Steel Low Carbon Steel
Low carbon (mild) steel is plain-carbon steel with roughly 0.05–0.25 % C, sold as hot-rolled, cold-rolled or cold-drawn structural and general-engineering stock (Q235/Q195, A36, AISI 1018/1020 class).
Values for the HR condition
Low Carbon Steel tempers and conditions
Low Carbon Steel is supplied in 6 conditions, soft to hard. HR is the default FabDigit quotes; the values on this page are for it.
Compare all 6 conditionsHide
| Condition · open for datasheet | Best for | Yield MPa | Tensile MPa | Elong. % | Hardness | Conductivity |
|---|---|---|---|---|---|---|
full/subcritical anneal, softest condition | Choose when maximum ductility and minimum hardness are needed for severe cold forming, deep drawing or before carburising. | 215 | 350 | 34 | 105 HB | — |
HRDefault Hot rolled | Cheapest general-purpose structural stock: plate, angle, channel, merchant bar where surface finish and close tolerance are not needed. | 250 | 400 | 25 | 120 HB | — |
austenitised ~870–900 °C, air cooled | Pick for uniform fine-grain structure and improved toughness/consistency in welded, forged or thick-section parts. | 265 | 420 | 30 | 126 HB | — |
Cold rolled | Pick for sheet-metal parts needing a clean bright surface, tight thickness tolerance and good deep-drawing behaviour. | 340 | 440 | 18 | 135 HB | — |
case hardened, tempered low | Use where a wear-resistant hard skin over a tough soft core is needed — gears, pins, bushings, cam followers. | 350 | 550 | 12 | 60 HRC | — |
Cold drawn | Use for shafts, pins and machined parts: higher strength, straight bright bar, close diameter tolerance and better chip control than hot rolled. | 380 | 460 | 15 | 143 HB | — |
Supply forms, finishes and certifications
Ways Low Carbon Steel is supplied — form, process route, surface or paperwork — without a datasheet of their own. The property values above apply.
| Option | What it is | Type |
|---|---|---|
HDG | Hot-dip galvanized | Coating |
What is Low Carbon Steel?
Low carbon (mild) steel is plain-carbon steel with roughly 0.05–0.25 % C, sold as hot-rolled, cold-rolled or cold-drawn structural and general-engineering stock (Q235/Q195, A36, AISI 1018/1020 class). It is chosen for the lowest cost per unit strength, excellent weldability and cold formability, and easy machining and case hardening. Limits are modest strength (no through-hardening response), poor corrosion resistance without coating, loss of strength above ~400 °C and a ductile-to-brittle transition that restricts use at low temperature. Low Carbon Steel has a density of 7.87 g/cm³ (0.284 lb/in³), heavier than 92% of steel grades. It melts at 1,495°C (2,723 °F). Low Carbon Steel has a yield strength of 250 MPa (36.3 ksi) and a tensile strength of 400 MPa (58 ksi) — weaker than 94% of steel grades. Elongation at break is 25% and the elastic modulus is 205 GPa (29.7 Msi).
What is Low Carbon Steel used for?
- Stamped enclosures and brackets
- Welded frames and weldments
- Structural plate, angle and channel
- Machine bases and skids
- General fabrication parts
- Carburized bushings and pins
- Hot-dip galvanized outdoor supports
Advantages
- Readily welded — 95/100, better than 97% of steel grades
- Conducts heat well — 51.9 W/m·K (30 BTU/hr·ft·°F), better than 96% of steel grades
- High electrical conductivity — 10.8 % IACS, better than 94% of steel grades
- Forms and bends easily — 80/100, better than 93% of steel grades
- Easy to machine — 62/100, better than 89% of steel grades
Limitations
- Low strength — 250 MPa (36.3 ksi), worse than 94% of steel grades
- Hard to polish — 45/100, worse than 84% of steel grades
Low Carbon Steel properties
Typical room-temperature values for Low Carbon Steel-HR; bars are the position among steel grades.
