FabDigit

Steel Mild Steel · finish state

Steel Mild Steel-HDG

Properties of the HDG condition, compared with the other Mild Steel tempers.

Choose for outdoor or damp service where painting is impractical; zinc coating gives sacrificial protection for decades.

CNC machiningSheet metalStandard cost $$
Request a quote in Mild Steel-HDGMild Steel overview

What is Mild Steel-HDG?

Mild Steel-HDG is Mild Steel supplied in the HDG condition — choose for outdoor or damp service where painting is impractical; zinc coating gives sacrificial protection for decades. Mild Steel-HDG has a yield strength of 250 MPa (36.3 ksi) and a tensile strength of 360 MPa (52.2 ksi) — weaker than 94% of steel grades. Elongation at break is 28% and the elastic modulus is 200 GPa (29 Msi). Mild Steel-HDG has a density of 7.85 g/cm³ (0.284 lb/in³), heavier than 56% of steel grades. It melts at 1,495°C (2,723 °F). HR is the default condition FabDigit quotes; HDG is available on request or by drawing note.

Advantages

  • Good corrosion resistance — 45/100, better than 98% of steel grades
  • High electrical conductivity — 10.8 % IACS, better than 94% of steel grades
  • Conducts heat well — 51 W/m·K (29.5 BTU/hr·ft·°F), better than 92% of steel grades
  • Forms and bends easily — 80/100, better than 92% of steel grades
  • Ductile — tolerates forming and impact — 28%, better than 88% of steel grades

Limitations

  • Low strength — 250 MPa (36.3 ksi), worse than 94% of steel grades
  • Limited service temperature — 200°C (392 °F), worse than 93% of steel grades

Mild Steel-HDG properties

Typical room-temperature values for Mild Steel-HDG — 8 properties are specific to this condition; the rest are grade-level values shared by every Mild Steel temper. Each bar shows where the value sits among the steel grades in FabDigit's library — further right is higher.

Physical3

Mild Steel-HDG has a density of 7.85 g/cm³ (0.284 lb/in³), heavier than 56% of steel grades. It melts at 1,495°C (2,723 °F).

Density7.85 g/cm³0.28 lb/in³
Melting Point (Solidus)1,495°C2,723 °F
Liquidus Temperature1,520°C2,768 °F

Mechanical16

Mild Steel-HDG has a yield strength of 250 MPa (36.3 ksi) and a tensile strength of 360 MPa (52.2 ksi) — weaker than 94% of steel grades. Elongation at break is 28% and the elastic modulus is 200 GPa (29 Msi).

Elastic (Young's) Modulus200 GPa29 Msi
Shear Modulus79 GPa11.5 Msi
Bulk Modulus160 GPa23.2 Msi
Poisson's Ratio0.29
Tensile Strength (Ultimate)360 MPa52.2 ksi
Yield Strength (0.2% offset)250 MPa36.3 ksi
Elongation at Break28%
Reduction in Area45%
Compressive Strength250 MPa36.3 ksi
Shear Strength250 MPa36.3 ksi
Fatigue Strength (Endurance Limit)200 MPa29 ksi
Fracture Toughness (K_IC)110 MPa·√m100 ksi·√in
Charpy V-Notch Impact (RT)50 J36.9 ft·lbf
Hardness, Brinell120 HB
Hardness, Rockwell B67 HRB
Hardness, Vickers126 HV

Thermal6

Mild Steel-HDG is rated for continuous service to 200°C (392 °F). It conducts heat at 51 W/m·K (29.5 BTU/hr·ft·°F), better than 92% of steel grades. Thermal expansion is 12 µm/m·K (6.67 µin/in·°F).

Thermal Conductivity51 W/m·K29.5 BTU/hr·ft·°F
Specific Heat Capacity480 J/kg·K0.11 BTU/lb·°F
Thermal Expansion (CTE, 20–100 °C)12 µm/m·K6.7 µin/in·°F
Latent Heat of Fusion247 J/g106 BTU/lb
Max Service Temperature (continuous)200°C392 °F
Min Service Temperature-20°C-4 °F

Electrical3

Mild Steel-HDG conducts electricity at 10.8 % IACS, better than 94% of steel grades.

Electrical Conductivity10.8 % IACS
Electrical Resistivity1.6×10⁻⁷ Ω·m6.3 µΩ·in
Magnetic Responseferromagnetic

Chemical & Environmental3

Corrosion resistance is fair (45/100), better than 98% of steel grades.

Galvanic Potential (seawater, vs SCE)-1 V
Corrosion ResistanceFair45/100
Chemical Resistance SummaryRusts freely in humid air, water and chlorides; attacked rapidly by dilute acids; acceptable in dry environments, strong alkalis, oils and most non-oxidising solvents. Always needs paint, zinc, phosphate or oil protection.

Sustainability4

Producing a kilogram of Mild Steel-HDG takes about 25 MJ of energy and emits 2.1 kg of CO₂ — less than 82% of steel grades. Typical recycled content is 30%.

Embodied Energy (primary production)25 MJ/kg10,748 BTU/lb
Embodied Carbon (primary production)2.1 kg CO₂/kg
Embodied Water40 L/kg4.8 gal/lb
Typical Recycled Content30%

Manufacturability8

Mild Steel-HDG's machinability is good (60/100, better than 83% of steel grades); weldability good (60/100); formability very good (80/100).

