Steel Q355D · supply condition · default condition
Steel Q355D-HR
Properties of the HR condition, compared with the other Q355D tempers.
Standard stocked condition for plate, section and bar; cheapest and adequate for most welded structures up to ~40 mm.
What is Q355D-HR?
Q355D-HR is Q355D supplied in the HR condition — standard stocked condition for plate, section and bar; cheapest and adequate for most welded structures up to ~40 mm. Q355D-HR has a yield strength of 380 MPa (55.1 ksi) and a tensile strength of 530 MPa (76.9 ksi) — weaker than 67% of steel grades. Elongation at break is 25% and the elastic modulus is 210 GPa (30.5 Msi). Q355D-HR has a density of 7.85 g/cm³ (0.284 lb/in³), heavier than 56% of steel grades. It melts at 1,450°C (2,642 °F).
Advantages
- Readily welded — 88/100, better than 87% of steel grades
- Forms and bends easily — 70/100, better than 85% of steel grades
- Tough — resists crack growth — 120 MPa·√m (109.2 ksi·√in), better than 80% of steel grades
- Ductile — tolerates forming and impact — 25%, better than 76% of steel grades
Limitations
- Hard to polish — 45/100, worse than 84% of steel grades
Q355D-HR properties
Typical room-temperature values for Q355D-HR — 9 properties are specific to this condition; the rest are grade-level values shared by every Q355D temper. Each bar shows where the value sits among the steel grades in FabDigit's library — further right is higher.
Physical3
Q355D-HR has a density of 7.85 g/cm³ (0.284 lb/in³), heavier than 56% of steel grades. It melts at 1,450°C (2,642 °F).
Mechanical16
Q355D-HR has a yield strength of 380 MPa (55.1 ksi) and a tensile strength of 530 MPa (76.9 ksi) — weaker than 67% of steel grades. Elongation at break is 25% and the elastic modulus is 210 GPa (30.5 Msi).
Thermal6
Q355D-HR is rated for continuous service to 400°C (752 °F). It conducts heat at 46 W/m·K (26.6 BTU/hr·ft·°F), better than 71% of steel grades. Thermal expansion is 12 µm/m·K (6.67 µin/in·°F).
Electrical3
Q355D-HR conducts electricity at 8.6 % IACS, better than 66% of steel grades.
Chemical & Environmental3
Corrosion resistance is not recommended (12/100), worse than 53% of steel grades.
Sustainability4
Producing a kilogram of Q355D-HR takes about 25 MJ of energy and emits 2 kg of CO₂ — less than 82% of steel grades. Typical recycled content is 25%.
Manufacturability6
Q355D-HR's machinability is good (55/100, better than 62% of steel grades); weldability excellent (88/100); formability very good (70/100).
Common Calculations5
Values are nominal handbook figures for design screening. Certified mill or lot data ships with every FabDigit order on request.
Other Q355D tempers and conditions
Q355D is also supplied in 3 other conditions. The full side-by-side table is on the Q355D overview.
- HRDefaultStandard stocked condition for plate, section and bar; cheapest and adequate for most welded structures up to ~40 mm.380 MPa yield · 155 HB
- MPick for heavy welded fabrication: lowest carbon equivalent, best toughness and least preheat, but avoid hot forming or PWHT above ~580 °C.400 MPa yield · 150 HB
- NChoose for thick plate, pressure or low-temperature duty where uniform fine grain and higher, more consistent impact energy are needed.390 MPa yield · 150 HB
Working with Q355D-HR
Is Q355D easy to machine?
Machines like A572-50 mild-alloy steel — use carbide at ~120–180 m/min with good chip breaking; sticky, stringy chips in the as-rolled condition, so favour positive rake and adequate feed.
Can Q355D be welded?
Excellent weldability with Ceq ≤0.45 (E5015/ER50-6 or matching); preheat 50–100 °C only for thick sections or restraint, and use low-hydrogen practice to protect the −20 °C toughness.
Can Q355D be formed, bent or molded?
Cold bends to 2a–3a mandrel radius across the grain; hot forming 900–1050 °C followed by normalizing is fine for AR/N material, but avoid hot forming TMCP plate.
