Stud Bolt Supplier India | ASTM A193 B7 & A194 2H Nut Sets | Krishna Industries

Premium B2B supplier of ASTM A193 B7 Stud Bolts with A194 2H Heavy Hex Nut sets. Manufactured from quenched and tempered AISI 4140 alloy steel. Available in ASME B18.2 dimensions: UNC (½”–4″) and Metric (M12–M48). Finishes include plain, yellow zinc, hot-dip galvanized (HDG), PTFE, and Xylan.

MOQ: 10 Nos · EN 10204 3.1 MTC Provided · GST Invoice · Pan-India Dispatch from Ahmedabad

An ASTM A193 B7 Stud Bolt is a fully threaded alloy steel rod (AISI 4140 chromium-molybdenum steel, quenched and tempered) designed to be used with two ASTM A194 2H heavy hex nuts. This combination is the industry standard for bolting flanged joints on valves, flanges, heat exchangers, and pressure vessels in process plant piping.

Krishna Industries (KELOR), Ahmedabad, is a trusted B2B stud bolt supplier in India. We supply all standard grades (B7, B7M, B8, B8M, B16, A320 L7) with strict adherence to ASME B18.2 dimensions. Every order includes an EN 10204 3.1 Mill Test Certificate (MTC). Enquire for ASTM A193 B7 stud bolt prices via WhatsApp for project BOM pricing within 4 hours.

🔩 Complete Flange & Valve Solutions

Procuring Flanged Valves & Bolting for Your Piping Project?

While you specify A193 B7 stud bolts for your carbon steel flanges, don’t forget the valves that clamp between them. KELOR manufactures API 594 Wafer Check Valves that perfectly match ASME B16.5 flange dimensions, requiring no additional bolts—saving you weight, space, and installation time.

Wafer Design Advantage: Clamps directly between your ASME/DIN flanges using the same stud bolts—eliminates the need for separate valve body bolts.
Ready Stock: CI & SS304/316 Wafer NRVs (DN50 to DN600) ready for immediate dispatch alongside your stud bolt orders.
Single Vendor BOM: Combine your stud bolts, nuts, gaskets, and wafer check valves into one KELOR GST invoice and one MTC package.

View API 594 Wafer Check Valve Catalog →

⚠️ Critical Site Bolting Warning: The most common cause of flanged joint leakage in Indian process plants is pairing an A193 B7 stud with an IS Grade 5 or IS Grade 8 nut instead of an A194 2H nut. ASME PCC-1 requires the nut proof load to exceed the stud yield strength. A194 2H (175 ksi proof load) safely exceeds A193 B7 (105 ksi yield). IS Grade 5 (85 ksi proof load) is weaker than B7 yield, causing the nut to strip before adequate preload is achieved. Always use matched ASTM A194 nut grades. Never substitute IS nuts on ASTM stud bolts.

Complete Stud Bolt Grade Range

MOST COMMON

A193 B7 + A194 2H (Alloy Steel)

AISI 4140 Cr-Mo alloy steel — Quenched & Tempered
Tensile: 125 ksi / 862 MPa (≤2½” / M64)
Yield: 105 ksi / 724 MPa | Max Hardness: HRC 35
Temperature: −45°C to +450°C
Finish: Plain / Zinc / HDG / PTFE / Xylan
Use: Standard process plant Class 150–2500

SOUR SERVICE / NACE

A193 B7M + A194 2HM

Same AISI 4140 base as B7 — hardness restricted
Max hardness: HRC 26 (NACE MR0175 / ISO 15156)
Prevents hydrogen-induced stress cracking (HISC)
For H₂S sour gas environments & offshore platforms
NACE compliance report available on request

STAINLESS STEEL

A193 B8/B8M + A194 8/8M

B8: AISI 304 | B8M: AISI 316 (2–3% Mo)
Class 1: Solution annealed | Class 2: Strain hardened
Prevents galvanic corrosion on SS flanged connections
Ideal for chemical, pharma, food GMP, and marine
Do NOT pair B7/2H with SS flanges in wet service.

