Short answer
Order C-276 fasteners by UNS N10276, exact dimensions and threads, required delivery condition, and the tests and documents needed to accept the finished parts. State the heat-treatment or cold-work condition, include matching nuts and washers, and require records that connect the delivered parts to their material heat and manufacturing lot. ASTM B574 can define the starting rod or bar; a B574 material certificate alone does not confirm that the finished bolt has the right dimensions, thread fit or mechanical properties.
If you already have a drawing, send it with the quantity and service conditions. Without a drawing, send a part description, known dimensions, a sketch or reference part, quantity and service conditions. Ask the supplier to list missing details and propose a drawing for approval before manufacture.
- Define the part: drawing, thread and mating parts.
- Confirm the condition: material form and manufacturing route.
- Agree the checks: finished-part limits and inspection.
- Connect the records: delivered parts to heat and lot.
What belongs on a C-276 fastener order?
“C-276 bolts, M12” leaves a supplier guessing about length, pitch, condition and inspection. A usable order answers the following questions.
| Order item | What to specify | Why it changes the purchase |
|---|---|---|
| Grade and condition | Hastelloy C-276, UNS N10276; required delivery condition and relevant material specification | A grade name does not define the processing condition or finished strength |
| Part and dimensions | Bolt, stud, nut or washer; drawing revision; head, length, thread and tolerances | Parts can share a nominal thread size and still fail to fit the assembly |
| Mating components | Nut dimensions, material and load requirements; washer dimensions and material | A suitable bolt does not make an unsuitable nut or washer acceptable |
| Finished-part acceptance | Applicable fastener specification or agreed drawing requirements, with mechanical limits and inspection scope | Material tests and finished-fastener tests represent different things |
| Documents and identification | Material certificate, relevant test and inspection reports, heat/lot identification | The paperwork must be connected to the delivered lot |
| Supply scope | Quantity, permitted alternatives, required date, packaging and repeat-order identification | Comparable prices depend on comparable supply and acceptance requirements |
HASTELLOY® is a Haynes International trademark. If the order requires material from that producer, state the origin requirement separately. UNS N10276 identifies the alloy; it does not by itself establish the mill or brand origin. [1]
Jump to the RFQ example if you are ready to prepare an enquiry.
Which standards cover the material—and which cover the fastener?
Start with the form of material being purchased. A bar, a plate and a forging are not covered by the same product specification simply because they are all C-276.
| Standard | What it addresses | What the buyer still needs |
|---|---|---|
| ASTM B574 | Rod and bar of specified nickel alloys, including UNS N10276 | Finished geometry, threads, processing requirements and fastener acceptance |
| ASTM B575 | Plate, sheet and strip of specified nickel alloys, including UNS N10276 | Washer or other part dimensions, manufacturing requirements and acceptance |
| ASTM B564 | Nickel-alloy forgings within its stated grade and product scope | Confirmation of the actual manufacturing route and finished-part requirements |
These three standards address material forms; add the requirements for the finished part. [1] [2] [3] [4]
If your project calls for ASTM F468 for bolts or F467 for nuts, have the supplier confirm that the alloy, condition, part type and size are covered by the specified edition. F468M and F467M are separate metric specifications with their own scopes. Do not assume N10276 is covered from a catalogue heading such as “ASTM F468 C-276”; request the applicable grade and condition provisions. [5] [6]
Do not accept an unexplained substitution of standards. If a supplier cannot support the requested fastener specification, have it state the material specification, proposed manufacturing condition, finished-part tests and acceptance limits for engineering review. Agree those requirements before ordering. If you do not have an engineering team, ask the equipment manufacturer or the engineer responsible for the assembly to confirm the condition and acceptance limits.
For more on the inch/metric and bolt/nut distinctions, see ASTM F468 vs F467.
Does the proposed C-276 condition suit the job?
