ASTM A194
Grade 2 & 2M
Alloy Steel Hex Nuts
Grade 2 vs Grade 2M — The Actual Difference
Grade 2 and Grade 2M are not different materials or different strength classes — they are the identical quenched and tempered carbon or alloy steel specification, differing only in thread and dimensional sizing convention. Grade 2 is sized to standard inch-based threading, following ASME B18.2.2. Grade 2M is sized to metric threading, following the metric dimensional standard, for projects specified in metric units.
This distinction matters at the point of ordering, not at the point of material selection — a project team working from metric drawings orders Grade 2M; a project team working from inch/imperial drawings orders Grade 2. Mixing the two on the same joint is a real, avoidable error, since a metric nut will not properly engage an inch-threaded stud and vice versa, regardless of the fact that the underlying steel and mechanical properties are identical.
Both grades are the standard nut counterpart to ASTM A193 Grade B7 stud bolts — one of the most common bolted-joint combinations across piping systems, pressure vessels, valves, and structural steelwork in industries ranging from oil and gas to power generation to general industrial construction.
Akbar Fasteners Pvt. Ltd. exports to over 50 countries, and we manufacture both inch (Grade 2) and metric (Grade 2M) sizing to order, verified by mechanical testing under our ISO 9001:2015 quality system — please specify which sizing convention your project requires when ordering.
Where This Grade Genuinely Applies
Genuine Higher Strength Than Grade 1
Quenched and tempered heat treatment delivers meaningfully higher proof load for structural-grade bolting.
Correct Default Pairing With B7 Studs
The standard, widely-used nut match for one of the industry’s most common stud bolt grades.
Available in Both Sizing Systems
Manufactured to inch (Grade 2) or metric (Grade 2M) thread standards, matched to your project drawings.
Verified Mechanical Properties
Batch hardness and proof load testing confirms consistent heat-treated strength for every lot.
Choosing Between Related Carbon & Alloy Steel Grades
Grade 1
Plain carbon steel, lower cost, general-purpose strength — for applications not needing B7-level strength.
View Grade 1 →Grade 2 / 2M (This Page)
Higher-strength alloy steel, the standard match for ASTM A193 Grade B7 studs — available inch or metric.
You Are HereGrade 2H
Heavy hex, higher-hardness carbon steel nut, one of the most widely specified industrial nut grades.
View Grade 2H →Grade 2 vs Grade 2M — Quick Reference
Confirming the sizing convention before ordering avoids a genuinely common and avoidable thread-mismatch error. This table is the quick reference we use with buyers before quoting.
| Aspect | Grade 2 (Inch) | Grade 2M (Metric) |
|---|---|---|
| Base Material | Carbon or alloy steel | Identical composition |
| Heat Treatment | Quenched and tempered | Identical treatment |
| Thread Sizing | Inch, per ASME B18.2.2 | Metric, per metric dimensional standard |
| Matching Bolt | ASTM A193 Grade B7 | ASTM A193 Grade B7M (metric) |
Grade 2 / 2M Specification Details
Nominal Composition
- Base Type Medium Carbon or Alloy Steel
- Chromium/Molybdenum Present in Alloy Variants
- Carbon Medium Range
- Heat Treatment Required — Quench & Temper
Typical Mechanical Range
- Proof Load Per ASTM A194 Grade 2/2M
- Condition Quenched and Tempered
- Hardness Structural-Grade Range
- Matching Bolt Grade ASTM A193 B7 / B7M
Fastener Types We Manufacture
- Hex Nuts Standard & Heavy Hex
- Jam Nuts Thin Profile
- Sizing Inch (Grade 2) or Metric (Grade 2M)
- Custom Sizes On Request
Application Areas
Wherever ASTM A193 Grade B7 or B7M studs are specified — among the most common bolted joints in industrial construction.
Oil & Gas Piping and Flanges
bolting across the industry
Pressure Vessel Assembly
pressure-retaining joints
Power Generation Piping
and process piping bolting
Structural Steel Connections
needing B7-level strength
Standard Export Documentation
Prepared as standard practice for every Grade 2 or 2M nut shipment.
Mill Test Certificate (MTC)
Heat number, chemical composition, and mechanical property verification for every lot.
Mechanical Property Report
Confirms actual quenched and tempered hardness meets the specified Grade 2/2M proof load requirement.
Certificate of Conformance
Confirms the shipment matches the purchase order grade/sizing specification in full.
Certificate of Origin (COO)
Confirms India as country of manufacture for destination customs purposes.
Dimensional Inspection Report
Confirms correct inch or metric thread sizing per your specified sizing convention.
Commercial Invoice & Packing List
Itemized value, Incoterm, and detailed carton/weight breakdown for customs clearance.
Internationally Recognised Standards Coverage
Related Fastener Grades & Materials
ASTM A194 Grade 1
Our general-purpose carbon steel grade, for applications not requiring B7-level strength.
View Grade 1 →ASTM A194 Grade 2H
Our heavy hex, high-hardness carbon steel grade — an alternative high-strength nut option.
View Grade 2H →ASTM A194 Grade 8
Our stainless steel baseline, for applications needing corrosion resistance beyond carbon/alloy steel.
View Grade 8 →Stainless Steel Fasteners Manufacturer India
Our broader fastener manufacturing capability across all major carbon, alloy, and stainless grades.
View SS Manufacturer Guide →Inch or Metric?
We Manufacture Both
Tell us your project’s sizing convention and requirements — we’ll confirm manufacturability, matched to your B7 or B7M studs, and quote with full documentation. Akbar Fasteners Pvt. Ltd. responds within 24 hours.
Sales: +91 724 0000 733 · Support: +91 800 9315 333 · sales@akbarfasteners.in