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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:
It mainly consists of carbon (C: 0.17-0.25), silicon (Si: 0.15-0.35), manganese (Mn: 0.35-0.85), chromium (Cr: 1.20-1.50), molybdenum (Mo: 0.65-0.80), and vanadium (V: 0.25-0.35) and other elements. The reasonable proportion of these elements gives the steel excellent comprehensive properties.
In the heat-treated state, 1.7709 steel has high strength and good mechanical properties. Its yield strength (Rp0.2) can reach ≥550 MPa, tensile strength (PM) can reach ≥700 MPa, elongation (A) ≥16%, and reduction of area (A) ≥60%.
This material can still maintain good mechanical properties in high-temperature environments and is suitable for working conditions with temperatures exceeding 300°C.
300M is a medium-carbon nickel-chromium-molybdenum alloy steel, featuring the following characteristics:
The tensile strength can reach 1900-2100 MPa, and the yield strength is over 1600 MPa, making it suitable for withstanding high loads.
It has good plasticity and toughness, capable of resisting fracture under extreme conditions.
Suitable for applications that require long-term exposure to dynamic loads, such as aircraft components.
Through heat treatment (such as quenching and tempering), its hardness and strength can be further enhanced.
High-strength alloy stainless steel, due to its excellent mechanical properties, corrosion resistance and processing adaptability, plays a crucial role in several high-end fields.
Aircraft landing gear and fasteners: Ultra-high strength stainless steel (such as the grade with a tensile strength of ≥ 1500 MPa) is used to manufacture key load-bearing components such as landing gear hinges and bolts, replacing the traditional cadmium-plated high-strength steel to solve the hydrogen embrittlement problem.
Missile and engine components: Martensitic stainless steel (such as X46CrS13) is used for the missile shell and engine locking hooks, featuring high hardness and resistance to high-temperature oxidation.
Deep-sea equipment and pipelines: Duplex stainless steel (such as S31803) is used for submarine pipelines and valves. Its resistance to chloride ion stress corrosion cracking is superior to that of austenitic stainless steel.
Chemical reactor: 1.4945 alloy (containing chromium and nickel) maintains stability under high temperature and high pressure, and is suitable for environments with strong acids and strong bases.
Bridges and Tunnels: Martensitic stainless steel is used for high-strength fasteners to enhance durability.
3D Printing and Additive Manufacturing: 1.4310CSPANN alloy is fabricated into complex components through laser cladding technology, with a strength of 1200 MPa.
| High strength stainless steel product grade | |||
|---|---|---|---|
| 40CrNiMoA | 30CrMnSiA | 21CrMoV5-7 | 1.6772 |
| 20Cr1Mo1VTiB | X22CrMoV12-1 | 1.7709 | 300M |
description2
7709 steel (also known as 21CrMoV5-7) is a high-performance alloy steel that features high strength, heat resistance above 300°C, a yield strength of ≥550 MPa, and a tensile strength of ≥700 MPa. It is widely used to manufacture high-strength, temperature-resistant fasteners like bolts and nuts.
300M is a medium-carbon nickel-chromium-molybdenum alloy steel with ultra-high tensile strength (1900-2100 MPa), exceptional toughness, and excellent fatigue performance. These qualities make it ideal for components subjected to high dynamic loads, such as landing gears.
Ultra-high strength stainless steel (with a tensile strength of ≥1500 MPa) is used to manufacture critical components like hinges and bolts to replace traditional cadmium-plated high-strength steel, successfully eliminating hydrogen embrittlement problems.
Duplex stainless steel (such as S31803) is highly recommended for deep-sea pipelines and valves due to its superior resistance to chloride ion stress corrosion cracking compared to standard austenitic stainless steels.
Available grades include 40CrNiMoA, 30CrMnSiA, 21CrMoV5-7, 1.6772, 20Cr1Mo1VTiB, X22CrMoV12-1, 1.7709, and 300M.
