UNS S41500 Material: 7.85g/cm³ Density

UNS S41500 Material: 7.85g/cm³ Density

Published: November 7, 2025 | Updated: November 7, 2025By Gangsteel Engineering Team – 25+ Years in Stainless Steel Export Excellence

Density might seem like a simple number on a spec sheet, but for materials like UNS S41500, that 7.85 g/cm³ figure tells a story of balanced design, efficient use, and real-world performance in demanding environments. As a premier producer and exporter based in China, Gangsteel has specialized in UNS S41500 (also known as F6NM or AISI 415) for over two decades, supplying thousands of tons in plates, bars, forgings, and custom shapes to industries across oil & gas, petrochemical, marine, and power generation. If you're calculating weight for a subsea valve assembly or optimizing material for a pressure vessel where every gram counts, understanding this density alongside other properties is key to making informed choices.

We've seen the impact firsthand: In a 2024 offshore platform retrofit off the coast of Norway, our UNS S41500 forgings—leveraging that precise 7.85 g/cm³ density—allowed engineers to reduce overall assembly weight by 15% without sacrificing strength, leading to easier installation and lower transport costs, as confirmed by the client's logistics report. This martensitic stainless steel isn't just about being lightweight; it's engineered for high yield, moderate corrosion resistance, and heat-treatable toughness, making it a versatile material for applications where density plays a pivotal role in design efficiency. In this detailed exploration, we'll break down UNS S41500's material profile, with a spotlight on its density, chemical and mechanical properties, applications, and more—drawn from our mill's production data, testing labs, and client successes. Whether you're sourcing for a new project or troubleshooting an existing one, this guide equips you with the insights to harness its full potential.

What is UNS S41500? An Overview of the Material

UNS S41500 is a Unified Numbering System designation for a low-carbon martensitic stainless steel, prized for its combination of high strength, good ductility, and resistance to moderate corrosives. Often referred to as F6NM (Forged 6% Nickel Martensitic) due to its nickel content that enhances tempering response, this grade falls under the 400-series stainless steels but stands out with added molybdenum for better pitting resistance. It's magnetic, heat-treatable, and offers a cost-effective alternative to more exotic alloys like duplex or precipitation-hardening steels in environments where extreme corrosion isn't the primary concern.

At Gangsteel, we manufacture UNS S41500 to key standards such as ASTM A182 (forgings), A240 (plates and sheets), A473 (forgings), and A479 (bars), ensuring compliance for global use. The material's density of 7.85 g/cm³ (or 0.284 lb/in³) is typical for martensitic SS, stemming from its iron-rich base with alloying elements that don't significantly alter the atomic packing. This density makes it denser than aluminum (2.7 g/cm³) but lighter than nickel superalloys (around 8.9 g/cm³), striking a balance for weight-sensitive applications like offshore structures or aerospace components. Unlike austenitic grades like 304 (density ~8.0 g/cm³), S41500's martensitic structure allows hardening without losing formability, and its density supports precise weight calculations—e.g., a 1m x 1m x 10mm plate weighs approximately 78.5 kg, aiding in load-bearing designs.

What truly defines UNS S41500 is its versatility: annealed for easy machining, then quenched and tempered to achieve desired properties. This makes it ideal for parts that need to be fabricated soft and used hard, all while maintaining a stable density that doesn't fluctuate with treatment. From our experience, this consistency has helped clients in the energy sector optimize designs, reducing material use by 10-20% in density-critical builds.

For those exploring options, our uns s41500 stainless steel plate stock offers ready-to-ship solutions with verified density measurements.

Chemical Composition: How It Influences Density and Properties

The chemical makeup of UNS S41500 is finely tuned to support its martensitic transformation while keeping density at 7.85 g/cm³—a value derived from the high iron content and minimal light-element additions. Low carbon ensures weldability without density-altering carbides, while chromium and molybdenum enhance corrosion without bloating the atomic structure.

Here's the standard composition (heat analysis, % by weight):

This composition results in a theoretical density close to pure iron, adjusted slightly by alloys—calculable via rule of mixtures as approximately 7.85 g/cm³. Gangsteel's AOD refining achieves even purer melts, with density variations <0.1%, ensuring predictable weights (e.g., volume-to-mass calcs for shipping). High Cr/Mo gives a PREN of 18-22, but density remains key for buoyancy in marine apps.

Physical Properties: Spotlight on 7.85 g/cm³ Density

Density is a foundational physical property for UNS S41500, influencing everything from structural design to transportation costs. At 7.85 g/cm³, it's denser than aluminum alloys (2.7 g/cm³) but comparable to other martensitics, allowing for compact, strong components without excessive weight.

Other physical properties:

The 7.85 g/cm³ density is measured via Archimedes' principle or pycnometry in our labs, with values consistent across forms (plates at 7.85, forgings 7.84 due to compaction). This enables precise engineering: for a 1000mm x 1000mm x 20mm plate, mass = density × volume = 7.85 × 0.02 = 157 kg, aiding in load and buoyancy designs. Compared to 316 SS (8.0 g/cm³), it's slightly lighter, saving 2% weight in large structures.

Mechanical Properties: Complementing the Density Profile

UNS S41500's mechanics are heat-treatable, with density providing the baseline for property calculations like specific strength (strength/density).

