Description: BBN steel is a well-known steel manufacturer and service provider in China, JIS G3125 SPA-C steel plate Sheet is our superior product, we are favored by customers with high quality, competitive price and excellent service
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JIS G3125 SPA-C Corten Steel | Weathering Steel Plate, Sheet, Bar & Section | Hot Rolled & Cold Rolled
Japanese Industrial Standard Atmospheric Corrosion Resistant Steel | Yield ≥325 MPa, Tensile ≥450 MPa | Cu-Cr-Ni Alloyed for Long-Term Weathering | 10,000+ Tons Monthly Stock
Atmospheric Corrosion ResistanceCu, Cr and Ni alloying forms a dense protective rust layer, giving SPA-C far longer outdoor service life than ordinary carbon steel.
Weldable & FormableStable chemistry supports cutting, drilling, welding and bending with standard fabrication processes — suitable for complex structures.
Full Form SupplyHot rolled & cold rolled plate, sheet, bar, section steel and structural shapes, all from stable monthly stock with custom processing.
01Product Overview & Specifications
JIS G3125 SPA-C is a Japanese Industrial Standard weathering (atmospheric corrosion resistant) steel widely used in air preheaters, economizers, railway carriages, shipping containers, bridges and building structures. Its copper, chromium and nickel additions develop a stable protective oxide layer that slows down further atmospheric corrosion.
SPA-C is supplied as hot rolled and cold rolled plate and sheet, and can also be produced as bar, section steel and structural shapes. With flexible delivery conditions (AR / CR / N / TMCP / T / QT) and a large monthly stock, it serves both standard and project-specific requirements.
Item
Specification Details
Steel Grade
JIS G3125 SPA-C Weathering Steel
Executive Standard
JIS G3125 Hot Rolled Atmospheric Corrosion Resisting Steels for Welded Structure
Product Type
Hot Rolled / Cold Rolled Plate, Sheet, Bar, Section & Structural Shapes
Delivery Condition
ARCRNTMCPTQT
Core Advantage
Atmospheric corrosion resistance, good weldability & formability, low maintenance for outdoor structures
Main Application
Air preheater, economizer, railway carriage, containers, bridge building, construction
Monthly Stock
10,000+ tons hot rolled & cold rolled SPA-C in stock
MOQ
1 Ton / Negotiable
Delivery Time
5–10 days (stock goods); 15–30 days (custom processing)
Certification
MTC, EN 10204 3.1, Third-party inspection supported
Custom Service
Cutting, drilling, welding, milling, machining and steel structure fabrication
02Equivalent & Comparable Grades
SPA-C is the JIS G3125 grade for welded atmospheric-corrosion-resistant structures. Comparable weathering grades exist in other major standards, supporting material substitution for international projects.
Standard System
Comparable Grade
Note
JIS G3125 (Japan)
SPA-H
Same standard; thicker hot-rolled grade for heavier welded structures
ASTM (USA)
Corten A / A588 Gr.A
Most common Corten / ASTM weathering equivalents
ASTM (USA, legacy)
A242 Type 1
Early-generation high-strength weathering steel
GB/T 4171 (China)
Q355NH / Q355GNH
Chinese weathering steel equivalents
EN 10025-5 (EU)
S355J0WP / S355J2WP
European weathering structural steel
Note: These grades share the same weathering-steel concept but differ in chemistry limits, thickness ranges and test requirements. For critical or long-cycle structures, verify project specifications before cross-standard substitution.
03Chemical Composition (Ladle Analysis)
Cu, Cr and Ni are the key alloying elements that give SPA-C its atmospheric corrosion resistance. Values below per JIS G3125.
Grade
C ≤
Si
Mn
P
S ≤
Cu
Cr
Ni ≤
SPA-C
0.12
0.25–0.75
0.20–0.50
0.070–0.150
0.040
0.25–0.60
0.30–1.25
0.65
Note: Phosphorus content is intentionally higher than ordinary structural steel (0.070–0.150%). Phosphorus works with copper and chromium to improve atmospheric corrosion resistance — a defining feature of weathering steels.
04Mechanical Properties
Tensile requirements for JIS G3125 SPA-C (as delivered condition).
