
• Manganese (Mn): Up to 1.50%
• Silicon (Si): Up to 1.50%
• Nitrogen (N): Typically not significant
• Iron (Fe): Balance

Key Differences and Implications

Chromium and Nickel Content

SS 316L has a narrower chromium range (16-18%) and a broader nickel range (10-14%), while CF3M has a higher chromium content (17-21%) and slightly lower nickel content (9-13%). These variations affect their corrosion resistance and mechanical strength, with CF3M generally exhibiting better resistance in more aggressive environments due to its higher chromium content.

Manganese and Silicon

SS 316L allows higher levels of manganese (up to 2.00%) and silicon (up to 1.00%) compared to CF3M, which allows up to 1.50% for both elements. These differences can enhance SS 316L’s strength and machinability.

Carbon Content

Both SS 316L and CF3M maintain a maximum carbon content of 0.03%, which is crucial for preventing intergranular corrosion, especially after welding. This low carbon content helps prevent carbide precipitation during welding, making both materials suitable for applications that involve joining.

Nitrogen

SS 316L may contain up to 0.10% nitrogen, which helps maintain its mechanical strength, whereas CF3M typically does not have significant nitrogen content. Nitrogen can enhance the tensile strength and pitting resistance of SS 316L.

Impact of Chemical Composition on Material Properties

Higher chromium and molybdenum contents generally improve corrosion resistance, making CF3M slightly more resistant in harsh environments. Nickel and nitrogen in SS 316L contribute to its high strength and ductility. The presence of elements like manganese and silicon in SS 316L affects machinability and formability, with SS 316L being slightly easier to machine and form due to its composition.

These differences make SS 316L more suitable for applications requiring extensive welding and forming, such as in marine and medical industries, while CF3M is preferred for casting applications where complex shapes and high corrosion resistance are necessary, like in valves and pumps.

Mechanical Properties

Tensile Strength

Tensile strength measures the maximum load a material can endure before it breaks.

• SS 316L: The tensile strength of SS 316L ranges from 530 to 1160 MPa. This wide range provides flexibility for various applications requiring different degrees of strength.
• CF3M Steel: CF3M steel has a tensile strength of at least 483 MPa. While this is generally lower compared to the upper range of SS 316L, it is adequate for many casting applications where high tensile strength is not the primary requirement.

Yield Strength

Yield strength is the stress level at which a material starts to deform permanently.

• SS 316L: The yield strength of SS 316L varies from 190 to 870 MPa. This variability provides options for applications demanding both lower and higher yield strengths.
• CF3M Steel: The yield strength of CF3M steel is at least 207 MPa. This consistent yield strength is suitable for components that require reliable and predictable performance under stress.

Elongation

Elongation shows how much a material can stretch before it breaks, indicating its ductility.

• SS 316L: SS 316L exhibits an elongation range of 9% to 50%. This wide range indicates its excellent ductility, making it suitable for applications that require significant forming and shaping.
• CF3M Steel: CF3M steel has an elongation of at least 30%, which provides sufficient ductility for casting applications where the material needs to absorb energy and resist impact.

Hardness

Hardness indicates how resistant a material is to deformation and wear.

• SS 316L: The hardness of SS 316L typically falls within a range suitable for machining and forming processes, offering a balance between strength and workability.
• CF3M Steel: CF3M steel’s hardness is generally higher due to its casting nature, providing excellent wear resistance for components subjected to abrasive environments.

Impact of Mechanical Properties on Performance

The mechanical properties of SS 316L and CF3M steel directly affect their performance in different applications:

• SS 316L: With its high tensile and yield strengths, along with excellent elongation, SS 316L is well-suited for applications that require both strength and ductility. This makes it ideal for structural components, medical devices, and marine applications where material performance under stress is critical.
• CF3M Steel: The mechanical properties of CF3M steel, particularly its consistent yield strength and adequate elongation, make it ideal for casting complex shapes. Its hardness and wear resistance are beneficial in applications like valves and pump parts, where components must maintain integrity under mechanical stress and abrasive conditions.

These mechanical property differences help determine the suitability of SS 316L and CF3M steel for specific industrial applications, ensuring that the right material is chosen based on the required performance characteristics.

Corrosion Resistance

Factors Influencing Corrosion Resistance

Corrosion resistance is a material’s ability to withstand damage from chemical reactions with its environment. For SS 316L and CF3M Steel, several elements in their chemical compositions are key to their corrosion resistance.

