1. What Do ASTM and EN Stand For?

In simple terms: ASTM is a technical standard developed by a respected US private organization. EN is a mandatory standard uniformly implemented by EU member countries.

Both are the most widely used standard systems in global stainless steel pipe trade.

2.Quick Comparison Table

3.Three Key Differences

3.1 Grade : Alphanumeric vs Numeric Code

ASTM uses easy-to-remember combinations like 304 or 316L. EN uses a 5-digit numeric system: 1.4301, 1.4404. European engineers recognize these instantly.

3.2 Dimension System: Inch vs Metric

ASTM pipe OD is in inches (1/2″, 1″, 2″).

EN pipe OD is in mm (21.3mm, 33.7mm, 60.3mm).

3.3 Inspection Requirements: EN is Generally Stricter

EN standards demand tighter control on chemical composition, mechanical properties, and traceability per heat number. ASTM offers more flexibility.

As a professional stainless steel welded tubes manufacturer, MW Metal can supply both ASTM and EN tubes as your requirements.

Interested in our product catalog and our price level? Please feel free to contact Vivian in [email protected] at any time.

Lower material cost may lead to higher total project cost

Some suppliers suggest substituting 304 with 201 stainless steel to reduce costs, especially for price-sensitive overseas orders. But is it always a wise move? Here are three real risk scenarios that procurement and engineering teams should carefully evaluate.

Scenario 1: Humid or Mildly Corrosive Environments – Rust Spots Within 1 Year

201 stainless steel has a lower nickel content , offering weaker resistance to chlorides and weak acids. In coastal humid warehouses, food processing plants, or outdoor decorative structures, rust spots or yellow stains may appear within 6–12 months.

Consequences of replacing 304 with 201 stainless steel welded pipes in this case:

Rejection by the client or full return of the batch

Additional costs for pickling, or even material replacement — exceeding the initial "savings"

Scenario 2: Bending, Expanding or Flattening – Higher Weld Cracking Rate

201 stainless steel work-hardens faster and has lower ductility than 304. During bending, tube expansion, or flattening, the weld zone and heat-affected zone are more prone to micro-cracks or complete fracture.

Consequences of replacing 304 with 201 stainless steel welded pipes in this case:

Reject rate increases from <1% to 5–10%

Delivery delays, rework, and additional material costs

Higher risk of leakage if used in pressure piping systems

Scenario 3: Post-Weld Appearance Requirements – Weld Discoloration Cannot Be Polished to Match

201 stainless steel tends to form thicker heat tint (grey, blue, or even black) during welding, which is difficult to remove by pickling or mechanical polishing to match the base metal.

Consequences of replacing 304 with 201 stainless steel welded pipes in this case:

Visual rejection for decorative tubes (railings, furniture, curtain walls)

Extra grinding, coating, or full painting — erasing cost advantage

Multiple rework cycles may reduce local corrosion resistance

Substitution Is Possible — But Know the Price

If the project budget is tight, consider instead:

1.Reducing wall thickness (through optimized design)

2.Adjusting lengths or reducing custom processing

3.Do not simply downgrade the material grade.

As countries around the world accelerate their pursuit of carbon neutrality, the green energy sector is expanding at an unprecedented pace. Within this transformation, stainless steel tubes are quietly playing a critical role—serving as the structural backbone and fluid-carrying veins of clean energy infrastructure. Stainless steel’s resistance to corrosion, high temperatures, and extreme pressures makes it indispensable in demanding operating environments.

1.Concentrated Solar Power (CSP): Reliable Performance Under Extreme Conditions

In concentrated solar power systems, thousands of collector tubes must endure long-term exposure to high-temperature molten salts, thermal oils, and cyclic thermal stresses. Traditional carbon steel often falls short in such environments. Austenitic stainless steels (e.g., 304, 316L) have become the preferred material for heat collector tubes, thermal storage tanks, and connecting pipelines due to their excellent oxidation resistance and chloride corrosion resistance.