LOW TEMP / CRYOGENIC

A320 L7 + A194 4

Cr-Mo alloy steel — Charpy impact tested
Service temperature down to −101°C
Used in LNG terminals, liquid nitrogen, cryogenic piping
Complies with ASME B31.3 low-temperature service
Impact test certificates mandatory

HIGH TEMP / STEAM

A193 B16 + A194 7

Cr-Mo-V alloy steel for elevated temperatures
Up to 540°C continuous (exceeds B7 creep limit)
Power plant high-pressure steam headers
ASME Boiler & Pressure Vessel Code compliant

ASTM A193 B7 Chemical Composition (AISI 4140)

ASTM A193 B7 stud bolts are manufactured from AISI 4140/4142 chromium-molybdenum alloy steel, quenched in a liquid medium and tempered at a minimum of 620°C (1150°F). The specific alloying elements provide the high tensile strength and elevated temperature resistance required for critical flanged joints.

Element	ASTM A193 B7 (AISI 4140/4142) — % by Weight	Functional Role
Carbon (C)	0.37 – 0.49%	Base strength and quench hardenability
Manganese (Mn)	0.65 – 1.10%	Enhances hardenability and toughness
Chromium (Cr)	0.75 – 1.20%	Corrosion resistance, hardenability, high-temp strength
Molybdenum (Mo)	0.15 – 0.25%	High-temperature strength, creep resistance
Silicon (Si)	0.15 – 0.35%	Deoxidation and strength
Phosphorus (P)	Max 0.035%	Impurity limit (embrittlement control)
Sulphur (S)	Max 0.040%	Impurity limit (machinability vs. toughness)

Mechanical Properties by Diameter

Diameter Range (UNC)	Metric Equiv.	Min Tensile (ksi / MPa)	Min Yield (ksi / MPa)	Min Elongation (%)	Max Hardness
≤ 2½” (2.5″)	≤ M64	125 ksi / 862 MPa	105 ksi / 724 MPa	16%	HRC 35 / HBW 321
2½” – 4″ (incl.)	M64 – M100	115 ksi / 793 MPa	95 ksi / 655 MPa	15%	HRC 35 / HBW 321
4″ – 7″ (incl.)	M100 – M175	100 ksi / 690 MPa	75 ksi / 517 MPa	13%	HRC 35 / HBW 321

💡 B7M Note (NACE Service): B7M shares the same chemical composition and strength requirements as B7. The only difference is a restricted maximum hardness of HRC 26 (HBW 237) per NACE MR0175 / ISO 15156. Always specify B7M for H₂S sour gas service.

ASME B16.5 Stud Bolt Length — UNC Imperial (Class 150 & 300)

Standard reference for flanged joint stud bolt length on raised face (RF) flanges with a 3mm spiral wound gasket. Length shown is the total stud bolt length including both threaded ends. Quantity represents stud bolts + nut sets per flanged joint.

Pipe Size	DN	Class 150 Length	Class 150 Qty	Class 150 Thread	Class 300 Length	Class 300 Qty	Class 300 Thread
½”	DN15	95 mm	4	½” UNC	108 mm	4	½” UNC
¾”	DN20	95 mm	4	½” UNC	108 mm	4	½” UNC
1″	DN25	108 mm	4	½” UNC	121 mm	4	⅝” UNC
2″	DN50	121 mm	4	⅝” UNC	152 mm	8	¾” UNC
4″	DN100	152 mm	8	⅝” UNC	190 mm	8	¾” UNC
6″	DN150	165 mm	8	¾” UNC	210 mm	12	⅞” UNC
8″	DN200	184 mm	8	¾” UNC	235 mm	12	1″ UNC
12″	DN300	210 mm	12	⅞” UNC	286 mm	16	1⅛” UNC
24″	DN600	305 mm	20	1¼” UNC	425 mm	24	1½” UNC

ASTM A193 B7 Stud Bolt — Metric Sizes M12 to M48

For Indian projects utilizing IS or DIN flanges with metric bolting. Metric B7 stud bolts are increasingly specified on IS 1538 / DIN PN10 / PN16 flanges in water treatment, HVAC, and general industry projects.

Metric Size	Approx UNC	Thread Pitch	2H Nut Across Flats	Nut Height	Min Tensile	Min Yield
M12	~½”	1.75 mm	19 mm	10.8 mm	862 MPa	724 MPa
M16	~⅝”	2.00 mm	24 mm	14.8 mm	862 MPa	724 MPa
M20	~¾”	2.50 mm	30 mm	18.0 mm	862 MPa	724 MPa
M24	~1″	3.00 mm	36 mm	21.5 mm	862 MPa	724 MPa
M30	~1¼”	3.50 mm	46 mm	25.6 mm	862 MPa	724 MPa
M36	~1½”	4.00 mm	55 mm	31.0 mm	862 MPa	724 MPa
M42	~1¾”	4.50 mm	65 mm	34.0 mm	793 MPa	655 MPa
M48	~2″	5.00 mm	75 mm	38.0 mm	793 MPa	655 MPa

A193 B7 Tightening Torque Reference (Lubricated)

Reference torque values for ASTM A193 B7 stud bolts with A194 2H nuts in lubricated assembly (zinc plated or PTFE coated), targeting 70% of bolt proof load. These are reference values only. Actual torque must be verified per the gasket manufacturer’s joint assembly procedure and ASME PCC-1 guidelines.