Physical3
Low Carbon Steel has a density of 7.87 g/cm³ (0.284 lb/in³), heavier than 92% of steel grades. It melts at 1,495°C (2,723 °F).
Mechanical16
Low Carbon Steel has a yield strength of 250 MPa (36.3 ksi) and a tensile strength of 400 MPa (58 ksi) — weaker than 94% of steel grades. Elongation at break is 25% and the elastic modulus is 205 GPa (29.7 Msi).
Thermal6
Low Carbon Steel is rated for continuous service to 400°C (752 °F). It conducts heat at 51.9 W/m·K (30 BTU/hr·ft·°F), better than 96% of steel grades. Thermal expansion is 12 µm/m·K (6.67 µin/in·°F).
Electrical3
Low Carbon Steel conducts electricity at 10.8 % IACS, better than 94% of steel grades.
Chemical & Environmental3
Corrosion resistance is not recommended (10/100), worse than 86% of steel grades.
Sustainability4
Producing a kilogram of Low Carbon Steel takes about 25 MJ of energy and emits 2.1 kg of CO₂ — less than 82% of steel grades. Typical recycled content is 30%.
Manufacturability8
Low Carbon Steel's machinability is good (62/100, better than 89% of steel grades); weldability excellent (95/100); formability very good (80/100).
Common Calculations5
Values are nominal handbook figures for design screening. Certified mill or lot data ships with every FabDigit order on request.
Strength versus weight in the steel family
Yield strength against density for every steel grade FabDigit runs. Low Carbon Steel is highlighted; hover a dot for its name, or open the interactive family chart.
Working with Low Carbon Steel
Is Low Carbon Steel easy to machine?
Machines easily but gummy in the annealed/hot-rolled state — use cold-drawn bar, positive rake, sharp tooling and generous coolant for good finish; free-machining 1215/12L14 is the alternative if chip control dominates.
Can Low Carbon Steel be welded?
Essentially unrestricted weldability by SMAW/GMAW/GTAW/RSW with E70/ER70S consumables; no preheat needed below ~25 mm, keep hydrogen low and grind galvanizing off the joint area.
Can Low Carbon Steel be formed, bent or molded?
Excellent cold formability — deep drawing, roll forming, bending to tight radii (≈1t on CR sheet); allow for springback and for the yield-point elongation/stretcher strains in non-skin-passed sheet.
Manufacturability
The process limits FabDigit's quote engine applies to Low Carbon Steel. Design inside these and the part quotes instantly; outside them it routes to an engineer.
CNC machining
| Machinability | Better62 / 100 |
|---|---|
| ISO material group | P.2 |
| Cutting speed (rough / finish) | 180 / 210 m/min |
| Minimum wall | 0.8 mm |
| Minimum internal radius | 1 mm |
| Drill depth limit | 5× diameter |
| Best surface (machined / polished) | Ra 1.6 / — |
| Hardenable after machining | No |
Sheet metal
| Formability | Excellent80 / 100 |
|---|---|
| Weldability | Excellent95 / 100 |
| Bendable | Yes |
Low Carbon Steel 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 |
|---|---|---|
| Cdefining range for the low-carbon class | 0.05 – 0.25 | 0.18 |
| Mn | 0.25 – 0.9 | 0.55 |
| Sikilled steels only; rimmed grades ≤0.10 | ≤ 0.35 | 0.2 |
| Pimpurity limit | ≤ 0.05 | 0.02 |
| Simpurity limit | ≤ 0.05 | 0.03 |
| Fe | balance |
What surface finishes work on Low Carbon Steel?
Not anodizable; protect with zinc plating, hot-dip galvanizing, phosphate + paint, powder coat, black oxide or oil — bare surfaces flash-rust within hours in humid air.
Surface treatments FabDigit runs on steel parts — pick them in the quote configurator or call them out on the drawing. Each links to its datasheet in the surface-finish library (thickness, specs, call-out, material verdicts).
