Here is a number that puts everything in perspective: grade 304 accounts for roughly 50% of all global stainless steel production — more than any other single grade. When engineers, procurement managers, and manufacturers need a reliable, versatile 304 stainless steel foil, they are choosing the material that the entire industry has standardized around.
So what exactly is it? In its simplest definition, 304 stainless steel foil is an ultra-thin, cold-rolled austenitic stainless steel sheet with a thickness below 0.2 mm. It offers an exceptional balance of corrosion resistance, formability, and cost-effectiveness that no competing grade can match across the board. From electronics shielding and aerospace composites to food packaging and hydrogen fuel cells, this single grade serves more end-use applications than any other stainless steel on the market.
The reasons for its dominance are straightforward. Its 18/8 chromium-nickel composition resists corrosion in most atmospheric and mild chemical environments without the cost premium of molybdenum-bearing grades like 316. It cold-rolls cleanly to gauges as thin as 10 microns. It welds, forms, and polishes with minimal difficulty. And because global production volumes are enormous, pricing and lead times remain more favorable than for specialty alloys.
Whether you are designing EMI shielding for a next-generation EV battery pack, specifying food-grade barriers for a processing line, or sourcing corrosion-resistant liners for chemical equipment, 304 foil delivers. This guide covers everything you need to know — from chemical composition and mechanical properties to manufacturing processes, tolerances, and how to source directly from a specialized Chinese manufacturer with nearly three decades of experience. Explore our full
304 stainless steel foil product range to see what is available today.
What Exactly Is 304 Stainless Steel Foil? (Definitions & Standards)
AISI 304 foil is identified by multiple designations across international standards. Understanding these equivalencies is essential for cross-border procurement and specification compliance. The table below maps every major designation:
| Standard Body | Designation | Numeric ID | Region |
| ASTM / AISI | 304 | UNS S30400 | United States |
| EN | 1.4301 / X5CrNi18-10 | — | Europe |
| JIS | SUS304 | — | Japan |
| GB/T | 06Cr19Ni10 | — | China |
| GOST | 08Kh18N10 | — | Russia |
| DIN (legacy) | X5CrNi18-10 | 1.4301 | Germany |
The chemical composition of 304 is tightly defined: 17.5–20% chromium, 8–10.5% nickel, ≤0.08% carbon, ≤2% manganese, with the balance being iron. This chromium-nickel ratio creates the passive oxide film responsible for the grade’s excellent corrosion resistance, while the low carbon content minimizes carbide precipitation during welding. Additional trace elements include silicon (≤1%), phosphorus (≤0.045%), and sulfur (≤0.03%), each controlled to optimize mechanical performance and surface quality.
It is important to note that while these ranges are broadly consistent across standards, the exact limits do vary slightly. For instance, the JIS SUS304 specification allows marginally different nickel ranges compared to ASTM A240. When procuring across international supply chains, always confirm the specific standard the material is certified to, and verify the mill test certificate (MTC) against that standard’s composition table.
Metallurgically, 304 has a face-centered cubic (FCC) crystal structure — the hallmark of austenitic grades. This structure is what gives ss foil its characteristic non-magnetic behavior (in the annealed condition), outstanding ductility, and the ability to be cold-rolled to extremely thin gauges without cracking.
It is worth clarifying the thickness hierarchy: material below 0.2 mm is classified as foil, 0.2–2 mm as strip, and above 2 mm as sheet. Myriad specializes in the 0.01–0.1 mm range — the thinnest end of the spectrum. Learn more about
how thin stainless steel foil can actually get.