Stud Size (UNC)	Metric Equiv.	Torque — Lubricated (Nm)	Torque — Dry/Plain (Nm)	Target Bolt Load (kN)
½”	M12	45 – 55	65 – 80	~32
⅝”	M16	90 – 110	130 – 155	~55
¾”	M20	160 – 190	230 – 270	~90
1″	M24–M27	380 – 450	550 – 650	~178
1¼”	M30–M33	760 – 900	1,090 – 1,290	~310
1½”	M36–M39	1,300 – 1,550	1,870 – 2,230	~500

⚠️ Never torque B7 stud bolts dry (plain/black oxide) without lubrication. The dry torque coefficient (K factor) is ~0.20–0.22, versus 0.13–0.15 for lubricated. Dry bolting at the same torque setting achieves only 60–70% of the required bolt load, risking flanged joint leakage. Always lubricate threads and nut faces before assembly.

Industries & Applications

🏭 Process Plant Flanges

A193 B7/2H plain or zinc — default on Indian piping class documents for Class 150–2500 ASME B16.5 flanges at chemical plants, refineries, and CGD networks.

⚡ Power Plants

B7/2H and B16/7 for high-pressure steam. Pressure vessel and heat exchanger bolting requiring mandatory MTC 3.1 certificates for ASME VIII compliance.

⛽ Oil & Gas

B7M/2HM NACE MR0175 for sour gas. L7/4 for LNG cryogenic. B8M/8M SS316 with Xylan for offshore SS flanged joints.

💧 Water Treatment

B7/2H HDG for outdoor WTP flanged connections. Prevents bolt seizure in damp outdoor conditions (ETP, STP, municipal water plants).

⚗️ Chemical Plants

B7/2H for CS piping. B8M/8M for SS316 flanged connections across the Gujarat chemical belt (Ankleshwar, Vapi, Dahej, Surat).

💊 Pharma & Food

B8M/8M SS316 with PTFE coating for pharma GMP piping. FDA-safe, no zinc contamination, and anti-galling on SS flange faces.

🏗️ EPC Projects

Full project BOM supply, including wafer check valves, mixed fastener grades, and finishes. Single GST invoice and MTC package.

🔧 MRO & Maintenance

Standard B7/2H plain in all sizes for plant maintenance stores. Fast dispatch from Ahmedabad for urgent shutdown requirements.

Why EPC Contractors Choose Krishna Industries

📍

Ahmedabad Supply Hub

Fastest supply to the Gujarat chemical cluster (Ankleshwar, Vapi, Dahej), Mumbai, and Pan-India via VRL. Shorter transit times than Mumbai-based suppliers for Gujarat buyers.

📄

MTC EN 10204 3.1

Mill test certificate with heat number traceability for chemical and mechanical properties. 3.2 third-party witnessed (TUV / BV / Lloyd’s) available on request.

🔩

Matched B7 / 2H Sets

Stud and nut supplied as a matched grade set per ASME PCC-1. B7 with 2H, B8M with 8M. Zero mismatched pairing risk.

🧾

100% GST Compliant

GSTIN: 24AKLPP6499B1ZT. E-Way bill provided for interstate transport. HSN 73181590 (studs) / 73182900 (nuts).

📦

Project BOM Supply

Mixed grades (B7, B8M, L7), sizes, and finishes. From 10 Nos to 100,000+ Nos in a single consignment, invoice, and MTC package.

⏱️

4-Hour Project Quote

WhatsApp your grade, thread size, finish, length, and quantity. Single-item pricing within 2 hours. Full project BOM pricing within 4 hours.

Need A193 B7 Stud Bolt Pricing or a Project BOM Quote?

Share grade (B7 / B7M / B8M / L7) · thread size (UNC ½”–4″ or metric M12–M48) · finish (plain / HDG / zinc / PTFE) · stud length (or flange size + class) · quantity.

