Stainless Steel HH Aged vs HH-ST
Stainless Steel · HH temper comparison
HH Aged and HH-ST are two conditions of the same stainless steel grade, HH: Aged (aged / service-exposed) versus ST (solution annealed). The chemistry is identical, so every difference below comes from the condition. HH Aged is the stronger of the two: yield strength 380 MPa (55.1 ksi) against 260 MPa (37.7 ksi) for HH-ST, about 46% more; tensile strength follows at 620 MPa (89.9 ksi) vs 540 MPa (78.3 ksi). In exchange, HH-ST is the more ductile: elongation 25% versus 5% for HH Aged, and HH Aged is harder (215 HB vs 165 HB). On the shop floor, HH-ST machines more easily (fair vs poor) and HH-ST welds better (fair vs poor).
HH AgedChoose it when strength drives the design.
HH-STChoose it when the part is bent, formed or impact-loaded, or when the part is machined in volume.
HH Aged vs HH-ST: propertiesHow to read these bars
- One bar per material. A full bar is the highest value among all stainless 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 stainless 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.
Elastic (Young's) Modulus
Tensile Strength (Ultimate)
Yield Strength (0.2% offset)
Elongation at Break
Reduction in Area
Shear Strength
Fatigue Strength (Endurance Limit)
Fracture Toughness (K_IC)
Charpy V-Notch Impact (RT)
Hardness, Brinell
Hardness, Rockwell B
Hardness, Vickers
Same in both: Shear Modulus 73 GPa10.6 Msi · Bulk Modulus 150 GPa21.8 Msi · Poisson's Ratio 0.29
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
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 · Max Service Temperature (continuous) 1,090°C1,994 °F · Min Service Temperature -45°C-49 °F
Electrical
Conductivity and insulation.
Electrical Conductivity
Electrical Resistivity
Chemical & Environmental
Corrosion and environmental resistance (0–100 scores).
Corrosion Resistance
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
Machinability Rating (AISI 1212 = 100 %)
Weldability
Formability (cold)
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.
HH Aged vs HH-ST — frequently asked
Is HH Aged stronger than HH-ST?
Yes. HH Aged has a typical yield strength of 380 MPa (55.1 ksi) against 260 MPa (37.7 ksi) for HH-ST — about 46% more. Tensile strength is 620 MPa (89.9 ksi) vs 540 MPa (78.3 ksi).
Which condition does FabDigit quote by default, Aged or ST?
F is the default HH condition in the FabDigit quote flow (neither Aged nor ST). 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, HH Aged or HH-ST?
HH-ST. Its machinability rates fair (35/100) against poor (22/100) for HH Aged; for welding the order is HH-ST first (fair, 50/100) then HH Aged (poor, 25/100).
Ready to make it?
Upload a CAD file and FabDigit prices the part in HH Aged and HH-ST 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.