Stainless Steel 310S Stud Bolts

Stainless Steel 310S Stud Bolts are threaded fasteners that are machined from a high chromium, high nickel austenitic grade designed for elevated temperature service. The 310S grade contains 24-26% chromium and 19-22% nickel, offering excellent oxidation resistance in continuous service to 1050°C. The low-carbon version (310S) minimises the risk of sensitisation in welded assemblies. These studs are ASTM A193 Grade B8T and are used in furnace parts, heat exchangers, boilers, and high-temperature piping. Available across a wide size range and paired with ASTM A194 Grade 8T nuts, UNS S31008 stud bolts are the go-to choice wherever standard 304 or 316 grades fall short of heat demands.

Price of Stainless Steel 310S Stud Bolts

The approximate price range of Stainless Steel 310S Stud Bolts per kg/unit is mentioned below, along with the factors affecting the cost.

Approx Price Range

The price of SS 310S stud bolts in India is Rs. 175 – 250 per kg (Indicative price range). Prices based on size, finish, and quantity ordered.

Price Per Unit / Kg

Pricing for ASTM A193 B8T stud bolts is typically quoted per kg. Smaller diameters or non-standard lengths may be priced per piece. The table below gives a general reference.

Diameter	Approx Price Per Piece (INR)
M8 – M12	Rs. 30 – 65
M16 – M20	Rs. 75 – 165
M24 – M30	Rs. 200 – 420
M36 and above	Rs. 500 – 950+

Factors Affecting Price

Size, quantity, raw material costs, grade certification, surface finish, and thread specification all influence the final price of SS 310S stud bolts.

Types of ASTM A193 B8T 310S Stud Bolts

SS 310S stud bolts come in several configurations to suit different joint designs and service conditions.

Fully Threaded Stud Bolts (UNS S31008)
Double-End Stud Bolts (ASTM A193 B8T Stud Bolts)
Tap-End Stud Bolts
Collar Stud Bolts
Stud Bolts with Heavy Hex Nuts

Specifications of Stainless Steel 310S Stud Bolts

The table given below covers the key specification standards for Stainless Steel 310S stud bolts, including length, diameter, and finish.

Parameter	Details
Material Standard	ASTM A193 / ASME SA193
Grade	B8T (Class 1 and Class 2)
UNS Number	UNS S31008
Nut Standard	ASTM A194 Grade 8T
Thread Type	UNC, UNF, Metric
Length	25 mm to 3000 mm (custom available)
Diameter Range	M6 to M100 / 1/4" to 4"
Finish	Plain, Passivated, Electropolished
Max Service Temp	1050°C (continuous), 1150°C (intermittent)
Certification	Mill Test Certificate, EN 10204 3.1

Chemical Properties of Stainless Steel 310S Stud Bolts

The chemical composition below is for grade 310S (UNS S31008) stud bolts, listed along with their proportion in percentage.

Element	Value (%)
Carbon (C)	0.08
Manganese (Mn)	2.00
Phosphorus (P)	0.045
Sulphur (S)	0.030
Silicon (Si)	1.50
Chromium (Cr)	24.00 - 26.00
Nickel (Ni)	19.00 22.00
Iron (Fe)	Balance

Mechanical Properties of Stainless Steel 310S Stud Bolts

The table below lists mechanical properties for ASTM A193 B8T (Class 1) and B8T (Class 2) stud bolts.

Property	Class 1	Class 2
Tensile Strength	515 MPa (75 ksi) min	690 MPa (100 ksi) min
Yield Strength (0.2% offset)	205 MPa (30 ksi) min	450 MPa (65 ksi) min
Elongation	30% min	20% min
Reduction of Area	50% min	45% min
Hardness (Brinell)	223 HBW max	321 HBW max

Physical Properties of Stainless Steel 310S Stud Bolts

These are the standard physical properties of the 310S base material used in stud bolt manufacture.

Property	Value
Density	7.98 g/cm³
Melting Point	1400 – 1450°C
Modulus of Elasticity	200 GPa
Thermal Conductivity	14.2 W/m.K at 100°C
Electrical Resistivity	0.78 µΩ.m
Magnetic Permeability	Non-magnetic (annealed state)
Specific Heat Capacity	500 J/kg.K
Coefficient of Thermal Expansion	15.9 µm/m°C (0–100°C)

Dimension Chart of SS 310S Stud Bolts

The table below provides standard dimensions for double-end stud bolts per ASME B16.5 for raised-face flanges at 150 Class.

