A tungsten copper electrode that passes your receiving dock without inspection is a warranty on the supplier’s paperwork, not on the part. Most W/Cu shipments are sound — but the failures that slip through, a soft batch, an out-of-round bore, a profile cut to the wrong revision, cost far more on the line than they would have cost at the dock. This checklist covers what a buyer should actually check on incoming W/Cu electrode wheels and machined parts, and what documentation should arrive with the box.
Before opening: the paperwork
Check the shipment against the order before touching a part:
- Batch traceability record — every batch should be checked for composition, density and hardness at the factory. If your quality system requires dimensional records per wheel — bore, OD, runout, thickness against your drawing revision — those ship on request; make sure the request was in the order.
- External certificates — third-party stamped test reports per ASTM B702 are typically available when your system needs an external certificate rather than a factory report. These must be requested in the RFQ, not after arrival.
- Drawing revision match — confirm the shipment was made to the revision you last approved. A repeat order machined “to the same program” is only correct if the program matches the current revision.
Physical checks on arrival
W/Cu is dense — typically around 14.5–15.2 g/cm³ depending on grade — so packaging failures show up as dings and edge damage. Inspect before stocking:
- Packaging condition. Vacuum bags with foam lining, rods in cartons, blocks in wooden crates. A crushed corner of the crate deserves a photo before you sign.
- Visible damage on faces, threads and profile edges. Surface oxidation of the copper phase is cosmetic and normal; dented profile edges are not.
- Weight sanity check. A wheel noticeably light against the invoice weight is the cheapest density alarm you will ever get — a low-density batch means incomplete infiltration and short electrode life.
The five measurable checks
These are the dimensions and properties that decide whether the part works. A workshop with calipers, a dial indicator, a bench and a hardness tester can do all of them:
- Density. Typically ≈ 15.2 g/cm³ for W/Cu 75/25 and ≈ 14.5 g/cm³ for 70/30. Water-displacement measurement on a sample part confirms infiltration quality; certify against the batch record rather than testing every part.
- Electrical conductivity. Typically ≥38% IACS for 75/25 and ≥42% IACS for 70/30. A conductivity meter on the face catches a wrong-grade shipment instantly — the most common mix-up is 75/25 supplied against a 70/30 order.
- Hardness. Typically 85–95 HRB (75/25) and 80–90 HRB (70/30); machinable-wheel specs are often quoted around 175–195 HB. A soft batch dresses fast and drifts out of profile — the failure that looks like “bad electrodes” three weeks later.
- Bore and keyway. H7 is the typical bore tolerance. Gauge the bore and slide the wheel onto a master shaft or the actual arbor: a bore that needs force or has play will hunt on the seam and wear the shaft.
- Runout and profile. Mount the wheel and check runout with a dial indicator — typically 0.02 mm is the specification that keeps the wheel tracking instead of chattering. Verify the edge profile (flat, bevel, R or knurled) against the drawing revision; this is the check most often skipped and most often wrong after a revision change.
For threaded electrodes, add go/no-go thread gauges to both the bore and thread checks — a thread that gauges true on arrival is the only one that screws into the gun the first time. The callouts worth inspecting against are listed in how to specify threaded tungsten copper electrodes.
When to reject
Reject, and say why in writing, when: density or conductivity falls outside the batch record; hardness is materially below the typical band; bore, runout or profile exceeds the drawing; or the drawing revision is wrong. A supplier confident in its floor will want the failed parts back or at least the gauge data — that conversation improves the next batch.
Inspection paperwork with your order
ArcTung ships batch traceability records on request and can include per-wheel dimensional inspection records — bore, OD, runout, thickness — against your drawing revision, with third-party ASTM B702 reports available for qualifying orders. Standard wheels ship in 10–14 days, custom in 20–25, samples in 10 days or less, no MOQ, FOB Shenzhen/Nansha. Send your inspection requirements with your RFQ to sales@arctung.com and they will be on the packing list, not negotiated at the dock.