POM-H HI BK vs POM-H HI ST
Polymer · POM-H HI grade comparison
POM-H HI BK and POM-H HI ST are two grades of the same polymer grade, POM-H HI: BK (carbon-black pigmented toughened grade) versus ST (solution annealed). The chemistry is identical, so every difference below comes from the condition. Both yield at about 45 MPa — the mechanical properties are the same, and the difference is in how the stock is processed and what it is certified to (carbon-black pigmented toughened grade versus solution annealed). On the shop floor, POM-H HI ST welds better (45 vs 35 out of 100) and POM-H HI ST forms better (good vs fair).
POM-H HI STChoose it when it will be welded.
POM-H HI BK vs POM-H HI ST: propertiesHow to read these bars
- One bar per material. A full bar is the highest value among all polymer 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 polymer 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.
Elongation at Break
Fracture Toughness (K_IC)
Izod Impact, Notched
Same in both: Elastic (Young's) Modulus 1.4 GPa0.2 Msi · Shear Modulus 0.5 GPa0.07 Msi · Poisson's Ratio 0.4 · Tensile Strength (Ultimate) 45 MPa6.5 ksi · Yield Strength (0.2% offset) 45 MPa6.5 ksi · Compressive Strength 45 MPa6.5 ksi · Compressive Modulus 1.4 GPa0.2 Msi · Flexural Strength 48 MPa7 ksi · Flexural Modulus 1.3 GPa0.19 Msi · Shear Strength 45 MPa6.5 ksi · Hardness, Shore D 72 Shore D · Hardness, Rockwell M 58 HRM · Hardness, Rockwell R 105 HRR
Physical
Density and transition temperatures.
Same in both: Density 1.34 g/cm³0.05 lb/in³ · Melting Temperature (Tm) 178°C352 °F · Glass Transition (Tg) -60°C-76 °F · Water Absorption (24 h) 0.25% · Water Absorption (Saturation) 0.9%
Thermal
How each material carries heat and how hot it can run.
Same in both: Thermal Conductivity 0.25 W/m·K0.14 BTU/hr·ft·°F · Specific Heat Capacity 1,500 J/kg·K0.36 BTU/lb·°F · Thermal Expansion (CTE, 20–100 °C) 125 µm/m·K69.4 µin/in·°F · Max Service Temperature (continuous) 85°C185 °F · Min Service Temperature -50°C-58 °F · Heat Deflection Temp. @ 0.45 MPa 130°C266 °F · Heat Deflection Temp. @ 1.8 MPa 62°C144 °F · Vicat Softening Point (B50) 158°C316 °F · Limiting Oxygen Index 15% · Max Service Temperature (short-term) 130°C266 °F
Electrical
Conductivity and insulation.
Same in both: Electrical Resistivity 1×10¹² Ω·m3.94×10¹⁹ µΩ·in · Dielectric Strength 18 kV/mm457 V/mil · Dielectric Constant (1 MHz) 3.7 · Dissipation Factor (1 MHz) 0.005 · Volume Resistivity 1×10¹⁴ Ω·cm · Surface Resistivity 1×10¹⁵ Ω · Comparative Tracking Index (CTI) 600 V
Chemical & Environmental
Corrosion and environmental resistance (0–100 scores).
UV / Weathering Resistance
Same in both: Corrosion Resistance 68 / 100
Manufacturability
FabDigit workshop ratings (0–100 scores) — how each material behaves on the machine.
Weldability
Formability (cold)
Mold Shrinkage
Melt Flow Rate
Same in both: Machinability 72 / 100 · Polishability 55 / 100 · Processing Melt Temperature (typ.) 215°C419 °F · Mold Temperature (typ.) 90°C194 °F
Sustainability
Primary-production footprint per kilogram.
Same in both: Embodied Energy (primary production) 92 MJ/kg39,553 BTU/lb · Embodied Carbon (primary production) 4.4 kg CO₂/kg · Embodied Water 200 L/kg24 gal/lb · Typical Recycled Content 0%
Strength versus weight
Yield strength against density for every polymer grade in the FabDigit library; the compared grades are highlighted. Up and left is stronger for its weight.
POM-H HI BK vs POM-H HI ST — frequently asked
What is the difference between POM-H HI BK and POM-H HI ST?
POM-H HI BK and POM-H HI ST are two grades of the same polymer grade, POM-H HI: BK (carbon-black pigmented toughened grade) versus ST (solution annealed). The chemistry is identical, so every difference below comes from the condition. Both yield at about 45 MPa — the mechanical properties are the same, and the difference is in how the stock is processed and what it is certified to (carbon-black pigmented toughened grade versus solution annealed).
Which grade does FabDigit quote by default, BK or ST?
ST is the default POM-H HI 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 welds better, POM-H HI BK or POM-H HI ST?
POM-H HI ST. Its weldability rates fair (45/100) against fair (35/100) for POM-H HI BK.
Ready to make it?
Upload a CAD file and FabDigit prices the part in POM-H HI BK and POM-H HI 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.