Incoloy 926 (also known as Alloy 926, N08926 or 1.4529) is a highly corrosion-resistant nickel-chromium-molybdenum alloy. Nitrogen is added to enhance its performance. It has both high-temperature strength (maximum operating temperature of about 650°C) and extreme environmental corrosion resistance (especially resistance to chloride and acidic media corrosion). Its fasteners (bolts, nuts, hexagon socket bolts, etc.) are irreplaceable in the following fields:

I. Core application fields

1. **Chemical and petrochemical equipment**

**Acidic reactors/tanks**: used for reactor flange bolts and tank connectors containing strong corrosive media such as chloride ions, sulfuric acid, hydrofluoric acid, and acetic acid, significantly extending the life of the equipment.

**Refinery high-temperature pipelines**: Resistant to hydrogen sulfide (H₂S) stress corrosion cracking, suitable for acidic oil and gas field wellhead equipment and refining equipment.

**Phosphoric acid/sulfuric acid production system**: Fasteners used in evaporators, mixers, and filters, resistant to high-temperature concentrated acid corrosion.

2. **Marine Engineering and Energy**

**Seawater Desalination Equipment**: Evaporator bolts are resistant to high-concentration brine corrosion, preventing pitting and crevice corrosion.

**Deep-sea Oil Platform**: Underwater wellhead tools and Christmas tree bolts maintain stability in high-pressure, high-chloride ion environments.

**Nuclear Power Plant Components**: Nuclear reactor heat exchanger pipe fasteners are resistant to radiation swelling and high-temperature pure water corrosion.

3. **Environmental Protection and Power System**

**Flue Gas Desulfurization (FGD) Device**: Absorber and flue bolts resist corrosion from sulfur dioxide and wet desulfurization media.

**Power Plant Condensation System**: Circulating water pipeline bolts serve for a long time in chlorinated cooling water to avoid rust and leakage.

4. **Aerospace and High-end Manufacturing**

**Jet Engine Combustion Chamber**: High-temperature bolts (such as turbine disc fasteners) maintain strength at 650°C and resist oxidation gas scouring.

**Rocket Propulsion System**: Liquid oxygen/fuel pipeline connectors are resistant to thermal cycling stress.

2. Precautions for use and processing

1. **Heat treatment requirements**

It needs to be treated in a vacuum furnace or a gas protection furnace to avoid sulfur and phosphorus pollution that may lead to performance degradation.

2. **Work hardening control**

Cold processing requires intermediate annealing, and the hot processing temperature range is 1200℃～900℃, followed by water quenching and solid solution.

3. **Installation specifications**

Avoid direct contact with aluminum/magnesium alloys to prevent galvanic corrosion; high temperature conditions require regular re-tightening to offset stress relaxation.

**Conclusion**:

Incoloy 926 fasteners are the preferred solution for the three extreme environments of **chemical strong acid, marine high chlorine, and energy high temperature**, especially when replacing high-cost nickel-based alloys (such as Hastelloy), which are both economical and reliable. The selection needs to match the heat treatment process based on the medium composition (such as Cl⁻, H₂S concentration) and temperature and pressure parameters.