Casting X-ray inspection and radiographic testing of castings for porosity

Casting X-ray results are only useful when the drawing or purchase order says what to grade against. These are the standards US labs most often quote.

A typical drawing note reads like "radiograph zones A and B per ASTM E1030, accept to E155 gas porosity level 2". If your drawing only says "X-ray for porosity", ask the lab to propose zones and a severity level, and confirm them with your customer before parts are shot. Our industrial X-ray inspection page covers film, computed radiography and digital detectors in more depth.

High pressure aluminum die castings are the largest single use of casting X-ray in the US. Gas porosity and shrinkage are part of the process, so the real question is whether the porosity sits where it matters. Most programs X-ray every part at launch and during PPAP, then move to a sampling plan once the die and the process window are stable. Many die casters run a real time X-ray cabinet next to the trim press for 100 percent checks on safety parts, and send overflow, first article and dispute samples to an outside lab. If a pore near a sealing face or bolt boss keeps showing up, the next step is usually a CT scan that measures the pore volume and its distance to the machined surface. The guide CT vs X-ray inspection for castings explains when that switch pays off, and casting inspection services for automotive covers the full PPAP method mix.

Aluminum and magnesium parts are easy to penetrate with a standard X-ray tube. Steel castings over about 2 inches thick often need a higher energy source, such as a linear accelerator or a gamma source, which fewer labs own. Say the alloy and the thickest section in your request so labs without the right source can decline early.

Foundry quality managers send launch samples and suspect lots when a customer rejects parts for leaks or porosity. Buyers at OEMs order third party X-ray on incoming castings from a new or offshore supplier, because an independent grade settles disputes faster than two sets of opinions. Aerospace and defense suppliers need radiography on Class 1 and Class 2 castings with documented technique sheets and a Level II or Level III interpreter. Pump, valve and oil and gas manufacturers radiograph pressure retaining steel castings to ASME and API requirements. Product engineers use one X-ray round to decide whether a gating change fixed a shrinkage problem before they release a die modification.

1. You send the part number, alloy, weight, the thickest and thinnest sections, quantity, the zones to inspect and the acceptance standard and severity level.
2. The lab writes a technique: energy, detector or film, number of views per zone, and the image quality indicator that proves sensitivity.
3. Parts arrive on a pallet or in crates. Large lots can be shot at the foundry with a mobile crew.
4. A qualified radiographer reads each view against the reference radiographs and records the grade per zone.
5. You receive a report with part serial numbers, technique, grades, accept or reject and the images, plus a certificate of conformance if your customer needs one.

Lab work on castings commonly turns in two to seven business days. Many labs offer next day service on small lots for a rush fee.

These are typical US planning ranges, not quotes. Part size, alloy, number of views and the report format set the real price.

Most labs charge a minimum, often one hour or a set lot fee. The cheapest way to buy casting X-ray is to fix the zones and views once, then send repeat lots on the same technique so setup is not charged again. Our guide to NDT inspection cost explains how labs build quotes across methods.

Start with capability. Ask which reference radiograph sets the lab owns, because ASTM sets are bought separately and a lab without E505 cannot grade die castings to it. Ask the highest energy source on site and the largest part their cabinet or bay accepts. Ask who reads the images and at what level, and whether the lab holds Nadcap for radiography if you supply aerospace. Then ask for a sample report with a grade per zone. A report that only says "acceptable" gives you nothing to show a customer in a dispute. Our list of NDT companies shows how to compare labs on scope rather than price alone, and industrial CT scanning covers the next step when 2D images cannot settle where a pore sits.