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Stainless Steel HH-ST vs HH TYPE-II

Stainless Steel · HH temper comparison

HH-ST and HH TYPE-II are two conditions of the same stainless steel grade, HH: ST (solution annealed) versus TYPE-II. The chemistry is identical, so every difference below comes from the condition. HH TYPE-II is the stronger of the two: yield strength 275 MPa (39.9 ksi) against 260 MPa (37.7 ksi) for HH-ST, about 6% more. In exchange, HH-ST is the more ductile: elongation 25% versus 18% for HH TYPE-II, and HH TYPE-II is harder (178 HB vs 165 HB). On the shop floor, HH-ST welds better (50 vs 40 out of 100).

HH-STChoose it when the part is bent, formed or impact-loaded, or when it will be welded.

HH TYPE-IIChoose it when strength drives the design.

HH-ST vs HH TYPE-II: properties

HH-STHH TYPE-II

Mechanical

Strength, stiffness, ductility and hardness at room temperature.

Tensile Strength (Ultimate)

540 MPa78.3 ksi
550 MPa79.8 ksi

Yield Strength (0.2% offset)

260 MPa37.7 ksi
275 MPa39.9 ksi

Elongation at Break

25%
18%

Reduction in Area

30%
27%

Shear Strength

350 MPa50.8 ksi
360 MPa52.2 ksi

Fatigue Strength (Endurance Limit)

220 MPa31.9 ksi
230 MPa33.4 ksi

Charpy V-Notch Impact (RT)

55 J40.6 ft·lbf
45 J33.2 ft·lbf

Hardness, Brinell

165 HB
178 HB

Hardness, Rockwell B

85 HRB
87 HRB

Hardness, Vickers

173 HV
187 HV

Same in both: Elastic (Young's) Modulus 190 GPa27.6 Msi · Shear Modulus 73 GPa10.6 Msi · Bulk Modulus 150 GPa21.8 Msi · Poisson's Ratio 0.29 · Fracture Toughness (K_IC) 90 MPa·√m81.9 ksi·√in

Physical

Density and transition temperatures.

Same in both: Density 7.72 g/cm³0.28 lb/in³ · Melting Point (Solidus) 1,400°C2,552 °F · Liquidus Temperature 1,425°C2,597 °F

Thermal

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

Thermal Conductivity

14 W/m·K8.1 BTU/hr·ft·°F
13.5 W/m·K7.8 BTU/hr·ft·°F

Max Service Temperature (continuous)

1,090°C1,994 °F
1,120°C2,048 °F

Same in both: Specific Heat Capacity 500 J/kg·K0.12 BTU/lb·°F · Thermal Expansion (CTE, 20–100 °C) 15 µm/m·K8.3 µin/in·°F · Latent Heat of Fusion 270 J/g116 BTU/lb · Min Service Temperature -45°C-49 °F

Electrical

Conductivity and insulation.

Electrical Conductivity

2 % IACS
1.9 % IACS

Electrical Resistivity

8.7×10⁻⁷ Ω·m34.3 µΩ·in
8.9×10⁻⁷ Ω·m35 µΩ·in

Chemical & Environmental

Corrosion and environmental resistance (0–100 scores).

Corrosion Resistance

66 / 100
65 / 100

Same in both: Galvanic Potential (seawater, vs SCE) -0.1 V

Manufacturability

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

Machinability

35 / 100
32 / 100

Machinability Rating (AISI 1212 = 100 %)

40%
37%

Weldability

50 / 100
40 / 100

Formability (cold)

12 / 100
10 / 100

Same in both: Castability 75 / 100 · Brazeability / Solderability 35 / 100 · Polishability 55 / 100

Sustainability

Primary-production footprint per kilogram.

Same in both: Embodied Energy (primary production) 48 MJ/kg20,636 BTU/lb · Embodied Carbon (primary production) 4 kg CO₂/kg · Embodied Water 200 L/kg24 gal/lb · Typical Recycled Content 75%

Strength versus weight

Yield strength against density for every stainless steel grade in the FabDigit library; the compared grades are highlighted. Up and left is stronger for its weight.

3005007001,0001,5002,0007.27.47.67.888.2Density (g/cm³)Yield strength (MPa) — log scaleHH

HH-ST vs HH TYPE-II — frequently asked

Is HH TYPE-II stronger than HH-ST?

Yes. HH TYPE-II has a typical yield strength of 275 MPa (39.9 ksi) against 260 MPa (37.7 ksi) for HH-ST — about 6% more. Tensile strength is 550 MPa (79.8 ksi) vs 540 MPa (78.3 ksi).

Which condition does FabDigit quote by default, ST or TYPE-II?

F is the default HH condition in the FabDigit quote flow (neither ST nor TYPE-II). 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 welds better, HH-ST or HH TYPE-II?

HH-ST. Its weldability rates fair (50/100) against fair (40/100) for HH TYPE-II.

Ready to make it?

Upload a CAD file and FabDigit prices the part in HH-ST and HH TYPE-II 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.