Steel 20Kh-A vs 20Kh-CH
Steel · 20Kh temper comparison
20Kh-A and 20Kh-CH are two conditions of the same steel grade, 20Kh: A (solution annealed) versus CH (carburized and hardened). The chemistry is identical, so every difference below comes from the condition. 20Kh-CH is the stronger of the two: yield strength 700 MPa (102 ksi) against 300 MPa (43.5 ksi) for 20Kh-A, about 133% more; tensile strength follows at 900 MPa (131 ksi) vs 490 MPa (71.1 ksi). In exchange, 20Kh-A is the more ductile: elongation 26% versus 10% for 20Kh-CH, and 20Kh-CH is harder (600 HB vs 156 HB). 20Kh-A runs hotter in service (400°C vs 180°C continuous). On the shop floor, 20Kh-A machines more easily (good vs not recommended) and 20Kh-A welds better (good vs poor).
20Kh-AChoose it when the part is bent, formed or impact-loaded, or when the part sees heat.
20Kh-CHChoose it when strength drives the design.
20Kh-A vs 20Kh-CH: propertiesHow to read these bars
- One bar per material. A full bar is the highest value among all steel grades in the FabDigit library; each bar is drawn as a share of that.
- The better value (by the usual engineering direction) is in bold. Rows with no direction — density, thermal conductivity — have no bold.
- Values are typical room-temperature figures for the condition named on each card.
- Confirm against the certified mill or resin datasheet before design release.
How to read these bars
- One bar per material. A full bar is the highest value among all steel grades in the FabDigit library; each bar is drawn as a share of that.
- The better value (by the usual engineering direction) is in bold. Rows with no direction — density, thermal conductivity — have no bold.
- Values are typical room-temperature figures for the condition named on each card.
- Confirm against the certified mill or resin datasheet before design release.
Mechanical
Strength, stiffness, ductility and hardness at room temperature.
Tensile Strength (Ultimate)
Yield Strength (0.2% offset)
Elongation at Break
Reduction in Area
Fatigue Strength (Endurance Limit)
Fracture Toughness (K_IC)
Charpy V-Notch Impact (RT)
Hardness, Brinell
Same in both: Elastic (Young's) Modulus 211 GPa30.6 Msi · Shear Modulus 82 GPa11.9 Msi · Bulk Modulus 160 GPa23.2 Msi · Poisson's Ratio 0.29 · Compressive Strength 300 MPa43.5 ksi · Shear Strength 320 MPa46.4 ksi · Hardness, Rockwell B 82 HRB
Physical
Density and transition temperatures.
Same in both: Density 7.82 g/cm³0.28 lb/in³ · Melting Point (Solidus) 1,460°C2,660 °F · Liquidus Temperature 1,510°C2,750 °F
Thermal
How each material carries heat and how hot it can run.
Max Service Temperature (continuous)
Same in both: Thermal Conductivity 43 W/m·K24.8 BTU/hr·ft·°F · Specific Heat Capacity 466 J/kg·K0.11 BTU/lb·°F · Thermal Expansion (CTE, 20–100 °C) 11.6 µm/m·K6.4 µin/in·°F · Latent Heat of Fusion 270 J/g116 BTU/lb · Min Service Temperature -40°C-40 °F
Electrical
Conductivity and insulation.
Same in both: Electrical Conductivity 8.2 % IACS · Electrical Resistivity 2.1×10⁻⁷ Ω·m8.27 µΩ·in
Chemical & Environmental
Corrosion and environmental resistance (0–100 scores).
Same in both: Galvanic Potential (seawater, vs SCE) -0.6 V · Corrosion Resistance 11 / 100
Manufacturability
FabDigit workshop ratings (0–100 scores) — how each material behaves on the machine.
Machinability
Machinability Rating (AISI 1212 = 100 %)
Weldability
Polishability
Same in both: Formability (cold) 65 / 100 · Castability 30 / 100 · Brazeability / Solderability 65 / 100
Sustainability
Primary-production footprint per kilogram.
Same in both: Embodied Energy (primary production) 25 MJ/kg10,748 BTU/lb · Embodied Carbon (primary production) 1.9 kg CO₂/kg · Embodied Water 45 L/kg5.4 gal/lb · Typical Recycled Content 25%
Strength versus weight
Yield strength against density for every steel grade in the FabDigit library; the compared grades are highlighted. Up and left is stronger for its weight.
20Kh-A vs 20Kh-CH — frequently asked
Is 20Kh-CH stronger than 20Kh-A?
Yes. 20Kh-CH has a typical yield strength of 700 MPa (102 ksi) against 300 MPa (43.5 ksi) for 20Kh-A — about 133% more. Tensile strength is 900 MPa (131 ksi) vs 490 MPa (71.1 ksi).
Which condition does FabDigit quote by default, A or CH?
A is the default 20Kh condition in the FabDigit quote flow. The other condition is available on request or by drawing note — specify it in the material field or the part notes and the quote is priced for it.
Which is easier to machine, 20Kh-A or 20Kh-CH?
20Kh-A. Its machinability rates good (60/100) against not recommended (12/100) for 20Kh-CH; for welding the order is 20Kh-A first (good, 62/100) then 20Kh-CH (poor, 15/100).
Ready to make it?
Upload a CAD file and FabDigit prices the part in 20Kh-A and 20Kh-CH side by side — material, machining time, tolerance and finish in one quote. Certified material data ships with the order on request.
Typical handbook values for the conditions named above, normalised for comparison. Hardness on non-Brinell scales is converted approximately for charting only. Request certified data with your order for design-critical properties.