Wilhelm Schulz GmbH specializes in the supply of premium buttwelded steels and corrosion-resistant alloys engineered for the most demanding industrial environments. With decades of experience and a commitment to quality, we support industries worldwide—from chemical processing and marine engineering to oil & gas, power generation, and aerospace.
304 / 304L, 316 / 316L, 317L, 321 / 321H, 347 / 347H
S31254 (6 Moly)
S31803 / S32205, S32750, S32760
Alloy 400, 600, 625, 825, C276
Steel Grades 304 / 304L | UNS S30400 / UNS S30403 | 1.4301 / 1.4307
Grades 304 and 304L stainless steel are among the most commonly specified stainless steels and are widely regarded as the standard for basic stainless applications. They belong to the 300 Series of austenitic chromium-nickel alloys, as defined by SAE standards. Often referred to as "18/8 stainless," these alloys contain approximately 18% chromium and 8% nickel by weight. These steels are known for their excellent formability, weldability, and ease of fabrication. Their strong resistance to corrosion—particularly from acids naturally found in food—makes them ideal for use in the food and beverage processing industries.
Types 304 and 304L share nearly identical chemical and mechanical characteristics, and it is common for a single material test certificate to cover both when the material meets the specifications for each. Type 304L is a low-carbon variant of Type 304, offering improved weldability and reduced risk of corrosion in welded areas. However, it typically has slightly lower yield and tensile strength compared to Type 304.
Grades 316 / 316L | UNS S31600 / UNS S31603 | 1.4401 / 1.4404
Stainless steels 316 and 316L are the second most commonly specified grades after Type 304. They belong to the 300 Series of austenitic chromium-nickel alloys, as defined by SAE standards. These austenitic steels are widely used due to their excellent general corrosion resistance, superior cryogenic toughness, and outstanding formability and weldability.
Type 316 contains 2–3% molybdenum, which enhances its resistance to specific types of corrosion, particularly in chloride-rich environments. This added protection makes it especially suitable for marine applications, earning it the nickname “marine grade” stainless steel. Type 316L is a low-carbon version of Type 316. While it has slightly lower yield and tensile strength, it offers improved weldability and reduces the risk of corrosion in heat-affected zones near welds.
As with many stainless steel plate products, multiple designations may be used to refer to these materials depending on the standards and specifications applied.
Grade 317L | UNS S31703 | 1.4438
Alloy 317L is a low-carbon, molybdenum-bearing austenitic stainless steel that offers enhanced corrosion resistance due to its higher levels of chromium, nickel, and molybdenum. It is particularly effective in resisting chemical attack from acids such as sulphurous, acetic, formic, citric, and tartaric.
Thanks to its low carbon content, 317L provides excellent resistance to sensitization during welding, along with improved creep strength, stress rupture resistance, and tensile strength at elevated temperatures. In its annealed state, the alloy is non-magnetic, though it may exhibit slight magnetism after welding.
This grade is widely used in environments involving sulfur compounds, pulp liquors, acid dyes, acetylating and nitrating mixtures, bleaching agents, and other aggressive chemical compounds.
As with most stainless steel plate products, multiple designations are used for this alloy. The most common include:
Grades 321 / 321H | UNS S32100 / UNS S32109 | 1.4541 / 1.4878
Stainless steel grades 321 and 321H are titanium-stabilized austenitic alloys known for their excellent oxidation resistance up to 1600°F (870°C) and superior resistance to polythionic acid stress corrosion cracking. These properties make them a cost-effective and reliable choice for high-temperature service.
Grade 321 is specifically designed for use in the 1000–1600°F (540–870°C) temperature range. For optimal resistance to intergranular corrosion and polythionic acid stress corrosion cracking, a stabilizing heat treatment at 1550–1650°F (840–900°C) followed by air cooling is recommended.
321 stainless steel is easily weldable using all standard methods, including submerged arc welding. Recommended filler materials include AWS ER347 bare wire and E347 covered electrodes.
In terms of machinability, 321 stainless performs similarly to 304 stainless steel, with a machinability rating of 45% relative to AISI B1112.
As with many stainless steel grades, multiple designations are used.
