What the names tell you
The names identify closely related grades in different standards. They help buyers communicate a material family across regions, but they do not automatically align every chemistry limit, test method, dimensional tolerance or certificate requirement.
How to choose the ordering designation
Use the standard required by the drawing, customer specification or internal material system. If more than one designation appears, identify which one governs and whether the others are reference equivalents. Require written approval for substitutions when traceability matters.
What matters beyond the grade name
Product form, section size, remelting route, delivery condition, machining allowance, heat treatment, inspection and documentation can have more effect on order suitability than the cross-reference itself. Include all of them in the RFQ.
A practical comparison method
Ask each supplier to quote the same governing standard and the same complete supply scope. Compare certificate type, heat traceability, testing, supplied dimensions, processing, packaging, lead time and exclusions before comparing unit price.