NPS	Bolt Dia (inches)	Bolt Length (inches)	No. of Bolts
1/2"	1/2	2-1/2	4
3/4"	5/8	2-3/4	4
1"	5/8	3	4
1-1/2"	3/4	3-1/2	4
2"	5/8	3-1/2	8
3"	3/4	4	8
4"	3/4	4-1/2	8
6"	3/4	5	12
8"	7/8	5-1/2	12
10"	1	6-1/2	16
12"	1	7	16

Size Chart of Stainless Steel 310S Stud Bolts

The chart below covers metric sizes available from standard suppliers, including thread pitch and approximate weight per piece.

Diameter (mm)	Thread Pitch (mm)	Shank Length Range (mm)	Weight Per Piece (g, approx.)
M6	1.0	20 – 150	2 – 12
M8	1.25	20 – 200	4 – 25
M10	1.5	25 – 250	7 – 50
M12	1.75	30 – 300	12 – 85
M16	2.0	40 – 400	28 – 180
M20	2.5	50 – 500	55 – 340
M24	3.0	60 – 600	95 – 600
M30	3.5	80 – 700	190 – 1100
M36	4.0	100 – 800	325 – 1900

Torque Chart of Stainless Steel 310S Stud Bolts

Use these values as a starting reference. Always follow the equipment manufacturer's torque specification for final assembly.

Bolt Diameter	Lubricated Torque (Nm)	Dry Torque (Nm)
M8	12 – 16	16 – 22
M10	24 – 32	33 – 44
M12	40 – 55	56 – 75
M16	100 – 130	140 – 180
M20	190 – 250	270 – 350
M24	330 – 430	460 – 600
M30	660 – 850	920 – 1200
M36	1150 – 1480	1600 – 2050

Key Features of Stainless Steel 310S Stud Bolts

Here's what makes UNS S31008 stud bolts stand out in high-heat environments.

Superior oxidation and carburisation resistance at high temperatures.
Rated for continuous service.
Low risk of sensitisation in welded or heat-affected zones.
Non-magnetic in the annealed condition.
Compliant with ASTM A193 / ASME SA193 B8T.
Available in Class 1 (solution treated) and Class 2 (strain hardened) to meet different load requirements.
Resistant to sulphidation and scaling in high-temperature gas environments.
Paired with ASTM A194 Grade 8T nuts for a correctly matched high-temperature fastener assembly.

Applications of Stainless Steel 310S Stud Bolts

ASTM A193 B8T 310S stud bolts are specified wherever elevated temperature and oxidising conditions are involved.

Industrial furnaces and kilns
Heat exchangers and boilers
Petrochemical and refinery units
Power generation
Cement and lime kilns
Chemical processing
Incinerators and waste-to-energy plants
Aerospace and defence ground support

How to Choose the Right SS 310S Stud Bolt Supplier?

Follow the steps below to choose the right SS 310S Stud Bolts for your projects.

Supplier Selection Criteria

Look for a supplier that has in stock ASTM A193 Grade B8T certified material and can provide Mill Test Certificates with each order. Look for suppliers that carry both Class 1 and Class 2 options and can verify heat-specific traceability.

Technical Considerations

Select the desired thread standard ( UNC or metric ) and the appropriate Class 1 or Class 2 mechanical properties. If the flanges are pressure rated for high temperatures, ensure the studs are tested for the proper temperature class. Nut grade match: ASTM A194 Gr. 8T for B8T studs.

Quality and Certification Check

NABL-accredited test reports or 3rd party inspection certificates are required. Material shall comply with ASTM A193, ASME SA193, and applicable ISO standards. Request material certification EN 10204 3.1 or 3.2 for export or EPC projects as required.

Procurement Tips for Bulk Orders

For larger quantities, ask for a quote per kg. The unit price is generally less for bulk quantities. Specify surface finish and thread form on PO. For export documentation projects, confirm that the supplier can provide country of origin documentation and export-grade packaging.