Trace Undercarriage Parts from Heat Number to Shipment
A heat number on a material certificate is the beginning of a traceability chain, not the whole chain. Between raw steel and a shipped undercarriage part, material may be cut, divided among production lots, heat treated, machined, assembled, reworked, packed and relabeled. Each transition needs a record that preserves the relationship between the incoming identity and the outgoing items.
For context on processes and service factors, see the broader manufacturing factors that affect undercarriage parts. The narrower task here is evidence control: starting from a shipped batch, can the supplier identify the source heat and every intervening lot? Starting from a suspect heat, can the supplier identify every potentially affected finished batch and shipment?
Define the identifiers used at each production stage
Begin with a dictionary for the actual order. Record what each identifier means, who creates it, where it appears and what quantity it covers. Terms such as heat, lot and batch are often used loosely. Two records containing the same word do not necessarily identify the same physical group.
Heat, process lot and finished batch
A heat number normally identifies steel produced under one heat record. An incoming material lot may be a delivered subset of that heat. After cutting, the pieces can enter different forging, casting, heat-treatment or machining lots. Inspection can use another lot definition, and final packing may group products by order or shipment. An assembly can contain components from several source heats.
Give every stage a separate field. Useful fields include the source heat, incoming material receipt, cut-piece or traveler identity, process lot, subcontract dispatch and return reference, heat-treatment lot, inspection lot, finished batch, serial number where used, package and shipment. Record quantity and date at each transition. The structure should allow relationships among the fields instead of compressing them into one generic “batch” column.
A code does not prove conformity by itself. It provides a key to supporting records. The relevant material certificate, process record, inspection result or disposition must still be linked and evaluated against the order. Metcast’s quality page is one manufacturer example that describes links among material, process and inspection records; it is not evidence of another supplier’s system or of KTSU’s order-specific capability.
Follow the records through transformation
Traceability becomes difficult where the physical material changes form or grouping. At every split, record which child items came from the parent quantity. At every combination, record every contributing component. Reconcile quantities, including test coupons, machining allowance, scrap and rework, so unexplained material does not disappear from the genealogy.
Splitting a heat
Suppose bars from heat H-2407 are cut into 60 blanks. Thirty-two blanks enter forging lot F-A, 24 enter F-B and four are recorded as scrap. The traveler or cut record should preserve that 32 + 24 + 4 equals the original 60. If F-A later divides into two heat-treatment lots, each child quantity must remain linked to H-2407 and F-A.
A paint mark or handwritten label may help physical control, but the genealogy also needs an authorized record. If a container is split, repacked or relabeled, capture the old identifier, new identifier, quantities, reason, date and responsible person. Never infer that adjacent labels share the same heat merely because they were stored together.
Combining components into an assembly
A finished roller, idler or track assembly can combine parts with different histories. The assembly record should link each controlled component to its source batch. The final assembly code then becomes a junction, not a replacement for all earlier identities. If one component is substituted, the record must show which assemblies received the change.
Unite Manufacturing’s material-traceability guide distinguishes heat, lot, batch and cut-piece relationships as material moves through production. Use it as a method illustration. The required depth and exact identifiers still come from the purchase, drawing and quality agreement for the actual product.
In the diagram, one source heat divides into two recorded process lots. One branch retains its link through the finished batch and shipment. The broken branch represents a returned or relabeled group whose mapping was not preserved. A later certificate carrying the heat number does not reconstruct which physical items were on that branch.
Test traceability in both directions
A static list of codes can look complete while failing the decision the records are supposed to support. Test the chain with two practical queries. Record the tester, time, starting identifier, sources opened, quantities reconciled, elapsed retrieval time if relevant and every unresolved junction.
Shipment to source
Select a finished batch, package or shipped item without warning the record owner which example will be used. Walk backward from shipment and packing records to the finished batch, assembly components, inspection and process lots, incoming receipt and source heat. At each step, confirm that the identifier and quantity refer to the same physical group.