2.The Hydrogen Economy: Reliable Solutions from Production to End-Use

Hydrogen is widely regarded as the ultimate clean energy carrier. However, its small molecular size, high permeability, and potential to cause embrittlement demand exceptionally robust piping materials.

Hydrogen Production: In water electrolysis systems, stainless steel tubes are used to transport high-purity hydrogen and alkaline electrolytes. Low-carbon grades such as 316L are widely adopted for their superior resistance to stress corrosion cracking.

Storage & Transportation: For high-pressure gaseous hydrogen (35MPa/70MPa) and liquid hydrogen (-253°C), 316/316L and higher-grade austenitic stainless steels retain excellent toughness at cryogenic temperatures. They are the standard choice for tube trailers and high-pressure pipelines in hydrogen refueling stations.

3.Carbon Capture, Utilization, and Storage (CCUS): Tackling Corrosive Environments

Carbon capture is essential for deep decarbonization in heavy industries. During the capture process, CO₂ streams often contain impurities such as moisture, oxygen, and acidic gases (e.g., H₂S, SOₓ), creating highly corrosive conditions.

Duplex stainless steels (e.g., 2205) and super austenitic stainless steels offer a combination of high strength and exceptional localized corrosion resistance, making them ideal for absorbers, reboilers, and CO₂ transport pipelines in carbon capture systems. Selecting the appropriate stainless steel grade can significantly extend equipment service life and reduce total lifecycle costs, enhancing the economic viability of CCUS technologies.

Conclusion

The advancement of green energy depends not only on breakthroughs in power generation or conversion technologies but also on the availability of high-performance base materials. With their ability to withstand extreme environments, deliver long-term reliability, and support extended service life, stainless steel tubes are transitioning from conventional industrial applications to the forefront of the clean energy transition.

As a professional stainless steel pipe manufacturer, we are committed to supporting the evolving material demands of the green energy sector. Our products comply with ASTM, EN and other international standards, and we provide tailored solutions from material selection to custom fabrication.

Many people instinctively believe seamless pipes are superior. When you hear "welded pipe," that weld seam sounds like a weakness—a scar that must make the pipe less reliable than its seamless counterpart.

This idea is common, but in the world of stainless steel pipes, the truth might surprise you.

1.The Misunderstood Weld

Where does this "seamless is better" impression come from? Early welding technology truly was immature—weld zones were prone to rust and lacked strength.

But as technology has advanced, this stereotype needs updating.

In modern high-end welded pipes, after solution treatment and precision finishing, the weld zone microscopically resembles the base material.

More importantly, welded pipes actually excel in certain critical areas. Take inner surface smoothness: welded pipes are cold-formed from precision-rolled steel strip, achieving remarkably smooth interior walls. Seamless pipes, manufactured through hot piercing, inevitably have microscopic irregularities and defects. In industries like food processing, pharmaceuticals, and semiconductors—where pipes need easily cleanable, bacteria-resistant surfaces—precision welded pipes are actually the preferred choice.

2.Hidden Advantages of Welded Pipes

Beyond smooth interiors, welded pipes offer two easily overlooked benefits.

One is dimensional accuracy. Produced through cold-forming dies, welded pipes maintain consistent wall thickness and roundness. Seamless pipes, undergoing hot working, have greater dimensional variation.

Another is length. Welded pipes are continuously produced from steel coils, theoretically unlimited in length and cut as needed. Those drainage risers in tall buildings, or handrail tubes—they're all welded pipes. Seamless pipes, limited by manufacturing equipment, require more joints for long installations.

3.How to Choose?

This isn't to dismiss seamless pipes. For ultra-high pressure applications or extreme temperature conditions, seamless pipes—with no weld as a potential weak point—remain irreplaceable.

The key is: choose based on application.

