26CrMo4 belongs to the Cr-Mo series of alloy steels. Its actual composition includes Cr (0.95%–1.10%) and Mo (0.40%–0.50%). The typical composition also includes:

• C: 0.22%–0.28%

• Mn: 0.50%–1.00%

• Si: ≤0.40%

• P/S: ≤0.015% (Strictly controlled at low levels to reduce impurities)

• Trace elements like Ti, Nb, and B, which are used for grain refinement and improving hardenability.

2. Mechanical Properties and Heat Treatment Process

（1）Basic Mechanical Properties:

• Tensile strength: 850–1100 MPa (in hot-rolled state), can reach 1325 MPa after tempering at 400°C.

• Yield strength: 650–850 MPa (in hot-rolled state); after quenching and tempering, it can reach 1138 MPa at 480°C.

• Elongation: ≥20%.

• Impact toughness: The impact energy at 0°C can reach 227 J (after tempering at 700°C).

（2）Heat Treatment Process:
26CrMo4 is optimized through a quenching and tempering process:

• Quenching: Water quenching at 910°C results in a fine martensitic structure with austenite grain size reaching grade 9.

• Tempering: The temperature range is 400–740°C. As the tempering temperature increases, strength decreases, but toughness improves.

400–600°C: Tensile strength decreases at a rate of 1.685 MPa/°C, forming tempered sorbite.

640–730°C: The tensile strength decreases more rapidly at a rate of 2.822 MPa/°C, and carbides precipitate and aggregate.

At 700°C, tempering achieves the best impact toughness, maintaining 110 J low-temperature toughness at -70°C.

3. Applications

（1）Petroleum and Natural Gas Industry:

• Used for manufacturing P110-grade high-extrusion-resistant oil casings, suitable for harsh environments in deep wells and H2S-containing environments, meeting API standards for extrusion resistance.

• In tertiary compound drive (ASP) solution, it shows a low corrosion rate, with the main corrosion products being Fe(OH)₃ and FeCO₃.

（2）Engineering Machinery:

• Used in the manufacture of high-load components such as excavator arms and hydraulic cylinders, relying on its high strength and wear resistance.

（3）Aerospace:

• Used for aircraft engine components and structural parts, ensuring stability under high-temperature and high-pressure conditions.

4. Production Process Control
Strict control is required at several stages of production:

（1）Smelting and Refining:

• Using the “BOF-LF-VD-CC” process (blast furnace → steel refining → vacuum degassing → continuous casting), the steel’s purity is controlled to ensure gas content of [N] ≤ 60 ppm, [H] ≤ 1.5 ppm, and [O] ≤ 30 ppm.

（2）Continuous Casting Process:

• Full protection during casting, weak cooling process reduces central porosity (≤2.0 level) and shrinkage defects.

5. Corrosion Resistance

• 26CrMo4 significantly enhances resistance to hydrogen sulfide stress corrosion (SSC) through carbon reduction, increased molybdenum, and trace additions of B, Ti, and Nb. 

• It performs better than ordinary Cr-Mo steels in H2S-containing oil fields and is suitable for acidic environments.

6. Comparison with Similar Materials
Compared with regular Cr-Mo steels, 26CrMo4 offers the following advantages:

（1）Better Hardenability: The addition of B delays the bainitic transformation, ensuring high hardenability even with low carbon content.

（2）Structural Stability: The addition of Nb/Ti refines the grain structure, and the dispersed distribution of carbides enhances high-temperature tempering stability.

7. Summary
26CrMo4,with its high strength, excellent corrosion resistance, and machinability, has become a key material for advanced equipment manufacturing. Its performance optimization relies on precise composition design, heat treatment processes, and strict production control. In the future, as oil and gas exploration extends to deeper and more complex formations, the application prospects for this material will continue to expand.

8. About Suzhou Bolaibao Metal
At Suzhou Bolaibao Metal, we are committed to providing high-performance materials that meet the needs of advanced industries. With its outstanding strength, corrosion resistance, and excellent machinability, 26CrMo4 plays a critical role in the manufacturing of key equipment in the petrochemical, aerospace, and heavy machinery industries.

We ensure that every stage of the production process, from precise chemical composition design to strict heat treatment control, guarantees the reliability and durability of our products in the harshest environments.

Choose Suzhou Bolaibao Metal for premium alloy steel material solutions, meeting your most challenging engineering needs. 

For more technical information and cooperation opportunities, please contact us:

• Phone: +86 15366282159

• Email: sale@bolaibao1.com

• Official website: http://blbmetal.com