C-276 is a nickel-chromium-molybdenum alloy used for demanding chemical service. Its corrosion resistance is a reason to consider it, not permission to ignore the actual fluid and operating conditions. Give the supplier the medium, concentration, temperature, contaminants and cleaning conditions, including wet crevices around nuts and washers. Haynes publishes environment-specific corrosion information rather than a universal “acid-proof” rating. [1]
The material condition matters too. Haynes describes its wrought C-276 products as normally supplied solution heat treated. ASTM B574 also addresses certain cold-worked conditions; “C-276” therefore does not mean that every offer has the same strength or processing history. State the condition your design requires and ask the supplier to explain the condition of the delivered parts. [1] [2]
Ask one practical question: what happens to the material after the mill certificate is issued? Forming, thread manufacture and any subsequent heat treatment can affect the final part. Haynes notes that cold work can affect stress-corrosion-cracking resistance and discusses re-annealing after substantial deformation. This is a reason to review the proposed route, not an instruction to apply the same heat treatment to every bolt. [1]
Check which condition, specimen and product an advertised strength result represents before using it to compare offers.
Define the bolt, nut and washer as a set
For a bolt, specify the head form, diameter, pitch, length reference, threaded length and any special shank or runout requirement. For a stud, identify the length references and the threaded ends. Add the external thread tolerance and the mating internal thread requirement; matching nominal diameter and pitch is only the starting point.
The drawing should make clear whether a stated dimension is overall length or under-head length. These small details are expensive to discover after manufacture. Our guides to stud bolt length and bolt grip and thread length show the different references.
For nuts, agree the style, height, thread and material condition, together with the relevant load or mechanical acceptance requirement. “C-276 nut” is not a complete strength specification. For washers, define inside diameter, outside diameter, thickness, flatness where relevant, and material. Do not assume a standard steel washer hardness class applies to a C-276 washer.
Specify the surface condition and any lubricant or coating that the assembly permits. Nickel-alloy threads can gall, and lubrication changes the relationship between tightening torque and preload. Use the approved assembly procedure; do not copy a carbon-steel torque chart for a C-276 joint. See our nickel-alloy galling guide for the checks to discuss.
A C-276 fastener RFQ you can adapt
The example below is a quotation enquiry, not a released engineering specification or a statement of stock availability. The dimensions, quantity and solution-annealed starting condition are illustrative choices, to be replaced with your approved requirements.
Item: 24 sets of C-276 hex bolts, nuts and washers for a chemical-processing assembly. Each set: one M12 × 1.75 × 60 bolt, one nut and two washers.
Geometry: Bolt length measured under the head. All head, shank, thread, nut and washer details to [your drawing number and revision]. Without a drawing, attach a sketch or reference-part details and request a proposed drawing for approval. Supplier to flag missing dimensions or tolerances before quoting.
Material: Alloy C-276, UNS N10276. Quote solution-annealed starting material to the applicable product-form specification. Describe forming, threading and any later heat treatment, and identify the proposed delivered-part condition.
Finished-part acceptance: Identify the applicable fastener specification and edition, or propose a separate mechanical and inspection schedule for review by the engineer responsible for the assembly. List test methods, acceptance limits, sampling and whether results represent starting material or finished parts. Resolve these before purchase-order release.
Documents: Material certificate with heat identification; heat/lot linkage to the supplied sets; mechanical test reports identifying what was tested; dimensional and sampled GO/NO-GO thread-gauge inspection records (gauges that check thread acceptance). Quote any requested positive material identification (PMI) or third-party inspection separately.
Service and delivery: Buyer to provide the actual fluid, concentration, operating temperature and required delivery date. Supplier to state lead time, the events that start it, and any exceptions. Offer changes of alloy, condition or manufacturing route as separately identified alternatives.
You do not need to rewrite an existing drawing into a long email. Attach it and state the quantity, service and deadline. Ask for a quotation that lists compliance, exceptions and unresolved points.
For a standard hex-head enquiry, see C-276 hex bolts. For a special shape or drawing-specific requirement, use custom manufacturing.
Which tests and certificates should you ask for?
