Liste de contrôle pour la demande de devis de boulons de structure : spécifier la nuance, le type et les assemblages complets selon ASTM F3125

These details matter because two suppliers can quote the same nominal bolt grade while offering different packages. One price may cover bolts only; another may include matched nuts and hardened washers. A third may use a different coating or propose a substitute that has not been approved for the connection. All three quotations can appear competitive until the actual supply scope is compared.

A useful RFQ therefore connects the engineer’s approved requirements to a defined purchase item and an acceptance basis. The checklist below explains what to specify, what to verify, and which decisions should remain with the project engineer.

Specify ASTM F3125 Grade, Type, Style and the Governing Edition

Start with the complete product designation rather than an informal grade name.

ASTM F3125/F3125M covers several structural bolting grades and product configurations. Its classification separates three questions that buyers sometimes combine:

• Grade : Which specified mechanical-strength classification is required?
• Type : Which material-chemistry classification applies?
• Style : Which product configuration is required, such as a heavy-hex bolt or a twist-off tension-control assembly?

The current published ASTM F3125/F3125M-26 scope includes the established A325 and A490 classifications and additional grades such as Grade 144. This does not mean every grade, type and style is available in every diameter or combination. The applicable standard tables, product configuration and project requirements govern what can actually be specified.

The standard edition is another important distinction. An engineering package approved against an earlier edition does not automatically change because a newer edition has been published. The RFQ should reproduce the contractually applicable designation and revision. Where the project documents are silent or inconsistent, request clarification rather than silently substituting the latest version.

For a buyer, the practical sequence is to check the structural drawing or approved specification, identify the complete designation, and ask suppliers to quote that exact product. Any alternative grade, style or specification edition should be shown as a deviation requiring technical approval.

For example, the following two requests are not equivalent:

The second column describes the information needed to make the RFQ complete; it is not a declaration that every possible combination is permitted. Suppliers should confirm the offered configuration against the specified edition.

Lock Down Sizes, Threads and Connection Inputs

A bolt grade identifies a category of product performance, not whether the supplied fastener will fit the connection.

At minimum, the RFQ needs the nominal diameter, length, thread designation and required head or assembly style. The buyer should also identify whether the order uses inch-series or metric dimensions. These systems have distinct dimensional requirements; converting a nominal diameter between inches and millimeters does not establish interchangeability.

For relevant inch-series structural fasteners, ASME B18.2.6 provides dimensional requirements for applicable product forms. ASTM F3125 supplies the product specification framework. The connection drawings establish how the selected fastener must fit the actual joint. These documents have different responsibilities and should not be treated as substitutes.

Why nominal bolt length is not enough

Consider a structural connection containing several steel plates, a nut and any required washers. The joint grip—the combined thickness of material being clamped—is only part of the length-selection problem. The selected bolt must also provide suitable nut engagement, account for the applicable washer arrangement and satisfy the project’s restrictions on thread position.

A bolt that is too short may not provide the required engagement. A longer bolt is not automatically a safer replacement: it may introduce interference or change where threads lie relative to the connected material. Whether thread position is important depends on the designed connection and applicable project requirements.

The procurement team should not invent a length from a general rule when the approved drawing already controls the joint. If the drawing gives only the joint grip or an ambiguous fastener callout, send the question back for engineering confirmation before freezing the order.

The RFQ should distinguish these inputs:

For a standard catalog item, not every measurement needs to be reproduced in the RFQ if the governing product and dimensional specifications define it clearly. Nonstandard geometry, project-specific exceptions and critical interfaces need explicit identification.

A supplier should not be asked to select an alternative bolt length, switch between heavy-hex and TC styles, or change a thread configuration merely to improve availability unless the responsible engineer has approved the change.

In an illustrative bid comparison, two quotations show the same bolt grade and diameter, but one includes a different thread configuration and omits a required washer allowance from the length review. Price alone hides the difference. Issue the approved size and joint inputs to both suppliers, using dimension and thread checks to make the orderable configuration explicit.

Specify the Bolt, Nut, Washer and Coating Package

A structural bolting assembly is not necessarily complete when the bolts have been specified correctly. The mating nuts, required washers and surface treatment must also suit the selected bolt group and the intended connection.