Mechanical Properties: The Numbers That Matter
The mechanical behavior of 304 stainless steel foil sheet changes dramatically with temper. Cold rolling work-hardens the austenitic microstructure, progressively increasing tensile strength and hardness at the expense of elongation. The table below summarizes the key values:
| Temper | Tensile Strength (MPa) | Yield Strength (MPa) | Elongation (%) | Hardness (HV) |
| Annealed | ≥515 | ≥205 | ≥40 | ≤200 |
| Quarter Hard | 860–960 | ≥515 | ≥25 | 250–290 |
| Half Hard | 1030–1130 | ≥760 | ≥10 | 290–340 |
| Full Hard | ≥1275 | ≥965 | ≥5 | ≥380 |
Understanding work hardening is critical when specifying foil for demanding applications. Each cold-rolling pass compresses the grain structure, increasing dislocation density and boosting strength. Myriad achieves elongation values exceeding 10% even at half-hard temper — a performance benchmark that many competitors struggle to match, and one that matters greatly for applications requiring post-forming.
Beyond mechanical strength, the thermal properties of 304 make it suitable for elevated-temperature environments: thermal conductivity of 16.2 W/m·K, a maximum continuous service temperature of 870°C, and a density of 7.93 g/cm³. These values are governed by ASTM A240 (flat product specification) and ASTM A666 (austenitic stainless steel work-hardened materials).
A key point for international buyers: no universally adopted production standard exists specifically for stainless steel foil below 0.06 mm. At these ultra-thin gauges, Myriad follows the AISI standard framework as the most widely recognized global benchmark. For related discussion, see our
stainless steel foil heat treatment guide.
8 Top Industries Using 304 Stainless Steel Foil (With Real Use Cases)
The versatility of 304 foil means it appears across an extraordinarily wide range of sectors. Below are the eight most significant, with specific applications and market context.
1. Electronics
EMI and RFI shielding layers, flexible printed circuit board (FPCB) substrates, and lithium-ion battery current collectors all rely on 304 foil. The electric vehicle battery market is growing at roughly 22% CAGR through 2030, driving sharp increases in demand for precision-rolled stainless steel foil. In consumer electronics, the trend toward thinner devices and higher component density makes ultra-thin foil an increasingly critical material for electromagnetic compatibility compliance.
2. Aerospace
Honeycomb composite core structures, turbine insulation wraps, and heat treatment contamination barriers demand the combination of temperature resistance, low weight, and formability that 304 foil provides. The aerospace foil segment is the fastest-growing, with market analysts projecting a 7.8% CAGR.
3. Automotive
Exhaust gaskets, catalytic converter wraps, precision shims, and fuel cell bipolar plates are core automotive applications. As emission standards tighten globally, demand for high-temperature-resistant foil components continues to grow. The push toward hydrogen fuel cell vehicles is creating an entirely new demand segment, as bipolar plates require thin, corrosion-resistant foil with tight thickness tolerances and consistent surface quality.
4. Medical
Surgical instrument shields, sterilization packaging, and implant barriers must meet FDA and ISO 10993 biocompatibility standards. Grade 304 satisfies these requirements, making it a cost-effective choice relative to more exotic alloys.
5. Food Processing
304 stainless steel is FDA-compliant for direct food contact, making it the standard material for food-grade barriers, packaging, and processing equipment liners. Its ease of cleaning and resistance to organic acids give it an edge in hygiene-critical environments.
6. Chemical Processing
Corrosion-resistant liners, reactor vessel components, and sensor housings benefit from 304’s broad chemical resistance. For environments with elevated chloride concentrations, upgrading to 316 is advisable — but for most general chemical service involving organic acids, alkaline solutions, and mild inorganic acids, 304 is the industry default. Its combination of pitting resistance and cost efficiency makes it the go-to material for instrumentation housings and process monitoring equipment.
7. Energy and Hydrogen
Fuel cell assemblies and hydrogen pipeline sealing components represent a rapidly emerging application area. The US Hydrogen Roadmap targets 1.2 million fuel cell vehicles by 2030, creating substantial new demand for compatible foil materials. Beyond transport, stationary fuel cells for backup power and grid balancing also require precision-rolled 304 foil for membrane electrode assembly (MEA) components and gas diffusion layer supports.
8. Architecture
Decorative panels, architectural trim, and exterior cladding use 304 stainless steel foil roll for its aesthetic appeal and weather resistance. BA (bright annealed) and mirror finishes are particularly popular in high-end architectural projects.