For ordinary fluid transport or structural support, welded pipes are perfectly adequate and more economical. For applications requiring smooth interiors and precise dimensions—like food-grade piping or precision instrument lines—high-end welded pipes are actually the superior solution. Only when facing extreme conditions like ultra-high pressure, severe corrosion, or dramatic temperature swings should seamless pipes be your go-to.

So next time you encounter stainless steel pipe, don't automatically label welded as inferior. That seemingly "imperfect" weld, refined through modern processes, might be far stronger than you imagine.

When requesting a quote or placing an order, have you ever wondered:

- Why are prices for large-volume standard pipes so competitive?

- Why do lead times for small-batch, special pipes tend to be longer?

- How do you choose the most suitable production process for different project needs?

The answers lie in understanding the two core production modes: "Online Welding" and "Offline Welding." As a stainless steel welded pipe manufacturer with complete capabilities, we will demystify these two processes and show you how we tailor the optimal solution for your needs.

1.Core Concept: The Fundamental Difference

In essence, it boils down to whether the welding process is integrated into the continuous main production line.

A.Online Welding: The High-Speed Assembly Line, Built for Scale

The welding is an online, automated station within a continuous forming and welding line. The entire process—from strip uncoiling, progressive forming, immediate welding, online solution annealing, sizing/straightening, to cut-to-length—happens on one high-speed, automated line.

Think of it like an "automotive assembly line"—rhythmic, efficient, producing standardized outputs.

B.Offline Welding: The Precision Workstation, Designed for Customization

The welding process is completed on dedicated equipment separate from the main production line. The formed pipe blank is transferred to an independent precision welding station (e.g., TIG, Plasma, Laser welder) for welding, with subsequent processing also potentially done separately.

Think of it as a "bespoke atelier" focusing on precision fabrication for single pieces or small batches.

2.Comparative Analysis: Impact on Your Project's Key Factors

3.Our Capability: Dual-Mode Production for Your Complete Needs

MW Metal understands the diverse needs of global markets and projects. That's why we have invested in a dual-mode advanced production system:

Powerful Online Welding Lines: We operate 36 high-speed automated continuous lines. This ensures your bulk orders for standard round pipes and square/rectangular tubes receive the most competitive pricing with fast, stable, and consistent delivery—perfect for your large-scale projects or inventory needs.

Precision Offline Welding Stations: We are equipped with several top-tier precision welding systems and a team of seasoned process engineers. Whether it's ultra-high standards for internal/external weld beads or special end finishes, our offline welding mode delivers precision manufacturing.

We are not just equipment owners but process experts. Our sales and engineering team will professionally evaluate your drawings, standards, budget, and end-use to proactively recommend the most cost-effective and reliable production route.

Amid the tide of the Industrial Revolution, rust became humanity's persistent nightmare. Whether on ship decks, bridge girders, or household iron pots, time's touch was enough to leave metal surfaces mottled and worn.

Scientists, engineers, and ordinary people alike have long pondered: Is there a metal that can withstand the erosion of time and the environment?

The answer to this battle against rust was found in the invention of stainless steel.

The Invention and Optimization of Stainless Steel

The invention of stainless steel marked a major breakthrough in 20th-century materials science, with its development and application tracing back to the era of World War I.

As early as the beginning of the 1900s, German chemist Benno Strauss began systematically researching the impact of chromium on steel properties to address the challenge of traditional steel's susceptibility to corrosion in humid environments. Having already demonstrated exceptional corrosion resistance in other applications, Strauss recognized chromium's potential. He hypothesized that embedding chromium within steel—rather than merely coating it—could fundamentally transform the material's properties.

He discovered that while ordinary steel rapidly rusted in damp conditions, chromium-treated samples miraculously retained their shine, showing no rust spots even weeks later. Yet his experiments remained like an incomplete puzzle: he had uncovered chromium's magic but failed to find a way to stably bond it with steel.

