Steel Q345R-CR (Cold rolled)
Supply condition
GB Q345R
Only for thin sheet blanks and formed parts where a smoother surface and tighter thickness tolerance matter; higher strength but lower ductility and toughness than plate.
Values for the CR condition
Other Q345R tempers and conditions
Q345R is listed in 3 conditions; see the grade overview at Q345R.
Compare all 3 conditionsHide
| Condition · open for datasheet | Best for | Yield MPa | Tensile MPa | Elong. % | Hardness | Conductivity |
|---|---|---|---|---|---|---|
Normalized | Mandatory for thick plate (>36 mm) and low-temperature/impact-critical vessels; refines grain and raises toughness uniformity. | 360 | 545 | 26 | 155 HB | — |
HRDefault Hot rolled | Default stock condition for plate up to ~36 mm; cheapest and covers most vessel and tank work. | 370 | 550 | 24 | 160 HB | — |
CRThis page Cold rolled | Only for thin sheet blanks and formed parts where a smoother surface and tighter thickness tolerance matter; higher strength but lower ductility and toughness than plate. | 470 | 600 | 16 | 11 HRC | 8.4 % IACS |
What is Q345R-CR?
Q345R-CR is Q345R supplied in the CR condition — only for thin sheet blanks and formed parts where a smoother surface and tighter thickness tolerance matter; higher strength but lower ductility and toughness than plate. Q345R-CR has a yield strength of 470 MPa (68.2 ksi) and a tensile strength of 600 MPa (87 ksi) — stronger than 57% of steel grades. Elongation at break is 16% and the elastic modulus is 206 GPa (29.9 Msi). Q345R-CR has a density of 7.85 g/cm³ (0.284 lb/in³), heavier than 56% of steel grades. It melts at 1,440°C (2,624 °F). HR is the default condition FabDigit quotes; CR is available on request or by drawing note.
Advantages
- 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
Q345R-CR properties
Typical room-temperature values for Q345R-CR; 24 are specific to this condition. Other listed values are Q345R reference data and may not represent this condition. Bars are the position among steel grades.
Physical3
Q345R-CR has a density of 7.85 g/cm³ (0.284 lb/in³), heavier than 56% of steel grades. It melts at 1,440°C (2,624 °F).
Mechanical16
Q345R-CR has a yield strength of 470 MPa (68.2 ksi) and a tensile strength of 600 MPa (87 ksi) — stronger than 57% of steel grades. Elongation at break is 16% and the elastic modulus is 206 GPa (29.9 Msi).
Thermal6
Q345R-CR is rated for continuous service to 350°C (662 °F). It conducts heat at 48 W/m·K (27.7 BTU/hr·ft·°F), better than 79% of steel grades. Thermal expansion is 11.8 µm/m·K (6.56 µin/in·°F).
Electrical3
Q345R-CR conducts electricity at 8.4 % IACS, better than 62% of steel grades.
Chemical & Environmental3
Corrosion resistance is not recommended (12/100), worse than 53% of steel grades.
Sustainability4
Producing a kilogram of Q345R-CR takes about 25 MJ of energy and emits 2.1 kg of CO₂ — less than 82% of steel grades. Typical recycled content is 22%.
Manufacturability8
Q345R-CR's machinability is good (57/100, better than 71% of steel grades); weldability very good (82/100); formability good (58/100).
Values are nominal handbook figures for design screening. Confirm any required mill or lot documentation when quoting.
Working with Q345R-CR
Is Q345R easy to machine?
Cuts like ordinary C-Mn plate: uncoated carbide at 120–180 m/min, generous feed to avoid work hardening; gummy chips, so use coolant and sharp edges for drilling nozzle holes.
Can Q345R be welded?
Excellent weldability by SMAW/SAW/GMAW with J507/H08A-class consumables per NB/T 47015; preheat 100–150 °C above ~30 mm or in cold shops, PWHT 600–640 °C for thick or stress-critical vessels.
Can Q345R be formed, bent or molded?
Cold flanging and rolling of shells are routine (bend radius ≥2t); hot forming of heads at 900–1000 °C should be followed by normalizing to restore GB/T 713 impact values.
