ISO 16468:2015

Overview

ISO 16468:2015 - Investment castings (steel, nickel alloys and cobalt alloys) - General technical requirements - defines the general technical requirements for parts produced by the investment-casting (lost-wax) process in steel, nickel and cobalt alloys. The standard forms an integral part of the material specification and takes precedence if its requirements conflict with individual material standards. It replaces the 2005 edition and is intended for use where controlled melting, remelting, inspection and documentation are required.

Key topics and technical requirements

• Scope and precedence: Applies to investment castings of steel, nickel and cobalt alloys; its requirements integrate with and override conflicting material specifications.
• Materials & manufacture: Defines primary-heat and sub-heat practices, permitted melting and remelting routes (electric furnace, induction, vacuum/inert atmospheres) and limitations on remelting of revert material.
• Sampling & test blocks: Requirements for sampling chemical and mechanical test specimens - poured from the same primary heat or representative sub-heat - and acceptable test-block forms.
• Inspection & testing: General delivery requirements follow ISO 4990; supplementary nondestructive testing options include:
  • Magnetic particle inspection (MPI) - ISO 4986
  • Liquid penetrant inspection (LPI) - ISO 4987
  • Radiographic inspection (RT) - ISO 4993
  • Ultrasonic inspection (UT) - ISO 4992-1 / 4992-2
• Mechanical & hardness testing: References for tensile and hardness testing methods (Brinell, Rockwell, Vickers) and frequencies for chemical analysis and tensile tests.
• Quality, cleaning and dressing: Requirements for surface cleaning to permit inspection and agreed visual standards (ISO 11971 may be used).
• Production welding: Production welding procedures and approval are covered via ISO 11970.
• Supplementary requirements: Agreement options for manufacturing approval, inspection extent, retests, weld maps, impact testing at low temperatures, ferrite measurement in austenitic alloys, and metallurgical cleanliness.

Applications and who uses it

ISO 16468:2015 is used by:

• Foundries and investment-casting manufacturers to standardize production and testing.
• Quality assurance and NDT inspectors to define inspection methods and acceptance.
• Purchasers and specifiers (aerospace, power generation, oil & gas, automotive, medical devices) to ensure castings meet metallurgical and inspection requirements.
• Design and procurement engineers who include material and inspection requirements in contracts and material specifications.

Related standards

Key normative references cited in ISO 16468:2015:

• ISO 4990 (general technical delivery requirements)
• ISO 4986, ISO 4987, ISO 4993 (MPI, LPI, radiography)
• ISO 4992-1 / 4992-2 (ultrasonic)
• ISO 6506/6507/6508 (Brinell, Vickers, Rockwell hardness)
• ISO 11970 (welding procedures)
• ISO 10474 (inspection documents)
• ISO 13520 (ferrite determination)

Keywords: ISO 16468:2015, investment castings, steel casting, nickel alloys, cobalt alloys, inspection, NDT, sampling, melting, foundry quality.