A general-purpose injection-molding ABS has a tensile strength of about 45 MPa (6,500 psi), reported as tensile stress at yield at 23 °C.
Across unfilled grades, producer datasheets run from 38 MPa for a very-high-impact grade to 47 MPa. Every one of these figures comes from a molded test bar pulled at room temperature, and a part in service can fall well short of it.
ABS Tensile Strength by Grade
On the producers’ ISO 527 datasheets, unfilled ABS grades sit between 38 and 47 MPa at yield, with the high-impact grades at the low end.
| Grade (producer) | Family | Tensile stress at yield (MPa) | Tensile stress at break (MPa) |
|---|---|---|---|
| Terluran GP-22 (INEOS Styrolution) | General purpose, easy flow | 45 | not reported |
| Terluran GP-35 (INEOS Styrolution) | General purpose, high flow for thin walls | 44 | not reported |
| CYCOLAC MG47 (SABIC) | Multi-purpose injection molding | 47 | 35 |
| CYCOLAC MG94 (SABIC) | High flow for thin walls | 46 | 35 |
| CYCOLAC EX58F (SABIC) | High impact, sheet extrusion and blow molding | 41 | 30 |
| Terluran HI-10 (INEOS Styrolution) | Very high impact, molding and extrusion | 38 | not reported |
| LNP THERMOCOMP AF004 (SABIC) | 20 % glass fiber | not reported | 76 |
All values are typical values at 23 °C.
The spread follows the rubber content: more butadiene rubber raises impact resistance and lowers tensile strength and stiffness.
Why ABS Tensile Strength Values Differ Between Datasheets
Two ABS datasheets usually disagree because they put different measurements under the same heading, “tensile strength”. The two differences that matter most are whether the figure is the stress at yield or at break, and whether it was tested to ASTM D638 or to ISO 527.
Every figure on these sheets is also a typical value. A small gap between two producers’ typical values therefore says little about which delivered lot will test stronger; the lot itself is documented by its certificate of analysis.
Tensile Strength at Yield vs at Break
ABS datasheets report tensile stress at yield, and that is the figure to compare between grades. For unfilled ABS the stress at break is lower than the stress at yield.
Unfilled ABS has a defined yield point. ISO 527-1 defines strength as the “stress at the first local maximum observed during a tensile test”, and for unfilled ABS that maximum is the yield point. At room temperature, unfilled ABS is not brittle in tension.
The 20 % glass-fiber grade reports only a stress at break. Its 76 MPa is the stress at which it fractures. A general-purpose grade’s 45 MPa is the stress at which it starts to deform permanently.
For a load check, compare the stress in the loaded section with the yield figure. The stress is the force divided by the area of that section:
Stress (MPa) = Force (N) ÷ Cross-sectional area (mm²)
ASTM D638 vs ISO 527 Values for ABS
For the same ABS grade, ASTM D638 and ISO 527 can give figures a few MPa apart, and the gap can run in either direction, so no factor converts one into the other. Compare an ASTM figure only with another ASTM figure, and an ISO figure with an ISO one.
One producer can publish the same grade under both standards: an Americas datasheet in psi to ASTM D638 and an EMEA datasheet in MPa to ISO 527. A psi figure converted to MPa is still an ASTM figure.
What Changes the Tensile Strength of a Molded ABS Part
Temperature, the molding itself, UV exposure and sustained load all move a molded ABS part away from its datasheet figure.
For moisture, the producer warns about the molding rather than the tensile figure. Damp pellets cause surface faults on the finished part.
In a 2020 study, 360 hours of UVA exposure simulating sunlight behind window glass cut an unstabilized ABS’s tensile strength by about 11 %, while its elongation at break fell more than tenfold.
Sustained load lies outside the tensile test altogether. The producer’s creep curves for a general-purpose grade show strain still rising after years at 40 % of the yield stress.
Temperature
ABS loses tensile strength as it warms and gains it as it cools: at 85 °C its yield stress is a little over half the room-temperature value. A published fatigue study measured the yield stress of an injection-molded ABS to ISO 527 at three temperatures.
At −27 °C the same ABS yielded at a higher stress and failed in a brittle way, so a cold part can crack on impact even though its tensile figure has risen.
Molding Conditions
Molding conditions change a part’s tensile strength at its weld lines and through molded-in stress. The producer states that mold surface temperature influences the mechanical properties of the molding, and that a higher one gives better weld-line strength and lower molded-in stress.
ABS Tensile Strength vs Other Plastics
A general-purpose ABS sits in the middle of the common plastics: above PP homopolymer, HDPE, high-impact polystyrene and LDPE, and below polycarbonate, nylon 66 and general-purpose polystyrene. Each bar is one injection-molding grade per polymer.
Among the unfilled grades here, dry nylon 66 has the highest figure. The much higher nylon figures in comparison tables come from glass-filled grades: with 25 % glass fiber, nylon 66 reaches 175 MPa at break when dry.