SMA570P when you need a high-strength, weather-resistant structural plate with a built-in protective patina and lower life-cycle maintenance costs than routine painted carbon steels; for procurement in mid-2025 typical delivered prices range widely by region and specification — roughly USD $550–1,100 / metric ton (China FOB), USD $600–1,500 / t (India domestic ranges), USD $800–1,050 / t (Europe ex-works / distributor quotes), and USD $850–980 / t (U.S. hot-rolled coil / plate benchmarks used for costing) — final project pricing will depend on thickness, heat treatment, certification, volume, and freight.
What is SMA570P
SMA570P is a Japanese designation within JIS G3114 for hot-rolled, atmospheric-corrosion-resisting steel plate with elevated yield strength (the “570” marking signals high-strength performance class). It belongs to the family commonly labelled “weathering steel” or “Corten” in industry parlance. The alloy is engineered to form a protective rust layer in many exposed environments, which reduces through-thickness corrosion rates and can reduce lifetime maintenance costs when detailing and environment are appropriate.
Standards, equivalence and naming
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Primary reference: JIS G3114 covers hot-rolled atmospheric corrosion resisting steels and contains SMA570P among its grades. Buyers often specify the JIS grade for Japanese origin material or accept equivalent chemical/mechanical guarantees from other standards.
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Common western standards: ASTM A242, A588 and A606 are widely used weathering steel standards in the U.S./EU market; these are not identical but are functionally similar materials with different permitted chemistries and mechanical property windows. When cross-referencing SMA570P to ASTM grades, require explicit mill guarantees, MTRs and welding instructions rather than relying on a simple “equivalent” label.
Chemical composition & mechanical properties
Producers and stockholders report SMA570P chemistry that intentionally includes small amounts of Cu, Cr and Ni to promote the protective patina. Typical non-iron elements and value ranges, reported by multiple mill/stock sources, include: Cu (~0.2–0.6%), Cr (~0.4–0.8%), Ni (~0.3–0.7%), plus controlled C, Si and Mn for strength and formability. Minimum mechanical properties correspond to the “570” family (yield and tensile will be guaranteed on the mill test report for the chosen thickness). Always verify the MTR for the batch you buy.
How the protective patina forms and limitations
Weathering steels depend on cyclic wetting and drying to form an adherent oxide layer. That layer protects the substrate by slowing active corrosion when it can dry between wetting events. There are important caveats:
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In coastal or salt-laden atmospheres, airborne chlorides can keep the surface wet and disrupt the patina, producing continuous corrosion. Guidance documents recommend caution within certain distances of the shoreline unless local chloride data prove suitability.
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In continuously wet conditions or where organic/soil deposits trap moisture, the patina will not stabilize and accelerated loss may result. Design for drainage and avoid crevices that hold moisture.
These performance limits must be evaluated during specification and site selection.
Principal applications
SMA570P is used for heavy structural plates, rail and rolling stock, industrial housings, container bodies and architectural façades where a weathered finish is acceptable. Architects often choose it for aesthetic projects because the oxide finish ages naturally and rarely needs repainting when detailed correctly. Civil engineers use it for bridges and infrastructure where uncoated weathering steel offers long service life at reduced maintenance cost — again subject to environmental restrictions.
Fabrication, welding and inspection notes
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Pre-qualification of welding procedures and selection of compatible filler metals are essential; welds can weather at a different rate so matching metallurgy and welding technique matters.
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Post-weld cleaning of spatter and slag is important because trapped residues can interfere with patina formation.
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Supply chain: insist on mill test reports, heat numbers and NDT results when structures are safety-critical. Use approved fabrication practices from AISC/NSBA or local codes for uncoated weathering steel.
Detailing and environmental restrictions
We follow published guidance when detailing weathering steel structures:
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Avoid water traps and pockets; provide drainage and positive falls.
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Do not use in high-chloride environments unless site testing proves acceptability; many authoritative guides recommend avoiding uncoated weathering steel within a specified coastal band.
Procurement factors that materially affect price
When pricing SMA570P plate, these variables matter most:
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Thickness (thin coils vs heavy plate have different mill routes).
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Width/length (large standard sizes are cheaper per ton than cut-to-size plate).
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Certification (JIS MTR, third-party inspection, chemical and mechanical tests).
