ASTM A193
Grade B8CLN / B8CLNA
SS 347LN Bolts
Why ASTM A193 Grade B8CLN / B8CLNA SS 347LN Bolts Genuinely Matters Here
Standard low-carbon L-grade stainless (like B8LN’s plain 316LN base) fights weld decay by simply removing most of the carbon — less carbon means less chromium carbide forms at grain boundaries during welding heat, but that approach alone caps how much carbon-driven strength the base alloy can retain.
SS 347LN, the base material behind B8CLN and B8CLNA, takes a genuinely different route to the same weld-decay problem — niobium (also called columbium) is added specifically because it preferentially combines with carbon to form stable niobium carbides instead of chromium carbides, protecting the grain boundary chromium that would otherwise be depleted. That’s stabilization, a distinct mechanism from simply stripping carbon out.
The nitrogen addition solves an entirely separate problem — controlled nitrogen genuinely increases strength in austenitic stainless without needing higher carbon, which is exactly why B8CLN and its strain-hardened counterpart B8CLNA can offer better mechanical properties than a plain low-carbon grade at a similar corrosion-resistance level.
Akbar Fasteners Pvt. Ltd. exports to over 50 countries, and our B8CLN and B8CLNA stud bolt range is verified by chemical composition and mechanical testing under our ISO 9001:2015 quality system.
Where This Grade Genuinely Applies
Genuine Weld-Decay Resistance via Stabilization
Niobium carbide formation protects grain-boundary chromium, a distinct mechanism from low-carbon alone.
Genuine Strength Advantage via Nitrogen
Controlled nitrogen addition delivers real strength without sacrificing corrosion resistance.
Correct Choice for High-Temperature Welded Assemblies
Stabilized composition resists sensitization during and after high-temperature welded service.
Verified Chemical & Mechanical Properties
Batch testing confirms genuine niobium and nitrogen content for the ordered grade.
B8CLN vs B8CLNA — Side by Side
ASTM A193 Grade B8CLN
Solution-annealed condition, offering the base mechanical properties of stabilized, nitrogen-enhanced SS 347LN without additional cold-working for strength.
Moderate Strength, Full Ductility →ASTM A193 Grade B8CLNA
Strain-hardened (cold-worked) condition of the same base material, delivering genuinely higher tensile and yield strength than B8CLN at a modest reduction in ductility.
Higher Strength, Slightly Reduced Ductility →B8CLN vs B8CLNA — Quick Reference
Confirming whether the joint genuinely needs the higher strength of the strain-hardened class avoids overspecifying. This table is the quick reference we use with buyers before quoting.
| Aspect | Grade B8CLN | Grade B8CLNA |
|---|---|---|
| Condition | Solution annealed | Strain hardened (cold worked) |
| Relative Tensile Strength | Moderate | Higher |
| Relative Ductility | Higher | Slightly reduced |
| Typical Use | General stabilized bolting | Higher-load stabilized bolting |
B8CLN / B8CLNA Specification Details
Nominal Composition
- Chromium 17.0 – 20.0%
- Nickel 9.0 – 13.0%
- Niobium (Columbium) ~10x Carbon Min
- Nitrogen Controlled Addition
Typical Mechanical Range
- B8CLN Tensile ~515 MPa Min
- B8CLNA Tensile ~690 MPa Min
- B8CLN Yield ~205 MPa Min
- B8CLNA Yield ~450 MPa Min
Fastener Types We Manufacture
- Stud Bolts Continuous & Double-End
- Hex Bolts Standard & Heavy Hex
- Matching Nuts ASTM A194 Grade 8C/8CA
- Custom Sizes On Request
Application Areas
Wherever stabilized weld-decay resistance and elevated strength are both genuinely needed.
High-Temperature Welded Piping
sustained heat and weld exposure
Pressure Vessel Flange Bolting
for critical joints
Chemical Process Equipment
needing stabilized resistance
Power Generation Piping Systems
steam and process lines
Refinery Process Piping
weld exposure bolting
LNG & Cryogenic Equipment
for demanding service conditions
Nuclear-Adjacent Process Equipment
critical traceable bolting
General High-Temperature Welded Bolting
needing stabilized, strengthened bolting
Standard Export Documentation
Prepared as standard practice for every B8CLN / B8CLNA bolt shipment.
Mill Test Certificate (MTC)
Heat number, chemical composition, and mechanical property verification for every lot.
Chemical Composition Report
Confirms actual niobium and nitrogen content fall within the specified 347LN grade range.
Certificate of Conformance
Confirms the shipment matches the purchase order grade/size specification in full.
Certificate of Origin (COO)
Confirms India as country of manufacture for destination customs purposes.
NABL Accredited Test Reports
Independent mechanical, dimensional, and corrosion testing available on request.
Commercial Invoice & Packing List
Itemized value, Incoterm, and detailed carton/weight breakdown for customs clearance.
Internationally Recognised Standards Coverage
Related Fastener Grades & Materials
ASTM A193 Grade B8LN
Our plain low-carbon, nitrogen-enhanced stainless bolting grade without niobium stabilization.
View Grade B8LN →ASTM A193 B7 / B7M / B6
Our alloy steel stud bolt grade guide, for non-stainless bolting applications.
View ASTM A193 Guide →SS 317 Fasteners
Our higher-molybdenum austenitic grade, corrosion-focused rather than stabilization-focused.
View SS 317 Guide →Stainless Steel Fasteners Manufacturer India
Our broader stainless steel fastener manufacturing capability across all major grades.
View SS Manufacturer Guide →Stabilized Strength,
Weld-Decay Resistance
Tell us your service temperature, welding requirements, and strength needs — we’ll confirm whether B8CLN or B8CLNA genuinely fits 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