ASTM A193
Grade B8CLNCuB
UNS S34752 Bolts
Understanding This Highly Specific Grade
B8CLNCuB is not a grade most fastener buyers encounter routinely — it sits at the far specialized end of the ASTM A193 stainless bolting family, and every letter in its name corresponds to a genuine, deliberate compositional decision rather than an arbitrary label. Reading the name itself is the most reliable way to understand what this grade is built to do: C and L point to controlled carbon, N to a nitrogen addition, and Cu and B to deliberate copper and boron micro-alloying on top of the base composition.
The niobium stabilization and nitrogen strengthening logic follows the same principle covered on our B8CLN and B8CLNA grade page — niobium protects grain-boundary chromium from carbide depletion during welding, while nitrogen adds real strength without relying on higher carbon content.
The copper and boron additions are the genuinely specialized part of this grade, and because this designation is used for a narrow set of specific, often customer- or project-driven applications, we recommend confirming the exact composition limits, mechanical property requirements, and intended service condition directly against the current ASTM A193 standard text or your project specification before finalizing an order — a grade this specific is exactly the kind of case where the governing document, not a general description, should be the final word.
Akbar Fasteners Pvt. Ltd. exports to over 50 countries, and we’re glad to manufacture to this specification once the exact composition and property requirements from your project or the governing standard are confirmed, verified under our ISO 9001:2015 quality system.
An Honest Note on This Specific Grade
B8CLNCuB is a considerably less common designation than the general ASTM A193 grades we cover elsewhere on this site, and published, detailed reference material on its precise composition limits and typical service applications is genuinely limited compared to more widely used grades. We manufacture to this specification when a customer provides the exact composition and property requirements — either from the current ASTM A193 standard text or a project-specific data sheet — rather than relying on general description alone. If you’re specifying this grade, please share the governing document with your inquiry so we can confirm manufacturability accurately.
Where This Designation Typically Comes From
Project-Specific Specification
Typically called out by name on a specific project drawing or purchase specification, not chosen from a general catalog.
Inherited Stabilization Benefits
Shares the same niobium stabilization logic as B8CLN/B8CLNA for weld-decay resistance.
Additional Micro-Alloying Control
Copper and boron additions are specified deliberately for reasons defined by the governing project standard.
Verified Against Your Governing Document
We manufacture to the composition and property requirements you provide, confirmed before production.
What Each Part of the Name Signals
Controlled Carbon
Carbon content controlled to a low band, consistent with the low-carbon logic used across the B8C/B8L family.
Nitrogen Addition
Controlled nitrogen addition for real strength gain without relying on higher carbon.
Copper Micro-Alloy
Deliberate copper addition, specified for a purpose defined by the governing standard or project spec.
Boron Micro-Alloy
Deliberate boron addition, again specified for a purpose defined by the governing standard or project spec.
B8CLNCuB Specification Approach
Shared Elements With B8CLN/B8CLNA
- Base Type Niobium-Stabilized Austenitic
- Carbon Low, Controlled Band
- Nitrogen Controlled Addition
- Chromium/Nickel Per Governing Standard
What Makes This Grade Different
- Copper Confirmed to Project Spec
- Boron Confirmed to Project Spec
- UNS Designation S34752
- Mechanical Properties Confirmed Per Order
Our Order Process for B8CLNCuB
- Step 1 Confirm Governing Document
- Step 2 Verify Composition Limits
- Step 3 Manufacture & Test to Spec
- Step 4 Issue Full Documentation
Application Context
A specification this specific is generally driven by a particular project or customer standard, not a general application category.
Specialized Chemical Process Equipment
with defined composition needs
High-Value Custom Fabrication
tied to a governing standard
Power & Energy Infrastructure Projects
standards and specifications
Engineering-Specified Critical Bolting
is dictated by design engineering
Standard Export Documentation
Prepared as standard practice once composition and property requirements are confirmed for your order.
Mill Test Certificate (MTC)
Heat number, chemical composition, and mechanical property verification for every lot.
Chemical Composition Report
Confirms actual composition, including copper and boron content, against your confirmed specification.
Certificate of Conformance
Confirms the shipment matches the purchase order specification in full.
Certificate of Origin (COO)
Confirms India as country of manufacture for destination customs purposes.
NABL Accredited Test Reports
Independent mechanical and chemical testing available on request for critical applications.
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 B8CLN / B8CLNA
Our niobium-stabilized, nitrogen-enhanced grade family without the copper/boron additions.
View B8CLN / B8CLNA →ASTM A193 Grade B8LN
Our plain low-carbon, nitrogen-enhanced 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 →Stainless Steel Fasteners Manufacturer India
Our broader stainless steel fastener manufacturing capability across all major grades.
View SS Manufacturer Guide →Have the Governing
Specification for This Grade?
Share your project standard or the ASTM A193 edition you’re working to, and we’ll confirm manufacturability, composition, and mechanical property alignment before quoting. Akbar Fasteners Pvt. Ltd. responds within 24 hours.
Sales: +91 724 0000 733 · Support: +91 800 9315 333 · sales@akbarfasteners.in