{"id":19257,"date":"2026-07-22T12:12:59","date_gmt":"2026-07-22T04:12:59","guid":{"rendered":"https:\/\/daxuns.com\/?p=19257"},"modified":"2026-07-22T12:12:59","modified_gmt":"2026-07-22T04:12:59","slug":"ams4930m-vs-ams4931h-grade-23-bar-daxun","status":"publish","type":"post","link":"https:\/\/daxuns.com\/ja\/ams4930m-vs-ams4931h-grade-23-bar-daxun\/","title":{"rendered":"AMS4930M vs AMS4931H Grade 23 Titanium Bar"},"content":{"rendered":"

AMS4930M vs AMS4931H Grade 23 Titanium Bar<\/h1>\n

Direct answer:<\/strong> AMS4930M and AMS4931H both cover Ti-6Al-4V ELI bar, but they are not interchangeable. AMS4930M is an annealed product route, while AMS4931H is duplex annealed and specifically includes fracture-toughness control. The engineering drawing must select the route, size range, test orientation, ultrasonic acceptance basis, heat-treatment evidence, and any customer-approved-source requirements.[1][2]<\/p>\n

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Supply Scope for Aerospace Technical Review<\/h2>\n

DAXUN can coordinate Grade 23 titanium bar, machining blanks, inspection, process records, and export delivery against the approved drawing and purchase order. The written quotation identifies the applicable mill, processor, laboratory, and inspection responsibilities.<\/p>\n

\n
\n\n\n\n\n\n\n\n\n\n\n
Item<\/th>\nScope that may be coordinated<\/th>\n<\/tr>\n<\/thead>\n
Principal material<\/td>\nTi-6Al-4V ELI bar to AMS4930M or AMS4931H, as specifically ordered<\/td>\n<\/tr>\n
Product form<\/td>\nRound bar, specified bar shapes, cut lengths, and machining blanks within the selected standard’s scope<\/td>\n<\/tr>\n
Condition<\/td>\nAnnealed under AMS4930M, or duplex annealed with the AMS4931H fracture-toughness route<\/td>\n<\/tr>\n
Preparation<\/td>\nSaw cutting, facing, chamfering, peeling, rough turning, centerless grinding, or another confirmed condition<\/td>\n<\/tr>\n
Verification package<\/td>\nMaterial certification, heat and lot identity, heat-treatment records, mechanical and fracture-toughness reports when required, UT report, dimensions, surface condition, and agreed third-party records<\/td>\n<\/tr>\n
Important boundary<\/td>\nBase-material conformity does not by itself establish aircraft-program approval, design allowables, finished-part release, or source approval<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n<\/div>\n<\/div>\n

The most useful quotation begins with the drawing requirement, not the phrase “aerospace Grade 23.” The selected AMS route changes the heat-treatment condition, bar-size boundary, required evidence, and technical meaning of the certificate.<\/p>\n

What Is the Practical Difference Between AMS4930M and AMS4931H?<\/h2>\n

AMS4930M and AMS4931H describe different engineering routes for the same nominal ELI alloy family. AMS4931H is not simply a stronger version of AMS4930M; its distinguishing purpose is duplex-annealed material with fracture-toughness control.[1][2]<\/p>\n

\n
\n\n\n\n\n\n\n\n\n\n\n
Decision point<\/th>\nAMS4930M<\/th>\nAMS4931H<\/th>\nProcurement effect<\/th>\n<\/tr>\n<\/thead>\n
Published condition<\/td>\nAnnealed<\/td>\nDuplex annealed<\/td>\nDo not substitute a generic anneal or heat-treatment statement<\/td>\n<\/tr>\n
Distinguishing requirement<\/td>\nGeneral annealed ELI product route<\/td>\nELI route specifically identified with fracture toughness<\/td>\n4931H is design-driven, not merely a higher-strength option<\/td>\n<\/tr>\n
Published bar-size scope<\/td>\nThrough 10.000 in. (254 mm), with a maximum cross-sectional-area rule for bars over 4.000 to 10.000 in.<\/td>\n6.000 in. (152.40 mm) and under in nominal diameter or least distance between parallel sides<\/td>\nCheck section size before requesting a certificate<\/td>\n<\/tr>\n
Other listed forms<\/td>\nWire, forgings, flash-welded rings, and stock within the published scope<\/td>\nForgings, flash-welded rings, and related stock within the published scope<\/td>\nProduct form must match the drawing<\/td>\n<\/tr>\n
Fracture-toughness evidence<\/td>\nNot identified as the specification’s defining route<\/td>\nA defining part of the specification title and purpose<\/td>\nThe report, specimen orientation, test validity, and applicable acceptance requirement must be reviewed<\/td>\n<\/tr>\n
Substitution<\/td>\nOnly with engineering approval<\/td>\nOnly with engineering approval<\/td>\nSame nominal alloy does not create automatic equivalence<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n<\/div>\n<\/div>\n

