⚙ Products Features

7709 steel is a high-performance alloy steel, also known as 21CrMoV5-7, and is widely used in the manufacturing of high-strength, high-temperature-resistant fasteners such as bolts and nuts. The following is an in-depth introduction to the screws made of 1.7709 material:

🔧 Application

High-temperature high-strength fasteners (H-T H-S Fasteners) need to simultaneously meet requirements such as high-temperature strength, anti-rust property and corrosion resistance in extreme environments. Their core application fields are as follows:

• (1) Aerospace Field

  Aerospace engine: The turbine blade fasteners are manufactured using nickel-based high-temperature alloys (such as GH4049), maintaining a tensile strength of ≥ 1000 MPa at 600–900℃, and achieving complex shape processing through die forging technology.

  Spacecraft structure: Components used for connecting the combustion chamber of the rocket engine, must withstand instantaneous high temperatures (>1200℃) and vibration loads.

• (2) Energy and Power Industry

  Nuclear power plant: The bolts of the reactor pressure vessel must meet a lasting strength of ≥ 95 MPa (at 700°C/100,000 hours), to prevent hydrogen embrittlement and stress corrosion cracking.

  Gas turbine: High-temperature bolts (such as A286 alloy) are used to fix the turbine discs and must undergo creep limit tests (1% total deformation/1000 hours).

• (3) Petroleum Chemical Industry and Marine Engineering

  Refining and processing unit: The bolts of the hydrogenation reactor need to be used for a long time under high temperature and high pressure (400℃/20MPa), and the material must pass the hydrogen-induced delayed fracture test.

• (4) Commercial Installation

  Mold manufacturing: The fastening components of composite material molds need to match a low thermal expansion coefficient (CTE ≤ 10⁻⁶/℃) to maintain dimensional stability.

• (5) Automobiles and Rail Transit

  New energy vehicles: The motor shaft bolts are made of titanium alloy (such as TC4), with a tensile strength of up to 900 MPa and no magnetic interference. The tapping process needs to be optimized to reduce work hardening.

📋 The Following Is the Main Types of High Temperature Fasteners