Brass SEMS Screws
Brass SEMS screws and Silicon Bronze SEMS screws for the fastening industry.
We are one of the leading manufacturers and exporters of Brass SEMS Screws and Silicon bronze SEMS screws and allied fasteners from India. SEMS screws are an acronym of-‘Screw with Engineered Mechanical Safety’. We have been supplying these specialized fasteners and Brass Machine Screws , Bronze Machine Screws to the world market for many decades. Our state-of-the-art manufacturing facility located in the industrial hub of Gujarat, India, is equipped with cutting-edge machinery and staffed by skilled technicians with extensive experience in precision engineering. Our commitment to quality, customization capabilities, and adherence to international standards has established us as a trusted name in the fastener industry globally. With a focus on customer satisfaction and product excellence, we continue to expand our reach to diverse industries across continents while maintaining the highest standards of manufacturing and delivery.
Product Overview
Brass SEMS Screws are specialized fasteners featuring pre-assembled washers permanently attached to the screw. These innovative fasteners combine a screw and washer into a single unit, eliminating the need for separate installation of washers and significantly improving assembly efficiency. The term “SEMS” stands for “Screw with Engineered Mechanical Safety,” highlighting their enhanced stability and load distribution capabilities.
Our Brass SEMS Screws are manufactured through a sophisticated process that involves first attaching a washer to the screw blank, followed by precision thread rolling. This unique manufacturing sequence ensures the washer remains securely in place during installation and throughout the fastener’s service life. Available in multiple thread standards including Metric, UNC (Unified National Coarse), and UNF (Unified National Fine), our SEMS screws are crafted from premium Brass and Silicon Bronze materials to provide exceptional corrosion resistance and electrical conductivity.
Material Specifications
| Material | Composition | Properties | Applications |
|---|---|---|---|
| Brass | Copper (63-68%), Zinc (32-37%) | Excellent corrosion resistance, good electrical conductivity, low magnetic permeability | Electrical applications, marine environments, decorative hardware |
| Silicon Bronze | Copper (96-98%), Silicon (1.5-3.5%), Manganese (0.1-1.5%) | Superior corrosion resistance in marine environments, high tensile strength, excellent fatigue resistance | Marine hardware, outdoor applications, historic restoration |
Material Grades Available:
- Brass: C26000 (Cartridge Brass), C27000 (Yellow Brass), C22000 (Commercial Bronze), C23000 (Red Brass)
- Silicon Bronze: C65500, C65100
International Standards Compliance:
- ASTM B36/B36M (Brass Plate, Sheet, Strip, and Rolled Bar)
- ASTM B134/B134M (Brass Wire)
- ASTM B98/B98M (Silicon Bronze Rod, Bar, and Shapes)
- ASTM F738M (Metric Specifications for Stainless Steel Fasteners)
- DIN 7985 (Cross Recessed Pan Head Screws)
- IS 1367 (Technical Supply Conditions for Threaded Fasteners)
- JIS B1111 (Cross Recessed Pan Head Machine Screws)
Material Properties
| Property | Brass C26000 | Silicon Bronze C65500 |
|---|---|---|
| Tensile Strength | 330-430 MPa | 480-620 MPa |
| Yield Strength | 150-300 MPa | 380-520 MPa |
| Elongation | 25-55% | 18-30% |
| Hardness (Brinell) | 70-130 HB | 100-180 HB |
| Density | 8.53 g/cm³ | 8.8 g/cm³ |
| Electrical Conductivity | 28% IACS | 7% IACS |
| Thermal Conductivity | 120 W/m·K | 50 W/m·K |
| Corrosion Resistance | Excellent | Superior |
Manufacturing Process
Our Brass SEMS Screws undergo a sophisticated multi-stage manufacturing process:
- Material Selection and Testing: Raw material is inspected and tested for chemical composition and mechanical properties.
- Blank Formation: Wire or rod stock is cut to precise lengths and undergo initial forming.
- Head Formation: The screw head is formed through cold forging using Cartridge Brass (C26000) or Yellow Brass (C27000), which offer excellent formability without the brittleness associated with leaded brasses.
- Washer Assembly: Precision-manufactured washers are placed onto the screw blank before threading.
- Thread Rolling: Rather than cutting threads (which would remove material and weaken the fastener), we employ thread rolling technology that compresses and forms the threads, resulting in stronger fasteners with superior fatigue resistance.
- Heat Treatment: Screws undergo controlled heating and cooling processes to achieve optimal mechanical properties.