Grade 347 | UNS S34700 | 1.4550
Alloy 347 is a columbium-stabilized austenitic stainless steel that offers slightly improved corrosion resistance over Type 321, particularly in strongly oxidizing environments. Its stabilization makes it especially suitable for aqueous and low-temperature applications, where it provides excellent resistance to intergranular corrosion.
Both 347 and 321 stainless steels are known for their resistance to polythionic acid stress corrosion cracking, a common concern in oil refinery environments. The oxidation resistance of Alloy 347 is comparable to that of Type 304 and remains effective at temperatures up to 1500°F (816°C).
In many product forms, the grain size and carbon content of the material can meet the requirements for both 347S and 347H grades. For welding, suitable filler materials include AWS ER347 bare wire and E347 covered electrodes.
As with most stainless steel grades, multiple designations are used for Alloy 347, depending on the standard or specification.
Grade 6 Moly | UNS S31254 | 1.4547
Stainless steel grade S31254 is a premium austenitic alloy engineered for exceptional performance in highly corrosive environments. Often referred to as 6 Moly, this grade is recognized for its outstanding resistance to chloride-induced stress corrosion cracking, as well as pitting and crevice corrosion.
With mechanical strength approximately twice that of standard 300 series stainless steels, S31254 is a robust and reliable choice for demanding applications. It also offers excellent impact toughness and workability, making it suitable for both fabrication and forming processes.
In certain cases, S31254 has proven to be a cost-effective alternative to high-nickel and titanium-based alloys, particularly where corrosion resistance is critical.
As with many stainless steel products, multiple designations are used for this grade. The most common include:
Duplex | UNS S31803 / S32205 | 1.4462
Duplex stainless steel features a microstructure composed of approximately equal parts austenite and ferrite. This balanced structure offers several key advantages:
Another standout characteristic of Duplex stainless steel is its superior corrosion resistance. While corrosion resistance can’t be measured by a single metric, the Pitting Resistance Equivalent Number (PREN) is commonly used to compare different grades.
Using this formula, Duplex 31803 achieves a PREN of 35 — significantly higher than the PREN values for Type 304 (18) and Type 316 (24) — highlighting its enhanced resistance to pitting and crevice corrosion.
In summary, Duplex stainless steel offers a compelling combination of high strength, extended service life, and cost efficiency due to its lower alloy content, making it a smart choice for demanding engineering applications.
Super Duplex | UNS S32750 | 1.4410
Super Duplex stainless steel UNS S32750 offers exceptional corrosion resistance across a broad range of aggressive environments, making it an ideal choice for applications exposed to the most demanding chemical conditions. It provides outstanding resistance to pitting and crevice corrosion in seawater and other chloride-rich settings, with a Critical Pitting Temperature (CPT) exceeding 50°C.
Compared to austenitic and 22% chromium duplex stainless steels, S32750 delivers significantly higher strength, making it especially suitable for high-stress environments. Its excellent ductility and impact toughness at both ambient and sub-zero temperatures further enhance its performance, positioning it as a top-tier super duplex grade.
S32750 also exhibits high resistance to abrasion, erosion, and cavitation, along with superior resistance to stress corrosion cracking in chloride-containing environments. These properties make it particularly well-suited for subsea oil and gas equipment, where materials must withstand some of the harshest conditions on the planet.
This alloy is approved under NACE MR0175 for sour service, confirming its suitability for oilfield equipment exposed to hydrogen sulfide (H₂S) environments. It is also ASME-certified for use in pressure vessel applications.
Super Duplex | UNS S32760 | 1.4501
Super Duplex stainless steel UNS S32760 (also known as F55 / 1.4501) offers exceptional corrosion resistance across a broad spectrum of aggressive environments.
It demonstrates outstanding resistance to pitting and crevice corrosion in seawater and other chloride-rich conditions, with a Critical Pitting Temperature (CPT) exceeding 50°C.
With significantly higher strength than both austenitic and 22% chromium duplex stainless steels, S32760 is well-suited for demanding applications in industries such as chemical processing, oil and gas, and marine engineering.
This alloy is approved under NACE MR0175 for sour service, confirming its suitability for use in hydrogen sulfide (H₂S) environments. It is also ASME-certified for use in pressure vessel applications.
Alloy C276 | UNS N10276 | 2.4819
Alloy C276 is a high-performance, corrosion-resistant material that represents an enhanced wrought version of the original Alloy C. It retains the same exceptional corrosion resistance while offering significantly improved fabricability.
