SS 310 series

Stainless steel 310/310S is an austenitic heat-resistant alloy with excellent resistance to oxidation under mildly cyclic conditions through 2000°F. Its high chromium and nickel contents provide comparable corrosion resistance, superior resistance to oxidation and the retention of a larger fraction of room temperature strength than the common austenitic alloys like Type 304. Stainless 310 is often used at cryogenic temperatures, with excellent toughness to -450°F, and low magnetic permeability.

Stainless Steel 310/310S was designed to be the low-carbon version of SS 310, medium-carbon stainless steel. 310S has many of the same characteristics and applications as 310, such as the ability to withstand high temperatures, resistance to oxidation and corrosion, and machinability similar to that of Type 304. Composed of 20% nickel and 25% chromium, 310S is efficient in reducing environments such as those that contain sulfur. Combined with its low carbon content, the metal is also effective at resisting embrittlement. The metal is commonly utilized in extreme conditions, such as furnace manufacturing and heat-treating equipment. While both hot and work practices can be applied, cold working is not commonly done on Stainless Steel 310S; however, it is the only way to work harden the metal. This resistance to cold temperatures is useful in cryogenic environments, as 310S is incredibly tough. However, it can be subject to thermal shock and therefore should be treated and hot-worked with care.

Stainless Steel 310H is the preferred metal of choice for high-temperature conditions out of the 310 Stainless Steel grades. It finds use in the heat treatment industry, including the containment of concentrated acids. 310H is often exposed to sulfur dioxide environments and displays a high level of resistance to negative effects, as well as those from oxidation at high temperatures. The metal also displays increased resistance against creep corrosion. While 310S is the low-carbon version of the 310 grades, 310H is the high-carbon modification of the metal specifically designed for better resistance to creep, as aforementioned. Its resistance to corrosion in high-temperature environments exceeds that of many other stainless steel alloys. However, it does not display the same resistance against aqueous corrosion. In wet environments, its high carbon content works as a limitation. While the metal can be easily welded and is relatively ductile, cold work practices should be carried out with caution. Extended exposure to cold work can cause carbon precipitation.

As you can see below, Grade 310S is a low-carbon version of Grade 310. 310S is less prone to embrittlement and sensitization in service.

Difference between SS310 - SS310S - SS310H

310, 310S and 310H stainless steel plate is austenitic stainless steel used in high-temperature applications. It is used in temperatures up to 2,100℉ in continuous service. This grade contains 25% chromium and 20% nickel, making it highly resistant to oxidation and corrosion. 310S stainless steel is the lower carbon version of the 310 plate which is less prone to embrittlement and sensitization in service. 310H stainless steel plate is the high-carbon version. They are widely used in moderately carburizing atmospheres, as encountered in petrochemical environments. These grades are not recommended for frequent liquid quenching as it suffers from thermal shock. It is often used in cryogenic applications, due to its toughness and low magnetic permeability.

Specification

These properties are specified for flat rolled products (plate, sheet and coil) in ASTM A240/A240M (310S and 310H) and ASTM A167 (310). Similar but not necessarily identical properties are specified for other products such as pipes and bars in their respective specifications.

Chemical Composition, %

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Applications of Stainless Steel 310 Series

• Cryogenic Components
• Food Processing
• Furnaces — burners, doors, fans, piping and recuperators
• Fluidized Bed Furnaces — coal combustors, grids, piping, wind boxes
• Ore Processing/Steel Plants — smelter and steel melting equipment, continuous casting equipment
• Petroleum Refining — catalytic recovery systems, flares, recuperators, tube hangers
• Power Generation — coal gasifier internals, pulverized coal burners, tube hangers
• Sintering/Cement Plants — burners, burner shields, feeding and discharging systems, wind boxes
• Thermal Processing — annealing covers and boxes, burner grids, doors, fans, muffles and retorts, recuperators, walking beams

Physical Properties 

• Density: 0.285 Ibs/in³  - 7.89 g/cm³
• Electrical Resistivity: 30.7 Microhm-in at 68°F - 78.0 Microhm-cm at 20°C
• Melting Range: 2470 – 2555°F - 1354 – 1402°C
• Specific Heat: 0.12 BTU/lb-°F (32 – 212°F)  -  502 J/kg-°K (0 – 100°C)
• Modulus of Elasticity: 28.5 x 10⁶ psi  - 196 GPa
• Thermal Conductivity: 8.0 BTU/hr/ft2/ft/°F  -  10.8 W/m-°K

