I. Product Function
1. Used as supporting fastening connectors for high-pressure sealing of various flanges, pressure vessels, composite pipe fittings, and marine panels. Threads at both ends can lock flange sealing surfaces from both directions;
2. Dedicated fasteners for complete flange assembly in chemical engineering, oil and gas, power plant desulfurization, and high-temperature and high-pressure pipeline systems;
3. Pressure-bearing sealing and locking components for overlay-welded composite flanges, lined composite pipe flanges, and inlet and outlet connections of large storage tanks;
4. Suitable for heavy industrial equipment, offshore platforms, and high-temperature and high-pressure working conditions, especially flange installation scenarios with narrow or limited operating space.
II. Specification and Standard Parameter Table
Parameter Item | Production Range / Optional Type |
Applicable Standard | GB/T 898, GB/T 899, GB/T 900, GB/T 901 |
Metric Size Range | Cold forged: M5–M36; hot forged: M39–M56 |
Imperial Size Range | Cold forged: 10#–1-3/8"; hot forged: 1-1/4"–2" |
Forming Process | Cold forging and thread rolling; hot forging with quenching and tempering heat treatment |
Surface Treatment | Black oxide anti-rust treatment, phosphating, high-temperature black paint, molybdenum disulfide coating for high-temperature working conditions |
Available Materials | Grade 4.8, 8.8, 10.9, and 12.9 high-strength carbon steel; 304 / 316L stainless steel |
Length Range | Hot-forged models from M16 are available in lengths of 60–500mm; other specifications can be customized according to corresponding bolt length standards |
III. Material & Strength Grade Application Scenarios
1. Grade 4.8 / 8.8 blackened carbon steel: suitable for normal-temperature and low-pressure water supply and drainage systems, ventilation systems, and ordinary carbon steel flange assembly;
2. Grade 10.9 / 12.9 quenched and tempered carbon steel: suitable for high-temperature and high-pressure steam, oil and gas, and chemical desulfurization pressure-bearing flanges;
3. 316L stainless steel double-end stud bolts: suitable for marine seawater piping systems and coastal high-salt-spray corrosion-resistant composite flanges;
4. 2205 duplex stainless steel: suitable for offshore drilling platforms and high-pressure equipment sealing under severe acid and alkali corrosion conditions.
IV. Product Advantages
1. Fully threaded design at both ends eliminates the need to reserve operating space for a bolt head, making it suitable for thick-wall flanges, bulkheads, and enclosed equipment installation;
2. High-strength quenched and tempered models provide excellent tensile and fatigue resistance, and are not prone to stretching, deformation, loosening, or leakage under high-temperature and high-pressure working conditions;
3. Precision thread rolling ensures smooth nut tightening, uniform force distribution, and resistance to thread stripping under long-term vibration conditions;
4. Multiple material grades and surface treatments are available, covering all working conditions from normal pressure to high pressure and from standard environments to highly corrosive environments;
5. Matching standard nuts, flat washers, and spring washers can be supplied, and can be provided as complete sets with carbon steel, stainless steel, and overlay-welded composite flanges.