This is a common source of RFQ ambiguity. A quotation described as “1,000 A325 bolts” might cover 1,000 individual bolts, while another supplier interprets the request as 1,000 assemblies containing bolts, nuts and washers. Even if the bolt dimensions are identical, the quotations do not represent the same deliverable.

The buyer should therefore define an assembly before requesting a unit price. State which components belong in each set, how many of each are required, and whether the supplier is responsible for supplying them as an approved compatible package.

Matching nuts and washers to the selected bolt

La RCSC Spécification pour les assemblages structuraux utilisant des boulons à haute résistance organizes applicable fasteners into structural bolting groups and provides requirements for mating components. ASTM A563 is a relevant nut product specification; ASTM F436 covers applicable hardened steel washers. Certain configurations can involve other permitted component specifications.

The key procurement distinction is that an acceptable nut or washer is determined by the applicable bolt group, type, finish and project requirements—not merely by nominal thread diameter.

For example, two nuts may share the correct thread designation, yet have different mechanical grades or surface conditions. Both may physically engage the bolt, but that does not establish that both are acceptable for the specified structural assembly.

Washer requirements also depend on the connection and installation arrangement. The RFQ should identify the required washer standard, type, size and quantity where the project specifies them. It should not automatically assume that every structural bolt needs exactly one washer, nor should it substitute a general-purpose flat washer for a specified hardened washer.

For twist-off tension-control assemblies, the supplier must also confirm the required matched configuration and the applicable supply and verification conditions. A TC assembly should not be treated as an ordinary heavy-hex bolt with interchangeable accessories.

If the project hardware schedule already identifies the approved component combination, include that schedule with the RFQ and reference its revision. If it does not, request engineering clarification rather than asking bidders to make independent assumptions.

Coatings change more than appearance

Surface treatment can affect corrosion protection, thread fit, lubrication and the behavior of the installed assembly.

Common purchasing descriptions such as plain, hot-dip galvanized et zinc flake coated identify different finishes, but they do not independently prove that a coating is permitted for the selected grade and style.

The applicable coating requirements must be checked against the governing ASTM specification, RCSC requirements and project documents. Restrictions differ across bolt groups and product configurations. A coating accepted for one heavy-hex bolt classification must not automatically be offered for another grade or for a twist-off assembly.

Coating thickness also matters at threaded interfaces. Some galvanized configurations require a corresponding nut-thread allowance and specified lubrication or assembly verification. Ordering coated bolts from one source and unverified replacement nuts from another can introduce a mismatch that was absent from the originally qualified package.

For procurement, the important questions are whether the proposed finish is permitted, whether the supplied nut and washer configuration is compatible, and what assembly-related testing or documentation applies.

Do not accept a quotation simply marked “galvanized” or “anti-corrosion coating” when the project calls for a specific coating specification. Ask the supplier to identify the coating process, governing specification and relevant component treatment.

The same caution applies to branded coating names. A commercial name is not a substitute for the required coating standard, product restrictions or supporting documentation.

Define Inspection Records and Supplier Deliverables

A complete RFQ should tell the supplier what evidence must accompany the supplied goods and what documents must be available for review.

ASTM F3125 is a product specification. Its applicable product tests and acceptance requirements address the fasteners being supplied. RCSC provisions address structural bolting assemblies and their use in structural joints, including relevant installation and inspection responsibilities.

These responsibilities are connected, but they are not interchangeable. A product test report does not establish that a particular field connection has been installed correctly. Likewise, successful field pre-installation verification does not replace the specified product manufacturing and acceptance evidence.

ASTM F606/F606M provides methods for mechanical testing of applicable fasteners. The applicable product specification determines which tests and acceptance conditions are required. Listing every test method in F606 on a purchase order without understanding its applicability does not necessarily improve quality control.

What should the RFQ request?

The purchasing documents should make the required evidence explicit.

RCSC 2025 addresses the availability of applicable fastener and assembly test reports for engineering and inspection review. However, this should not be interpreted as an automatic promise that every supplier will furnish a particular document format with every shipment.

If a project requires an EN 10204 3.1 inspection certificate, specify that requirement separately and confirm the supplier can provide an acceptable document for the product and order. An ASTM-compliant product, a supplier CoC and an EN 10204 3.1 certificate are not three interchangeable descriptions of the same record.

The RFQ should also state whether inspection records are required with the quotation, before shipment or with delivery, and whether any independent inspection or witness activity is contractually required.

