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Steel 18Kh2N4MA-QT200 vs 18Kh2N4MA-QT500

Steel · 18Kh2N4MA temper comparison

18Kh2N4MA-QT200 and 18Kh2N4MA-QT500 are two conditions of the same steel grade, 18Kh2N4MA: QT200 versus QT500 (Q&T 500–560). The chemistry is identical, so every difference below comes from the condition. 18Kh2N4MA-QT200 is the stronger of the two: yield strength 980 MPa (142 ksi) against 880 MPa (128 ksi) for 18Kh2N4MA-QT500, about 11% more; tensile strength follows at 1,250 MPa (181 ksi) vs 1,030 MPa (149 ksi). In exchange, 18Kh2N4MA-QT500 is the more ductile: elongation 16% versus 13% for 18Kh2N4MA-QT200, and 18Kh2N4MA-QT200 is harder (363 HB vs 310 HB). 18Kh2N4MA-QT500 runs hotter in service (400°C vs 200°C continuous).

18Kh2N4MA-QT200Choose it when strength drives the design.

18Kh2N4MA-QT500Choose it when the part is bent, formed or impact-loaded, or when the part sees heat.

18Kh2N4MA-QT200 vs 18Kh2N4MA-QT500: properties

18Kh2N4MA-QT20018Kh2N4MA-QT500

Mechanical

Strength, stiffness, ductility and hardness at room temperature.

Tensile Strength (Ultimate)

1,250 MPa181 ksi
1,030 MPa149 ksi

Yield Strength (0.2% offset)

980 MPa142 ksi
880 MPa128 ksi

Elongation at Break

13%
16%

Reduction in Area

55%
62%

Fatigue Strength (Endurance Limit)

560 MPa81.2 ksi
480 MPa69.6 ksi

Fracture Toughness (K_IC)

80 MPa·√m72.8 ksi·√in
105 MPa·√m95.6 ksi·√in

Charpy V-Notch Impact (RT)

95 J70.1 ft·lbf
130 J95.9 ft·lbf

Hardness, Brinell

363 HB
310 HB

Hardness, Rockwell C

39 HRC
32 HRC

Same in both: Elastic (Young's) Modulus 210 GPa30.5 Msi · Shear Modulus 80 GPa11.6 Msi · Bulk Modulus 163 GPa23.6 Msi · Poisson's Ratio 0.29 · Compressive Strength 1,000 MPa145 ksi · Shear Strength 750 MPa109 ksi

Physical

Density and transition temperatures.

Same in both: Density 7.85 g/cm³0.28 lb/in³ · Melting Point (Solidus) 1,420°C2,588 °F · Liquidus Temperature 1,490°C2,714 °F

Thermal

How each material carries heat and how hot it can run.

Max Service Temperature (continuous)

200°C392 °F
400°C752 °F

Same in both: Thermal Conductivity 33 W/m·K19.1 BTU/hr·ft·°F · Specific Heat Capacity 470 J/kg·K0.11 BTU/lb·°F · Thermal Expansion (CTE, 20–100 °C) 11.5 µm/m·K6.4 µin/in·°F · Latent Heat of Fusion 270 J/g116 BTU/lb · Min Service Temperature -70°C-94 °F

Electrical

Conductivity and insulation.

Same in both: Electrical Resistivity 3.5×10⁻⁷ Ω·m13.8 µΩ·in

Chemical & Environmental

Corrosion and environmental resistance (0–100 scores).

Same in both: Galvanic Potential (seawater, vs SCE) -0.6 V · Corrosion Resistance 14 / 100

Manufacturability

FabDigit workshop ratings (0–100 scores) — how each material behaves on the machine.

Machinability

22 / 100
28 / 100

Machinability Rating (AISI 1212 = 100 %)

20%
27%

Same in both: Weldability 22 / 100 · Formability (cold) 18 / 100 · Brazeability / Solderability 45 / 100 · Polishability 70 / 100

Sustainability

Primary-production footprint per kilogram.

Same in both: Embodied Energy (primary production) 36 MJ/kg15,477 BTU/lb · Embodied Carbon (primary production) 2.7 kg CO₂/kg · Embodied Water 70 L/kg8.4 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.

2005001,0002,0007.588.5Density (g/cm³)Yield strength (MPa) — log scale18Kh2N4MA

18Kh2N4MA-QT200 vs 18Kh2N4MA-QT500 — frequently asked

Is 18Kh2N4MA-QT200 stronger than 18Kh2N4MA-QT500?

Yes. 18Kh2N4MA-QT200 has a typical yield strength of 980 MPa (142 ksi) against 880 MPa (128 ksi) for 18Kh2N4MA-QT500 — about 11% more. Tensile strength is 1,250 MPa (181 ksi) vs 1,030 MPa (149 ksi).

Which condition does FabDigit quote by default, QT200 or QT500?

QT200 is the default 18Kh2N4MA 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, 18Kh2N4MA-QT200 or 18Kh2N4MA-QT500?

18Kh2N4MA-QT500, by a small margin. Both rate poor for machinability — 28/100 against 22/100 for 18Kh2N4MA-QT200.

Ready to make it?

Upload a CAD file and FabDigit prices the part in 18Kh2N4MA-QT200 and 18Kh2N4MA-QT500 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.