The man who completed this puzzle was Henry Brearley, known as the “Father of Stainless Steel.” During World War I, the British government commissioned Henry Brearley to research and improve weapon materials to address the issue of rifle barrels wearing down easily. Brayley and his team collected numerous steel and alloy samples from around the world, conducting extensive experiments. It wasn't until sample number 1008 that he achieved a breakthrough: he successfully developed stainless steel with corrosion resistance and high-temperature tolerance, determining its optimal chemical composition—12.8% chromium and 0.24% carbon.

This invention is celebrated as one of the 20 most significant inventions of the 20th century that profoundly impacted human life.

Early Applications and Promotion of Stainless Steel

Stainless steel was initially used to manufacture tableware such as fruit knives, forks, and spoons. Its corrosion resistance and ease of cleaning quickly made it popular.

Industrial Expansion

As technology matured, stainless steel found widespread use in machinery, petroleum, chemical, food, and pharmaceutical industries, becoming an indispensable material for modern manufacturing.

By the 1920s, stainless steel applications steadily expanded. In 1930, the Chrysler Building in New York incorporated stainless steel for its crown decoration, marking a landmark in architectural history.

In the early 20th century, French metallurgist Léon Gillette conducted extensive research on chromium steel compositions, providing invaluable data for subsequent studies.

By the mid-20th century, scientists led by William Kraft discovered that adding titanium and molybdenum significantly enhanced stainless steel's heat resistance and strength. This breakthrough enabled the development of stainless steel alloys capable of withstanding extreme temperatures in aerospace applications.

Additionally, during the Manhattan Project, scientists utilized specialized stainless steel to design uranium enrichment equipment, demonstrating that stainless steel was not merely a revolutionary material for civilian applications but also integral to national strategic needs.

Nowadays, stainless steel has been applied to every aspects of life and has great change the whole world.

The story of stainless steel's invention is an ode to perseverance, innovation, and collaboration. It reminds us that behind every technological advancement lies countless failures, controversies, and renewed attempts.

Stainless steel is not a single metal but a large family of alloys. Its "stainless" property primarily comes from a chromium content, which forms an extremely thin and robust chromium-rich oxide film on the surface, effectively resisting corrosion.

Based on their microcrystalline structures, stainless steels are mainly categorized into austenitic, ferritic, martensitic, and duplex grades. This article will focus on the three most widely used and representative types: Austenitic, Ferritic, and Duplex stainless steels, providing an in-depth analysis of their characteristics, differences, and applications.

Ⅰ Austenitic Stainless Steel

Austenitic stainless steel is the most common type encountered in daily life, with typical grades being 304 and 316.

1.Characteristics

1.1 Microstructure: Its crystal structure is face-centered cubic (FCC). By adding high levels of austenite-forming elements like nickel (usually >8%), manganese, and nitrogen, it maintains a stable austenitic structure even at room temperature.

1.2 Mechanical Properties:

• Advantages: Excellent toughness, ductility, and formability, making it easy for cold working . It is non-magnetic or weakly magnetic (may become slightly magnetic after cold working).
• Disadvantages: Relatively low strength, especially yield strength, which is the lowest among the three types.

1.3 Corrosion Resistance:

• Advantages: Overall excellent corrosion resistance, particularly against various organic acids, inorganic acids, and alkalis. Molybdenum-containing grades like 316 offer good resistance to pitting and crevice corrosion, suitable for marine and chemical environments.
• Disadvantages: Susceptible to chloride stress corrosion cracking (SCC).

1.4 Weldability: Excellent weldability, the best among the three types.

1.5 Heat Treatment: Cannot be strengthened by heat treatment; can only be strengthened by cold work hardening.

2. Primary Applications:

Tableware, kitchenware, sinks, architectural decoration (curtain walls, railings), medical instruments, food processing equipment, chemical containers and pipelines, cryogenic pressure vessels.

Ⅱ Ferritic Stainless Steel

Ferritic stainless steel is another major category, with typical grades being 430 and 444.

