We offer a wide variety of in-house investment casting quality verification and product testing services to find casting defects through destructive and non-destructive testing design to provide our customers with the highest quality cast product. No matter where the product is applied, each precision investment castings is inspected and approved before delivery. Inspection allows foundry and clients to feel confident they have a quality casting.
Non-destructive Testing (NDT)
Nondestructive Testing (NDT) is one of the main procedures of quality control in steel casting, and plays an important role in assuring that steel castings will perform well during service. Non-destructive testing is done by our foundry QC person, customers’ QC engineers, and third-party NDT technicians to verify the internal and external soundness of a casting, these tests are performed in a manner that does not affect the future usefulness of steel castings and without damaging the casting itself.
Non-destructive Testing (NDT) Methods Performed on Steel Investment Casting
Visual and Optical Testing (VT)
Visual Examination can be an effective way to recognize surface imperfections that could adversely affect our steel castings. Visual Examiners use knowledge of how a steel cast part is manufactured, the function of the human eye, lighting requirements, and precise measuring tools to evaluate materials.
Liquid Dye Penetrant Inspection (LPI)
LPI is a testing method used for surface defects of all metal investment castings. In this inspection process, the tester first cleans the casting to remove any particles of grit or dust that may prevent the liquid dye from going into cracks in the metal. Once clean and dry, a dye solution with color is applied to the surface of the castings. The dye, which is suspended in penetrating oil, finds its way into the surface defects. When a special developer is applied, the casting defects become clearly visible. The solution is to detect any cracks or other surface defects due to porosity or gas that produced on the surface. Sometimes it is difficult to find the surface defects by naked eye, such as tiny cracks, pores or other surface defects.
Magnetic Particle Inspection (MPI)
MPI is similar to LPI in that it is used to find small cracks and holes on or near the surface or shallow subsurface of investment castings. It is accomplished by inducing a magnetic field into a ferromagnetic material and applying iron particles to the surface of the metal castings being examined. MPI testing is convenient and affordable. Cracks and defects have differing magnetic properties than those of the surrounding material. Their presence will interrupt the magnetic field, causing distortion, which indicates the shape and position of the crack or void.
Ultrasonic Testing (UT)
Ultrasonic Examination finds defects by using high frequency acoustic energy transmitted into a steel casting, to detect discontinuities or locate changes in material characteristics. Sound waves travel through a casting until they hit the opposite surface or an interface or defect. Any barrier reflects the sound waves, which bounce back and are recorded for an analyst to look at. Ultrasonic Testing (UT) in a technology similar to the ultrasounds used by medical technicians
Radiographic Inspection (X-Ray)
Radiographic Examination involves using radioactive isotopes (gamma rays) or X-rays on steel casting create images or films. The ghostly images produced through casting X-Ray show dark spots where there are shrinkage cavities, the small breaks and crevices of heat cracking, or the pinhole dots of porosity. These images help an experienced metalworker decide if the casting’s mechanical properties are compromised by shrinkage, inclusions, or holes and whether they can be fixed before castings are shipped.
After all of the inspections are completed, we will submit all the reports with related photos for our customer approval. Then we’ll arrange the shipment once we got the approval from our customer. If you have any request for metal castings, please do not hesitate to email Ningbo Investment Casting Co., Ltd for price.