Chromium forms a protective oxide layer on the metal’s surface, preventing further corrosion. SS 316L contains 16.0% – 18.0% chromium, while CF3M has 17.0% – 21.0%. A higher chromium content generally enhances this protective layer, giving CF3M a potential advantage in some corrosive conditions.

Nickel stabilizes the passive layer and increases resistance to acids. SS 316L has 10.0% – 14.0% nickel, compared to 9.0% – 13.0% in CF3M. The higher nickel content in SS 316L can offer better resistance in acidic environments.

Molybdenum boosts resistance to pitting and crevice corrosion, especially in chloride-rich environments. SS 316L contains 2.0% – 3.0% molybdenum. Although CF3M is known to have similar molybdenum content, its exact value isn’t always specified, potentially affecting its performance in chloride settings.

Performance in Different Environments

Marine Environments

In marine environments with high salt and moisture levels, both SS 316L and CF3M Steel are used for their corrosion resistance. SS 316L, with its low carbon content (less than 0.03%), minimizes carbide precipitation during welding, reducing the risk of intergranular corrosion. Its combination of chromium, nickel, and molybdenum content makes it highly resistant to seawater’s corrosive effects, including pitting and crevice corrosion.

CF3M Steel also offers good corrosion resistance but may not be as effective as SS 316L in all marine applications. The unspecified molybdenum content could limit its performance against aggressive chloride ions in seawater.

Chemical Processing Environments

Chemical processing environments vary widely, involving acids, alkalis, and solvents. SS 316L suits many chemical processing applications well. Its high nickel and molybdenum content provide good resistance to various acids, including sulfuric and phosphoric acids at certain concentrations.

CF3M Steel is also used in chemical processing, particularly for components like valve bodies and pump casings. Its performance can be application-specific. In less aggressive chemical environments where complex shapes are needed, CF3M’s casting properties make it a viable option. However, in highly corrosive settings, SS 316L often offers better long-term corrosion resistance.

Practical Implications for Material Selection

When choosing between SS 316L and CF3M Steel, consider the specific environment. For marine applications or where high-quality welding is required, SS 316L is the better choice due to its resistance to intergranular corrosion and seawater’s corrosive effects. If the application involves casting complex shapes in a relatively mild corrosive environment, CF3M Steel can be cost-effective. However, in highly corrosive chemical environments, a careful assessment of the chemical composition and corrosion resistance is essential to ensure the component’s long-term performance.

Applications in Industry

Common Applications of SS 316L

SS 316L is highly versatile and finds use in various industries due to its superior corrosion resistance, high strength, and excellent formability.

Marine Applications

The marine industry depends on SS 316L for its exceptional resistance to seawater and marine environments. It is commonly used in the construction of boat fittings, marine hardware, and coastal architectural components. Its ability to resist pitting and crevice corrosion in saline conditions makes it an ideal choice for prolonged exposure to seawater.

Chemical Processing

The chemical industry prefers SS 316L due to its ability to withstand various chemicals and corrosive substances. It is often employed in the fabrication of tanks, piping systems, and reactors. Its high resistance to acids, such as sulfuric and phosphoric acids, ensures the longevity and reliability of equipment in these harsh environments.

Medical Devices

The medical field uses SS 316L because it is biocompatible and non-reactive. It is used in the manufacture of surgical instruments, orthopedic implants, and medical devices. The material’s ability to withstand sterilization processes without degrading ensures patient safety and device durability.

Common Applications of CF3M Steel

CF3M Steel, with its excellent casting properties and resistance to corrosion, is predominantly used in the manufacture of complex and high-strength components.

Valve Components

CF3M is extensively used in valve components, especially for casting complex shapes that must resist corrosion from chemical plant, oil refinery, and water treatment fluids.

Pump Parts

In the pump manufacturing industry, CF3M steel is valued for its strength and durability. It is often used to cast pump casings and impellers, which need to withstand high pressure and abrasive environments. The material’s resistance to wear and corrosion ensures that pumps maintain their performance and reliability over extended periods.

Chemical Processing Equipment

Similar to SS 316L, CF3M is also employed in chemical processing. However, its application is more focused on components that require intricate shapes and high strength. CF3M is ideal for casting items such as flanges, fittings, and pressure-containing parts that operate in corrosive environments.

Case Studies and Real-World Examples

SS 316L in Marine Environments

An example of SS 316L’s application in the marine industry is its use in the construction of offshore oil rigs. These structures are exposed to harsh sea conditions and require materials that can withstand constant exposure to seawater. SS 316L’s corrosion resistance ensures the structural integrity and longevity of these rigs.