1. Characteristics:

1.1 Microstructure: Its crystal structure is body-centered cubic (BCC). Chromium is the main alloying element, with low or no nickel content.

1.2 Mechanical Properties:

• Advantages: Yield strength is higher than austenitic stainless steel. It has moderate strength and hardness.
• Disadvantages: Poor toughness, especially at low temperatures where it drops sharply; it has a high ductile-to-brittle transition temperature. Formability and ductility are inferior to austenitic steel. It is magnetic.

1.3 Corrosion Resistance:

• Advantages: Resistance to chloride stress corrosion cracking (SCC) is far superior to austenitic stainless steel. Good resistance to uniform corrosion.
• Disadvantages: Overall corrosion resistance is generally inferior to austenitic steel. Susceptible to intergranular corrosion.

1.4 Weldability: Poor weldability. The grain structure in the heat-affected zone (HAZ) tends to coarsen during welding, leading to reduced toughness and corrosion resistance.

1.5 Heat Treatment: Cannot be strengthened by heat treatment.

2.Primary Applications:

Automobile exhaust systems, household appliances (washing machine drums, microwave oven exteriors), architectural decoration (its magnetism is beneficial for applications like elevator cars where magnetic fixation is needed), kitchen equipment, water heater tanks.

Ⅲ Duplex Stainless Steel

Duplex stainless steel is a "rising star," . It is named for its unique microstructure.

1. Characteristics:

1.1 Microstructure: As the name implies, its microstructure is a two-phase mixture of approximately 50% austenite (γ) and 50% ferrite (α). This structure combines the advantages of both.

1.2 Mechanical Properties:

• Advantages: Very high strength and hardness; its yield strength is more than twice that of austenitic stainless steel. It also maintains good toughness and ductility, which fall between those of austenitic and ferritic grades.
• Disadvantages: Toughness is lower than austenitic steel, especially at low temperatures. It is magnetic.

1.3 Corrosion Resistance:

• Advantages: Excellent overall corrosion resistance, especially in chloride-containing environments. Its resistance to pitting, crevice corrosion, and stress corrosion cracking (SCC) is far superior to 304 and 316 austenitic steels, even approaching some super austenitic grades.
• Disadvantages: At high temperatures (>300°C), brittle phases may precipitate, leading to embrittlement and reduced corrosion resistance.

1.4 Weldability: Good weldability, better than ferritic but slightly inferior to austenitic steel. Requires strict control of welding procedures and heat input to maintain the phase balance and avoid the precipitation of harmful phases.

1.5 Heat Treatment: Cannot be strengthened by heat treatment.*

2. Primary Applications:

Oil and gas industry (subsea pipelines, pressure vessels), chemical and petrochemical processing equipment, pulp and paper industry, seawater handling equipment (desalination plants, heat exchangers), bridges and structural applications (benefiting from its weight-saving advantage).

Ⅳ Summary of Key Differences:

• Strength vs. Toughness: Austenitic grades excel in strength but lag in toughness; duplex grades excel in toughness but lag in strength; ferritic grades fall in the middle but exhibit poor low-temperature toughness.
• Corrosion Resistance Focus: Austenitic grades resist uniform corrosion well but are vulnerable to chloride-induced stress corrosion cracking (SCC); ferritic grades resist chloride-induced SCC but are susceptible to intergranular corrosion; duplex grades perform excellently in nearly all aspects, making them all-around performers.
• Cost and Magnetic Properties: Austenitic grades are costly and non-magnetic; ferritic grades are low-cost and magnetic; duplex grades are costly and magnetic, but their high strength permits thinner material usage, potentially reducing overall costs.

Within the large family of stainless steels, ferritic stainless steel is the second most produced and applied category, following austenitic stainless steel. While not as widely recognized as its austenitic counterpart, it plays a crucial, often silent role in many key areas of our lives.

