Steel LCB Q+T
Heat-treated state
UNS J03003 · ASTM A352 Grade LCB
Q+T = quenched and tempered
Choose for heavy-section castings or when higher yield strength and better low-temperature CVN margin at -46 °C are required.
Values for the Q+T condition
Other LCB tempers and conditions
LCB is listed in 2 conditions; see the grade overview at LCB.
- N+T
- Q+T
Compare all 2 conditionsHide
| Condition · open for datasheet | Best for | Yield MPa | Tensile MPa | Elong. % | Hardness | Conductivity |
|---|---|---|---|---|---|---|
N+TDefault Normalized and tempered | Standard supply condition for A352 LCB valve and fitting castings; best balance of strength, toughness at -46 °C and weld-repairability. | 285 | 500 | 28 | 150 HB | — |
Q+TThis page Quenched and tempered | Choose for heavy-section castings or when higher yield strength and better low-temperature CVN margin at -46 °C are required. | 340 | 545 | 27 | 165 HB | — |
What is LCB Q+T?
LCB Q+T is LCB heat treated to Q+T — choose for heavy-section castings or when higher yield strength and better low-temperature CVN margin at -46 °C are required. LCB Q+T has a yield strength of 340 MPa (49.3 ksi) and a tensile strength of 545 MPa (79 ksi) — weaker than 76% of steel grades. Elongation at break is 27% and the elastic modulus is 200 GPa (29 Msi). LCB Q+T has a density of 7.83 g/cm³ (0.283 lb/in³), lighter than 80% of steel grades. It melts at 1,425°C (2,597 °F). N+T is the default condition FabDigit quotes; Q+T is available on request or by drawing note.
Advantages
- Ductile — tolerates forming and impact — 27%, better than 86% of steel grades
- High electrical conductivity — 10 % IACS, better than 83% of steel grades
- Readily welded — 82/100, better than 81% of steel grades
- Conducts heat well — 48 W/m·K (27.7 BTU/hr·ft·°F), better than 79% of steel grades
Limitations
- Limited formability — 15/100, worse than 87% of steel grades
- Low strength — 340 MPa (49.3 ksi), worse than 76% of steel grades
LCB Q+T properties
Typical room-temperature values for LCB Q+T; 11 are specific to this condition. Other listed values are LCB reference data and may not represent this condition. Bars are the position among steel grades.
Physical3
LCB Q+T has a density of 7.83 g/cm³ (0.283 lb/in³), lighter than 80% of steel grades. It melts at 1,425°C (2,597 °F).
Mechanical15
LCB Q+T has a yield strength of 340 MPa (49.3 ksi) and a tensile strength of 545 MPa (79 ksi) — weaker than 76% of steel grades. Elongation at break is 27% and the elastic modulus is 200 GPa (29 Msi).
Thermal6
LCB Q+T is rated for continuous service to 425°C (797 °F). It conducts heat at 48 W/m·K (27.7 BTU/hr·ft·°F), better than 79% of steel grades. Thermal expansion is 11.9 µm/m·K (6.61 µin/in·°F).
Electrical3
LCB Q+T conducts electricity at 10 % IACS, better than 83% of steel grades.
Chemical & Environmental3
Corrosion resistance is not recommended (12/100), worse than 53% of steel grades.
Sustainability4
Producing a kilogram of LCB Q+T takes about 28 MJ of energy and emits 2.2 kg of CO₂ — less than 56% of steel grades. Typical recycled content is 85%.
Manufacturability7
LCB Q+T's machinability is fair (54/100, better than 54% of steel grades); weldability very good (82/100); formability poor (15/100).
Values are nominal handbook figures for design screening. Confirm any required mill or lot documentation when quoting.
Working with LCB Q+T
Is LCB easy to machine?
Machines like normalized 1025–1030 cast steel (~65 % of AISI 1212); use sharp carbide inserts and rigid setups, watch for hard spots and sand inclusions near as-cast skin.