- Surface Finishing: Depending on customer requirements, screws may receive polishing, plating, or other surface treatments.
- Quality Control: Each batch undergoes rigorous inspection and testing for dimensional accuracy, material properties, and performance characteristics.
Manufacturing Equipment
Our state-of-the-art facility utilizes advanced machinery to ensure precision and consistency:
- Multi-Station Cold Headers: Capable of producing up to 300 parts per minute with minimal variation
- High Speed Thread Rolling Machines: Japanese technology providing superior thread quality and consistency
- Works Formers: Advanced forming technology for complex head designs
- Progressive Headers: Italian precision equipment for multi-stage forming operations
- Coordinate Measuring Machines (CMM): For high-precision dimensional inspection
Dimensional Specifications
Metric Thread SEMS Screws
| Size | Thread Pitch | Head Diameter (mm) | Washer Diameter (mm) | Head Height (mm) | Standard Lengths (mm) |
|---|---|---|---|---|---|
| M3 | 0.5 | 5.6 | 7.0 | 2.1 | 6, 8, 10, 12, 16, 20 |
| M4 | 0.7 | 7.0 | 9.0 | 2.6 | 8, 10, 12, 16, 20, 25 |
| M5 | 0.8 | 8.5 | 10.0 | 3.1 | 10, 12, 16, 20, 25, 30 |
| M6 | 1.0 | 10.0 | 12.0 | 3.6 | 12, 16, 20, 25, 30, 40 |
| M8 | 1.25 | 13.0 | 16.0 | 4.6 | 16, 20, 25, 30, 40, 50 |
| M10 | 1.5 | 16.0 | 20.0 | 5.6 | 20, 25, 30, 40, 50, 60 |
| M12 | 1.75 | 18.0 | 24.0 | 6.6 | 25, 30, 40, 50, 60, 75 |
Imperial Thread SEMS Screws (UNC/UNF)
| Size | Thread TPI | Head Diameter (in) | Washer Diameter (in) | Head Height (in) | Standard Lengths (in) |
|---|---|---|---|---|---|
| #4 | 40 UNC/48 UNF | 0.225 | 0.281 | 0.083 | 1/4, 3/8, 1/2, 5/8, 3/4 |
| #6 | 32 UNC/40 UNF | 0.270 | 0.344 | 0.097 | 1/4, 3/8, 1/2, 5/8, 3/4, 1 |
| #8 | 32 UNC/36 UNF | 0.322 | 0.400 | 0.112 | 3/8, 1/2, 5/8, 3/4, 1, 1-1/4 |
| #10 | 24 UNC/32 UNF | 0.375 | 0.438 | 0.127 | 3/8, 1/2, 5/8, 3/4, 1, 1-1/4 |
| 1/4″ | 20 UNC/28 UNF | 0.438 | 0.500 | 0.144 | 1/2, 5/8, 3/4, 1, 1-1/4, 1-1/2 |
| 5/16″ | 18 UNC/24 UNF | 0.547 | 0.625 | 0.178 | 5/8, 3/4, 1, 1-1/4, 1-1/2, 1-3/4 |
| 3/8″ | 16 UNC/24 UNF | 0.625 | 0.750 | 0.212 | 3/4, 1, 1-1/4, 1-1/2, 1-3/4, 2 |
Tolerance Standards
Our manufacturing process adheres to strict tolerance specifications:
| Dimension | Tolerance Range |
|---|---|
| Thread Major Diameter | ±0.05mm (Metric), ±0.002″ (Imperial) |
| Thread Pitch Diameter | ±0.03mm (Metric), ±0.001″ (Imperial) |
| Head Diameter | ±0.10mm (Metric), ±0.004″ (Imperial) |
| Head Height | ±0.08mm (Metric), ±0.003″ (Imperial) |
| Washer Diameter | ±0.15mm (Metric), ±0.006″ (Imperial) |
| Overall Length | ±0.20mm for lengths up to 20mm, ±0.5mm for longer (Metric) |
| ±0.008″ for lengths up to 1″, ±0.015″ for longer (Imperial) |
Performance Metrics
| Performance Criteria | Brass SEMS | Silicon Bronze SEMS |
|---|---|---|
| Torque Strength | 70-80% of steel equivalents | 85-90% of steel equivalents |
| Pull-Out Strength | Medium | High |
| Vibration Resistance | Excellent (due to washer) | Excellent (due to washer) |
| Corrosion Resistance (Salt Spray Test) | 500+ hours | 1000+ hours |
| Temperature Rating | -40°C to 200°C | -50°C to 260°C |
| Electrical Conductivity | Excellent | Good |
| Magnetic Properties | Non-magnetic | Non-magnetic |
| Galling Resistance | Excellent | Superior |
| Service Life in Marine Environment | 15-20 years | 25-30 years |
Industries Served
Our Brass and Silicon Bronze SEMS Screws are utilized across diverse industries:
- Marine and Shipbuilding: Corrosion-resistant fasteners for deck equipment, interior fittings, and electrical components
- Electrical Engineering: Terminal connections, switchgear, and control panel assembly
- Automotive: Electrical systems, decorative trim, and specialized applications requiring conductivity
- Aerospace: Non-magnetic fasteners for sensitive equipment and electrical systems
- Architectural Hardware: Decorative and functional hardware for doors, windows, and fixtures
- Musical Instruments: Tuning mechanisms, bridges, and structural components