What surface finishes work on Q345R?
Shot-blast to Sa2½ then epoxy/zinc-rich primer, or hot-dip galvanize for outdoor structures; internal surfaces are usually rubber-lined, glass-flake coated or stainless clad.
Q345R 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 |
|---|---|---|
| CGB/T 713-2014 | ≤ 0.2 | 0.18 |
| Si | ≤ 0.55 | 0.35 |
| Mn | 1.2 – 1.7 | 1.45 |
| P | ≤ 0.03 | 0.02 |
| S | ≤ 0.01 | 0.01 |
| Nbmicroalloying, optional | ≤ 0.05 | 0.02 |
| Vmicroalloying, optional | ≤ 0.05 | 0.02 |
| Timicroalloying, optional | ≤ 0.03 | 0.01 |
| Altotal Al, killed steel | ≥ 0.02 | 0.03 |
| Crresidual | ≤ 0.3 | 0.05 |
| Niresidual | ≤ 0.3 | 0.05 |
| Curesidual | ≤ 0.3 | 0.05 |
| Moresidual | ≤ 0.08 | 0.02 |
| Fe | balance |
Q345R-CR — frequently asked
What is Q345R-CR used for?
Q345R-CR is typically used for pressure-vessel shells and heads, welded boiler drums, storage tanks, heat-exchanger shells, separator and column bodies and nozzles and reinforcing pads. In short: pressure-vessel structural plate.
What is the yield strength of Q345R-CR?
Q345R-CR has a typical yield strength of 470 MPa (68.2 ksi) and a tensile strength of 600 MPa (87 ksi) — stronger than 57% of steel grades. Strength varies by condition: see the 3 listed tempers.
Is Q345R-CR easy to machine?
Reasonably — machinability is rated good (57/100, better than 71% of steel grades). Cuts like ordinary C-Mn plate: uncoated carbide at 120–180 m/min, generous feed to avoid work hardening; gummy chips, so use coolant and sharp edges for drilling nozzle holes.
Can Q345R-CR be welded?
Yes — weldability is rated very good (82/100). Excellent weldability by SMAW/SAW/GMAW with J507/H08A-class consumables per NB/T 47015; preheat 100–150 °C above ~30 mm or in cold shops, PWHT 600–640 °C for thick or stress-critical vessels.
What surface finishes work on Q345R-CR?
Shot-blast to Sa2½ then epoxy/zinc-rich primer, or hot-dip galvanize for outdoor structures; internal surfaces are usually rubber-lined, glass-flake coated or stainless clad.
Can Q345R-CR be formed, bent or molded?
Cold flanging and rolling of shells are routine (bend radius ≥2t); hot forming of heads at 900–1000 °C should be followed by normalizing to restore GB/T 713 impact values.
What is the maximum service temperature of Q345R-CR?
Q345R-CR is rated for continuous use to about 350°C (662 °F). Strength falls off well before that limit — check the elevated-temperature data for load-bearing parts.
What is the difference between Q345R-HR and Q345R-CR?
HR is the default condition — default stock condition for plate up to ~36 mm; cheapest and covers most vessel and tank work. CR: only for thin sheet blanks and formed parts where a smoother surface and tighter thickness tolerance matter; higher strength but lower ductility and toughness than plate. Yield strength is 370 MPa in HR versus 470 MPa in CR.
Can FabDigit make parts in Q345R-CR?
Yes — Q345R-CR is available for CNC machining and sheet metal; every part is priced by an engineer rather than instantly. Upload a STEP file to get a price and a DFM check.
Sources
- GB/T 713 Steel plates for boilers and pressure vessels (2014)
- GB/T 150.2 Pressure vessels — Materials — SAC (2011)
- NB/T 47015 Welding specification for pressure vessels (2011)
- ASM Handbook Vol.1 — Properties and Selection: Irons, Steels — ASM International (1990)
- ASM Handbook Vol.19 — Fatigue and Fracture — ASM International (1996)
- worldsteel LCI data for steel plate — World Steel Association (2023)
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.