Can LCB be welded?
Readily weldable by SMAW/GTAW/FCAW with low-hydrogen E7018-type or ER70S consumables; preheat 100–150 °C on heavy sections and post-weld heat treat per A352 to restore -46 °C toughness.
Can LCB be formed, bent or molded?
Supplied as sand/investment castings — design generous radii, directional solidification and risering; cold forming is not applicable.
What surface finishes work on LCB?
No natural corrosion resistance — shot-blast then epoxy/zinc-rich paint, galvanize or electroless-nickel plate; machined sealing faces may be overlaid with stainless or Stellite.
LCB chemical composition (wt %)
Limits by weight percent from the governing specification, written the way the spec states them — a single maximum for impurities, a range for alloying elements, and the base element as balance. Nominal is the typical mid-range value.
| Element | Spec limit (wt %) | Nominal |
|---|---|---|
| Cmax per ASTM A352 LCB | ≤ 0.3 | 0.25 |
| Mn | ≤ 1 | 0.8 |
| Si | ≤ 0.6 | 0.4 |
| P | ≤ 0.04 | — |
| S | ≤ 0.05 | — |
| Curesidual | ≤ 0.3 | — |
| Niresidual | ≤ 0.5 | — |
| Crresidual | ≤ 0.5 | — |
| Moresidual | ≤ 0.2 | — |
| Vresidual; total residuals ≤ 1.00 % | ≤ 0.03 | — |
| Fe | balance | — |
LCB Q+T — frequently asked
What is LCB Q+T used for?
LCB Q+T is typically used for low-temperature valve bodies, pump casings for cold service and cryogenic pressure fittings. In short: stronger than LCA; impact qualified at -46 °C; weldable cold-service casting.
What is the yield strength of LCB Q+T?
LCB Q+T has a typical yield strength of 340 MPa (49.3 ksi) and a tensile strength of 545 MPa (79 ksi) — weaker than 76% of steel grades. Strength varies by condition: see the 2 listed tempers.
Is LCB Q+T easy to machine?
Reasonably — machinability is rated fair (54/100, better than 54% of steel grades). Machines like normalized 1025–1030 cast steel (~65 % of AISI 1212); use sharp carbide inserts and rigid setups, watch for hard spots and sand inclusions near as-cast skin.
Can LCB Q+T be welded?
Yes — weldability is rated very good (82/100). Readily weldable by SMAW/GTAW/FCAW with low-hydrogen E7018-type or ER70S consumables; preheat 100–150 °C on heavy sections and post-weld heat treat per A352 to restore -46 °C toughness.
What surface finishes work on LCB Q+T?
No natural corrosion resistance — shot-blast then epoxy/zinc-rich paint, galvanize or electroless-nickel plate; machined sealing faces may be overlaid with stainless or Stellite.
Can LCB Q+T be formed, bent or molded?
Supplied as sand/investment castings — design generous radii, directional solidification and risering; cold forming is not applicable.
What is the maximum service temperature of LCB Q+T?
LCB Q+T is rated for continuous use to about 425°C (797 °F). Strength falls off well before that limit — check the elevated-temperature data for load-bearing parts.
Sources
- ASTM A352/A352M — Steel Castings, Ferritic and Martensitic, for Pressure-Containing Parts, Suitable for Low-Temperature Service — ASTM International (2023)
- ASME BPVC Section II Part D — Properties (Metric) — ASME (2023)
- Steel Castings Handbook, 6th ed. — Steel Founders' Society of America / ASM (1995)
- ASM Handbook Vol. 1: Properties and Selection — Irons, Steels, and High-Performance Alloys — ASM International (1990)
- UNS J03003 alloy record — SAE/ASTM Unified Numbering System (2017)
Property data is compiled from published supplier and standards handbooks and normalised for comparison. Nothing on this page is a certification — request mill certs, CoC or material test reports with your order.