Steel Channel (U-Channel / PFC) Buying Guide: Sizes, Grades, and How to Specify Channels for Frames, Purlins, and Machinery
Steel channels — U-shaped hot-rolled sections also called U-channel or PFC (parallel flange channel) — frame trailers and machines, act as purlins and girts, edge concrete slabs, and build stair stringers. Specify the wrong flange type, grade, or length and the channel won’t bolt flush, welds poorly in the cold, or arrives too short for the bay.
This guide compares the channel families, sizes, grades, standards, and a complete RFQ checklist.
Channel Families Compared
| Type | Flange | Best For |
|---|---|---|
| PFC (parallel flange) | Parallel faces | Bolting, frames, modern builds |
| UPN (tapered flange) | Tapered inner faces | European legacy, rolling stock |
| JIS channel | Sloped, light | Japanese-standard projects |
| Misc./ship channel | Varies | Marine, special frames |
Prefer PFC wherever connections are bolted — the parallel flanges need no tapered washers.
Sizes Buyers Specify
- PFC: 100×50 to 380×100 mm; state depth × flange × kg/m.
- UPN: UPN 80–400; tapered-flange European sizes.
- Lengths: 6 / 9 / 12 m; cut-to-length on request.
Grades Compared
| Grade | Standard | Yield | Use |
|---|---|---|---|
| Q235B | GB/T 700 | 235 MPa | General Chinese work |
| Q355B | GB/T 1591 | 355 MPa | Heavier frames |
| A36 | ASTM A36 | 250 MPa | US general |
| S275JR / S355JR | EN 10025 | 275 / 355 MPa | CE projects |
Standards and Tolerances
- ASTM A6: US dimensional tolerances.
- EN 10279: European channel tolerances.
- JIS G3192: Japanese dimensions.
- EN 1090: CE execution for structural use.
Surface Options
- As-rolled: cheapest; primer after fabrication.
- Shot-blast + shop primer: fabrication standard.
- Hot-dip galvanized: outdoor, trailers, coastal.
Common Applications
- Trailer and truck chassis rails.
- Purlins, girts, and bracing.
- Machine frames and conveyor beds.
- Stair stringers and lintels.
RFQ Checklist
- Family: PFC / UPN / JIS + designation & kg/m
- Grade and standard
- Lengths and cutting tolerance
- Surface: as-rolled / primed / HDG
- Quantity (tonnes per size) + piece marks
- MTC, inspection, destination / Incoterm
FAQ
PFC or UPN? PFC for bolted modern frames; UPN only when the drawing calls for it.
What grade for a trailer? Q355B / S355 for strength-to-weight; A36/Q235 for light duty.
Galvanize a 12 m channel? Check the kettle length first — over-length sections need split dipping or duplex paint.
Why Source Channels from Yihang Metal
Yihang Metal supplies PFC, UPN, and JIS channels in Q235/Q355, A36, and S275/S355 to ASTM, EN, and JIS tolerances, as-rolled, primed, or hot-dip galvanized, with mill test certificates and third-party inspection. Standard sizes typically ship in 20–30 days.
Ready to specify your channels? Send us the designation, grade, lengths, and tonnage, and we will confirm availability and lead time with a fixed-price quote and MTC. Email [email protected] or use the quote form on this page — our team replies within one business day.