Ask for evidence that answers a specific acceptance question. More certificates do not help if none can be linked to the parts in the box.
| Evidence | What it helps establish | What it does not establish alone |
|---|---|---|
| Material certificate | Reported heat chemistry, condition and test results for the material described | The dimensions, threads or mechanical performance of every finished fastener |
| Finished-part mechanical report | Results for the identified specimen or fastener lot under the agreed method | Acceptance of other lots, untested properties or a different service condition |
| Dimensional and GO/NO-GO records | Conformity of the dimensions and gauged threads actually checked | Alloy identity, corrosion suitability or joint load capacity |
| PMI report, when ordered | The measured composition within the method’s capability and sampling scope | Heat treatment, mechanical properties or complete traceability by itself |
| Heat/lot identification | The connection between delivery items and their corresponding records | Compliance unless the linked records meet the order |
An EN 10204 type 3.1 certificate is an inspection-document type, not a universal list of bolt tests. Check what product it describes and which results it contains. A starting-bar 3.1 certificate should not be relabelled as a finished-bolt test report. For a fuller explanation, read MTC vs PMI vs inspection report. [7]
Where ASTM F606/F606M is specified, distinguish the mechanical test method from the product’s acceptance limits. The applicable fastener specification or agreed engineering requirement must tell the laboratory which results are acceptable. [8]
Special inspection requirements belong in the quotation and purchase order: for example, the PMI method and sample coverage, a defined corrosion test, third-party witnessing, or additional lot testing. Do not add them at receipt and assume they were included in the quoted price.
BYBOLT’s delivery baseline includes heat traceability, MTC / EN 10204 3.1 documentation and mechanical testing; threaded products include sampled GO/NO-GO checks. Confirm with us which results cover the starting material and which cover the finished fastener lot. Agree the finished-part acceptance criteria and any additional testing or inspection before ordering.
Can C-22, Inconel 625 or another condition replace C-276?
Only after the proposed change has been reviewed against the actual service and part requirements. Availability, a similar UNS designation or a higher tensile value is not approval to substitute.
C-22 and C-276 are separate alloys with environment-dependent corrosion behaviour. Inconel 625 adds another set of material and mechanical considerations. Ask the supplier to keep the specified C-276 offer separate from any alternative, including differences in condition, dimensions, tests, price and delivery. Use our Hastelloy vs Inconel comparison when reviewing the material choice. [1] [9]
A condition change within C-276 also needs review. Do not treat an annealed and a cold-worked offer as equivalent just because both certificates show N10276. Check the mechanical requirement and corrosion implications before accepting the change. [1] [2]
Compare quotations—and check what arrives
First compare offers against the same drawing revision, material condition, nut/washer scope, tests and documentation. A lower price may reflect fewer parts, a different condition, fewer tests or a shorter document package. Ask what is excluded before judging the difference.
Illustrative comparison: one offer covers 24 bolts with a bar certificate; another covers 24 complete sets with nuts, two washers per set and agreed finished-part inspection. Those prices are not comparable until the quantities, condition and inspection requirements match.
Distinguish material available from finished fasteners ready to ship. Bar availability does not tell you how long forming, machining, threading, heat treatment and inspection will take. Request a delivery commitment tied to the approved drawing and inspection requirements, with separately stated lead times for any alternative route.
At receipt, work through five checks:
- Match the order: part numbers, drawing revision, quantities and the complete bolt/nut/washer set.
- Match the identity: grade, heat and lot references on labels and records. If individual marking was required, check it against the order.
- Read the results: confirm the stated condition and which material or finished lot the test reports represent.
- Check the parts: review the agreed dimensions, thread inspection and surface requirements; investigate damaged threads or mixed lots.
- Resolve differences before use: separate a discrepant lot and agree whether it will be replaced, reworked or accepted following technical review. Archive the accepted records with the order for repeat purchases.
Send your C-276 requirement for a quote
Send the drawing or part description, quantity, service conditions and required date. If you have a specified standard, condition or inspection plan, include it. If some details are missing, identify the intended use so they can be resolved during quotation review.