Browse the full Myriad product catalog to match foil specifications to your application requirements.
How 304 Stainless Steel Foil Is Manufactured: From Coil to 0.01 mm
Producing ultra-thin stainless steel foil is a multi-stage precision process. Each step must be tightly controlled to achieve the dimensional tolerances and surface quality that end-use applications demand. Unlike commodity sheet production, foil manufacturing at the 0.01–0.1 mm range is closer to precision engineering than to conventional steel processing.
Step 1 — Raw Material Selection. Hot-rolled coil (HRC) is sourced from major mills such as TISCO or POSCO. Incoming material undergoes spectrometer verification to confirm chemical composition before entering production.
Step 2 — Annealing. The coil is heated in a controlled atmosphere to soften the grain structure, restoring ductility for subsequent rolling passes.
Step 3 — Pickling. Oxide scale formed during annealing is removed by passing the material through an acid bath, leaving a clean, uniform surface.
Step 4 — Cold Rolling. The material is reduced on a 20-roll Sendzimir mill through multiple passes with intermediate annealing between cycles. Producing 0.02 mm foil, for example, requires four rolling passes and 24 hydraulic pressure cycles at 180 tons each. The 20-roll configuration is essential at these gauges because the small-diameter work rolls minimize deflection and deliver the uniform pressure distribution needed to hold thickness tolerance across the full strip width.
Step 5 — Tension Leveling / Skin Pass. Internal stresses are relieved and flatness is improved through controlled tension and light reduction, simultaneously enhancing surface brightness.
Step 6 — Precision Slitting. The master coil is cut to customer-specified widths using precision slitting equipment with burr-controlled edges.
Step 7 — Quality Control. Every batch undergoes spectrometer analysis (chemical composition), hardness testing, CNC-controlled thickness gauging (±0.005 mm), and visual surface inspection under controlled lighting. For critical applications, additional testing may include tensile testing per ASTM A370, salt spray corrosion testing, or grain size analysis per ASTM E112.
Step 8 — Packaging. Finished foil is interleaved with protective paper, wrapped in PVC film, strap-banded, and palletized on wooden crates — fully export-ready.
For a deeper look at how annealing and temper control affect foil performance, read our stainless steel foil heat treatment guide.
Specifications, Tolerances & Available Dimensions
Myriad produces thin stainless steel foil across a comprehensive range of thicknesses, widths, and surface finishes. The following tables detail the standard specifications.
Thickness Range
Minimum 0.01 mm (10 microns / 0.0004″) to maximum 0.1 mm (100 microns / 0.004″).
Thickness Tolerances
| Nominal Thickness (mm) | Tolerance (mm) | Tolerance (%) |
| 0.06 | ±0.02 | ±33% |
| 0.05 | ±0.03 | ±60% |
| 0.02 | ±0.005 | ±25% |
Width Range
3 mm to 610 mm (24″). Width tolerance: ±5 mm for widths above 100 mm; ±2 mm for widths below 50 mm.
Surface Finishes
2B (standard smooth mill finish), BA (bright annealed, mirror-like reflectivity), No. 4 (brushed/satin), and Mirror (No. 8, highest reflectivity). The 2B finish is the most commonly specified for industrial applications due to its smooth, uniform appearance and low cost. BA finish is preferred for decorative, optical, and cleanroom applications where maximum reflectivity and minimum surface roughness are required. Specify the required finish when placing your order.
Edge Types
Standard slit edge, deburred edge, and round/smooth edge are available depending on your downstream process requirements.
Temper Options
Annealed (soft), Quarter Hard (1/4H), Half Hard (1/2H), Three-Quarter Hard (3/4H), and Full Hard. Specify your hardness requirement in HV or target tensile strength in MPa when ordering. Stainless steel foil roll can be supplied in any of these tempers to match your application’s forming and strength requirements.
See all available stainless steel strip and coil products for wider-gauge options.
304 vs 304L: When Does the ‘L’ Grade Matter?
The distinction between 304 and 304L comes down to a single element: carbon. Standard 304 permits up to 0.08% carbon, whereas 304L (the “low carbon” variant) caps it at 0.03%.
