Special Stud-bolts
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Sunmach manufactures high-performance Stainless Steel Stud Bolts and heavy-duty Duplex Stud Bolts featuring a continuous, full-length thread design engineered to replace traditional bolts in high-pressure flanged assemblies and vessel piping systems. Traditional hex bolts contain an unthreaded shank that creates a sharp transition line where stress concentrates, making them prone to snapping under sudden pressure surges or constant vibrations. Sunmach's continuous-thread design completely eliminates these weak failure points, distributing up to 2,000 kN of crushing clamping force evenly across the entire stud length. Additionally, these studs are machined to a strict thread pitch tolerance, ensuring that every fastener engages perfectly and locks down identically to prevent flange tilting and catastrophic gasket seal blowouts. To ensure long-term, fail-safe operation in demanding power generation, subsea extraction, and chemical processing facilities, Sunmach produces these components using only premium, virgin metals sourced from trusted global mills. High-strength choices within our line of Stainless Steel Stud Bolts provide superior strength to maintain critical sealing tension through severe thermal cycling, while specialized Duplex Stud Bolts deliver double the tensile strength of standard stainless steel and total compliance with NACE MR0175 Standards for sour gas safety. Backed by an ISO 9001:2015 certified quality system, every production batch passes intense laboratory audits including extreme tensile pulling and cyclic fatigue verification and arrives at the job site with complete EN 10204 3.1 Mill Test Certificates for absolute material trace transparency.
Special Stud-bolts
Sunmach is one of the leading global manufacturer and supplier of Standard & Custom made Premium Nickel Alloys Special Stud-bolts engineered for the most critical industrial applications. We are an ISO 9001:2015 certified company, demonstrating our commitment to rigorous quality standards and consistent product excellence to deliver the best of the Nickel Alloys & Special Steel Fasteners.
Nickel Alloys Special Stud-bolts are manufactured by us from a range of high-performance & exotic materials such as : Hastelloy® C-276, Hastelloy® C-22, Hastelloy® B-2, Monel® 400, Monel® K-500, Inconel® 600, Inconel® 625, Inconel® 718, Titanium Grade 2, Titanium Grade 5, Titanium Grade 7, Duplex S31803, Duplex S32205, Super Duplex S32750 to various Stainless Steel grades of SS 304L, SS 316L SS 310, SS 310H, SS 347H, etc followed by Special Stainless Steel Grades such as 904L Stainless Steel, UNS N08904, DIN EN1.4539 Nitronic® 50, Nitronic® 60, UNS S21800, DIN EN, 254 SMO, UNS S31254, DIN EN 1.454, A4-80 Stainless Steel etc.
Sunmach’s extensive manufacturing capabilities and In-Stock Genuine & Authentic Raw Material availability allows us to support demanding industrial requirements with durable, corrosion-resistant, heat resistant & reliable Nickel Alloys Special Stud-bolts delivered dot in time to any corner of the world, supported by all required test certificates and with 100% traceability.
Nickel Alloy Special Stud-bolts Specifications
Using Advanced Hot Forming Technology, Our Nickel Alloys Special Stud-bolts are manufactured in various specifications including DIN, ISO, ANSI and IS standard in nominal diameters ranging from 1/4” to 3” (M6 to M76). We provide Special Stud-bolts in both Imperial and metric sizes to accommodate diverse application needs. Our Nickel Alloys Special Stud-bolts are specially engineered to withstand high temperature and high-pressure, ensuring superior strength and reliability.
Nickel Alloy Special Stud-bolts Application Industries
Sunmach serves a diverse range of markets including Chemical Processing, Semiconductor, Power Generation, Aerospace, Oil & Gas, Pharmaceutical, Food & Beverage, Marine, Pulp & Paper, Petrochemical & Refining, Air Pollution Control and Water Treatment.
Sizes
| Metric : | M6 to M76 |
| Imperial : | 1/4" to 3" |
| MOQ : | 1 Piece & Above |
| Certification : | EN 10204 3.1, EN 10204 3.2 (On Demand) |
Specification
| Bolt | DIN | ISO | ANSI | IS |
|---|---|---|---|---|
| Special Stud-bolt | 931 | 4014 | B18.2.1 | 1364 |
Frequently Asked Questions
Common questions about Sunmach Duplex Stud Bolts
They are primarily used for permanent flange connections in high-pressure piping, pressure vessels, offshore wellheads, and desalination equipment. The continuous thread design allows for double-nutting on both ends, which distributes high clamping forces more evenly across the sealing gasket compared to standard headed bolts, reducing the risk of fluid leakage.
Standard 316L Stainless Steel has lower yield strength and is highly vulnerable to stress corrosion cracking (SCC) and crevice corrosion underneath flange gaskets when exposed to warm saltwater. Duplex 2205 provides double the yield strength and outstanding resistance to chloride-induced pitting, preventing the stud bolts from stretching or deforming under high preloads, maintaining a secure seal over a 20-to-30-year operational life.
A Stud Bolt has no head and is threaded along its entire length (or on both ends), allowing nuts to be tightened on either side of the joint. A Hex Head Bolt has an integrated Hexagonal Head on one end and is threaded on the other. Stud Bolts are preferred for high-pressure flanges because they distribute axial tension more evenly, are easier to replace during maintenance, and allow for precise torque application.
We utilize SPC-controlled thread-rolling machinery to maintain a tight pitch diameter tolerance of ±0.05 mm. Thread rolling displaces the metal grains rather than cutting them, which preserves a continuous grain flow along the thread profile, increasing shear strength, reducing friction during nut installation, and preventing thread stripping or seizing under high preloads.