HY-130 Steel
HY-130 (High Yield 130) is the highest-strength member of the HY naval steel family, providing 130,000 psi minimum yield for the most depth-critical submarine hull and pressure vessel applications. Its 5Ni-Cr-Mo-V composition delivers the yield strength required for extreme-depth operation while maintaining sufficient fracture toughness for reliable performance in the demanding shock-loading environment of naval service.
Governed by MIL-S-24371 (now cancelled but historically applicable), HY-130 requires the most stringent weld procedures of any HY-grade — mandatory preheat of 300–400°F, low-hydrogen consumables, strict inter-pass temperature control, and post-weld heat treatment. The higher strength and lower ductility compared to HY-80/100 demand careful heat-affected zone management to prevent delayed hydrogen cracking during fabrication.
Product Forms & Size Range of HY-130 Steel
HY-130 plate per MIL-S-24371 is available in thicknesses up to 3.000″ and widths up to 120″, quenched and tempered. Minimum yield 130,000 psi (896 MPa), minimum tensile 140,000 psi (965 MPa). Charpy V-notch: ≥50 ft·lb at −60°F. All material requires NAVSEA certification and full traceability documentation.
HEAT TREATMENT OF HY-130 STEEL
HY-130 is produced quenched and tempered: austenitize at 1600–1700°F, water quench, temper at 950–1050°F (510–566°C) to achieve the 130 ksi minimum yield. Lower tempering temperatures than HY-80/100 are required. Welding demands preheat of 300–400°F, minimum inter-pass temperature maintained, and post-weld stress relief at 900–1000°F to prevent cold cracking in the heat-affected zone of the higher-strength material.
HY-100 Steel
Lower-strength companion grade at 100 ksi — less demanding weld procedure requirements, used for less depth-critical hull sections.
HY-80 Steel
The original HY-grade naval steel at 80 ksi yield — most widely used for submarine hull construction with best weldability of the HY family.
Certified Material for Critical Service
HY-130 steel is supplied to MIL-S-24371 (historical). Current procurement references NAVSEA Technical Publication T9074-BD-GIB-010/0300 for high-strength naval structural steel. Full material traceability, NAVSEA qualification, and weld procedure qualification are required for all submarine pressure hull applications.