Why does this matter? During welding, temperatures in the heat-affected zone can cause carbon to combine with chromium, forming chromium carbides at grain boundaries — a process called sensitization. This depletes the chromium available to maintain the protective passive layer, leaving the steel vulnerable to intergranular corrosion. In aggressive chemical environments, sensitized material can fail catastrophically along grain boundaries, even though it looks perfectly fine on the surface.
For most foil applications where no welding is involved, the distinction between 304 and 304L has no practical impact on performance. Both grades share identical corrosion resistance, formability, and surface finish characteristics. The choice only becomes significant when the material will be welded or exposed to prolonged service between 425°C and 870°C — the sensitization temperature range.
Choose 304L when: the foil will be part of any welded assembly, or will operate in environments where intergranular corrosion is a risk — nuclear equipment, certain chemical containers, and process piping are common examples.
Choose 304 when: no welding is involved, or when higher tensile strength at elevated temperatures is required. Standard 304 offers marginally better high-temperature strength due to its higher carbon content.
From a cost perspective, 304L carries a small premium because tighter carbon control during steelmaking adds process complexity.
For a comparison with another common grade, visit our guide on what is 301 stainless steel foil.
Why Source 304 Stainless Steel Foil from Myriad?
For buyers searching for china 304 stainless steel foil or asking where to buy 304 stainless steel foil, Myriad offers a combination of experience, capability, and service depth that is difficult to match:
Established 1996. Founded by a metallurgy graduate, Myriad has been producing ultra-thin austenitic stainless steel foil for over 28 years.
20-Roll Mill Capability. Our Sendzimir-type 20-roll mills produce foil from 0.01 mm to 0.1 mm with CNC thickness control within ±0.005 mm.
Verified Composition. A German-imported spectrometer confirms chemical composition on every production batch.
100+ Tons Inventory. We maintain over 70 tons of 304, 316, and 301 foil in ready stock for fast dispatch.
ISO 9001 Certified. Quality management system certification ensures consistent production standards.
Buyer-Friendly Terms. Free samples for qualified buyers. Standard MOQ from 100 kg. Custom slitting to any width.
Global Reach. We serve clients across North America, Europe, and Russia with 24/7 support in English, Chinese, and Russian.
Sourcing stainless steel foil from China offers significant cost advantages over European and North American producers, but only when you work with a manufacturer that combines competitive pricing with verifiable quality assurance. Myriad bridges that gap with transparent testing, documented traceability, and a track record spanning hundreds of international shipments.
Contact Myriad today for pricing, samples, or technical consultation.
Frequently Asked Questions
Q: What is the thinnest 304 stainless steel foil Myriad produces?
A: The thinnest gauge we produce is 0.01 mm (10 microns). This is achieved using our 20-roll Sendzimir mill with CNC thickness control, making it among the thinnest commercially available 304 foil globally.
Q: Is 304 stainless steel foil food safe?
A: Yes. Grade 304 is FDA-compliant for direct food contact and is widely used throughout the food processing and packaging industries. Its corrosion resistance and ease of sanitation make it the default choice for food-grade applications.
Q: 304 vs 316 stainless steel foil — which should I choose?
A: Choose 304 for general-purpose applications where cost efficiency matters and chloride exposure is limited. Choose 316 when the environment involves chlorides, marine conditions, or aggressive chemical processing. Our 316 stainless steel coil is available for these applications.
Q: What is the MOQ for 304 stainless steel foil?
A: Our standard minimum order quantity is 100 kg. Free samples are available for new clients evaluating the material for their applications.
Q: Can 304 foil be welded?
A: Yes, although conventional arc welding is not recommended at ultra-thin gauges due to burn-through risk. Vacuum brazing and MIG brazing are the preferred joining methods for foil below 0.1 mm.
Q: What surface finish options are available?
A: We offer 2B (standard smooth), BA (bright annealed), No. 4 (brushed/satin), and mirror (No. 8) finishes. Specify your preferred finish when placing an order.