About 30CrMnSiA Alloy Structural Steel

I. Material Specifications and Applicable Standards

30CrMnSiA is a medium-carbon, low-alloy, ultra-high-strength quenched and tempered structural steel that complies with the national standard GB/T 3077-2015, "Alloy Structural Steels," and also meets the military standard GJB 2150A-2005, "Specifications for Hot-Rolled Steel Sheets of Alloy Structural Steels for Aerospace Applications." In the international market, this grade has properties similar to those of the U.S. SAE/AISI 4130 and the Russian 30ХГС (GOST standard), among others, and serves as a core material in the aerospace and high-end equipment manufacturing sectors.

II. Chemical Composition and Mechanical Properties

The chemical composition of 30CrMnSiA is precisely formulated: carbon content 0.28%–0.34%, silicon 0.90%–1.20%, manganese 0.80%–1.10%, chromium 0.80%–1.10%, and sulfur and phosphorus both controlled below 0.025%, ensuring the material’s high purity and excellent overall mechanical properties. After quenching and tempering, this material has a tensile strength of no less than 1080 MPa, a yield strength of no less than 835 MPa, an elongation of ≥10%, a reduction of area of ≥45%, and a room-temperature impact energy of ≥39 J, combining high strength with sufficient toughness. Research data indicates that under an optimized process involving quenching at 880°C followed by tempering at 520°C, the tensile strength can reach 1,098 MPa, the yield strength 985 MPa, and the impact energy absorption 181 J, demonstrating ample performance reserves.

III. Heat Treatment and Process Characteristics

The heat treatment specifications for 30CrMnSiA are quenching at 880°C followed by oil cooling, and tempering at 540°C followed by water or oil cooling. After tempering, the microstructure consists of tempered sorbite. This material exhibits good hardenability, minimal machining deformation, and high fatigue resistance. With regard to welding, 30CrMnSiA has a carbon equivalent of approximately 0.73%. Measures such as preheating before welding, controlling interpass temperatures, and post-weld heat treatment are required to achieve high-quality welded joints. It is suitable for processes such as arc welding and TIG welding. Additionally, this material can undergo surface carburizing or nitriding treatments to further meet wear resistance requirements.

IV. Typical Applications

Thanks to its high strength, high toughness, and excellent fatigue resistance, 30CrMnSiA is widely used in various high-end manufacturing sectors. In the aerospace industry, it is used to manufacture critical load-bearing components such as aircraft landing gear, rocket engine mounts, satellite deployment mechanism hinges, and high-strength bolts. In the defense and military industries, it is used for protective structural components of armored vehicles, load-bearing parts for artillery, and components for specialized equipment. In the construction machinery and automotive manufacturing sectors, it is widely used in hydraulic cylinder piston rods, excavator pins, heavy-duty truck axles, transmission gears, and key suspension system components.

V. Supply and Services

Yangtze Steel Group offers a full range of 30CrMnSiA alloy structural steel products, including hot-rolled sheets, round bars, seamless steel pipes, and custom forgings. Delivery conditions include hot-rolled, annealed, and normalized states, and hardness and machinability can be customized to meet customer requirements. Products are accompanied by third-party certified mechanical property test reports and non-destructive testing reports. We support both small-batch samples and bulk orders. We welcome inquiries based on drawings or samples and will provide you with professional technical selection support and competitive quotes.