Alloy Steel Blind Flange

As a trusted China manufacturer and supplier, longan professionally produces high-quality Alloy Steel Blind Flange for global markets. Our factory operates under strict quality standards and provides complete documentation, testing reports, and export support to ensure smooth international procurement. Request a quotation today and get free samples directly from our certified China factory.

Technical barriers of the product

1. Thermal cycle sealing

Bolt stress relaxation: Alloy Steel Blind Flange lasts for 2,000 hours at 538℃, and the preload attenuation is ≤3% (traditional blind flange>25%)

Thermal shock test: from -196℃ (liquid nitrogen) → 538℃, alternately cycle 500 times, and the leakage rate remains ≤10⁻⁷ mbar·L/s

Innovative structure: patented bimetallic thermal expansion compensation ring (CTE 5.2×10⁻⁶/℃), eliminating temperature difference stress

2. Breakthrough in corrosion resistance

Corrosion type Traditional 304 blind flange AlloySeal™ Improvement

Intergranular corrosion rate 1.2mm/year (65% HNO₃) 0.03mm/year ↓97%

Sulfide stress cracking 72h failure (H₂S 200ppm) 5,000h no crack >70 times

Core process: Sealing surface Laser cladding Hastelloy C276 layer (80μm), microporosity <0.01%

Chloride ion penetration threshold <5,000ppm >120,000ppm 24 times

3. Catastrophic failure prevention capability

Risk scenario Traditional blind plate consequences AlloySeal™ protection solution

Fire (538℃, 30min) Bolt melting (medium injection) Fireproof metal graphite gasket: maintain sealing

Sealing surface erosion (including solid particles) Sudden leakage (production suspension ≥72h) Embedded wear sensor: 30-day advance warning

Overpressure explosion (>1.5 times design value) Debris injection (risk of casualties) Directed tear groove design: controllable cracking pressure relief

Comparison of blind plate modification of hydrogenation reactor outlet in a refinery (DN400/Class 900):

Indicator | Traditional blind plate (2018-2021) | AlloySeal™ (2021-2024) |

Single leak loss | $480,000 (emergency stop + environmental protection) | $0

Maintenance hours | 340 hours/year | 16 hours/year (detection only)

Annual replacement times | 2.3 times | 0 times (continuous use) |

Total savings in three years: $2.17 Million

Solve polythionic acid corrosion and hydrogen-induced cracking

Hydrogen trap design: Nano-TiC particles are implanted in the lattice, and the hydrogen diffusion coefficient of Alloy Steel Blind Flange is reduced to 2.1×10⁻¹¹ m²/s, while traditional steel is >10⁻⁹

Grain boundary purification technology: Carbon content ≤ 0.02% + Niobium stabilization treatment completely eliminates Cr₂₃C₆ precipitation

Adaptation to extreme working conditions

Environment Performance boundary Certification standard

Neutron irradiation (nuclear power plant application) 1×10¹⁹ n/cm² flux after toughness retention 89%

High temperature sulfur corrosion (containing vanadium salts) Alloy Steel Blind Flange Corrosion rate at 650℃ <0.5mm/year

Wet carbon dioxide environment (CO₂ 30%) No pitting in 20MPa supercritical phase ISO 15156-3