CF3M Steel in Valve Manufacturing

CF3M steel is notably used to make high-performance valves for the chemical industry. These valves often need to handle highly corrosive fluids at high pressures. The casting properties of CF3M allow for the creation of complex valve geometries that can endure these demanding conditions, providing both reliability and efficiency in operation.

Austenitic Stainless Steel

Austenitic stainless steels are a type of stainless steel known for their face-centered cubic (FCC) crystal structure. This unique microstructure provides several key attributes:

• Non-Magnetic Nature: Austenitic stainless steels are generally non-magnetic, although they can become slightly magnetic when cold worked.
• High Chromium and Nickel Content: Typically containing 16-30% chromium and 6-20% nickel, these elements are crucial for enhancing corrosion resistance and mechanical properties.
• Excellent Corrosion Resistance: The high chromium content forms a passive oxide layer on the surface, providing significant protection against corrosion.
• Good Formability and Weldability: The FCC structure allows for excellent shaping and welding, making these steels ideal for complex forms.
• Temperature Resistance: They can withstand extreme temperatures, both high and low, making them suitable for a wide range of applications.

The unique properties of austenitic stainless steels offer numerous advantages, making them popular across various industries:

• Durability and Longevity: The excellent corrosion resistance and mechanical properties ensure long service life in harsh environments.
• Versatility: These steels can be used in diverse applications, from architectural components to marine equipment.
• Ease of Fabrication: Their good formability and weldability facilitate manufacturing complex components and structures.
• Hygiene and Cleanliness: Austenitic stainless steels are easy to clean and maintain, which is essential in industries like food processing and healthcare.

SS 316L and CF3M within the Austenitic Category

SS 316L

SS 316L is a low-carbon austenitic stainless steel known for its superior corrosion resistance, especially in chloride environments. Key features include:

• Low Carbon Content: Less than 0.03% carbon content minimizes carbide precipitation, enhancing resistance to intergranular corrosion.
• Molybdenum Addition: Contains 2-3% molybdenum, improving resistance to pitting and crevice corrosion.
• Applications: Due to its robustness and corrosion resistance, SS 316L is widely used in marine environments, chemical processing, and medical devices.

CF3M

CF3M is a cast austenitic stainless steel with specific properties suitable for high-stress and complex shape applications. Key features include:

• Higher Chromium Content: Contains 17-21% chromium, which provides excellent corrosion resistance.
• Casting Properties: Designed for casting, it allows for the creation of complex geometries with high precision.
• Applications: Commonly used in valve components, pump parts, and other high-pressure environments due to its ability to maintain integrity under stress.

Comparative Analysis: SS 316L vs CF3M

Chemical Composition

• SS 316L: Chromium (16-18%), Nickel (10-14%), Molybdenum (2-3%), Low Carbon (

Comparative Table

Comparative Table: SS 316L vs CF3M Steel

Chemical Composition

Mechanical Properties

Corrosion Resistance

Typical Applications

Standards Compliance

Each material’s unique properties and compliance with industry standards ensure their suitability for specific applications, allowing engineers to make informed choices based on performance requirements and environmental conditions.

Cost Differences

Factors Influencing Cost

Several factors influence the cost differences between SS 316L and CF3M steel. These factors include raw material prices, production processes, and the specific applications for which each material is used.

Raw Material Prices

SS 316L generally has higher concentrations of chromium and nickel than CF3M. Chromium and nickel are relatively expensive alloying elements, which increases the cost of SS 316L compared to CF3M.

Production Processes

The production process of SS 316L is more complex and labor – intensive compared to CF3M as SS 316L is a wrought material, shaped by rolling, forging, or extrusion. These processes require significant energy and labor, contributing to higher manufacturing costs.

On the other hand, CF3M is a cast material, which involves melting the alloy and pouring it into molds to achieve the desired shape. Casting is generally less labor – intensive and can be more cost – effective, especially for producing complex shapes and large quantities. This makes CF3M a more affordable option for many applications.

Cost Comparison in Applications

SS 316L

SS 316L is often chosen for applications where superior corrosion resistance and high strength are critical, such as in chemical processing, pharmaceutical manufacturing, and marine environments. Its ability to endure harsh conditions and stay intact over time often makes up for the higher upfront cost.

CF3M

CF3M is preferred in applications where cost is a significant consideration. It is still required to have good corrosion resistance and mechanical properties. It is used in applications like valve bodies, pump casings, and other industrial equipment where casting complex shapes is advantageous. The cost – effectiveness of CF3M makes it a popular choice for budget – conscious projects without compromising performance.