The current revisions reviewed for this page are AMS4930M, revised November 13, 2025, and AMS4931H, revised March 19, 2026.[1][2] A purchase order should state the exact revision required by the drawing or program. The word “latest” is not a substitute for configuration control.<\/p>\n

Why Is AMS4931H a Design-Driven Specification?<\/h2>\n

Fracture toughness answers a different question from tensile strength. A tensile test describes the response of a smooth specimen under a specified loading mode. A fracture-toughness test evaluates resistance to crack extension under defined crack, constraint, orientation, temperature, and environment conditions.<\/p>\n

ASTM E399-24 describes the determination of linear-elastic plane-strain fracture toughness, K_IC<\/code>, using fatigue-precracked specimens. It emphasizes that a valid result depends on specimen geometry and size, and that residual stress, crack orientation, temperature, environment, and product dimensions can affect interpretation.[3]<\/p>\n

This creates the following causal chain:<\/p>\n

Critical flaw assumption -> required damage tolerance -> material condition and microstructure -> valid fracture-toughness specimen and orientation -> reported result -> design and acceptance decision.<\/strong><\/p>\n

If a drawing invokes AMS4931H, the buyer should not ask only for a number labelled “KIC.” The file should show the applicable material lot, specimen orientation, test method, test temperature, result, and validity status required by the governing specification or drawing. A test that produces K_Q<\/code> but does not satisfy the method’s validity requirements should not be silently represented as a valid K_IC<\/code> result.<\/p>\n

The additional fracture-toughness requirement makes AMS4931H a design-driven specification rather than simply a higher-strength grade. Substituting AMS4930M because its tensile values appear similar would miss the reason the drawing selected 4931H.<\/p>\n

How Do Bar Size and Product Form Affect Specification Choice?<\/h2>\n

Size is a specification boundary, not just a pricing variable. The public SAE scopes set different bar limits.<\/p>\n

AMS4930M includes bars through 10.000 in. (254 mm) nominal diameter. For bars over 4.000 to 10.000 in. (101.60 to 254 mm), the published scope also limits maximum cross-sectional area to 79 in.\u00b2 (509.7 cm\u00b2).[1] AMS4931H lists bars 6.000 in. (152.40 mm) and under in nominal diameter or least distance between parallel sides.[2]<\/p>\n

\n
\n\n\n\n\n\n\n\n\n\n
Quoted geometry<\/th>\nReview question<\/th>\nRisk if ignored<\/th>\nRequired action<\/th>\n<\/tr>\n<\/thead>\n
Round bar at or below 152.40 mm<\/td>\nWhich condition and performance route does the drawing require?<\/td>\nSimilar dimensions encourage an unauthorized substitution<\/td>\nOrder the exact AMS revision and condition<\/td>\n<\/tr>\n
AMS4930M bar over 101.60 mm<\/td>\nDoes the section satisfy both diameter and area limits?<\/td>\nDiameter-only review may overlook cross-sectional-area scope<\/td>\nCalculate and record the actual section area<\/td>\n<\/tr>\n
AMS4930M bar approaching 254 mm<\/td>\nIs the nominal size inside the current scope and available with required tests?<\/td>\nCertificate requested outside scope or impractical sampling<\/td>\nComplete mill and test-plan review before quotation<\/td>\n<\/tr>\n
Non-round bar<\/td>\nWhat is the least distance between parallel sides and relevant section area?<\/td>\nRound-bar language is incorrectly applied<\/td>\nPut the exact shape and drawing dimensions on the PO<\/td>\n<\/tr>\n
Forging stock or finished forging<\/td>\nIs the order for bar, stock for forging, or a finished forging?<\/td>\nProduct form and testing responsibility become unclear<\/td>\nMatch product description and certification to the actual stage<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n<\/div>\n<\/div>\n

Do not assume that a finished forging can retain a bar certificate as its sole acceptance record. Forging, thermal processing, and final-part requirements may create a separate qualification and release route.<\/p>\n

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What Heat-Treatment Evidence Should Be Requested?<\/h2>\n

The certificate should identify the specified condition, but a one-line statement such as “heat treated” is not enough when the drawing requires a controlled aerospace route.<\/p>\n

AMS2750H covers pyrometric requirements for equipment used in thermal processing of metallic materials, including temperature sensors, instrumentation, correction factors, system accuracy tests, and temperature uniformity surveys.[4] It supports furnace-control evidence; it does not itself define the alloy’s annealing cycle or certify that the material meets AMS4930M or AMS4931H.<\/p>\n

For a project requiring heat-treatment traceability, the agreed file may include:<\/p>\n