The test fails when the chain stops at a summary that cannot expose the underlying relationship. For example, a shipment log may name finished batch B-19 and a certificate may name heat H-2407, yet no traveler shows that B-19 used pieces from H-2407. Both documents can be authentic and still lack the linking evidence needed for this genealogy.
Source to affected shipments
Now choose a source heat or process lot and trace forward. Find every cut group, child process lot, subcontract movement, inspection group, finished batch, assembly and shipment that may contain the selected material. Include stock still at the supplier and material that was scrapped, reworked or held. The quantities should reconcile to the recorded inputs and documented losses.
This direction is essential for containment. A backward lookup that finds the heat for one shipped part does not show whether a concern with that heat affects two other shipments. The result of the test is an evidence boundary, not a recall or warranty decision. The authorized parties decide notification, disposition and scope after reviewing the traceability result and technical issue.
| Case | Starting point | Backward result | Forward and quantity result | Status and next action |
|---|---|---|---|---|
| Normal | Shipment S-88, finished batch B-19 | Traveler links B-19 through F-A and its heat-treatment lot to H-2407 | All 32 F-A blanks resolve to finished, scrap or held quantities and named shipments | Chain demonstrated for the tested scope; retain the test record |
| Missing | Returned subcontract container R-6 | Return label names a process lot but has no dispatch-to-return mapping | The affected pieces cannot be assigned to finished batches | Unresolved; identify the record owner and hold the affected boundary |
| Conflict | Finished batch B-22 | Inspection record names H-2407; traveler names H-2411 | Forward searches from both heats overlap B-22 | Conflict; preserve both records and obtain an authorized correction or disposition |
Find gaps before a quality incident
Run the test while records and physical labels are easy to recover. A failed audit is more useful before shipment than after a quality concern. Review the transitions most likely to break: cutting and repacking, relabeling after surface treatment, subcontract dispatch and return, mixed containers, rework, and assembly of components from different lots.
Relabeling
When an original mark becomes unreadable or a container changes, record who authorized the replacement and which evidence connected the old identity to the new one. A clean new label without that bridge can make an uncertain item appear more certain. Photographing both labels during a controlled change can support the record, but a photo alone does not reconcile quantity or approval.
Subcontracted processes
An outside processor adds custody and identity transitions. Link the dispatch quantity and identifier to the processor’s receipt, process batch, results, return quantity and returned labels. Record shortages, samples, scrap or mixed returns. A purchase order for the service shows that work was requested; it does not prove which returned pieces received which process.
Missing links
Do not repair a gap with a likely story. Mark the affected quantity and latest confirmed identity, then assign an owner to search travelers, dispatch notes, system transactions or retained labels. If evidence remains absent, preserve the limitation for the authorized quality decision. “Probably from the same heat” is not a traceability status.
Casco’s supplier quality manual is one organization’s example of connecting traceability with part identity, production lots and retained records. Its detailed requirements and retention periods belong to that context. They should not be copied into an unrelated purchase agreement as universal rules.
Keep the accepted records with the order
Retention and access expectations
Before release, agree which records make up the accepted genealogy: material certificates, incoming receipts, travelers, split and merge logs, subcontract records, process results, inspection lots, assembly records, nonconformance dispositions, packing lists and shipment references. Define format, access owner, retrieval route and change history. Set the applicable retention period through the order or quality agreement rather than borrowing a number from a supplier manual.
Preserve superseded records with their status. If a heat number or batch link is corrected, the new record should identify what changed and who authorized it. Deleting the earlier version can hide whether shipped parties received inconsistent evidence. A clear correction history supports later review without allowing the old identity to remain active.
Test retrieval as well as retention. A file may technically exist but be unusable if the shipment reference cannot locate it, the responsible system has been retired, or a subcontract record is held under an unknown name. A sample lookup should return readable records with the same identifiers used in the genealogy. If access depends on one person’s memory, record that weakness and assign an owner before accepting the evidence set.
The stopping rule is simple: every controlled finished item in scope must be traceable backward through all material and process transitions, and every selected source heat or lot must be traceable forward to all affected stock and shipments. Any broken, missing or conflicting junction remains visible until the responsible authority resolves its disposition.