# ASTM, SAE, ISO and IATF for Aluminum Castings: Use Each Document Within Its Scope
Automotive casting RFQs often list ASTM, SAE, ISO and IATF references as though they were interchangeable. They are not. A material specification, tensile test method, reference radiograph, surface-texture vocabulary and quality-management-system requirement answer different questions.
Scope map
| Reference | Correct role in an RFQ |
|---|---|
| ASTM B108/B108M | Aluminium-alloy permanent-mold casting material specification |
| ASTM B26/B26M | Aluminium-alloy sand casting material specification |
| [ASTM B557/B557M](https://store.astm.org/standards/b557) | Tensile test method for aluminium- and magnesium-alloy products |
| [ASTM E505](https://store.astm.org/products-services/standards-and-publications/standards/nondestructive-testing-standards.html) | Reference radiographs for aluminium and magnesium **die castings** |
| ASTM E155 or applicable digital reference images | References that may be evaluated for other aluminium/magnesium casting routes, subject to scope, thickness and purchaser-manufacturer agreement |
| [SAE AMS2175](https://saemobilus.sae.org/standards/ams2175-castings-classification-inspection) | Casting classification and inspection, including NDT methods, sampling and acceptance criteria |
| [ISO 21920-2:2021](https://www.iso.org/standard/72226.html) | Terms, definitions and parameters for profile surface texture |
| IATF 16949 | Automotive quality-management-system requirements, not an alloy property table |
Two corrections that matter
First, AMS2175 is not a surface-finish standard. SAE describes it as a casting-classification and inspection specification establishing nondestructive-testing methods, sampling frequency and acceptance criteria.
Second, ISO 4287:1997 is withdrawn. ISO lists ISO 21920-2:2021 as the current published successor for profile surface-texture terms, definitions and parameters. A drawing conversion still needs engineering review because the new ISO 21920 series changed more than the document number.
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Radiographic references must match the process
ASTM E505 explicitly covers aluminium- and magnesium-alloy die castings. It should not be presented as the default acceptance table for a gravity permanent-mold casting. For other casting routes, select a reference image standard whose scope, material, thickness, image type and inspection method fit the part, then state the acceptance category and severity in the drawing or inspection plan.
Do not write "meet ASTM E505" without specifying what is being inspected and what acceptance level applies. A reference radiograph helps communicate discontinuity type and severity; it does not by itself create a complete acceptance plan.
IATF 16949 does not set A356 strength
IATF 16949 governs the automotive quality-management system and connects to customer-specific requirements, control plans, traceability and production approval. It does not prescribe a universal tensile strength, elongation or porosity level for an A356 casting. Those product requirements belong in the drawing, material specification and customer requirements.
RFQ checklist
For each cited document, record:
- •full designation and edition;
- •whether it is current, withdrawn or customer-mandated;
- •the document's actual scope;
- •the characteristic it controls;
- •inspection method, frequency and acceptance criterion;
- •any customer-specific requirement that overrides the general document;
- •responsibility for buying and interpreting the controlled copy.
Send the standards matrix with the drawing through the automotive casting RFQ form.
*This scope map is procurement guidance. The current controlled standards, drawing and customer-specific requirements govern the project.*
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