1. Womic Steel: Manufacturing Capabilities & Company Strength
Womic Steel Group operates multiple LSAW production lines capable of producing ASTM A500 Grade C structural pipes. A500 Grade C is a cold formed welded carbon steel structural tube (the “cold formed” refers to the forming temperature, not post-weld heat treatment). The LSAW process is ideal for large diameter round structural sections beyond the capacity of ERW or seamless mills.
● JCOE Line: For diameters 406mm – 1,422mm (16″–56″), wall thickness up to 50.8mm. Suitable for building columns and bridge truss members.
● UOE Line: For diameters 508mm – 1,220mm (20″–48″), wall thickness up to 40mm. Produces high roundness for exposed architectural steel.
● Rolled Plate (Single Seam): For diameters 600mm – 2,500mm (24″–98″), wall thickness from 25mm up to 80mm. Ideal for heavy wall columns and transmission tower legs.
● Rolled Plate (Double Seam): For diameters 1,200mm – 2,500mm (48″–98″), wall thickness up to 80mm.
Total LSAW capacity exceeds 300,000 tons annually, with A500 Grade C production exceeding 80,000 tons per year. Womic Steel holds ISO 9001, and can supply third-party inspection by SGS, BV, TÜV. Thousands of tons of A500 Grade C supplied for US infrastructure projects (bridges, stadiums, industrial plants).
Production Flexibility for A500 Grade C:
JCOE: 406–1,422mm OD × 5.0–50.8mm WT × ≤ 18m
UOE: 508–1,220mm OD × 5.0–40.0mm WT × ≤ 24m
Rolled plate (single seam): 600–2,500mm OD × 25–80mm WT × ≤ 18m
Rolled plate (double seam): 1,200–2,500mm OD × 25–80mm WT × ≤ 18m
Pipes can be supplied with primer coating (zinc-rich epoxy, 40-80 microns), bare (oiled), or hot-dip galvanized.
2. ASTM A500 Grade C: Material Composition & Performance Characteristics
ASTM A500 Grade C is the highest strength grade in the A500 specification for cold formed welded carbon steel structural tubing. Minimum yield strength of 345 MPa (50,000 psi) and tensile strength of 485 MPa (70,300 psi). It is approximately 25% stronger than Grade B (yield 290 MPa, tensile 400 MPa). Grade C is commonly specified for heavy-load structural applications.
Chemical Composition (max % by mass – ASTM A500 does not mandate strict limits, but typical ranges):
| Element | ASTM A500 Grade C (typical range) | Womic Control |
| C | 0.23 max (typical 0.20-0.23) | 0.20-0.23 |
| Mn | 1.35 max (typical 1.10-1.30) | 1.15-1.30 |
| P | 0.035 max | ≤ 0.030 |
| S | 0.035 max | ≤ 0.025 |
| Si | 0.30 max (typical) | 0.15-0.30 |
Mechanical Properties (Room Temperature):
| Property | ASTM A500 Grade C |
| Yield Strength (min) for round tubes | 345 MPa (50,000 psi) |
| Tensile Strength (min) | 485 MPa (70,300 psi) |
| Elongation (min) for round tubes – 50mm gauge | 21% |
| Elongation (min) for round tubes – 200mm gauge | 13% |
Comparison with A500 Grade B and A53 GR.B:
| Grade | Yield MPa | Tensile MPa | Typical Application |
| ASTM A53 GR.B | 240 | 415 | General structural, low strength |
| ASTM A500 Grade B | 290 | 400 | Medium strength structural |
| ASTM A500 Grade C | 345 | 485 | High strength structural, heavy loads |
Grade C’s higher strength allows for thinner walls or higher load capacity compared to Grade B.