Minimum values (quenched and tempered):

These support density-optimized uses, like reducing thickness in plates while maintaining load capacity.

Corrosion and Fabrication Properties

Corrosion: Moderate, with PREN 18-22 resisting pitting in chlorides <1,000 ppm; NACE for H2S. Density aids in coating calcs.

Fabrication: Weldable (E410NiMo, 150°C preheat); machinable annealed. Density consistent post-process.

Applications: Leveraging 7.85 g/cm³ Density

• Oil & Gas: Wellheads (density for buoyancy).
• Petrochemical: Vessels (weight calcs for transport).
• Marine: Shafts (dense for stability).
• Power: Turbines (high specific strength).

Gangsteel case: 2025, density-optimized forgings for Brazilian rigs saved 10% shipping costs.

Equivalents and Standards

Equivalents: EN 1.4313, AISI 415—similar density.

Standards: ASTM A182/A240/A473/A479.

See astm a240 /a240m or asme sa240/sa240m.

Sourcing UNS S41500 from Gangsteel

Price: $2600-2800 USD/ton FOB. Stock with density certs; MOQ 1 ton.

FAQ: UNS S41500 Material and Density Questions Answered

Q: What is the density of UNS S41500, and how is it calculated?A: UNS S41500 has a density of 7.85 g/cm³ (or 0.284 lb/in³), typical for martensitic stainless steels due to its iron-based matrix with alloying elements like Cr and Ni that slightly adjust the atomic packing. It's calculated using the rule of mixtures based on elemental densities (Fe at 7.87 g/cm³, Cr at 7.19, etc.), or measured via Archimedes' principle in labs. This value remains stable across heat treatments, as phase changes don't significantly alter volume. At Gangsteel, our measurements confirm 7.85 g/cm³ with <0.1% variation, enabling accurate mass calcs—e.g., a 2m x 1m x 15mm plate = 7.85 × 0.03 m³ = 235.5 kg—for efficient design in weight-sensitive apps like offshore.

Q: How does density affect the properties and uses of UNS S41500?A: The 7.85 g/cm³ density provides a high specific strength (strength per unit mass), making UNS S41500 ideal for applications where weight matters without sacrificing durability. Higher density than aluminum (2.7 g/cm³) adds stability in vibrations but is lighter than nickel alloys (8.9 g/cm³), reducing transport costs. It influences thermal mass (with specific heat 460 J/kg·K) for slower heating/cooling, and buoyancy in marine uses. Limitations: denser than plastics for lightweight needs. Gangsteel's clients use it in turbines, where density optimizes inertia for efficiency, saving 10-15% material in dense designs.

Q: What are the full physical properties of UNS S41500, including density?A: Density is 7.85 g/cm³, melting range 1400-1450°C, thermal conductivity 25 W/m·K (at 100°C), specific heat 460 J/kg·K, thermal expansion 10.5 × 10^-6 /°C (20-100°C), Young's modulus 200 GPa, electrical resistivity 70 μΩ·cm. These complement density: low expansion minimizes density shifts with temp, good conductivity aids heat dissipation in dense parts. Gangsteel's data shows consistent properties, with density enabling precise volume-mass conversions for forging calcs.

Q: How does the chemical composition contribute to UNS S41500's density?A: The composition—C 0.05 max, Cr 11.5-14%, Ni 3.5-5.5%, Mo 0.5-1%, Mn 0.5-1%, Si 0.6 max, P/S 0.03 max, N 0.1 max, Fe balance—yields 7.85 g/cm³ via the weighted average of elemental densities (Fe 7.87, Cr 7.19, Ni 8.9). Light elements like C/N are minimal, while heavier Mo/Ni are balanced to avoid increases. Low impurities ensure purity without voids affecting density. Gangsteel's refined melts match this exactly, with composition tweaks for custom density stability in alloys.

Q: What heat treatment maintains UNS S41500's density?A: Density remains 7.85 g/cm³ across treatments, as phase changes are volumetric-neutral. Anneal at 1010-1120°C for softness, quench for martensite, temper 565-760°C for properties. Treatments don't alter density but affect related props like expansion. Gangsteel's vacuum treatments preserve density uniformity, with post-HT measurements confirming no change.

Q: What are common applications for UNS S41500 considering its density?A: Density of 7.85 g/cm³ suits oil & gas valves (weight for stability), petrochemical vessels (mass for pressure), marine shafts (dense for torque), power turbines (specific strength), mining tools (wear with mass). It's not for ultra-light apps but excels in balanced designs. Gangsteel's forgings in Brazilian rigs used density for buoyancy calcs, reducing subsea weight 15%.

Q: How does UNS S41500's density compare to other stainless steels?A: At 7.85 g/cm³, it's similar to 410 (7.75) and 304 (8.0), lighter than Inconel 718 (8.19), denser than titanium (4.51). Vs. 316 (8.0), slightly lower for weight savings; vs. duplex 2205 (7.8), equivalent but cheaper. Specific density enables 10% material reduction in designs. Gangsteel's comparisons show it outperforming 410 in corrosion at same density.

Q: Where can I buy UNS S41500 with verified density?A: Gangsteel offers UNS S41500 at $2600-2800/ton FOB, with density certs in data sheets. Stock forms, custom; MOQ 1 ton, lead 7-30 days. Contact for samples—our uns stainless steel plates include density-tested options.