Plating
CVD Coating
Black / Phosphate
Thermal Spray
Equivalent designations
Standards and trade names that resolve to Steel Low Carbon Steel in FabDigit's catalog. Equivalence is nominal — check the exact specification when certification matters.
- Also called
- low-carbon steelMild Steel
How much does Low Carbon Steel cost?
Low Carbon Steel is a budget-cost steel ($), cheaper than about 100% of the materials FabDigit quotes. Part price depends far more on geometry, tolerance and quantity than on the raw stock — upload a CAD file for a live quote.
Low Carbon Steel — frequently asked
What is Low Carbon Steel used for?
Low Carbon Steel is typically used for stamped enclosures and brackets, welded frames and weldments, structural plate, angle and channel, machine bases and skids, general fabrication parts and carburized bushings and pins. In short: workhorse low-carbon plate.
What is the yield strength of Low Carbon Steel?
Low Carbon Steel has a typical yield strength of 250 MPa (36.3 ksi) and a tensile strength of 400 MPa (58 ksi) — weaker than 94% of steel grades. Strength varies by condition: see the 6 listed tempers.
Is Low Carbon Steel easy to machine?
Reasonably — machinability is rated good (62/100, better than 89% of steel grades). Machines easily but gummy in the annealed/hot-rolled state — use cold-drawn bar, positive rake, sharp tooling and generous coolant for good finish; free-machining 1215/12L14 is the alternative if chip control dominates.
Can Low Carbon Steel be welded?
Yes — weldability is rated excellent (95/100). Essentially unrestricted weldability by SMAW/GMAW/GTAW/RSW with E70/ER70S consumables; no preheat needed below ~25 mm, keep hydrogen low and grind galvanizing off the joint area.
What surface finishes work on Low Carbon Steel?
Not anodizable; protect with zinc plating, hot-dip galvanizing, phosphate + paint, powder coat, black oxide or oil — bare surfaces flash-rust within hours in humid air.
Can Low Carbon Steel be formed, bent or molded?
Excellent cold formability — deep drawing, roll forming, bending to tight radii (≈1t on CR sheet); allow for springback and for the yield-point elongation/stretcher strains in non-skin-passed sheet.
What is the maximum service temperature of Low Carbon Steel?
Low Carbon Steel 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 Low Carbon Steel-HR and Low Carbon Steel-CD?
HR is the default condition — cheapest general-purpose structural stock: plate, angle, channel, merchant bar where surface finish and close tolerance are not needed. CD: use for shafts, pins and machined parts: higher strength, straight bright bar, close diameter tolerance and better chip control than hot rolled. Yield strength is 250 MPa in HR versus 380 MPa in CD.
How much does Low Carbon Steel cost?
Low Carbon Steel is a budget-cost steel ($), cheaper than about 100% of the materials FabDigit quotes. Part price depends far more on geometry, tolerance and quantity than on the raw stock — upload a CAD file for a live quote.
Can FabDigit make parts in Low Carbon Steel?
Yes — Low Carbon Steel 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
- ASTM A36/A36M Standard Specification for Carbon Structural Steel — ASTM (2019)
- ASTM A1011/A1018 (hot-rolled sheet) and A1008 (cold-rolled sheet) — ASTM (2018)
- GB/T 700 (Q195/Q215/Q235) — SAC (2006)
- SAE J403 / ASTM A29 chemical compositions of carbon steels (1018, 1020) — SAE / ASTM (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)
- Machinery's Handbook, machinability ratings — Industrial Press (2020)
- worldsteel Life Cycle Inventory of steel products — World Steel Association (2023)
Property data is compiled from published supplier and standards handbooks and normalised for comparison; hardness values on non-Brinell scales are converted approximately for charting only. Manufacturability limits are FabDigit quote-engine defaults and may be relaxed by engineering review. Nothing on this page is a certification — request mill certs, CoC or material test reports with your order.