1. 1Cr15Ni4Mo3N Stainless Steel

1Cr15Ni4Mo3N, an alloy steel under the former designation of 13Cr15Ni4Mo3N, is a semi-austenitic precipitation-hardening stainless steel known for its unique combination of mechanical properties and corrosion resistance. Below, we provide an overview of its key features, applications, and specifications.

Key Characteristics:

Austenitic Structure: In its solid-solution state, 1Cr15Ni4Mo3N exhibits the characteristics of austenitic stainless steel, making it easily formable and suitable for cold processing.

Martensitic Transformation: Upon heat treatment, the microstructure transitions predominantly into martensite, significantly increasing its strength. This transformation provides an excellent balance between high strength, toughness, and resistance to corrosion.

Applications:

Aerospace Industry: 1Cr15Ni4Mo3N is widely used for critical structural components in the aerospace sector. These include bolts, landing gear joints, and engine fan shafts, all of which require materials with exceptional strength, reliability, and corrosion resistance.

Precision Machinery: In addition to aerospace, this steel is suitable for precision mechanical components such as rotating gears and fasteners, where dimensional accuracy and load-bearing capacity are paramount.

Standards:

The chemical composition and mechanical properties of 1Cr15Ni4Mo3N comply with the standards outlined in GJB 8268-2014, a specification for precipitation-hardened stainless steel bars for aerospace applications.

2. 07Cr16Ni6 Stainless Steel

07Cr16Ni6, previously known as 0Cr16Ni6, is another semi-austenitic precipitation-hardening stainless steel that combines excellent strength, toughness, and corrosion resistance. This alloy is widely used in the aerospace and mechanical industries for demanding applications. Below, we provide detailed specifications, characteristics, and applications.

Chemical Composition:

Carbon (C): 0.05%–0.09%

Silicon (Si): ≤ 0.7%

Manganese (Mn): ≤ 0.8%

Phosphorus (P): ≤ 0.03%

Sulfur (S): ≤ 0.015%

Chromium (Cr): 15.5%–17.5%

Nickel (Ni): 5%–8%

Copper (Cu): ≤ 0.2%

Molybdenum (Mo): ≤ 0.2%

Titanium (Ti): ≤ 0.05%

Tungsten (W): ≤ 0.2%

Vanadium (V): ≤ 0.2%

Niobium (Nb): ≤ 0.15%

Mechanical Properties (Post Heat Treatment):

Tensile Strength (σb): ≥ 1180 MPa

Yield Strength (σs): ≥ 980 MPa

Elongation (δ): ≥ 12%

Reduction of Area (ψ): ≥ 55%

Hardness (HBW): ≤ 302 (Annealed)

Impact Energy (KU2) at Room Temperature: ≥ 71 J

Impact Energy (KV2) at -192°C: ≥ 55 J

Heat Treatment:

Solution Treatment: Heat to 975-1000°C for 1 hour, followed by water quenching.

Aging Treatment: Hold at -70°C to -80°C for 2 hours, then return to room temperature, followed by aging at 350-400°C for 1-3 hours, and naturally cool.

Characteristics:

Microstructure: At room temperature, the material exists as a combination of austenite and a small amount of martensite. Following cold treatment, it transforms into over 90% martensite, which enhances the strength of the material while retaining some residual austenite, ensuring good toughness.

Toughness: The low notch sensitivity and excellent low-temperature toughness make this steel suitable for demanding applications in extreme environments.

Corrosion Resistance: This steel also offers good resistance to corrosion in a variety of environments, including atmospheric conditions, acetic acid, and salt-based solutions.

Applications:

Aerospace Components: Similar to 1Cr15Ni4Mo3N, 07Cr16Ni6 is used for critical load-bearing components in aircraft engines, such as turbine blades, bolts, and fasteners. The alloy is also employed in other flight systems that operate in challenging atmospheric, acidic, and saline environments.

Standards:

The mechanical properties of 07Cr16Ni6 are in accordance with the GJB 8268-2014 and GJB 7960-2012 aerospace standards. In the latter, the alloy is identified by its code S-07, and the standard specifies the notch sensitivity coefficient (RmH/Rm), a key indicator of material toughness. Materials with a higher coefficient indicate greater notch sensitivity, which correlates with reduced toughness.

Both 1Cr15Ni4Mo3N and 07Cr16Ni6 stainless steels are advanced materials used in industries that require superior strength, corrosion resistance, and toughness, particularly in aerospace and precision mechanical applications. The transformation from austenitic to martensitic microstructures through heat treatment enhances the mechanical properties of these steels, making them well-suited for critical, high-stress components. Understanding their composition, heat treatment processes, and mechanical behaviors is essential for selecting the right material for specific applications.