Long – Term Cost Considerations

Although SS 316L costs more initially, its durability and corrosion resistance can result in lower long – term maintenance and replacement costs. This makes it a cost – effective choice for long – term applications where reliability and longevity are paramount.

CF3M, being less expensive initially, is suitable for applications where budget constraints are more critical, and the environment is less corrosive. However, in highly corrosive environments, the potential for higher maintenance and replacement costs must be considered, which could diminish the initial cost savings.

Long-Term Performance

Long-Term Performance of SS 316L and CF3M Steel

Mechanical Stability

SS 316L:
SS 316L retains its mechanical properties across a broad range of temperatures, even in extreme cold. Its tensile strength, which can range from 530 to 1160 MPa, provides flexibility for different applications. The material’s yield strength, varying between 190 and 870 MPa, ensures that it can withstand significant stress without permanent deformation. Additionally, SS 316L offers excellent ductility, with elongation properties ranging from 9% to 50%. This flexibility is crucial for applications that involve significant forming and shaping.

CF3M Steel:
CF3M exhibits consistent mechanical performance, with a tensile strength of at least 483 MPa and a yield strength of 207 MPa. While its elongation at break is at least 30%, making it sufficiently ductile, it may become brittle in cold conditions. The material’s hardness, typically in the range of 150 to 350 Brinell, provides excellent wear resistance, which is beneficial for high-pressure environments and components subjected to mechanical stress.

Corrosion Resistance

SS 316L:
SS 316L is particularly noted for its superior corrosion resistance in moist or salty environments due to its combination of chromium, nickel, and molybdenum, which forms a protective passive oxide layer. This makes SS 316L highly durable in marine and chemical processing environments, even in extreme cold conditions where other materials might fail.

CF3M Steel:
CF3M also offers excellent corrosion resistance, attributed to its higher chromium content. However, its performance may be limited at temperatures above 427°C and in extremely cold conditions where it can become brittle. Despite this, CF3M remains a strong candidate for applications requiring high corrosion resistance in less severe temperature ranges.

Application-Specific Durability

SS 316L:
SS 316L’s resistance to pitting and crevice corrosion makes it ideal for long-term use in coastal and offshore applications. In chemical processing, its ability to withstand various acids and corrosive substances without degrading extends the lifespan of equipment and reduces maintenance costs.

CF3M Steel:
CF3M is ideal for casting complex shapes, making it suitable for components such as valves, pumps, and fittings that require high precision and durability. Its wear resistance ensures that these components maintain their performance over time, even under high-stress conditions. However, CF3M’s performance may be less reliable in extreme cold or high temperatures compared to SS 316L.

SS 316L and CF3M steel are both types of austenitic stainless steel, but they have distinct characteristics. In terms of chemical composition, SS 316L has a narrower chromium range but a broader nickel range. CF3M, however, contains a higher chromium content and slightly lower nickel content. These differences influence their corrosion resistance and mechanical strength, with CF3M generally more resistant in aggressive environments.

In terms of mechanical properties, SS 316L offers a wide range of tensile and yield strengths. It also has excellent elongation, making it suitable for applications requiring both strength and ductility. CF3M, on the other hand, has consistent mechanical performance and higher hardness, which is beneficial for high-pressure and wear-resistant applications.

When selecting materials, the specific application needs must be considered. For marine applications or those requiring high-quality welding and resistance to intergranular corrosion, SS 316L is the better choice. Its excellent corrosion resistance in salty environments and its ability to endure sterilization processes make it ideal for marine equipment and medical devices.

In contrast, CF3M is preferred for applications where casting complex shapes is necessary, such as valve components and pump parts. Its cost-effectiveness, especially for large-quantity production, makes it a popular option in industrial settings with relatively mild corrosive environments.

In the long run, SS 316L’s durability and corrosion resistance can lead to lower maintenance and replacement costs, despite its higher initial price. It is a cost-effective choice for long-term applications where reliability and longevity are crucial. CF3M, being less expensive initially, is suitable for budget-conscious projects in less corrosive environments. However, you should carefully consider potential long-term maintenance and replacement costs in highly corrosive conditions.

Frequently Asked Questions

Below are answers to some frequently asked questions:

What are the key differences between SS 316L and CF3M Steel in terms of composition and applications?

SS 316L and CF3M Steel are both known for their excellent corrosion resistance, but they differ in composition, fabrication processes, and applications. SS 316L is a wrought austenitic stainless steel containing 16-18% chromium, 10-14% nickel, and 2-3% molybdenum with a low carbon content (≤ 0.03%). It is highly ductile, weldable, and ideal for environments with high chloride exposure, such as marine applications and medical devices.

