kSil® US50
kSil® US50 is a solid silicone elastomer with a 50 Shore A durometer, offering a balanced combination of elongation (310%) and low compression set (12%). It meets AA-59588 and AMS 3302 specifications and is compliant with FAR 25.853 Horizontal and FDA 21 CFR 177.2600. The material is available in red-orange, black, and grey.
Key Properties
- Durometer: 50 Shore A (ISO 48-4)
- Tensile Strength: 7.5 MPa (ISO 37 Type 2)
- Elongation: 310% (ISO 37 Type 2)
- Compression Set, 24 Hours @ 150°C: 12% (ISO 815, 24h @150°C)
- Tear Strength: 18 N/mm (ASTM D624 Die B)
- Thermal Conductivity: 0.24 W/m·°C (ASTM C518)
We want to help!
Enter your information and we'll get you in touch with our knowledgable staff. We know how important to the right product for your project.
Request a Consultation
- Specifications
- Applications
- General Info
- FAQs
Physical Properties
| Property | Value | Test Method |
| Thermal Conductivity | 0.24 W/m·°C | ASTM C518 |
| Colors Available | Red-orange, Black, Grey | Visual |
Mechanical Properties
| Property | Value | Test Method |
| Durometer | 50 Shore A | ISO 48-4 |
| Tensile Strength | 7.5 MPa | ISO 37 Type 2 |
| Elongation | 310% | ISO 37 Type 2 |
| Tear Strength | 18 N/mm | ASTM D624 Die B |
| Compression Set — 24 Hours @ 150°C | 12% | ISO 815, 24h @150°C |
Compliance
- AA-59588 — Compliant
- AMS 3302 — Compliant
- FAR 25.853 Horizontal — Compliant
- FDA 21 CFR 177.2600 — Compliant
- Gaskets and seals requiring a medium durometer with low compression set for long-term seal retention
- Food contact components in processing and packaging equipment
- Aerospace sealing applications requiring AA-59588 and AMS 3302 qualification
- Aerospace flame compliance applications per FAR 25.853 Horizontal
- General industrial sealing where a balance of flexibility and elastic recovery is required
Common industries: Aerospace, Food Processing, Industrial Manufacturing, Automotive.
kSil® US50 is a medium-durometer grade in the kSil® US general purpose solid silicone series, with a 50 Shore A hardness. Qualified to AMS 3302 and meeting AA-59588, it is designed for aerospace and food contact sealing applications where a balance of compliance, elongation, and elastic recovery is required. The TDS specifically highlights the combination of elongation and low compression set as key performance attributes of this grade.
US50 achieves a tensile strength of 7.5 MPa, elongation of 310%, and a tear strength of 18 N/mm. Its compression set of 12% after 24 hours at 150°C is the lowest in the US solid silicone range, indicating strong long-term seal retention under sustained load. Thermal conductivity is 0.24 W/m·°C per ASTM C518. The material is available in red-orange, black, and grey.
Compliant with AA-59588, AMS 3302, FAR 25.853 Horizontal, and FDA 21 CFR 177.2600.
What differentiates US50 from US40 and US60 in the kSil® US solid silicone series?
US50 occupies the mid-point of the US series at 50 Shore A. Its most notable differentiator is its compression set of 12% — the lowest in the US solid silicone range — making it the preferred grade where long-term seal retention under sustained load is the primary concern. Compared to US40 (550% elongation), US50 offers less elongation (310%) but markedly better elastic recovery.
Why is compression set critical for solid silicone elastomers like US50?
Compression set measures the degree to which a material permanently deforms after sustained compressive loading at elevated temperature. For sealing applications, a low compression set means the material retains contact force against mating surfaces over time, maintaining an effective seal. US50's compression set of 12% after 24 hours at 150°C is the lowest recorded in the kSil® US solid silicone range.
What is the operating temperature range for US50?
No discrete operating temperature range is specified on the manufacturer's TDS for US50. The compression set test condition is 150°C. Contact H-O Products for service temperature guidance specific to your application.
Is US50 suitable for aerospace or food contact environments?
Yes. US50 is qualified to AMS 3302, meets AA-59588, and is compliant with FAR 25.853 Horizontal for aerospace applications. It is also compliant with FDA 21 CFR 177.2600 for food contact use.
How should US50 be specified?
Specify grade (US50), thickness, color (Red-orange, Black, or Grey), compliance requirements, dimensional tolerances, and finished format.