3. Dimensional Range & Standards Compliance
| Item | Specification |
| Standard | ASTM A500 Grade B, Grade C |
| Manufacturing Processes | JCOE, UOE, rolled plate (single/double seam) |
| Outside Diameter Range | 219mm – 2,500mm (8″ – 98″) |
| Wall Thickness Range | JCOE/UOE: 5.0mm – 50.8mm; Rolled plate: 25mm – 80mm |
| Length Range | Standard: 6m, 12m, 18m; Extended: up to 24m |
| End Finish | Plain End (PE), Beveled End (BE), or square cut |
| Surface Finish | Bare (oiled), Black, Primer coated, Hot-dip galvanized |
| Tolerances (ASTM A500) | OD: ±0.5% for precision; WT: ±10%; Length: ±25mm (for standard cuts) |
| Straightness | ≤ 0.2% of length |
| Out-of-roundness | ≤ 2% (structural standard) |
ASTM A500 tolerances are less stringent than API 5L, which makes large diameter LSAW production more economical for structural applications.
4. Available Dimensions & Specifications – ASTM A500 Grade C LSAW Steel Pipe (Selected Typical Sizes)
| OD (mm) | WT Options (mm) | Process | Approx Weight (kg/m) | Standard Length | Typical Application |
| 219 | 5.0, 6.0, 8.0, 10.0, 12.5 | JCOE | 26.4 – 63.6 | 12m | Building column |
| 273 | 6.0, 8.0, 10.0, 12.5, 14.0 | JCOE | 39.5 – 89.4 | 12m / 18m | Bridge chord |
| 324 | 8.0, 10.0, 12.5, 14.0, 16.0 | JCOE | 62.4 – 121.5 | 12m / 18m | Transmission tower |
| 406 | 8.0, 10.0, 12.5, 14.0, 16.0, 20.0 | JCOE/UOE | 78.5 – 190.4 | 12m / 18m | Crane boom |
| 508 | 10.0, 12.5, 14.0, 16.0, 20.0, 25.0 | UOE | 122.8 – 297.8 | 12m / 18m / 24m | Stadium truss |
| 610 | 12.5, 14.0, 16.0, 20.0, 25.0, 30.0 | UOE | 184.2 – 429.1 | 12m / 18m | Heavy column |
| 711 | 14.0, 16.0, 20.0, 25.0, 30.0, 35.0 | JCOE/UOE | 240.7 – 583.5 | 12m / 18m | Offshore topside |
| 813 | 16.0, 20.0, 25.0, 30.0, 35.0, 40.0 | JCOE | 314.4 – 762.7 | 12m / 18m | Bridge arch |
| 914 | 20.0, 25.0, 30.0, 35.0, 40.0, 45.0 | JCOE/Rolled | 441.0 – 964.8 | 12m / 18m | Industrial frame |
| 1,016 | 20.0, 25.0, 30.0, 35.0, 40.0, 50.0 | Rolled | 491.3 – 1,191.7 | 12m | Transmission monopole |
| 1,220 | 25.0, 30.0, 35.0, 40.0, 50.0, 60.0 | Rolled | 736.5 – 1,716.9 | 12m | Heavy industrial |
| 1,422 | 30.0, 35.0, 40.0, 50.0, 60.0, 70.0 | Rolled (single) | 1,030 – 2,335 | 12m | Mega structure |
| 1,600 | 35.0, 40.0, 50.0, 60.0, 70.0, 80.0 | Rolled (double) | 1,350 – 3,000 | 12m | Special project |
| 2,000 | 40.0, 50.0, 60.0, 70.0, 80.0 | Rolled (double) | 1,933 – 3,784 | 12m | Architectural |
| 2,500 | 50.0, 60.0, 70.0, 80.0 | Rolled (double) | 3,023 – 4,766 | 12m | Monumental |
For structural applications, dimensional tolerances are less strict, allowing more economical production. For exposed architectural steel, weld grinding and primer coating are recommended.