MachinabilityGood60/100
Machinability Rating (AISI 1212 = 100 %)60%
WeldabilityGood60/100
Formability (cold)Very good80/100
CastabilityFair45/100
Brazeability / SolderabilityVery good80/100
PolishabilityGood55/100
Anodizing Responsen/a — ferrous alloy; use zinc plating, hot-dip galvanizing, phosphate/black oxide or paint instead

Values are nominal handbook figures for design screening. Certified mill or lot data ships with every FabDigit order on request.

Other Mild Steel tempers and conditions

Mild Steel is also supplied in 7 other conditions. The full side-by-side table is on the Mild Steel overview.

Working with Mild Steel-HDG

Is Mild Steel easy to machine?

Easy but gummy in the annealed/hot-rolled state — use positive-rake tools, moderate speeds and flood coolant; cold-drawn bar chips and finishes noticeably better.

Can Mild Steel be welded?

Excellent by SMAW/GMAW/FCAW/TIG/resistance with no preheat below ~25 mm (CE typically <0.35); use E7018/ER70S-6 filler and remove mill scale, galvanizing or oil first.

Can Mild Steel be formed, bent or molded?

Very good cold formability — bends to 1t–2t radii, deep-draws in Al-killed CR sheet; hot forge 1050–1250 °C, allow springback and grain-direction effects.

What surface finishes work on Mild Steel?

Not anodizable; protect with zinc plating, hot-dip galvanizing, phosphate + paint/powder coat, black oxide or oil, since bare surfaces flash-rust within hours in humid air.

Mild 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.

ElementSpec limit (wt %)Nominal
C≤0.26 % for A36 plate; 0.14–0.22 % for Q235/10180.05 – 0.250.18
Mn0.25 – 1.20.6
Si≤0.05 % in Al-killed CR sheet0 – 0.40.2
P≤ 0.050.02
S≤ 0.050.03
Curesidual; 0.20 % min if copper-bearing specified≤ 0.350.1
Febalance—

Mild Steel-HDG — frequently asked

What is Mild Steel-HDG used for?

Mild Steel-HDG is typically used for welded frames and weldments, machine brackets and mounting plates, sheet metal enclosures and chassis, structural beams, base plates and gussets, laser-cut and formed panels and ducting and guarding. In short: workhorse mild-steel plate.

What is the yield strength of Mild Steel-HDG?

Mild Steel-HDG has a typical yield strength of 250 MPa (36.3 ksi) and a tensile strength of 360 MPa (52.2 ksi) — weaker than 94% of steel grades. Strength varies by condition: see the 8 listed tempers.

Is Mild Steel-HDG easy to machine?

Reasonably — machinability is rated good (60/100, better than 83% of steel grades). Easy but gummy in the annealed/hot-rolled state — use positive-rake tools, moderate speeds and flood coolant; cold-drawn bar chips and finishes noticeably better.

Can Mild Steel-HDG be welded?

Yes — weldability is rated good (60/100). Excellent by SMAW/GMAW/FCAW/TIG/resistance with no preheat below ~25 mm (CE typically <0.35); use E7018/ER70S-6 filler and remove mill scale, galvanizing or oil first.

What surface finishes work on Mild Steel-HDG?

Not anodizable; protect with zinc plating, hot-dip galvanizing, phosphate + paint/powder coat, black oxide or oil, since bare surfaces flash-rust within hours in humid air.

Can Mild Steel-HDG be formed, bent or molded?

Very good cold formability — bends to 1t–2t radii, deep-draws in Al-killed CR sheet; hot forge 1050–1250 °C, allow springback and grain-direction effects.

What is the maximum service temperature of Mild Steel-HDG?

Mild Steel-HDG is rated for continuous use to about 200°C (392 °F). Strength falls off well before that limit — check the elevated-temperature data for load-bearing parts.

What is the difference between Mild Steel-HR and Mild Steel CARB?

HR is the default condition — default, cheapest form for structural plate, sections and hot-rolled bar where mill scale and loose tolerances are acceptable. CARB: pick when a mild-steel part needs a wear-resistant surface (gears, pins, bushings) while keeping a tough low-carbon core. Yield strength is 250 MPa in HR versus 380 MPa in CARB.

Can FabDigit make parts in Mild Steel-HDG?

Yes — Mild Steel-HDG 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

  1. ASTM A36/A36M — Carbon Structural Steel — ASTM International (2019)
  2. GB/T 700 — (Q195–Q275) — SAC (2006)
  3. EN 10025-2 — Non-alloy structural steels (S235JR) — CEN (2019)
  4. ASTM A1008/A1008M — Cold-Rolled Carbon Steel Sheet — ASTM International (2021)
  5. ASTM A108 / A29 — Cold-Finished and Hot-Wrought Carbon Steel Bars — ASTM International (2018)
  6. ASM Handbook Vol.1 — Properties and Selection: Irons, Steels — ASM International (1990)
  7. Machinery's Handbook, 31st ed. — Industrial Press (2020)
  8. worldsteel LCI data for steel products — 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.