📲 WhatsApp for Stud Bolt Price

Stainless Steel Bolts — SS304 / SS316 hex bolts, socket head cap screws, carriage bolts (DIN 931 / 933 / 912) for SS flanged connections where B7/2H risks galvanic corrosion.
Stainless Steel Washers — SS304 / SS316 plain flat washers (DIN 125), commonly ordered with stud bolt sets for flanged joint assemblies.
Stainless Steel Threaded Rods — SS304 / SS316 all-thread rods for construction hangers, pipe supports, and suspension systems.

Pan-India Supply Coverage from Ahmedabad

Krishna Industries dispatches A193 B7 stud bolts from Ahmedabad to: Mumbai, Pune, Nashik, Nagpur (Maharashtra) · Chennai, Coimbatore, Bengaluru, Hyderabad, Vizag (South India) · Delhi, Noida, Gurugram, Jaipur (North India) · Surat, Vadodara, Rajkot, Ankleshwar, Vapi, Dahej (Gujarat) and all states via VRL / Professional Courier.

Frequently Asked Questions — A193 B7 Stud Bolt & 2H Nut

What nut must be paired with an A193 B7 stud bolt, and why not IS nuts?

The correct nut is the ASTM A194 Grade 2H heavy hex nut. ASME PCC-1 requires that the nut proof load must exceed the bolt minimum yield strength, ensuring the bolt yields before the nut strips, maintaining preload. A194 2H has a 175 ksi proof load against A193 B7’s 105 ksi yield (a 67% safety margin). An IS Grade 5 nut has only ~85 ksi proof load, which is weaker than B7 yield. The nut will strip before adequate preload is reached, causing the joint to leak. Never substitute IS Grade nuts for A194 2H on A193 B7 connections.

What is the price of ASTM A193 B7 stud bolts in India?

Pricing depends on thread size (½” to 4″ UNC or M12 to M48 metric), stud length, surface finish (plain, HDG, zinc, PTFE), and order quantity. Plain B7/2H sets are the most economical. HDG adds approximately a 15–25% premium. WhatsApp your grade, size, finish, length, and quantity to Krishna Industries Ahmedabad for current pricing within 2 hours. Project BOM pricing is provided within 4 hours.

What is the difference between A193 B7 and B7M stud bolts?

Both are AISI 4140/4142 chromium-molybdenum alloy steel with the same chemical composition and minimum tensile/yield strength. The only difference is maximum hardness. B7 has a max hardness of HRC 35. B7M has a restricted maximum hardness of HRC 26 (HBW 237) per NACE MR0175 / ISO 15156 to prevent hydrogen-induced stress cracking (HISC) in H₂S sour gas service. Specify B7M with A194 2HM nuts for sour gas environments.

Can A193 B7 stud bolts be used on stainless steel flanges?

Not recommended for outdoor or wet service. Carbon steel B7 in contact with a stainless steel flange face in the presence of moisture creates a galvanic couple. The carbon steel corrodes preferentially, and the nut seizes on the SS flange face, making removal impossible without drilling. For SS304 flanges, specify A193 B8 / A194 Grade 8. For SS316, specify A193 B8M / A194 Grade 8M.

How many stud bolts does a 6-inch Class 150 flange require?

A 6-inch (DN150) ASME B16.5 Class 150 flange requires 8 stud bolts with 2 nuts each (16 nuts total per flanged joint). The standard stud bolt length per ASME B16.5 for raised face flanges with a 3mm spiral wound gasket is 165mm, with a ¾” UNC thread. For Class 300, it requires 12 studs, 210mm length, ⅞” UNC thread.

What does EN 10204 3.1 MTC mean, and when is 3.2 required?

EN 10204 3.1 is a manufacturer’s test certificate signed by the manufacturer’s authorized quality representative, confirming chemical composition and mechanical properties with heat number traceability. This is provided standard with every KELOR order. EN 10204 3.2 is a third-party witnessed certificate (TUV, BV, Lloyd’s). 3.1 satisfies most Indian EPC QA plans and ASME VIII (UG-10). 3.2 is required for European PED-compliant exports, certain offshore specifications, and government PSU projects.

When should HDG finish be specified instead of plain for stud bolts?

Specify HDG (hot-dip galvanized per ASTM A153) for outdoor pipe racks, cooling water flanges, water treatment plant bolting, and any installation exposed to rain, humidity, or salt air. Plain black oxide B7 corrodes rapidly outdoors, and nuts seize on corroded threads within 2–3 years. HDG provides 10–25 years of corrosion protection and prevents nut seizure during maintenance shutdowns.