- Medical Equipment: Non-magnetic components for MRI-compatible equipment
- Telecommunications: Grounding systems and RF equipment assembly
- Historical Restoration: Period-appropriate fasteners for heritage structures and artifacts
- Plumbing and Valve Manufacturing: Corrosion-resistant threaded components for water systems
Our Competitive Advantages
Manufacturing Excellence
- Advanced Machinery: Our investment in cutting-edge equipment ensures precision and consistency
- Skilled Workforce: Our technicians have an average of 15+ years of experience in fastener manufacturing
- Rigorous Quality Control: 100% inspection protocols with advanced testing equipment
- Flexibility in Production: Capacity to handle both high-volume orders and specialized custom requirements
Customer-Focused Approach
- Customization Capabilities: Special head styles, thread configurations, and dimensions available upon request
- Flexible Production Schedule: Ability to prioritize urgent orders without compromising quality
- Technical Support: Our engineering team provides consultation on fastener selection and application
- Sample Development: Rapid prototyping and sample production for new designs
- Competitive Pricing: Direct manufacturing model eliminates intermediaries, reducing costs
Logistics and Service
- Global Shipping Expertise: Established relationships with freight forwarders ensuring reliable delivery worldwide
- Flexible Minimum Order Quantities: Accommodating both large volume and smaller specialized orders
- Comprehensive Documentation: Detailed material certifications, testing reports, and compliance documentation
- Customized Packaging: Private labeling, specialized protective packaging, and kit assembly options
- Digital Communication: Real-time order tracking and progress updates
Packaging and Shipping
Our Brass SEMS Screws are packaged with care to ensure they arrive in perfect condition:
- Standard Packaging: Heat-sealed polybags within corrugated cartons
- Premium Options: Anti-corrosion VCI paper wrapping, vacuum-sealed packages, or custom plastic containers
- Bulk Packaging: 25kg maximum per carton for easy handling
- Custom Labeling: Company logo, part numbers, and specifications printed on packaging as required
- Shipping Documentation: Comprehensive commercial documentation including packing lists, material certifications, and test reports
- Export Preparation: All shipments comply with international shipping regulations and customs requirements
- Shipping Methods: Sea freight (standard delivery), air freight (expedited delivery), and courier services (samples and urgent orders)
Turnaround Time
- Standard Production: 4-6 weeks from order confirmation
- Expedited Service: 2-3 weeks (subject to 15% expedite fee)
- Sample Development: 1-2 weeks for custom designs
- Stock Items: Select sizes available for immediate shipment
Frequently Asked Questions
Q: What makes Brass SEMS Screws different from standard screws?
A: SEMS Screws feature a pre-assembled washer that is permanently attached to the screw before the threads are formed. This design eliminates the need for separate washers during assembly, saving installation time and ensuring the washer cannot be lost or omitted.
Q: Why choose Brass or Silicon Bronze over Stainless Steel fasteners?
A: Brass and Silicon Bronze offer superior electrical conductivity, excellent corrosion resistance (particularly in marine environments), non-magnetic properties, and decorative appearance. They also provide excellent resistance to galling and seizing in threaded applications.
Q: Which Brass alloys are used in your SEMS screws manufacturing?
A: We primarily use C26000 (Cartridge Brass) and C27000 (Yellow Brass) for cold forging operations as they offer excellent formability and good mechanical properties without the brittleness or environmental concerns associated with leaded brasses. For specialized applications, we also use C22000 (Commercial Bronze) and C23000 (Red Brass).