In contrast, CF3M is a cast stainless steel with a composition of 17-21% chromium, 9-13% nickel, and 2-3% molybdenum, also with a maximum carbon content of 0.03%. The casting process allows CF3M to be formed into complex shapes, making it suitable for high-pressure applications like valves and pumps.

Key differences include SS 316L’s superior weldability and resistance to chloride-induced corrosion, while CF3M is preferred for its ability to maintain strength under high pressure and its suitability for intricate designs. The choice between the two depends on specific application requirements, such as the need for complex geometries or high corrosion resistance.

How does the corrosion resistance of SS 316L compare to that of CF3M Steel?

SS 316L and CF3M Steel both offer excellent corrosion resistance, but they have distinct differences. SS 316L, a low-carbon variant of the 316 stainless steel alloy, contains less than 0.03% carbon, significantly reducing the risk of carbide precipitation and enhancing resistance to intergranular corrosion during welding. It also has higher chromium and molybdenum content, providing superior resistance to general, pitting, and crevice corrosion, especially in moist and salty environments. This makes SS 316L ideal for marine applications, chemical processing, and medical devices.

CF3M Steel, a cast austenitic stainless steel, also has low carbon content and is designed for casting applications, which allows it to form complex shapes. While it offers good corrosion resistance due to its molybdenum content, it is limited to a maximum operating temperature of 800°F (427°C) and can become brittle in cold conditions. This makes CF3M less suitable for extreme cold environments compared to SS 316L.

Which material is more suitable for applications requiring high strength and complex shapes?

When determining the suitability of SS 316L versus CF3M steel for applications requiring high strength and complex shapes, several factors come into play.

CF3M steel, being a cast austenitic stainless steel, excels in applications requiring intricate geometries. This is due to its casting process, which allows for the production of complex shapes that would be challenging to achieve with wrought materials like SS 316L. CF3M offers sufficient mechanical strength for high-pressure environments, making it ideal for components such as valves, pumps, and fittings.

On the other hand, SS 316L provides a broader range of tensile and yield strengths, offering excellent durability and superior corrosion resistance, especially in chloride-rich environments. Its low carbon content enhances weldability, making it suitable for applications where welding is necessary.

What standards do SS 316L and CF3M Steel comply with?

SS 316L and CF3M Steel comply with different standards due to their distinct forms and applications. SS 316L, a low-carbon version of 316 stainless steel, is covered by ASTM A240 for pressure vessels and general applications, and ASTM A182 for forged fittings and valves. It is designated as S31603 under the Unified Numbering System (UNS) and 1.4304 under European standards, complying with the Pressure Equipment Directive (PED) according to EN 10028-7 and AD 2000 Merkblatt W2 and W10.

CF3M, a cast austenitic stainless steel, adheres to ASTM A351, A743, and A744 standards for castings. These standards ensure CF3M’s suitability for producing complex shapes like valve bodies and pump casings, with specific chemical and mechanical property requirements to maintain its performance in casting applications.

Are there any cost differences between SS 316L and CF3M Steel?

Yes, there are cost differences between SS 316L and CF3M Steel. SS 316L is typically more expensive. This is due to its higher chromium and molybdenum content, which enhances corrosion resistance and mechanical strength, and its more complex and labor – intensive production process. In contrast, CF3M is generally more affordable because of its lower production complexity and the nature of the casting process, making it suitable for budget – conscious applications.

How do SS 316L and CF3M Steel perform in long – term applications?

Both SS 316L and CF3M steel perform well in long-term applications, but their suitability depends on specific conditions and requirements.

SS 316L is known for its superior corrosion resistance, particularly in chloride-rich environments such as marine and chemical processing industries. Its low carbon content minimizes carbide precipitation during welding, enhancing resistance to intergranular corrosion and maintaining structural integrity. This makes SS 316L highly durable over time, even in harsh environments. It is also easy to weld and form, retaining its mechanical properties post-welding, which contributes to its long-term reliability.

CF3M steel, on the other hand, offers high tensile and yield strengths, making it suitable for high-pressure environments. Its ability to be cast into complex shapes is beneficial for components requiring intricate designs and high strength. However, its long-term performance may be affected by potential casting defects, which could impact its corrosion resistance. CF3M is less commonly used in applications where welding is critical, but it excels in applications requiring complex casting and high mechanical strength.

In summary, SS 316L is preferred for long-term applications requiring superior corrosion resistance and weldability, while CF3M steel is more suited for high-pressure environments with complex casting requirements. The choice between these materials should be based on the specific needs of the application in terms of corrosion resistance, strength, and fabrication processes.