This alloy can be hot worked and cold formed using standard industrial techniques. It is also compatible with all common welding methods, and crucially, it resists the formation of grain boundary precipitates in the heat-affected zone. This makes it ideal for use in chemical processing applications even in the as-welded condition.
Alloy C276 provides excellent resistance to pitting, stress-corrosion cracking, and oxidation at temperatures up to 1900°F (1038°C).
Monel® 400 | UNS N04400 | 2.4360
Monel® 400 is a nickel-copper alloy known for its excellent corrosion resistance and good mechanical strength across a wide range of environments. It performs particularly well in seawater, hydrofluoric acid, sulfuric acid, and alkaline solutions.
Although its properties can be enhanced through cold working or tempering, Monel 400 is typically supplied in the annealed condition, which provides a good balance of formability and corrosion resistance without the need for additional heat treatment.
This alloy is widely used in industries such as marine engineering, chemical and hydrocarbon processing, and power generation. Common applications include valves, pumps, shafts, fittings, fasteners, and heat exchangers.
INCONEL® 600 | UNS N06600 | 2.4816
INCONEL® Alloy 600 is a nickel-chromium-iron alloy known for its excellent high-temperature strength and corrosion resistance, making it a standard material across the chemical processing, automotive, aerospace, and nuclear industries.
Originally introduced in the 1930s, Alloy 600 has proven its versatility in a wide range of demanding applications. Its chromium content provides resistance to oxidation and corrosion, while nickel ensures structural stability and resistance to scaling and stress corrosion cracking. The iron component enhances resistance to internal oxidation.
In the nuclear sector, strict control of chemical composition is essential to prevent stress corrosion cracking in high-purity water environments containing chloride ions.
Alloy 600 is widely used as a thermocouple sheath in carbon- or nitrogen-rich atmospheres, and as a material for muffles, jigs, and fixtures in heat treatment processes. Proper thermal annealing and composition control are critical to maintaining its resistance to pitting and stress corrosion cracking in aggressive service conditions.
INCONEL® 625 | UNS N06625 | 2.4856
INCONEL® 625 is a nickel-chromium-molybdenum-niobium alloy renowned for its high strength, exceptional corrosion resistance, and excellent fabricability, including ease of welding and forming. Its versatility makes it a go-to material across a wide range of demanding industrial applications.
The alloy’s strength is derived from the solid-solution strengthening effect of molybdenum and niobium, which distort the alloy’s atomic structure. This provides high mechanical strength even in the annealed condition, without the need for additional heat treatment.
INCONEL® 625 is particularly effective in chloride-rich environments, offering strong resistance to pitting, crevice corrosion, and chloride-induced stress corrosion cracking. It performs reliably in potable, brackish, and seawater, making it ideal for offshore, marine, and sour gas applications.
Alloy 800 | UNS N08800 | 1.4876
Alloy 800 is a widely utilized material in high-temperature applications where corrosion resistance, mechanical strength, and oxidation resistance are essential. It is particularly effective in environments involving carburization and other forms of high-temperature degradation.
For applications requiring enhanced creep and rupture strength, Alloy 800HP is preferred. This variant includes increased aluminum and titanium content, enabling reliable performance at temperatures exceeding 700°C (1290°F).
The alloy’s chromium content provides excellent resistance to oxidation and corrosion, while its high nickel content ensures a stable austenitic structure, contributing to ductility and resistance to scaling, general corrosion, and stress corrosion cracking. The iron content further enhances resistance to internal oxidation.
Alloy 825 | UNS N08825 | 2.4858
Alloy 825 is a nickel-iron-chromium alloy enhanced with molybdenum, copper, and titanium, designed to offer exceptional resistance to a broad range of corrosive environments.
The nickel content provides strong resistance to chloride-induced stress corrosion cracking, while the combination of nickel, molybdenum, and copper ensures excellent performance in reducing environments, such as those containing sulfuric and phosphoric acids. Molybdenum also enhances resistance to pitting and crevice corrosion.
The chromium component contributes to resistance against oxidizing agents, including nitric acid, nitrates, and oxidizing salts. Additionally, titanium, when properly heat-treated, stabilizes the alloy against intergranular corrosion.
