RAYCHIN LIMITED

Complete Range of 310 Stainless Steel Lock Nuts

Manufacturing Standards for 310 Stainless Steel Lock Nuts

RAYCHIN LIMITED manufactures 310 stainless steel lock nuts to the following national and international standards, ensuring full compliance for projects worldwide. Both standard and non-standard custom configurations are available.

International Standards & Global Designations for 310 Stainless Steel Lock Nuts

To serve clients worldwide, RAYCHIN LIMITED manufactures 310 stainless steel lock nuts from material conforming to the following national and international specifications. This ensures full compliance for projects in the Americas, Europe, Asia, and the Middle East.

UNS S31000 UNS S31008 1.4845 X8CrNi25-21 SUS310 ASTM A479 DIN 980 ISO 7042

Chemical Composition (Weight %) – 310 Stainless Steel (UNS S31000 / 1.4845)

Our 310 stainless steel lock nuts are produced from melts that strictly conform to the limits below per ASTM A479 / UNS S31000. The high chromium (25%) and nickel (20%) content provide exceptional oxidation resistance and high-temperature strength. The high carbon content ensures excellent creep resistance at elevated temperatures.

Expert note: The high chromium content (25%) forms a protective Cr₂O₃ layer that provides exceptional oxidation resistance up to 1150°C (2100°F). The high nickel content (20%) stabilizes the austenitic structure and provides excellent resistance to carburization and thermal fatigue. For improved weldability and resistance to sensitization, 310S (UNS S31008) with lower carbon (0.08% max) is available. 310H (UNS S31009) with controlled carbon range (0.04-0.10%) is available for applications requiring optimum creep strength.

Complete Mechanical Properties of 310 Stainless Steel Lock Nuts (Solution Annealed Condition)

310 stainless steel lock nuts are supplied in the solution annealed condition (1040°C minimum followed by water quenching). The data below represent minimum values per ASTM A479 and EN 10088-3. Lock nuts are proof load tested to ensure compatibility with mating bolts.

Mechanical Properties at Room Temperature

High Temperature Performance of 310 Stainless Steel Lock Nuts

Grade 310 is specifically designed for high-temperature service. Its high chromium and nickel content provide exceptional resistance to oxidation and scaling, while maintaining good mechanical properties at elevated temperatures. 310 stainless steel lock nuts are widely used in furnace applications, heat treatment equipment, and power generation components. All-metal lock nuts maintain their locking properties throughout the full temperature range up to 1150°C.

Maximum Service Temperatures

The excellent oxidation resistance is due to the formation of a tight, adherent Cr₂O₃ scale that protects the underlying metal. This protective layer reforms rapidly if damaged, provided sufficient chromium is available. 310 also offers good resistance to sulfidation and other forms of hot corrosion, outperforming lower alloy grades.

Temperature-Dependent Mechanical Properties

The table below shows typical mechanical properties at elevated temperatures. Note that strength decreases with increasing temperature, but 310 maintains useful strength up to its maximum service temperature.

Creep and Rupture Strength

For applications requiring long-term stress at elevated temperatures, creep and rupture strength are critical considerations. 310 stainless steel offers excellent creep resistance due to its high carbon content and fully austenitic structure. Typical 10,000-hour rupture strength values:

Thermal Stability Limits

Corrosion Resistance of 310 Stainless Steel Lock Nuts

While 310 is primarily selected for high-temperature applications, it also offers excellent corrosion resistance in many environments due to its high chromium and nickel content.

Oxidation and Scaling Resistance

The high chromium content (25%) provides exceptional resistance to oxidation and scaling. 310 stainless steel lock nuts can be used in air up to 1150°C (2100°F) continuously without significant scaling. In intermittent service, the maximum temperature is slightly lower at 1095°C (2000°F).

Corrosion in Other Environments

High-Temperature Corrosion Considerations

• Sulfidation: Good resistance to sulfidation and atmospheres where sulfur dioxide gas is encountered at elevated temperatures.
• Carburization: High nickel content provides good resistance to carbon absorption, though in strongly carburizing atmospheres, higher nickel alloys may be preferred.
• Thermal Cycling: 310 provides high resistance to thermal fatigue and cyclic heating. It is not suggested for severe thermal shock of repeated liquid quenching.
• Sigma Phase: Avoid regular use from 425°C to 860°C when immediate aqueous corrosion resistance is required due to carbide precipitation.
• Nylon Insert Limitations: Nylon insert lock nuts are limited to 120°C maximum service temperature.

High-Temperature Engineering Note: For critical applications in high-temperature environments, RAYCHIN LIMITED can provide specialized surface treatments, passivation, or recommend optimal heat treatment conditions. Third-party testing per ASTM standards available upon request. When specifying 310 stainless steel lock nuts, consider the maximum service temperature, atmosphere composition, and mechanical load requirements. All-metal lock nuts are recommended for applications above 120°C.

Why RAYCHIN LIMITED – The 310 Stainless Steel Lock Nut Authority