Steel 340X-CR (Cold rolled)
Supply condition · default condition
ASTM J2340 340X
Standard stock condition for stamped body structural panels that are painted or later coated.
Values for the CR condition
Other 340X tempers and conditions
340X is listed in 2 conditions; see the grade overview at 340X.
- CR
- HR
Compare all 2 conditionsHide
| Condition · open for datasheet | Best for | Yield MPa | Tensile MPa | Elong. % | Hardness | Conductivity |
|---|---|---|---|---|---|---|
CRDefaultThis page Cold rolled | Standard stock condition for stamped body structural panels that are painted or later coated. | 370 | 450 | 26 | 140 HB | 9.5 % IACS |
Hot rolled | Choose for thicker gauges (≥2 mm) such as frame rails, brackets and suspension parts where surface finish is not critical. | 380 | 465 | 25 | 145 HB | 9.5 % IACS |
What is 340X-CR?
340X-CR is 340X supplied in the CR condition — standard stock condition for stamped body structural panels that are painted or later coated. 340X-CR has a yield strength of 370 MPa (53.7 ksi) and a tensile strength of 450 MPa (65.3 ksi) — weaker than 70% of steel grades. Elongation at break is 26% and the elastic modulus is 207 GPa (30 Msi). 340X-CR has a density of 7.85 g/cm³ (0.284 lb/in³), heavier than 56% of steel grades. It melts at 1,500°C (2,732 °F).
Advantages
- Readily welded — 89/100, better than 89% of steel grades
- Forms and bends easily — 74/100, better than 89% of steel grades
- Ductile — tolerates forming and impact — 26%, better than 82% of steel grades
- Conducts heat well — 48 W/m·K (27.7 BTU/hr·ft·°F), better than 79% of steel grades
- High electrical conductivity — 9.5 % IACS, better than 75% of steel grades
340X-CR properties
Typical room-temperature values for 340X-CR; 22 are specific to this condition. Other listed values are 340X reference data and may not represent this condition. Bars are the position among steel grades.
Physical3
340X-CR has a density of 7.85 g/cm³ (0.284 lb/in³), heavier than 56% of steel grades. It melts at 1,500°C (2,732 °F).
Mechanical16
340X-CR has a yield strength of 370 MPa (53.7 ksi) and a tensile strength of 450 MPa (65.3 ksi) — weaker than 70% of steel grades. Elongation at break is 26% and the elastic modulus is 207 GPa (30 Msi).
Thermal6
340X-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 12 µm/m·K (6.67 µin/in·°F).
Electrical3
340X-CR conducts electricity at 9.5 % IACS, better than 75% of steel grades.
Chemical & Environmental3
Corrosion resistance is not recommended (12/100), worse than 53% of steel grades.
Sustainability4
Producing a kilogram of 340X-CR takes about 25 MJ of energy and emits 2.1 kg of CO₂ — less than 82% of steel grades. Typical recycled content is 25%.
Manufacturability7
340X-CR's machinability is good (55/100, better than 62% of steel grades); weldability excellent (89/100); formability very good (74/100).
Common Calculations5
Values are nominal handbook figures for design screening. Confirm any required mill or lot documentation when quoting.
Working with 340X-CR
Is 340X easy to machine?
Machines like a medium-carbon-equivalent low-alloy sheet — good chip control but higher tool wear than mild steel; use carbide punches with adequate clearance for blanking and piercing.
Can 340X be welded?
Excellent resistance spot, MIG and laser weldability thanks to low C, S and P; zinc-coated variants need higher weld current and electrode-life management.
Can 340X be formed, bent or molded?
Cold stamps well but springback and edge-crack sensitivity are higher than DDQ steel — allow larger bend radii, control blank-edge quality and compensate die geometry.
What surface finishes work on 340X?
No anodizing; use zinc coating (GI/GA/EG), zinc-phosphate plus cathodic e-coat, or powder/paint; bare material must not be left uncoated in service.
340X 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 |
|---|---|---|
| Clow carbon for spot weldability | ≤ 0.13 | 0.07 |
| Mn | ≤ 1.6 | 0.9 |
| Si | ≤ 0.5 | 0.15 |
| P | ≤ 0.03 | 0.02 |
| Slow S for formability/hole expansion | ≤ 0.02 | 0.01 |
| Alkilled/deoxidized | 0.02 – 0.1 | 0.04 |
| Nbmicroalloy, grain refinement | ≤ 0.1 | 0.03 |
| Timicroalloy; Nb+Ti+V total typically ≤ 0.22 | ≤ 0.15 | 0.02 |
| Vmicroalloy | ≤ 0.1 | 0.01 |
| N | ≤ 0.01 | 0.01 |
| Fe | balance | — |
340X-CR — frequently asked
What is 340X-CR used for?
340X-CR is typically used for auto body reinforcements, seat frames and structural brackets. In short: formable 340 MPa HSLA sheet; spot-weldable body steel; available zinc-coated.
What is the yield strength of 340X-CR?
340X-CR has a typical yield strength of 370 MPa (53.7 ksi) and a tensile strength of 450 MPa (65.3 ksi) — weaker than 70% of steel grades. Strength varies by condition: see the 2 listed tempers.
Is 340X-CR easy to machine?
Reasonably — machinability is rated good (55/100, better than 62% of steel grades). Machines like a medium-carbon-equivalent low-alloy sheet — good chip control but higher tool wear than mild steel; use carbide punches with adequate clearance for blanking and piercing.
Can 340X-CR be welded?
Yes — weldability is rated excellent (89/100). Excellent resistance spot, MIG and laser weldability thanks to low C, S and P; zinc-coated variants need higher weld current and electrode-life management.
What surface finishes work on 340X-CR?
No anodizing; use zinc coating (GI/GA/EG), zinc-phosphate plus cathodic e-coat, or powder/paint; bare material must not be left uncoated in service.
Can 340X-CR be formed, bent or molded?
Cold stamps well but springback and edge-crack sensitivity are higher than DDQ steel — allow larger bend radii, control blank-edge quality and compensate die geometry.
What is the maximum service temperature of 340X-CR?
340X-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 340X-CR and 340X-HR?
CR is the default condition — standard stock condition for stamped body structural panels that are painted or later coated. HR: choose for thicker gauges (≥2 mm) such as frame rails, brackets and suspension parts where surface finish is not critical. Yield strength is 370 MPa in CR versus 380 MPa in HR.
Sources
- SAE J2340 — Categorization and Properties of Dent Resistant, High Strength, and Ultra High Strength Automotive Sheet Steel — SAE International (2022)
- ASM Handbook Vol.1 — Properties and Selection: Irons, Steels, and High-Performance Alloys (HSLA sheet steels) — ASM International (1990)
- ASM Handbook Vol.19 — Fatigue and Fracture — ASM International (1996)
- GB/T 20564 / HC340LA cold-rolled HSLA sheet (comparable grade) — SAC (China) (2017)
- WorldAutoSteel / worldsteel LCI data for automotive flat-rolled steel — worldsteel (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.