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Surface finish/processing (trimmed, mill-scale left on vs pickled/shot-blasted).
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Quantity and delivery terms (FOB/CIF/DDP changes landed cost heavily).
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Tariffs and freight (2025 trade measures and shipping rates remain significant cost drivers). See the price table and commentary below.
Global price comparison (mid-2025)
Prices are indicative ranges for SMA570P / Corten-type hot-rolled plate in mid-2025. Always request an up-to-date quotation and confirm INCOTERMS, thickness, certification and lead time.
| Region / Typical origin | Indicative price (USD / metric ton) | Basis / notes | |
|---|---|---|---|
| China (FOB ports) | $550 – $1,100 / t | Wide spread driven by thickness, mill, and volume; many Chinese mills list SMA570P in this band. | |
| India (domestic & local distributors) | $600 – $1,500 / t (₹85,000–150,000/t) | Domestic quotes vary by mill, thickness and stock; INR quoted suppliers show broad ranges. | |
| Europe (ex-works / distributors) | $650 – $1,050 / t | European stockists list Corten/S355WP family plates in mid-range; customs and transport to site add cost. | |
| United States (market benchmark influence) | $850 – $980 / t (hot-rolled steel benchmarks) | U.S. hot-rolled coil/plate pricing benchmarks in mid-2025 reflect tariffs and domestic supply; plate premiums apply. | |
| Global premium / branded COR-TEN® | $900 – $2,500 / t | Trademarked COR-TEN material or specialty processed plate can cost significantly more. |
How to read the table: the ranges include the main cost drivers — thickness, mill grade, certification (JIS vs ASTM), and transport. The low end typically reflects basic hot-rolled plate from Asian mills (small MOQ, FOB), and the high end reflects branded or specialty processed plate, tight chemical tolerances, and smaller volumes.
Costing methodology for a project
When you convert plate price to installed cost follow these steps:
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Calculate raw material tonnage from structural drawings (area × thickness × 7.85 kg/dm³).
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Select price from the appropriate regional range and confirm INCOTERM.
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Add processing and fabrication (cutting, bending, welding, finishing — typically 10–30% of plate cost depending on complexity).
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Include freight & insurance (ocean freight + inland haulage; for small orders sea freight can be 50–150 USD/t or more).
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Tariffs and duties (check current trade policy; mid-2025 tariffs affected flows in many regions).
Quality control & certificates to require
Require the following on every order:
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Mill Test Report (MTR) with heat number, chemical and mechanical test results referencing JIS G3114 (or the specified standard).
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Third-party inspection (when critical) — dimensional checks, UT/MT for weldable plate, and hardness where requested.
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Welding procedure qualifications (PQR/WPQ) and matching filler metal certifications for structural use.
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Traceability to production heat and rolling record.
Storage, handling and delivery tips
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Store plates in a dry, ventilated yard and stack with spacers to avoid trapped moisture.
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Protect cut edges from prolonged exposure if they will be stored for a long time; consider temporary sealing or fast shipment to fabrication.
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For architectural projects where appearance matters, plan patina development sequencing and temporary protection for adjacent surfaces during initial weathering.
FAQs
Q1 — Is SMA570P identical to COR-TEN?
No. COR-TEN is a trademarked product name historically used for U.S. weathering steels. SMA570P is a JIS grade with similar functional intent. Specify required tests and MTRs rather than a generic brand name if interchangeability is required.
Q2 — Can SMA570P be used for coastal bridges?
Use caution. High airborne chlorides near marine environments can prevent the protective patina from forming correctly. Refer to chloride mapping and guidance from national authorities before selecting uncoated weathering steel.
Q3 — How long until the surface stabilizes?
Patina formation depends on climate; it can take months in typical temperate urban atmospheres and longer in rural or low-pollution environments. Initial runoff and staining are common during early weathering.
Q4 — What should I ask a mill or supplier for when buying?
Ask for JIS G3114 (or specified standard) MTRs, welding guidance, heat number traceability, production/date stamping and packing list. If destiny is a safety-critical structure, require third-party inspection.
Q5 — Are SMA570P prices stable?
No. Plate pricing follows bulk steel markets, tariffs, freight and scrap cycles. Mid-2025 market volatility and policy measures mean you should lock pricing with written quotes and confirm lead times at the time of ordering.
