GJB 1998A-2021
General specification for rolled homogeneous steel armor parts for armored vehicles (English Version)
- Standard No.
- GJB 1998A-2021
- Language
- Chinese, Available in English version
- Release Date
- 2021
- Published By
- Military Standard of the People's Republic of China-General Armament Department
- Latest
- GJB 1998A-2021
- Introduction
Standard Evolution and Core Changes
Revision Dimensions 1994 Edition 2021 Edition Technical Impact Thickness Specification Limited Expanded to 4-80mm Covering more armored vehicle model requirements Brinell Hardness Single Range Classification Adjustment (Class 1/2) Adapt to different ballistic requirements Ballistic Test General conditions Bomb/shell refinement Test accuracy increased by 30%
Analysis of key technical requirements
Mechanical performance indicators
Take 4mm thickness Class 1 armor as an example, the Brinell hardness requirement is 444-514HBW (indentation diameter 2.90-2.70mm), and the hardness difference of the same piece is controlled within 0.15mm. The impact absorption energy must meet both GJB 31A-2000 and GJB 8223-2014 standards.
Fractometry Rating System
Thickness Range Fibrous Slate Layered 25-30mm Level 1 Qualified Judged by Shooting ≤2 Large Laminations >30mm 20% Crystallization Allowed Wood Grain Qualified Total Length≤150mm
Key Points for Implementation of Quality Inspection
Sampling Scheme Comparison
Anti-bullet performance test adopts double sampling rules: 1% (not less than 1 piece) of the conventional batch is sampled, and 100% of the batch with unqualified fracture surface is tested. The shooting distance must be ≥2.5 times the bullet diameter, and the effective impact area is defined based on the maximum straight-line distance of the crater.
Mechanism for handling non-conforming products
- Hardness/impact initial inspection failure: 2 quenching + unlimited tempering
- Fibrous fracture failure: Same as heat treatment correction
- Slate-like/stratified failure: Directly scrapped
Application implementation suggestions
- Material selection: 30CrNi2MnMoRE steel (GJB 31A) is preferred for Class 1 armor parts
- Process control: Hardness testing of large parts (>2㎡) needs to be increased to 3 measuring points
- Acceptance focus: Parts with thickness ≥25mm must be rated for the three elements of fracture
GJB 1998A-2021 history
- 2021 GJB 1998A-2021 General specification for rolled homogeneous steel armor parts for armored vehicles
- 1994 GJB 1998-1994 General specification for rolled homogeneous steel armor parts for armored vehicles