≥ 325 MPaYield Strength (ReL)minimum
≥ 450 MPaTensile Strength (Rm)minimum
≥ 26%Elongation (A)minimum
Grade
Plate Thickness
Yield Strength
Tensile Strength
Elongation
SPA-C
—
≥ 325 MPa
≥ 450 MPa
≥ 26%
Note: SPA-C is a weathering steel; its mechanical values are close to ordinary mild steel, but the corrosion-resistant alloy system is what delivers the long service life in atmosphere-exposed structures.
05Available Product Forms & Applications
One supplier, full range of SPA-C product forms — from plates and sheets to bars, sections and fabricated structures — with custom processing on every form.
1
SPA-C Steel Plate & Sheet
Hot rolled & cold rolled; the main form for containers, railway carriages, air preheaters and economizers.
2
SPA-C Steel Bar
Round, flat and square bars for fittings, fasteners and machined parts in weathering environments.
3
SPA-C Section Steel
Angle, channel, H/I beam and other sections for bridges, buildings and structural frames.
4
SPA-C Structural Shapes
Custom-cut and welded structural members ready for assembly in outdoor structures.
Application Field
Typical Use of SPA-C
Power & Boiler
Air preheater, economizer components
Railway & Transport
Railway carriage / wagon body panels
Shipping & Logistics
Shipping containers, freight structures
Bridge & Infrastructure
Bridge building, weathering-exposed structures
Building & Construction
Building cladding, structural frames, facades
06Processing Service, Stock & FAQ
Backed by 10,000+ tons of monthly hot rolled & cold rolled SPA-C stock and a full deep-processing center, we deliver cut-to-size and fabricated parts fast.
1
Cutting
Any size, any shape — plasma, flame and laser cutting to your drawings.
2
Drilling & Milling
Precision drilling, milling and machining for ready-to-assemble parts.
3
Welding
Expert welding and steel-structure fabrication per client specification.
4
Fast Logistics
Dedicated logistics team for fast delivery time and safe shipment worldwide.
10,000+ tons hot rolled & cold rolled SPA-C steel in stock every month
Any quantity supported — from sample lots to full project volumes
Cutting, drilling, welding, milling, machining and steel structure fabrication
High-quality logistics team ensuring fast delivery and reliable shipment
Q1What is the difference between SPA-C and SPA-H?
Both belong to JIS G3125. SPA-C is the thinner / cold-rolled grade mainly for containers and railway carriages; SPA-H is the thicker hot-rolled grade for heavier welded structures such as bridges and buildings. Chemistry and strength levels are similar.
Q2Is SPA-C the same as Corten A / A588?
They are comparable weathering steels from different standards (JIS vs ASTM). They share the Cu-Cr-Ni atmospheric-corrosion-resistant concept, but chemistry limits, thickness ranges and test requirements differ. Verify specs before substitution.
Q3Does SPA-C need painting?
SPA-C forms a stable protective rust layer and is often used bare in atmosphere. For aggressive or aesthetic requirements, painting / coating can be added. We can supply primed or uncoated as requested.
Q4What is your SPA-C stock and lead time?
We keep 10,000+ tons of hot rolled & cold rolled SPA-C in stock monthly. Stock items ship in 5–10 days; custom cutting and fabrication take 15–30 days.
Get Your JIS G3125 SPA-C Steel Official Quotation
Send us your product form, dimensions (or part drawings), quantity and processing requirements. We will reply with the latest stock status, competitive wholesale price and complete certification documents within 24 hours.
BBN Steel has established a complete set of production and supplier management system processes to ensure the improvement of product quality and better service to users.
Production Control
BBN Steel has established a complete production quality control process to ensure every link from research and development to mass production.
Supplier management
Our supplier selection will consider factors such as health and safety, ethics, environmental protection, price and quality to better serve customers.
Certification & Patent
We have successively won various international authoritative certifications, GB /T19001-ISO9001: 2000 quality management system was implemented.
After sales service
We provide booking space, shipping tracking service and after-sales service, we will always be first-class products and perfect pre-sale and after-sales service.
Get in Touch
Welcome to contact us through online consulting, emails and hotline if you are interested in our company or products. Our staff will reply you within 24 hours.
Address: HIGH-TECH DEVELOPMENT ZONE, ZHENGZHOU, CHINA
