Specification for stainless and heat-resistant steel round cakes and ring blanks for aviation (GJB 2455-1995)

GJB 2455-1995 Specification for stainless and heat- resistant steel billets and rings for aerospace

The provision of GJB 2455-1995 is issued with the intention of elaborating the requirements of stainless and heat-resistant steel billets and rings for aerospace.

The stainless and heat-resistant steel billets and rings specified in this specification are used for aircraft airframe parts, rocket components and other related products in the aerospace.

This specification covers stainless and austenitic, ferritic and martensitic heat-resistant steel billets and rings with a diameter ranging from 300 mm to 380 mm, manufactured in accordance with ASTM A240/A240M-18, ASTM A276/A276M-18, ASTM A312/A312M-18, ASTM A473-19 and ASTM A479/A479M-19 standards.

The material should be annealed in accordance with ASTM A240/A240M-18 and ASTM A312/A312M-18 standards.

1.1 The chemical compositions in percentage weight of stainless and heat-resistant steel billets and rings covered in this specification shall comply with the requirements prescribed in Table 1.

1.2 The mechanical properties of stainless and heat-resistant steel billets and rings specified in this specification shall comply with the requirements prescribed in Table 2.

Surface and Edges. The surface and edges of the steel billets and rings shall be free from scale and corrosion. The edges shall be free from cracks, oxides, and other defects.

2.3 The hardness of the surface of the steel billets and rings shall meet the requirements specified in Table 3.

2.4 The ultrasonic inspection of the steel billets and rings shall comply with the requirements specified in Table 4.

3.5 The ferrite content of the steel billets and rings shall be determined by means of magnetic particle inspection.

4. Application

The stainless and heat-resistant steel billets and rings specified in this specification are intended for use in the aerospace industry for aircraft airframe parts, rocket components and other related products.

This specification shall be read in conjunction with the applicable product standards.

TABLE 1

Quantity |

Chemical Composition (Weight %) |

Carbon (C) | 0.030 max

Manganese (Mn) | 1.00 max

Silicon (Si) | 0.75 max

Phosphorus (P) | 0.040 max

Sulfur (S) | 0.030 max

Chromium (Cr) | 17.0 - 19.0

Molybdenum (Mo) | 2.50 - 3.50

Nickel (Ni) | 8.0 - 11.0

Nitrogen (N) | 0.10 max

TABLE 2

Mechanical Properties |

Yield Strength | 0.2% offset, 25 ksi (170 MPa) minimum

Tensile Strength | 100 ksi (690 MPa) minimum

Elongation in 2 in. or 50 mm | 35% minimum

TABLE 3

Surface Hardness | Rockwell Hardness (HRc) 20-25

TABLE 4

Ultrasonic Testing Requirements |

Required | Exclusions |

Ultrasonic testing of the material is required. |

Ultrasonic testing is not required for parts with a thickness less than 6.25 mm (0.25 in.). |

Ultrasonic testing is not required for parts with a depth of notchless grooves less than 6.25 mm (0.25 in.). |

Ultrasonic testing is not required for internal profiles or other complex geometries. |

In conclusion, GJB 2455-1995 is a specification that provided requirements for stainless and heat-resistant steel billets and rings for aerospace. The steel billets and rings should be manufacture in accordance with ASTM standards and meet the specific chemical and mechanical requirements. Besides, ultrasonic testing and magnetic particle inspection should be conducted in order to ensure the quality of the steel billets and rings. The steel billets and rings shall be used in the aerospace industry for aircraft airframe parts, rocket components and other related products.

The GJB 2455-1995 standards for aircraft stainless steels and heat-resistant steel round blooms and hoops provide requirements for establishing mechanical and physical performance. This standard requires that the steels be thoroughly cleaned and inspected by trained professional personnel before use as a raw material. These items are also to be marked in accordance with the standard to ensure traceability and proper identification.

The mechanical properties of these items must be in accordance with GJB 2455-1995 requirements, which include yield strength, tensile strength, elongation, bend and impact tests. The physical properties of these items must also meet these standards, which includes density, thermal conductivity, electrical conductivity, thermal diffusivity, and magnetic permeability. In addition, the hardness, flaring, notching, corrosion resistance and other special requirements must meet the standard.

The GJB 2455-1995 requirements also specify the inspected dimensions, such as the allowable deviations from size, shape and weight. The standard further specifies the requirements for end-use structure products, including dimensional tolerances, surface requirements, surface coating and lubricants. These standards also specify necessary packaging and labeling requirements for transport and storage purposes.

It should be noted that the GJB 2455-1995 standard is not applicable to non-stainless steels and non-heat-resistant steel round blooms and hoops. In addition, non-aircraft steels used in other industries are also not subject to this standard. The application of this standard is strictly limited to aircraft stainless steels and heat-resistant steel round blooms and hoops. It is important to note that failure to comply with the GJB 2455-1995 standards can lead to serious safety and quality issues. Therefore, it is important to adhere to the requirements.