The core properties of ferritic stainless stem from its microstructure—ferrite. This is a body-centered cubic crystal structure, characterized by its chemical composition: it contains chromium(Cr) but little to no nickel(Ni). This feature directly defines its performance niche: a cost-effective stainless steel with good corrosion resistance, and particularly excellent resistance to stress corrosion cracking.

ⅠCharacteristics and Properties

The properties of ferritic stainless steel are closely tied to its ferritic crystal structure, creating a clear contrast with austenitic stainless steel.

1. Corrosion Resistance

• Basic Corrosion Resistance: Due to its chromium content (11%-30%), it also forms a protective passive chromium oxide layer. This gives it better resistance to atmosphere, steam, and many chemicals than carbon steel.
• Excellent Stress Corrosion Cracking (SCC) Resistance:This is one of its most outstanding advantages. In chloride-containing environments, austenitic stainless steels are susceptible to SCC, while ferritic grades exhibit very high immunity to this failure mode.

2. Mechanical and Physical Properties

• Magnetic: All ferritic stainless steels are ferromagnetic (magnetic). This property allows them to be used in applications requiring magnetic fixation.
• Strength and Hardness: Their yield strength and tensile strength are higher than those of austenitic stainless steels, but their plasticity and toughness, especially low-temperature toughness, are poor. They have a high ductile-to-brittle transition temperature, meaning they can become brittle at low temperatures and are therefore generally not used for cryogenic pressure equipment.
• Thermal Conductivity:They have a lower coefficient of thermal expansion and about 30-40% higher thermal conductivity than austenitic steels, making them good candidates for heat exchanger components.

3. Fabrication Properties

• Formability: Their formability is acceptable, better than martensitic stainless steels, but far inferior to the ductility of austenitic stainless steels. They are more prone to cracking during deep drawing or severe bending.
• Weldability:Weldability is poor. The heat-affected zone (HAZ) during welding is prone to grain coarsening, leading to reduced toughness and corrosion resistance in the weld area. This necessitates low heat input and special techniques.

ⅡPrimary Application Scenarios

The properties of ferritic stainless steel define its unique market applications.

1. Automotive Industry: This is its largest application field.

• Exhaust Systems: It is the standard material for manufacturing exhaust pipes, mufflers, catalytic converter shells, etc., due to its resistance to high-temperature exhaust gas corrosion, SCC resistance, and low cost.
• Trim: Decorative parts like window trim.

2. Household Appliance Industry:

Washing Machines, Microwave Ovens, Water Heaters and etc.

3. Architecture and Decoration:

Used for interior and exterior trim, architectural curtain walls, and elevator car paneling (utilizing its magnetism for easy installation and fixation).

4. Other Industrial Fields:

• Heat Exchangers:Used in components for hot water tanks and other equipment, leveraging its good thermal conductivity.
• Tanks and Pipelines: Used for handling certain chemical media that are not highly corrosive.

Ⅲ Conclusion

Ferritic stainless steel may not have the "star" power of austenitic stainless steel, but by virtue of its unique combination of properties—excellent stress corrosion resistance, high strength, stable magnetism, and most importantly, unparalleled cost advantage—it firmly occupies an indispensable strategic position in the world of stainless steel. It is the rational choice for engineers seeking the optimal balance between performance and cost, a truly unsung yet vital "Cost-Effective Corrosion Guardian".

In daily life, people always mix “tube” and “pipe” generally and naturally. And let’s take a brief skim in the explanation of these two words in Oxford Dictionary:

Tube: A long, hollow pipe made of metal, plastic, rubber, etc., through which liquids or gases move from one place to another.
Pipe: A tube through which liquids and gases can flow.

It seems there are no differences between TUBE and PIPE. But actually tube differs from pipe in many aspects. Please spend a little time reading this article and I’ll inform in which aspects can we distinguish stainless steel tube from stainless steel pipe.

