SEMS Screws
SEMS Screws are pre-assembled fasteners that combine a screw and a washer in a single unit, offering faster assembly, improved load distribution, and reduced risk of washer loss. These screws provide high resistance to loosening from vibration, making them ideal for automotive, electronics, industrial machinery, and structural applications.
At Rajal Industries, we manufacture precision-engineered SEMS screws that conform to ISO and ASME standards, ensuring high tensile strength, ease of installation, and long-lasting performance.
Sizes & Standards
| Size Range | Standards |
|---|---|
| Same as corresponding screw type | Washer Standards: |
| Metric & Imperial Sizes Available | ISO 7090 – Standard for plain washers with SEMS screws |
| ASME B18.21.1 – Standard for washers used with screws | |
| ASME B18.13 – American standard for SEMS screws | |
| ISO 10642 – Standard for countersunk head SEMS screws |
Material & Strength Grades
| Material Type | Available Strength Grades | Industry Standards |
|---|---|---|
| Carbon Steel & Mild Steel | 4.6, 5.6, 8.8 | ISO 7090, ASME B18.13 |
| Stainless Steel (Corrosion Resistant) | A2-70 (SS 304), A4-80 (SS 316) | ISO 10642, ASME B18.21.1 |
| Hardened Steel (Heat Treated) | Class 8.8, 10.9 | ISO 7090, ASME B18.13 |
- Heat-Treated for Maximum Strength –SEMS screws undergo quenching and tempering for enhanced durability and vibration resistance.
- Load Ratings Based on Material & Application:
- Carbon Steel Class 8.8 SEMS Screw: 800-900 MPa tensile strength
- Stainless Steel A4-80 SEMS Screw: 700-800 MPa corrosion-resistant strength
Head & Washer Design Specifications
Pre-Assembled Washer for Enhanced Grip & Stability
- The washer is locked onto the screw, preventing it from falling off during assembly.
- Available with plain, lock, and spring washers for different load requirements.
Multiple Head Styles for Versatile Applications
- Hex Head SEMS Screws (ASME B18.13) – Provides high torque and secure fastening in structural applications.
- Pan Head SEMS Screws (ISO 7090) – Ideal for electronics and automotive components.
- Countersunk Head SEMS Screws (ISO 10642) – Ensures a flush finish in precision assemblies.
Threaded & Self-Locking Variants for Secure Fastening
- Fully Threaded SEMS Screws – Allow maximum adjustability and secure engagement.
- Partially Threaded SEMS Screws – Enhance shear strength and vibration resistance.
Compatible with Various Washer Types
- Plain Washers (ISO 7090, ASME B18.21.1) – Ensure even load distribution.
- Spring Washers (DIN 127) – Provide locking action against loosening.
Serrated Lock Washers (ISO 10642) – Offer extra grip in high-vibration environments.
Thread Specifications & Precision Engineering
| Thread Type | Description | Application |
|---|---|---|
| Coarse Thread (UNC/Metric) | Provides quick penetration and strong grip | Machinery, industrial assembly |
| Fine Thread (UNF/Metric Fine) | Ensures higher tensile strength & load control | Electronics, precision fastening |
| Fully Threaded SEMS Screws | Allows maximum adjustability and secure fastening | Automotive, aerospace, medical devices |
| Partially Threaded SEMS Screws | Provides better shear strength & clamping force | Structural fastening, heavy machinery |
Thread Fitment & Compliance
- Metric threads conform to ISO 6g tolerances, ensuring precise engagement with mating components.
- Imperial SEMS screws meet ASME B18.13 and ISO 7090 standards for universal compatibility.
Common Applications of SEMS Screws
- Automotive & Aerospace Components – Used in engine assemblies, electrical systems, and safety mechanisms.
- Electronics & PCB Mounting – Ensures secure fastening in circuit boards, power supplies, and enclosures.
- Heavy Machinery & Industrial Equipment – Provides high-strength fastening in moving parts and high-vibration environments.
- Medical Devices & Precision Engineering – Used in diagnostic instruments and lab equipment.
- Renewable Energy & Solar Panel Mounting – Ensures secure installation of panels and frames.
Why Choose Rajal Industries for SEMS Screws?
Manufactured to International Standards
Ensuring precision engineering, durability, and compliance.
Pre-Assembled for Faster Installation
Reduces assembly time and eliminates lost washers.
Customizable Designs
Available in various head styles, drive types, and washer configurations.
Bulk & Custom Orders
Ideal for automotive, electronics, and industrial clients.
High Retention Strength & Vibration Resistance
Engineered for secure, maintenance-free fastening.
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Our Offices
C-204, Vaibhav Platina, Nr. Kaveri Trishra, S P Ring road, Shilaj, Ahmedabad, Gujarat-380054
Call us
+91-846 036 2030
Email Us
rajalfast@gmail.com sales@rajalindustries.com