Steel A633 Grade C N+SR
Heat-treated state
ASTM A633 Grade C · GB Q355C
N+SR = normalized then stress-relieved / tempered
Pick when heavy welding or cold forming demands residual-stress relief; slight strength drop, toughness retained.
Values for the N+SR condition
Other A633 Grade C tempers and conditions
A633 Grade C is listed in 4 conditions; see the grade overview at A633 Grade C.
Compare all 4 conditionsHide
| Condition · open for datasheet | Best for | Yield MPa | Tensile MPa | Elong. % | Hardness | Conductivity |
|---|---|---|---|---|---|---|
N | Heavy normalized plate; A633 allows reduced strength levels above 65 mm thickness. | 350 | 490 | 24 | 150 HB | 9 % IACS |
N+SRThis page Normalized then stress-relieved / tempered | Pick when heavy welding or cold forming demands residual-stress relief; slight strength drop, toughness retained. | 365 | 510 | 26 | 155 HB | 9 % IACS |
NDefault Normalized | Standard A633 Grade C supply condition — normalized plate meeting 345 MPa minimum yield with good low-temperature CVN. | 385 | 530 | 25 | 160 HB | — |
N + supplementary CVN | Order this when low-temperature notch toughness must be certified per A633 supplementary requirements (or S355J2 20 °C/-20 °C option). | 385 | 530 | 25 | 160 HB | 9 % IACS |
What is A633 Grade C N+SR?
A633 Grade C N+SR is A633 Grade C heat treated to N+SR — pick when heavy welding or cold forming demands residual-stress relief; slight strength drop, toughness retained. A633 Grade C N+SR has a yield strength of 365 MPa (52.9 ksi) and a tensile strength of 510 MPa (74 ksi) — weaker than 71% of steel grades. Elongation at break is 26% and the elastic modulus is 205 GPa (29.7 Msi). A633 Grade C N+SR has a density of 7.85 g/cm³ (0.284 lb/in³), heavier than 56% of steel grades. It melts at 1,425°C (2,597 °F). N is the default condition FabDigit quotes; N+SR is available on request or by drawing note.
Advantages
- Ductile — tolerates forming and impact — 26%, better than 82% of steel grades
- Readily welded — 84/100, better than 82% of steel grades
- Forms and bends easily — 63/100, better than 79% of steel grades
Limitations
- Hard to polish — 40/100, worse than 96% of steel grades
A633 Grade C N+SR properties
Typical room-temperature values for A633 Grade C N+SR; 22 are specific to this condition. Other listed values are A633 Grade C reference data and may not represent this condition. Bars are the position among steel grades.
Physical3
A633 Grade C N+SR has a density of 7.85 g/cm³ (0.284 lb/in³), heavier than 56% of steel grades. It melts at 1,425°C (2,597 °F).
Mechanical16
A633 Grade C N+SR has a yield strength of 365 MPa (52.9 ksi) and a tensile strength of 510 MPa (74 ksi) — weaker than 71% of steel grades. Elongation at break is 26% and the elastic modulus is 205 GPa (29.7 Msi).
Thermal6
A633 Grade C N+SR 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
A633 Grade C N+SR conducts electricity at 9 % IACS, better than 71% of steel grades.
Chemical & Environmental3
Corrosion resistance is not recommended (12/100), worse than 53% of steel grades.
Sustainability4
Producing a kilogram of A633 Grade C N+SR takes about 25 MJ of energy and emits 2 kg of CO₂ — less than 82% of steel grades. Typical recycled content is 30%.
Manufacturability7
A633 Grade C N+SR's machinability is good (59/100, better than 80% of steel grades); weldability very good (84/100); formability good (63/100).
Values are nominal handbook figures for design screening. Confirm any required mill or lot documentation when quoting.
Working with A633 Grade C N+SR
Is A633 Grade C easy to machine?
Machines like normalized C-Mn steel at ~60 % of 1212; use carbide, moderate speeds and positive rake, expect gummy chips at low feeds.
Can A633 Grade C be welded?
Excellent weldability by SMAW/GMAW/SAW/FCAW with E70/ER70S consumables; low carbon equivalent means preheat only for heavy sections (>40 mm) or high restraint, keep heat input moderate to preserve HAZ toughness.
Can A633 Grade C be formed, bent or molded?
Cold bends readily at 2–3 t inside radius transverse to rolling; hot forming above 900 °C requires re-normalizing to restore certified properties.
What surface finishes work on A633 Grade C?
Blast to SA 2.5 and paint, hot-dip galvanize or metallize for corrosion protection; no anodizing, and phosphating is used before powder coat.
A633 Grade C 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 |
|---|---|---|
| Cheat analysis, ASTM A633 Grade C | ≤ 0.2 | 0.16 |
| Mn | 1.15 – 1.5 | 1.3 |
| Si | 0.15 – 0.5 | 0.3 |
| P | ≤ 0.04 | 0.02 |
| S | ≤ 0.04 | 0.01 |
| Nboptional micro-alloying / grain refinement by producer agreement | ≤ 0.05 | 0.02 |
| Voptional micro-alloying addition | ≤ 0.06 | — |
| Algrain-refining / killed practice | ≈ 0.03 | 0.03 |
| Fe | balance | — |
A633 Grade C N+SR — frequently asked
What is A633 Grade C N+SR used for?
A633 Grade C N+SR is typically used for heavy machinery frames, welded structures and low-temperature service plate. In short: notch-tough normalized HSLA plate; certified low-temperature toughness; S355J2 plate equivalent.
What is the yield strength of A633 Grade C N+SR?
A633 Grade C N+SR has a typical yield strength of 365 MPa (52.9 ksi) and a tensile strength of 510 MPa (74 ksi) — weaker than 71% of steel grades. Strength varies by condition: see the 4 listed tempers.
Is A633 Grade C N+SR easy to machine?
Reasonably — machinability is rated good (59/100, better than 80% of steel grades). Machines like normalized C-Mn steel at ~60 % of 1212; use carbide, moderate speeds and positive rake, expect gummy chips at low feeds.
Can A633 Grade C N+SR be welded?
Yes — weldability is rated very good (84/100). Excellent weldability by SMAW/GMAW/SAW/FCAW with E70/ER70S consumables; low carbon equivalent means preheat only for heavy sections (>40 mm) or high restraint, keep heat input moderate to preserve HAZ toughness.
What surface finishes work on A633 Grade C N+SR?
Blast to SA 2.5 and paint, hot-dip galvanize or metallize for corrosion protection; no anodizing, and phosphating is used before powder coat.
Can A633 Grade C N+SR be formed, bent or molded?
Cold bends readily at 2–3 t inside radius transverse to rolling; hot forming above 900 °C requires re-normalizing to restore certified properties.
What is the maximum service temperature of A633 Grade C N+SR?
A633 Grade C N+SR 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 A633 Grade C-N and A633 Grade C N-HEAVY?
N is the default condition — standard A633 Grade C supply condition — normalized plate meeting 345 MPa minimum yield with good low-temperature CVN. N-HEAVY: heavy normalized plate; A633 allows reduced strength levels above 65 mm thickness. Yield strength is 385 MPa in N versus 350 MPa in N-HEAVY.
Sources
- ASTM A633/A633M Standard Specification for Normalized High-Strength Low-Alloy Structural Steel Plates — ASTM International (2018)
- EN 10025-2 Hot rolled products of structural steels — Non-alloy structural steels (S355J2) — CEN (2019)
- 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)
- AWS D1.1 Structural Welding Code — Steel — AWS (2020)
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.