5. Common Standards & Grades – Structural Round Tubes (LSAW)
| Standard | Steel Grades | Typical Application | Forming Process |
| ASTM A500 | Grade B, Grade C | Building frames, bridges, towers | JCOE/UOE/Rolled |
| ASTM A53 | GR.B | General structural, low strength | JCOE |
| ASTM A252 | Grade 2, Grade 3 | Piling (also structural) | JCOE/Rolled |
| EN 10219 | S355JRH, S355J2H | European structural | JCOE/Rolled |
| CSA G40.21 | 350W, 350WT | Canadian structural | JCOE |
| AS/NZS 1163 | C350L0, C450L0 | Australian structural | JCOE |
Usage summary: Building columns, bridge truss members, transmission tower legs, crane booms, stadium roof trusses, offshore topsides, industrial platforms.
6. Manufacturing Processes – LSAW for ASTM A500 Grade C Structural Pipe
For structural applications, weld quality must be sound, but aesthetics (smooth weld profile) are sometimes required. Mechanical expansion is optional.
JCOE Process (406–1,422mm OD, 5.0–50.8mm WT):
● Standard J-C-O sequential forming
● Inner and outer SAW welding
● Mechanical expansion (optional – improves roundness for visible structures)
● Weld grinding available (flush finish for exposed steel)
● Suitable for most structural sections
UOE Process (508–1,220mm OD, 5.0–40mm WT):
● U-press + O-press with expansion
● Produces very round pipes – good for exposed architectural applications
● Consistent weld geometry
Rolled Plate (Single Seam) for Heavy Wall (600–2,500mm OD, 25–80mm WT):
● 4-roll bending into cylinder
● Longitudinal SAW welding (multi-pass for thick walls)
● No expansion – ovality up to 1-2% acceptable for structural
● Used for heavy wall columns and large diameter truss chords
Post-weld finishing options:
● Weld grinding: For architectural exposed steel, we grind the weld cap flush.
● Primer coating: Zinc-rich epoxy primer (40-80 microns) standard for corrosion protection.
● Hot-dip galvanizing: Full pipe galvanizing available (max length 12.5m).
7. Quality Control & Testing Procedures for ASTM A500 Grade C LSAW Steel Pipe
| Stage | Inspection Method | Purpose |
| Plate | Chemical Analysis | Verify compliance (C, Mn, P, S limits) |
| Plate | Tensile Test | Verify yield ≥ 345 MPa, tensile ≥ 485 MPa |
| In-Process | Dimensional (OD, WT) | Ensure compliance |
| Weld seam | Ultrasonic Testing (100% for critical structures, spot for general) | Detect weld defects |
| Weld seam | Radiographic Testing (spot – 5-10% upon client request) | Weld quality |
| Weld seam | Magnetic Particle Inspection (optional) | Surface crack detection |
| Finished pipe | Flattening Test (required per ASTM A500) | Pipe body and weld ductility |
| Finished pipe | Guided Bend Test (weld) | Weld ductility |
| Finished pipe | Visual & Dimensional | Surface, straightness, marking |
For ASTM A500, flattening test is mandatory: a section of pipe is flattened to 1/3 of original diameter (or to weld if weld is at 90° position). No cracks or breaks allowed.
8. Primary Applications – ASTM A500 Grade C LSAW Steel Pipe
● Building columns – High-rise building vertical members, industrial plant columns
● Bridge truss chords and diagonals – Arch bridges, truss bridges, pedestrian bridges
● Transmission tower legs – Lattice tower legs (angle leg with tubular members), monopole bases
● Crane booms and outriggers – Mobile crane structural members, tower crane masts
● Stadium roof trusses – Large span trusses, space frames
● Offshore topside modules – Deck support legs, bracing on oil/gas platforms
● Industrial platform supports – Pipe racks, equipment supports, mezzanine columns
● Sign and lighting poles – Large diameter round poles for highways and stadiums
● Heavy equipment frames – Mining equipment structural members
● Bracing members in structural frames – Diagonal bracing for seismic resistance
9. Packaging & Shipping – ASTM A500 Grade C LSAW Steel Pipe
Packaging:
● Small diameters (≤ 610mm): Bundled with steel straps (5-10 tons per bundle) with edge protectors
● Large diameters (> 610mm): Individual pipes with wooden dunnage
● Architectural exposed pipes: Wrapped in plastic film to protect primer coating
● End caps: Plastic caps to prevent debris entry (if required for finish)
Shipping:
● Containers for small diameters and short lengths (≤ 12m)
● Break-bulk vessels for large diameters (> 1,000mm) and heavy wall
● Flat racks for extra-long pipes (up to 24m)
● Rail or truck for inland delivery
Documentation: Mill Test Certificate (EN 10204 Type 3.1), dimensional report, UT report (if specified), flattening test report, packing list, commercial invoice, COO.
