What an ultrasonic acceptance class actually fixes
An order line that says “ultrasonic tested” does not describe an acceptance decision. Four fields decide whether a bar passes: the method, the coverage, the calibration reflector and the acceptance class. Two mills can both report “UT passed” against different reflectors and reach opposite conclusions on the same bar.
| Field | What it decides |
|---|---|
| Method | Which discontinuities the scan can reach at all |
| Coverage | How much of the cross section and circumference is scanned |
| Calibration reflector | The reference echo that sets instrument sensitivity |
| Acceptance class | The indication level above which material is rejected |
The reflector, not the word “ultrasonic”, sets the sensitivity
A flat-bottom hole (FBH) is a calibration target. Sensitivity is set so that the echo from that hole reaches a stated screen height, and indications are then judged against it. A scan calibrated against a larger reflector passes material that a finer setting rejects, with every other condition equal.
The FBH is a reference, not a statement that every discontinuity of that size is detected.
Beiyu’s documented setting on the precision ground bar route
These are the values Beiyu runs on the precision centerless ground bar route. They belong on the purchase order rather than being inferred from the words “ultrasonic tested”.
| Ultrasonic parameter | Documented setting |
|---|---|
| Method | Water immersion, focused longitudinal wave |
| Coverage | 100 percent of the circumference |
| Calibration reflector | 1.2 mm diameter radial flat bottom hole, set to 80 percent full screen height |
| Probe frequency | 10 MHz |
| Acceptance class and specification | Recorded together on the ultrasonic report supplied with the order, against the specification the order names |
| Specifications worked to | AMS-STD-2154 or GB/T 5193, whichever the order calls for |
Where the acceptance specification changes the answer
AMS-STD-2154 and GB/T 5193 are both acceptance specifications for ultrasonic inspection of wrought product. An order that names one of them fixes the class definitions the mill works to. An order that names neither leaves the class letter without a definition behind it.
| Order states | What the mill can do |
|---|---|
| Class only, no specification | Class letter has no agreed definition; acceptance is negotiable after the fact |
| Specification only, no class | Mill applies its default class, which may not match the drawing intent |
| Both specification and class | Acceptance is objectively verifiable at receiving inspection |
Which specification defines the class letter
A class letter only means something inside the specification that defines it. Different ultrasonic specifications use different class systems, so an order that names a class without naming its specification leaves the acceptance level undefined.
| Specification | Scope it is written for |
|---|---|
| AMS 2631 | Ultrasonic inspection of titanium and titanium alloy bar, billet and plate |
| AMS-STD-2154 | Ultrasonic inspection of wrought metals, used across alloy families |
| GB/T 5193 | Ultrasonic inspection of titanium and titanium alloy plate, bar and forgings |
State the specification the class belongs to on the order. Where a drawing names a class letter alone, confirm which specification it is taken from before the material is released for inspection.
Why the finished bar route and the billet route are not the same scope
The settings above describe the finished precision ground bar route. Billet is inspected to the scope agreed on the order rather than to this set. State which route the material is being bought on, because the scan geometry and the accessible cross section differ.
What the certificate should carry
An ultrasonic report is only reviewable if it records the same four fields the order specified, plus the traceability that ties the report to the delivered material.
| Certificate line | Why a buyer checks it |
|---|---|
| Method and probe frequency | Confirms the scan matches what was ordered |
| Coverage statement | Distinguishes full coverage from sampling |
| Calibration reflector and screen height | Makes the sensitivity reproducible |
| Acceptance class and specification | Makes pass or fail objective |
| Heat number traceability | Ties the report to the material actually shipped |
How this sits alongside the other 100 percent inspections
Ultrasonic flaw detection is one of five inspections Beiyu runs at 100 percent on the precision ground bar route, meaning every bar rather than a sample from the lot. Chemistry and tensile testing are destructive tests run on specimens, reported per heat and per batch on the mill test certificate.
| Inspection at 100 percent on that route |
|---|
| Ultrasonic flaw detection |
| Eddy current flaw detection |
| Surface optical inspection |
| Infrared laser diameter measuring |
| Straightness detection |
Acceptance lines you can paste into your purchase order
Ultrasonic method: ______ (state immersion or contact, and wave mode) Coverage: ______ (state percentage and which surfaces) Calibration reflector: ______ (state hole diameter and screen height) Probe frequency: ______ Acceptance specification: ______ (name the specification first) Acceptance class: ______ (use a class letter defined inside that specification) Report requirement: ultrasonic report supplied with the order, traceable to the heat number on the mill test certificate
Fill those lines in on the enquiry. Beiyu checks them against the acceptance specification you named before any price is put against the line.
Use the UT acceptance class selector to check the fields and generate a complete order line before sending the RFQ.
Specification detail with sources
An ultrasonic acceptance class is not defined by the product standard itself. What ASTM B348 does fix is the order content: its ordering information clause requires the grade number, product classification, chemistry, mechanical properties, marking, finish, packaging, the required reports and the disposition of rejected material (ASTM B348, ordering information). An ultrasonic acceptance class is not one of those defaults. What the standard does guarantee is the certification content: the report shall include the results of all chemical analysis, tensile tests and all other tests required by the specification, together with the manufacturing method, whether hot rolled, forged, extruded or cold worked (ASTM B348, certification). An examination class has to be added to that on the order.
| Order field required by ASTM B348 | Where the ultrasonic requirement attaches |
|---|---|
| Grade number | Fixes chemistry and mechanical minimums, not the scan |
| Certification | ASTM B348 requires the report to cover chemical analysis, tensile tests, all other tests required by the specification, and the manufacturing method |
| Ultrasonic acceptance | Not a default; written onto the order as an additional requirement with its specification and class |
| Disposition of rejected material | Decides what happens to pieces the scan rejects |
The chemistry the same certificate reports against is fixed by that standard: ASTM B348 sets Grade 2 at 0.25 percent oxygen maximum and 0.30 percent iron maximum, and Grade 5 at 0.20 percent oxygen maximum and 0.40 percent iron maximum (ASTM B348, chemical requirements). Its referenced test methods include ASTM E1409 for oxygen and nitrogen by inert gas fusion and ASTM E1447 for hydrogen (ASTM B348, referenced documents). Naming a method settles how a number was produced. It does not set the acceptance limit, and it says nothing about the ultrasonic class, which comes from the acceptance specification you name. In Beiyu’s supply practice the ultrasonic settings quoted above apply to the precision centerless ground bar route only.
Send a technical RFQ
For titanium bar RFQs, include grade, ASTM or AMS standard, diameter, condition, surface finish, tolerance, quantity, the ultrasonic acceptance specification and class, and the required mill test certificate.