For more details click the PDF here and with all regulations here

Coefficient of linear thermal expansion 10^-6 K^-1 between 20°C and

 Thermal Conductivity 212°F (100°C)

• 8.0 BTU/hr/ft2/ft/°F
• 10.8 W/m-°K

 Electrical Resistivity (Annealed Condition)

• 30.7 Microhm-in at 68°F
• 78.0 Microhm-cm at 20°C

Specific Heat

• 0.12 BTU/lb-°F (32 – 212°F)
• 502 J/kg-°K (0 – 100°C)

 Heat Resistance of Stainless Steel 310 series

Steel 310/310S offers excellent oxidation resistance properties while intermittent service at temperatures 1035^oC and at 1050^oC while in regular use in the presence of air. It is superiorly resistant to carburization, oxidation and sulfidation.

310H has good resistance to oxidation in intermittent service in air at temperatures up to 1040°C and 1150°C in continuous service. Good resistance to thermal fatigue and cyclic heating. Widely used where sulphur dioxide gas is encountered at elevated temperatures. Continuous use in 425-860°C range is not recommended due to carbide precipitation if subsequent aqueous corrosion resistance is needed, but it often performs well in temperatures fluctuating above and below this range. Prone to sigma phase embrittlement in the temperature range 650 – 900°C.

 Hot Working of Stainless Steel 310 series

Most common hot work methods can be successfully performed after uniform heating to 2150 F (1177 C). Do not forge below 1800 F (982 C). Rapid cooling is required to maximize corrosion resistance.

Cold Working

Although this alloy has a high work hardening rate, it can be drawn, headed, upset, and stamped. Full annealing is required after cold work to remove internal stress.

Fabrication of Stainless Steel 310 Series

Fabrication Grades 310/310S are forged in the temperature range of 975 - 1175°C. Heavy work is carried out down to 1050°Cand a light finish is applied to the bottom of the range. After forging annealing is recommended to relieve all stresses from the forging process. The alloys can be readily cold-formed by standard methods and equipment.

Fabrication Grades SS 310H Seamless Tubes are done with the help of superior quality of stainless steel alloy that is 100% pure. This thus adds greater superiority in its quality. With the help of the latest technology and modern tools, the production of tubes has become effective. To make sure that produced product quality is well maintained, the quality control team is hired that looks at the quality maintenance. The fabrication is also done as per several product quality standards and according to industry setup norms.

 Mechanical Properties of Stainless Steel 310 Series

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Corrosion Resistance of Stainless Steel 310 Series

The high chromium content - intended to increase high-temperature properties – also gives these grades good aqueous corrosion resistance. The PRE is approximately 25, and seawater resistance is about 22°C, similar to that of Grade 316. In high-temperature service, they exhibit good resistance to oxidising and carburising atmospheres. Resist fuming nitric acid at room temperature and fused nitrates up to 425°C.

Machinability

This alloy machines similar to type 304 stainless. Its chips are stringy and it will work harden rapidly. It is necessary to keep the tool cutting at all times and use chip breakers.

Welding of Stainless Steel 310 Series

Good characteristics suited to all standard methods. Grade 310S electrodes are generally recommended for fusion welding. AS 1554.6 pre-qualifies welding of 310 with Grade 310 rods or electrodes. Oxyacetylene welding is not recommended. The filler metal should be AWS E/ER 310.

Stainless steel grade 310/310S are welded through similar electrodes and filler metals. These are readily weldable through SMAW, GMAW, GTAW and SAW. The preferred electrodes are AWS A5.4 E310-XX and A 5.22 E310T-X and the filler metal is AWS A5.9 ER310. Argon is used as a shielding gas. Preheating and post-heating are not essential, however, for performance in corrosive liquids, complete post-solution annealing processing is required. Pickling and passivation of metal are required to eradicate the elevated temperature metal oxides and make the steel fully corrosion-resistant subsequent to welding. This processing is not essential for elevated temperature functions, but welding slag should be completely eradicated.