①Shape
Tube: Tube can be round, square, rectangular, or other shapes.
Pipe: Pipe is usually in round shape.

②Measuring Method
Tube: Tube is specified by outside diameter (OD) and wall thickness (WT).
Pipe: Pipe is specified by nominal diameter (inside diameter/ID) and schedule (wall thickness/WT).

③Primary Usage
Tube: Tube is widely used in every aspects of life, such as structural applications, instrument, heat-exchanger and etc.
Pipe: Pipe is normally used in transporting fluids and gases (liquids or gases) under pressure.

④Mechanical Characteristic:
Tube: Tube can be more flexible than pipe, allowing for bending and shaping.
Pipe: Pipe is generally rigid and not easily bent or shaped.

⑤Metal Types
Tube: Tube can be formed from cold-rolled or hot-rolled metal materials.
Pipe: Pipe is generally made from hot rolled metal materials.

⑥Size Difference
Pipe is typically available in larger sizes than tube.

⑦Manufacturing Requirements
Tube has stricter requirements that manufacturers need to account for, including thickness, straightness, and roundness of the cylinder. These requirements lead to a higher degree of testing and inspection on tube compared to pipe.

MW Metal can provide all kinds of high-quality stainless steel tube and stainless steel pipe to meet all your customized requirements. If you’re interested in high quality stainless steel tubes or pipes with competitive prices, please don’t hesitate to contact with us. We’re always available to offer a quotation as your demand.

304, 304L, and 316L stainless steel are the most widely used stainless steel grades in the world, renowned for their excellent corrosion resistance and wide range of applications.
Let's take a brief review at the characteristics and applications of the above three different types of stainless steel first.

1.304 grade
304 stainless steel is one of the most common types of stainless steel grade, which has excellent corrosion resistance, heat resistance, low-temperature strength, and mechanical properties. It is commonly used in household appliances, medical equipment, ship components, and other applications.

2.304L grade
304L stainless steel, which refers to low-carbon 304 steel, has similar corrosion resistance to 304 steel under normal conditions. However, after welding or stress relief, it exhibits excellent resistance to intergranular corrosion. It is primarily used in outdoor machinery in the chemical, coal, and petroleum industries, as well as in heat-resistant parts for building materials, where high resistance to intergranular corrosion is required.

3.316L grade
316L stainless steel is a low-carbon series of the 316 steel grade, which enjoys featuring exceptional corrosion resistance, atmospheric corrosion resistance, and high-temperature strength, making it suitable for use in harsh conditions. Additionally, its resistance to intergranular corrosion is superior to that of 316 grade. It is ideal for products with special requirements for intergranular corrosion resistance.

After gaining a basic understanding of the characteristics and applications of the three types of stainless steel grade, let’s delve deeper into their differences. The following is an analysis of the chemical compositions of the three types of stainless steel grade.

The above chemical composition content is based on stainless steel pipes that comply with the ASTM A554 standard.

It can be seen that the most significant difference between 316L and 304/304L in terms of chemical composition is that 316L contains 2.0-3.0% molybdenum.

Molybdenum (Mo) is a silver-gray transition metal. As a refractory metal with a melting point as high as 2610°C, it exhibits high thermal conductivity and corrosion resistance, and does not react with oxygen at room temperature. This is why the corrosion resistance of 316L material containing molybdenum is superior to that of 304/304L.

MW Metal is committed to providing customers with high-quality stainless steel pipes. We offer a broad range of welded stainless steel pipes and tubes, providing customized sizes and shapes to meet customers’ specific needs, including material of grade 304/304L/316L/409L/430/439/441/200 series and duplex stainless steel, covering different standard of ASTM A554/A249/A269/A270/A789 and EN 10296-2/ EN 10217-7/ EN 10312/ EN 10357.
If you’re interested in high quality stainless steel tubes or pipes with competitive prices, please don’t hesitate to contact with us. We’re always available to offer a quotation as your demand.