The material for nuts, code 300100, defines the engineering material specifications for fastening nuts used throughout the MAN L21/31 engine. These fastening components are typically manufactured from carefully selected high-strength alloy steels capable of resisting high preload forces, cyclic mechanical stresses, vibration, corrosion, and elevated operating temperatures encountered during continuous engine service. Strict material specifications ensure consistent mechanical strength, dimensional stability, and reliable clamping performance throughout the service life of the engine. Proper material selection is essential for maintaining the integrity of bolted joints, preventing premature loosening or failure, and preserving the structural stability of critical engine assemblies. High-quality fastening materials therefore contribute directly to operational safety, maintenance efficiency, and the long-term reliability of the MAN L21/31 engine.