What surface finishes work on Q355D?
No inherent corrosion resistance — shot blast to Sa 2½ then zinc-rich primer, hot-dip galvanize (watch Si level for coating thickness) or metallize; welds and cut edges need the same protection.
Q355D 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 |
|---|---|---|
| C≤0.20 % for ≤150 mm sections per GB/T 1591-2018 | ≤ 0.2 | 0.16 |
| Si | ≤ 0.55 | 0.3 |
| Mn | ≤ 1.6 | 1.4 |
| P | ≤ 0.03 | 0.02 |
| S | ≤ 0.02 | 0.01 |
| Nbmicroalloying, optional | ≤ 0.05 | 0.02 |
| Vmicroalloying, optional | ≤ 0.1 | 0.03 |
| Timicroalloying, optional | ≤ 0.05 | 0.02 |
| Crresidual | ≤ 0.3 | 0.1 |
| Niresidual | ≤ 0.5 | 0.1 |
| Curesidual | ≤ 0.4 | 0.1 |
| Moresidual | ≤ 0.1 | 0.02 |
| N | ≤ 0.01 | 0.01 |
| Altotal Al, for fine-grain/killed practice | ≥ 0.02 | 0.03 |
| FeCeq (IIW) ≤ 0.45 % typical for Q355D | balance | — |
Q355D-HR — frequently asked
What is Q355D-HR used for?
Q355D-HR is typically used for bridge girders and plate weldments, crane and hoist structures, cold-climate structural frames, pressure-bearing welded structures, mobile equipment chassis and booms and machine bases and heavy frames. In short: workhorse structural plate.
What is the yield strength of Q355D-HR?
Q355D-HR has a typical yield strength of 380 MPa (55.1 ksi) and a tensile strength of 530 MPa (76.9 ksi) — weaker than 67% of steel grades. Strength varies by condition: see the 4 listed tempers.
Is Q355D-HR easy to machine?
Reasonably — machinability is rated good (55/100, better than 62% of steel grades). Machines like A572-50 mild-alloy steel — use carbide at ~120–180 m/min with good chip breaking; sticky, stringy chips in the as-rolled condition, so favour positive rake and adequate feed.
Can Q355D-HR be welded?
Yes — weldability is rated excellent (88/100). Excellent weldability with Ceq ≤0.45 (E5015/ER50-6 or matching); preheat 50–100 °C only for thick sections or restraint, and use low-hydrogen practice to protect the −20 °C toughness.
What surface finishes work on Q355D-HR?
No inherent corrosion resistance — shot blast to Sa 2½ then zinc-rich primer, hot-dip galvanize (watch Si level for coating thickness) or metallize; welds and cut edges need the same protection.
Can Q355D-HR be formed, bent or molded?
Cold bends to 2a–3a mandrel radius across the grain; hot forming 900–1050 °C followed by normalizing is fine for AR/N material, but avoid hot forming TMCP plate.
What is the maximum service temperature of Q355D-HR?
Q355D-HR is rated for continuous use to about 400°C (752 °F). Strength falls off well before that limit — check the elevated-temperature data for load-bearing parts.
What is the difference between Q355D-HR and Q355D-CD?
HR is the default condition — standard stocked condition for plate, section and bar; cheapest and adequate for most welded structures up to ~40 mm. CD: use for shafts and machined parts needing tight size and straightness; strength and hardness rise, ductility and toughness drop. Yield strength is 380 MPa in HR versus 500 MPa in CD.
Can FabDigit make parts in Q355D-HR?
Yes — Q355D-HR is available for CNC machining and sheet metal with instant online pricing. Upload a STEP file to get a price and a DFM check.
Sources
- GB/T 700 / GB 50017 (elastic constants, thermal data) — MOHURD / SAC (2017)
- ASM Handbook Vol.1 — Properties and Selection: Irons, Steels and High-Performance Alloys — ASM International (1990)
- ASM Handbook Vol.19 — Fatigue and Fracture — ASM International (1996)
- EN 10025-2 S355J2 (comparison grade) — CEN (2019)
- 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.