Q: Are your Brass SEMS Screws suitable for marine environments?
A: Yes, both our Brass and Silicon Bronze SEMS Screws provide excellent corrosion resistance in marine environments. Silicon Bronze offers superior performance in harsh saltwater conditions and is preferred for exterior marine applications, while Brass is often used for interior marine components.
Q: Can you produce custom thread specifications beyond standard offerings?
A: Yes, we can manufacture custom thread configurations including specialized thread pitches, left-hand threads, and modified thread profiles for specific applications. Our engineering team can work with you to develop fasteners that meet your exact requirements.
Q: What is the minimum order quantity (MOQ) for Brass SEMS Screws?
A: Our standard MOQ is 5,000 pieces for catalog items. For custom specifications, the MOQ is typically 10,000 pieces, though we can accommodate smaller orders with adjusted pricing.
Q: Do you provide material certifications and quality documentation?
A: Yes, we provide comprehensive documentation including material test reports (MTRs), dimensional inspection reports, and compliance certificates. Additional testing documentation is available upon request.
Q: How do Silicon Bronze SEMS Screws compare to Brass in corrosion resistance?
A: Silicon Bronze offers superior corrosion resistance, particularly in saltwater environments, making it ideal for exterior marine applications. Brass provides excellent corrosion resistance for most applications but may develop surface patina over time in harsh conditions.
Q: Can your Brass SEMS Screws be used in electrical applications?
A: Yes, Brass SEMS Screws are excellent for electrical applications due to their high conductivity. The pre-assembled washer provides increased surface contact area, enhancing electrical continuity between components.
Q: What finishing options are available for Brass SEMS Screws?
A: Our Brass SEMS Screws are available with natural finish, polished finish, lacquer coating (to prevent tarnishing), or various plating options including nickel, chrome, or tin. Silicon Bronze screws are typically supplied with natural or polished finish.
Q: How do thread-rolled screws differ from thread-cut screws?
A: Thread rolling forms threads by compressing the material, resulting in stronger threads with unbroken grain flow and work-hardened surfaces. This provides superior fatigue resistance and tensile strength compared to thread-cutting, which removes material and interrupts grain structure.
Q: Are your Brass alloys compliant with environmental regulations?
A: Yes, we use lead-free Brass alloys (C26000, C27000) that comply with RoHS, REACH, and other international environmental regulations, making them suitable for applications where lead content is restricted.
Customer Testimonial
M. Anderson, Procurement Manager, USA
“We’ve been sourcing Brass and Silicon Bronze SEMS Screws from this supplier for over five years now for our high-end marine hardware. The quality and consistency have been exceptional, and their technical support team has been invaluable in helping us specify the right fasteners for challenging applications.”
Glossary of Technical Terms
SEMS (Screw with Engineered Mechanical Safety): A fastener design featuring a pre-assembled washer permanently attached to the screw.
Thread Rolling: A cold-forming process that creates threads by compressing material rather than cutting it, resulting in stronger threads with superior fatigue resistance.
UNC (Unified National Coarse): A standard thread series featuring coarser thread pitch, providing easier assembly and greater strength in soft materials.
UNF (Unified National Fine): A standard thread series featuring finer thread pitch, providing greater tensile strength and better resistance to vibration loosening.
Cartridge Brass (C26000): A copper-zinc alloy containing approximately 70% copper and 30% zinc, offering excellent formability for cold working operations like heading and thread rolling.
Yellow Brass (C27000): A copper-zinc alloy containing approximately 65% copper and 35% zinc, with good strength and moderate formability.
Commercial Bronze (C22000): Despite its name, this is actually a brass alloy containing around 90% copper and 10% zinc, offering good corrosion resistance and formability.
Red Brass (C23000): A copper-zinc alloy containing approximately 85% copper and 15% zinc, offering excellent corrosion resistance and moderate strength.
Silicon Bronze: A copper alloy containing silicon (typically 1.5-3.5%) and small amounts of other elements, offering superior corrosion resistance and strength.
Cold Heading: A manufacturing process where metal is formed at room temperature by applying pressure through dies to create the screw head.
Thread Pitch: The distance between adjacent threads, measured in millimeters for metric threads or expressed as threads per inch (TPI) for imperial threads.
Galling: A form of wear caused by adhesion between sliding surfaces, often resulting in seized threads.
Work Hardening: The strengthening of metal by plastic deformation, occurring during the thread rolling process.
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