Separate product acceptance from installation verification

The connection design and installation method must be identified in the project documentation.

A snug-tightened connection and a pretensioned connection are not interchangeable installation requirements. Where the applicable RCSC provisions require pre-installation verification, it is performed for the relevant bolting assembly and installation method under the specified conditions.

This is particularly important when purchasing coated assemblies or tension-control components, because the supplied condition and installation method can affect the applicable verification process.

The buyer’s role is to carry the engineer’s requirements into the purchase order and ensure the necessary components and documentation are supplied. The buyer should not choose a pretensioning method, invent a target torque or approve a substituted assembly without the required engineering authority.

A hypothetical low bid includes only a generic declaration while the competing offer includes the contractually requested finished-lot records and assembly evidence. These are different supply scopes. Compare the document list, test basis and traceability requirements before evaluating price. Record exclusions in the bid comparison rather than assuming every certificate title means the same thing.

Copy-Ready Structural Bolt RFQ and Supplier Bid Comparison

The most useful RFQ is one that both suppliers and the receiving team can interpret without making different assumptions.

The following checklist can be copied into an RFQ spreadsheet or purchasing document. Fields marked as conditional should be completed when applicable to the specific design, product configuration or contract.

Structural bolt RFQ checklist

The most important distinction is between mandatory project requirements and items that require confirmation. Do not turn every possible line in this checklist into a universal ASTM requirement. The project specification determines which conditional items become contractual obligations.

Hypothetical RFQ example: heavy-hex structural bolt assemblies

Illustrative procurement scenario only. This is not a SUNHY customer order, tested assembly or statement of available stock.

Assume a structural engineer has approved an inch-series, uncoated heavy-hex bolt connection and provided a hardware schedule. For this illustration, the approved schedule is assumed to identify the following configuration:

The stated bolt size, length, component combination and washer count are assumptions of this illustrative approved design, not universal recommendations for Grade A325 connections. The actual grade compatibility, dimensions, thread conditions and applicable specification editions must be verified against the governing documents before using such a configuration in a real purchase order.

This example reveals why the order unit matters. If the purchaser requires 240 complete sets, the supplier must understand that the requested scope includes 240 bolts, 240 nuts and 240 washers under the assumed configuration.

A quotation covering only 240 bolts is incomplete even if its unit price looks substantially lower. A quotation using a different nut grade or coating is also not automatically equivalent to the requested package.

A useful RFQ statement for this hypothetical order would be:

Please quote 240 complete structural bolting assemblies in accordance with the attached approved hardware schedule. Each assembly shall include the specified bolt, nut and washer. Identify the applicable product specification editions, component finishes, unit price per complete assembly, relevant inspection documentation and delivery terms. State all technical deviations separately; do not substitute component grades, dimensions or coatings without purchaser approval through the project’s engineering review process.

This wording gives the supplier a clear scope while keeping engineering acceptance with the responsible project authority.

Compare supplier quotations on the same basis

Before selecting a supplier, confirm that each quotation covers the same approved technical requirements and unit of supply.

The following hypothetical comparison shows how a low quotation can conceal a different scope.

Supplier B should not be rejected simply because the initial quotation is incomplete, but its price should not be treated as directly comparable to Supplier A’s complete-assembly price. First clarify the missing items and request a revised offer.

The same principle applies to technical substitutions. A proposed alternative can sometimes be acceptable, but approval requires the appropriate project engineering review. A supplier’s statement that an item is “equivalent” is not itself an approval.

Final RFQ review before issuing a purchase order

The purchasing team should be able to answer three practical questions from the RFQ and supplier’s quotation.

Are both parties describing the same product? The applicable edition, designation, dimensions, finish and approved configuration must agree.

Does the quotation include the complete required assembly? Nuts, washers, coating-related requirements and special components must be included or clearly excluded.

Can the delivered goods be identified and accepted against the order? The required records, traceability, packaging and inspection scope must be defined before shipment rather than negotiated after goods arrive.

Where a technical field remains unresolved, label it for engineering clarification. Where the supplier offers an alternative, record the deviation. Where a documentation or supply capability is not established, request written confirmation.

A complete RFQ does not eliminate the need for engineering approval or receiving inspection. It ensures that suppliers are quoting the intended product and that procurement can make its commercial decision against a consistent technical scope.