Quick Answer
All three are cast carbon steels for pressure parts; they differ by guarantee. WCB (ASTM A216) is the general-purpose default. WCC (A216) gives higher yield strength at slightly better weldability. LCB (ASTM A352) is the low-temperature version, impact tested at −46°C for cold climates and cryogenic-adjacent service. The rule: moderate temperatures → WCB or WCC; anything below about −29°C → LCB or its tougher siblings.
Side-by-Side
| Attribute | WCB (A216) | WCC (A216) | LCB (A352) |
|---|---|---|---|
| Tensile | 485–655 MPa | 485–655 MPa | 450–620 MPa |
| Yield min | 250 MPa | 275 MPa | 240 MPa |
| Impact test | Not required | Not required | Charpy at −46°C, required |
| Carbon max | 0.30% | 0.25% | 0.30% |
| Typical service | −29 to ~425°C | −29 to ~425°C | −46 to ~340°C |
| Weldability | Good | Slightly better (lower C) | Good, procedures qualified for toughness |
Why WCC Quietly Replaced WCB at Many Valve OEMs
WCC caps carbon at 0.25% but allows more manganese, buying 10% more yield strength and a friendlier carbon equivalent for welding — two benefits with no real downside except marginally tighter melt control. If your drawing still says WCB from habit, WCC is usually a free upgrade worth asking about. Full WCB detail: our A216 WCB material guide.
When LCB Becomes Mandatory
Below −29°C, ordinary carbon steel castings lose impact toughness — the brittle-fracture zone. Codes for pipelines, LNG-adjacent equipment, arctic installations and refrigeration plants therefore call A352 grades with guaranteed Charpy values:
- LCB: −46°C — the standard cold-service workhorse
- LCC: −46°C with WCC-level strength
- LC2/LC3 (nickel-alloyed): −73°C / −101°C for deeper cold
Buying LCB “to be safe” for room-temperature service wastes money on impact testing and tighter heat treatment; buying WCB for a −40°C site is a code violation waiting for an auditor. Match the guarantee to the coldest design temperature — nothing more, nothing less.
Ordering Checklist
- Spec + grade: “ASTM A216 Gr. WCC” or “ASTM A352 Gr. LCB”
- Design temperature range stated in the RFQ — lets the foundry flag grade mismatches
- Heat treatment condition (normalized / normalized & tempered)
- NDT level for pressure parts: MPI standard, RT on critical sections per your code
- Charpy test temperature and acceptance values for LCB — per heat, on the certificate
All three grades pour at YCUMETAL via sand casting and investment casting depending on size and finish, with heat treatment and testing documented through quality assurance.
FAQ
Is LCB stronger than WCB?
No — slightly softer on paper. Its value is guaranteed toughness at −46°C, not strength.
Can one casting be dual-certified WCB/WCC?
Often yes: a melt at ≤0.25% C meeting the higher yield can certify to both. Useful for consolidating inventory — ask the foundry.
What about high temperatures — above 425°C?
Move to ASTM A217 alloy grades (WC6, WC9, C5…) designed for creep service. Carbon steel WCB family stops where creep begins.