10. Womic Steel Advantages & FAQ – ASTM A500 Grade C LSAW Steel Pipe
Why Womic Steel for ASTM A500 Grade C?
● Large diameter up to 2,500mm (98″) – ideal for heavy columns and transmission monopoles
● Heavy wall up to 80mm – for high-load structural members
● Weld grinding option for exposed architectural steel
● Primer coating and hot-dip galvanizing available
● Third-party inspection (SGS, BV, TÜV) accepted
● Competitive pricing for large-volume infrastructure projects
Frequently Asked Questions:
Q: What is the difference between ASTM A500 Grade C and ASTM A53 GR.B for structural pipe?
A: Grade C has much higher strength: 345 MPa yield vs 240 MPa for A53. Grade C also has tighter dimensional tolerances and requires a flattening test. For load-bearing columns and trusses, Grade C is preferred. A53 GR.B is acceptable for secondary members and non-critical structures.
Q: Does ASTM A500 require impact testing (Charpy)?
A: No. ASTM A500 does not mandate Charpy impact testing. However, for low-temperature applications (e.g., Arctic, some bridge codes), engineers may add supplementary requirements. Womic can provide Charpy impact testing at additional cost (typically at 0°C or -20°C) if specified.
Q: Can you supply A500 Grade C with hot-dip galvanizing for outdoor use?
A: Yes. We offer hot-dip galvanizing per ASTM A123. The maximum length for our galvanizing bath is 12.5m. For longer pipes, we can arrange sectional galvanizing or apply alternative coating (zinc-rich epoxy). Please specify your length requirements.
Q: What is the maximum length you can produce for A500 Grade C LSAW pipe?
A: Standard maximum length is 18m (JCOE) or 24m (UOE) for diameters ≤ 1,220mm. For larger diameters (rolled plate), maximum length is typically 12-18m due to plate size limitations. For lengths beyond 18m, we can weld multiple sections end-to-end (circumferential SAW welds). Contact us with your specific requirements.
Q: Do you provide third-party inspection for A500 Grade C pipes?
A: Yes. We work with SGS, BV, TÜV, and other agencies. Inspection can include visual and dimensional, flattening test, UT or RT of welds, and chemical/tensile testing. We issue EN 10204 Type 3.1 certificates as standard; Type 3.2 available upon request.
Q: What is the typical lead time for A500 Grade C LSAW structural pipe?
A: Standard lead time: 30-45 days for JCOE/UOE sizes. For rolled plate heavy wall (> 50mm): 45-60 days. For hot-dip galvanizing: add 1-2 weeks. For weld grinding (architectural finish): add 2 weeks.
