Properties and Applications of Grade 310/310s Stainless Steel

Stainless Steel Grade 310 is a medium carbon austenitic stainless steel, for high temperature applications such as furnace parts and heat treatment equipment. It is used at temperatures up to 1150°C in continuous service, and 1035°C in intermittent service. Grade 310S is a low carbon version of grade 310.

Applications of Grade 310/310S Stainless Steel

Typical Applications Grade 310/310S is used in fluidised bed combustors, stainless steel flanges, stainless steel pipe fittings and stainless steel pipes, radiant tubes, tube hangers for petroleum refining and steam boilers, coal gasifier internal components, lead pots, thermowells, refractory anchor bolts, burners and combustion chambers, retorts, muffles, annealing covers, saggers, food processing equipment, cryogenic structures.

Properties of Grade 310/310S Stainless Steel

These grades contain 25% chromium and 20% nickel, making them highly resistant to oxidation and corrosion. Grade 310S is a lower carbon version, less prone to embrittlement and sensitisation in service. The high chromium and medium nickel content make these steels capable for applications in reducing sulphur atmospheres containing H2S. They are widely used in moderately carburising atmospheres, as encountered in petrochemical environments. For more severe carburising atmospheres other heat resisting alloys should be selected. Grade 310is not recommended for frequent liquid quenching as it suffers from thermal shock. The grade is often used in cryogenic applications, due to its toughness and low magnetic permeability.

In common with other austenitic stainless steels, these grades cannot be hardened by heat treatment. They can be hardened by cold work, but this is rarely practiced.

Chemcial Composition of Grade 310/310S Stainless Steel

The chemical composition of grade 310 and grade 310S stainless steel are summarised in the following table.

Table 1. Chemical composition % of grade 310 and 310S stainless steel

Chemical Composition	310	310S
Carbon	0.25 max	0.08 max
Manganese	2.00 max	2.00 max
Silicon	1.50 max	1.50 max
Phosphorus	0.045 max	0.045 max
Sulphur	0.030 max	0.030 max
Chromium	24.00 – 26.00	24.00 – 26.00
Nickel	19.00 – 22.00	19.00 – 22.00

Mechanical Properties of Grade 310/310S Stainless Steel

The mechanical properties of grade 310 and grade 310S stainless steel are summarised in the following table.

Table 2. Mechanical properties of of grade 310/310S stainless steel

Mechanical Properties	310/ 310S
Grade 0.2 % Proof Stress MPa (min)	205
Tensile Strength MPa (min)	520
Elongation % (min)	40
Hardness (HV) (max)	225

Physical Properties of Ferritic Stainless Steel

The physical properties of grade 310 and grade 310S stainless steel are summarised in the following table.

Table 3. Physical properties of grade 310/310S stainless steel

Properties	at	Value	Unit
Density		8,000	Kg/m3
Electrical Conductivity	25°C	1.25	%IACS
Electrical Resistivity	25°C	0.78	Micro ohm.m
Modulus of Elasticity	20°C	200	GPa
Shear Modulus	20°C	77	GPa
Poisson’s Ratio	20°C	0.30
Melting Rnage		1400-1450	°C
Specific Heat		500	J/kg.°C
Relative Magnetic Permeability		1.02
Thermal Conductivity	100°C	14.2	W/m.°C
Coefficient of Expansion	0-100°C	15.9	/°C
	0-315°C	16.2	/°C
	0-540°C	17.0	/°C

Fabrication of Grade 310/310S Stainless Steel

Fabrication Grades 310/310S are forged in the temperature range 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.

Machinability of Grade 310/310S Stainless Steel

Machinability Grades 310/310SS are similar in machinability to type 304. Work hardening can be a problem and it is normal to remove the work hardened layer by using slow speeds and heavy cuts, with sharp tools and good lubrication. Powerful machines and heavy, rigid tools are used.

Welding of Grade 310/310S Stainless Steel

Welding Grades 310/310S are welded with matching electrodes and filler metals. The alloys are readily welded by SMAW (manual), GMAW (MIG), GTAW (TIG) and SAW. Electrodes to AWS A5.4 E310-XX and A 5.22 E310T-X, and filler metal AWS A5.9 ER310 are used. Argon is shielding gas. Preheat and post heat are not required, but for corrosion service in liquids full post weld solution annealing treatment is essential. Pickling and passivation of the surface to remove high temperature oxides are essential to restore full aqueous corrosion resistance after welding. This treatment is not required for high temperature service, but welding slag should be thoroughly removed.

Heat Treatment of Grade 310/310S Stainless Steel

Heat Treatment Type 310/310S are solution annealed by heating to temperature range 1040 -1065°C, holding at temperature until thoroughly soaked, then water quenching.

Heat Resistance of Grade 310/310S Stainless Steel

Grades 310/310S have good resistance to oxidation in intermittent service in air up to 1035°Cand 1050°Cin continuous service. The grades are resistant to oxidation, sulphidation and carburisation.

Available Forms of Grade 310/310S Stainless Steel

wilsonpipeline Pipe Industry can supply these grades as stainless steel flanges, stainless steel pipe fittings, stainless steel pipes, plate, sheet and strip, bar and rod, seamless tube and pipe, welded tube and pipe, forgings and forging billet, tube and pipe fittings, wire. Corrosion Resistance Grade 310/310S is generally not used for corrosive liquid service, although the high chromium and nickel content give corrosion resistance superior to grade 304. The alloy does not contain molybdenum, so pitting resistance is quite poor. Grade 310/310S will be sensitised to intergranular corrosion after service at temperatures in range 550 – 800°C. Chloride stress corrosion cracking may take place in corrosive liquids containing chlorides at temperatures exceeding 100°C. 

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