Project Reference – Los Angeles Stadium Transmission Tower Structures (USA)
Country: United States (Inglewood, California – SoFi Stadium area)
Standard & Grade: ASTM A500 Grade C (with supplementary Charpy impact at 0°C)
Dimensions & Quantity:
OD 610mm (24″) × WT 16.0mm – 2,400 meters (approx. 560 tons) manufactured by UOE process
OD 813mm (32″) × WT 20.0mm – 1,800 meters (approx. 700 tons) manufactured by JCOE process
OD 1,016mm (40″) × WT 25.0mm – 900 meters (approx. 550 tons) manufactured by rolled plate single seam
OD 1,220mm (48″) × WT 30.0mm – 600 meters (approx. 530 tons) manufactured by rolled plate single seam
Total: 5,700 meters (5.7 km), approx. 2,340 tons
Specifications: Plain ends with chamfer (for butt welding), weld caps ground flush (exposed structural requirement), zinc-rich epoxy primer coating (60 microns). Mandatory flattening test (no cracks at 1/3 diameter flattening). Guided bend test for weld ductility. 100% UT of weld seam. Charpy impact at 0°C (min 27J, achieved 60-90J). Straightness ≤ 0.15% (stricter than A500 standard). Third-party inspection by SGS USA.
Application: Decorative and functional transmission tower structures surrounding the SoFi Stadium and Hollywood Park development in Los Angeles. The LSAW pipes serve as the main vertical columns and diagonal bracing for large-scale architectural “super” transmission towers (approx. 60m height) that support signage, lighting, and also serve as architectural landmarks. The project required exposed steel with smooth weld finish and uniform appearance.
Technical Challenges & Solutions:
● Architectural exposed steel – weld grinding and finish – The towers are visible from the stadium and surrounding areas. Womic performed automated weld grinding followed by hand finishing to achieve a smooth surface (Ra ≤ 6.3μm). We also applied a uniform primer coating (zinc-rich epoxy, light gray color specified by architect). Each pipe was inspected for weld smoothness by the client’s QA team.
● Seismic zone requirements – ductility and toughness – Los Angeles is in Seismic Design Category D (high seismic risk). ASTM A500 Grade C normally does not require impact testing. The structural engineer added Charpy impact requirement of 27J at 0°C. Womic selected plates with controlled carbon (0.20-0.22%) and manganese (1.15-1.25%) and achieved 60-90J at 0°C, well above requirement.
● Large diameter tapered sections – Some tower legs were tapered (cone-shaped). Womic supplied straight pipes that were then fabricated by the contractor into tapered sections. We provided tight ovality control (≤ 0.5%) to facilitate the tapering process. Pipes were marked with orientation lines to ensure consistent welding.
● Primer coating for coastal environment – SoFi Stadium is located 5 km from the Pacific Ocean, with salt spray exposure. Zinc-rich epoxy primer (60 microns) was applied to all pipes. Coating passed 1,000 hours salt spray test (ASTM B117) with less than 2mm creep from scribe. Holiday detection at 2kV with zero failures.
● Logistics to active construction site – The Hollywood Park development is one of the largest urban construction projects in the US. Delivery of 2,340 tons of large diameter pipes needed to be sequenced. Womic delivered pipes in 6 shipments over 8 months, each scheduled to arrive just before installation. Pipes were shipped from Shanghai to Port of Los Angeles, then trucked 8 km to the site. We used flat rack containers for the 1,016mm and 1,220mm pipes to avoid damage.
● US Buy America requirements – The project required a waiver for foreign steel because US domestic mills could not produce the large diameters (1,220mm) in the required wall thickness within the schedule. Womic provided full documentation including mill certificates, country of origin, and material traceability. The waiver was approved by the owner.
● Result: The transmission tower structures were completed in 2022. They have become a recognizable feature of the SoFi Stadium complex. The contractor reported that all LSAW pipes fit perfectly with no rework. The exposed steel finish received praise from the architect. Womic Steel has since been invited to bid on additional architectural steel projects in the US.
Contact:
Website: www.womicsteel.com
E-mail: sales@womicsteel.com
Tel / WhatsApp / WeChat:
Victor: +86 15575100681
Jack: +86 18390957568
Womic Steel – Your reliable partner for ASTM A500 Grade C LSAW steel pipes for building columns, bridge trusses, transmission towers, and heavy structural applications worldwide.
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