ASTM A517Gr.Q quenched and tempered steel plates supplier

Grade Q purchasing begins with the actual plate thickness

ASTM A517 Grade Q is a high-strength quenched-and-tempered alloy plate grade intended for fusion-welded boilers and other pressure vessels. Its official A517/A517M-17(2023) public-Scope ceiling is 6 in. [150 mm]. A thickness assessment must therefore distinguish the Grade Q specification range from a particular mill’s smaller product offering.

For a Gangsteel enquiry, identify the exact plate thickness before applying a strength band or comparing data sheets. Above the strength breakpoint, assess the thicker band through the Grade Q ceiling rather than substitute another grade’s limit. The official ceiling does not itself establish availability or the complete material acceptance requirements.

Use both strength bands, including the thicker Grade Q range

These are Grade Q-specific mill restatements from ArcelorMittal USA’s public 2021 brochure, not an official ASTM mechanical-table extract. The upper band runs to the Grade Q Scope ceiling; it is not cut off at Grade P’s limit. Confirm properties and testing under the ordered edition and the actual supply agreement rather than treat the reference as a guarantee for every dimension.

SSAB’s Grade Q listing restates the same strength pattern within its own 0.197–3.60 in. range. That published mill range neither reduces the official Grade Q ceiling nor promises Gangsteel supply. The public Scope states that A517 grades share mechanical properties and general characteristics, but each grade still has its own chemistry and permitted thickness.

Elongation is meaningful only with its gauge and source

SSAB’s A517 Grade Q page and datasheet dated 19 April 2017 restate minimum elongation of 16% for its thinner band and 14% for its thicker band, both in a 2 in. gauge length, with an A20 elongation-adjustment footnote. These are mill product references, not official ASTM elongation-table values.

Interpret those values with the source’s prose distinction at 2.5 in. and its offering only to 3.60 in. They are not extended here into an elongation guarantee for plate up to 6 in. For the order, establish the applicable gauge, specimen basis and adjustments, and compare the certificate on that basis rather than use an unqualified percentage.

Grade Q heat analysis: a separately identified alloy basis

The chemistry below comes from the A517 Grade Q column in ArcelorMittal USA’s 2021 A514 and T-1 brochure. It is a heat-style mill restatement, not the current official ASTM chemistry table and not product analysis. SSAB’s cited Grade Q datasheet is a mechanical reference, not the chemistry source.

The mill column does not list boron, titanium, zirconium or copper as required Grade Q additions; that is not a zero-content guarantee. Do not infer finished-product tolerances from the heat values or substitute a wider, unexplained range. Any required product-analysis report must be assessed under the applicable specification provisions and agreement.

Place Grade Q in the official thickness framework

This public-Scope table describes specification ceilings, not stock or a confirmed supply catalogue. Inch-pound and SI values are independent systems, not exact conversions. In particular, Grade P’s 4 in. [100 mm] limit does not restrict Grade Q, and a mill advertising a larger product cannot change the official Grade Q limit.

The Grade Q alloy basis also differs from Grade P: the cited mill columns show higher manganese and chromium ranges and a vanadium range rather than Grade P’s boron addition. A larger permitted thickness is not proof that Grade Q is a universal upgrade. Keep material selection separate from a supplier’s size offering.

Transverse Charpy testing needs an agreed numerical basis

The official A517 public abstract specifies killed steel, fine austenitic grain size, analyses, tension testing and transverse Charpy V-notch testing. The public Scope does not publish numerical Charpy temperature or energy requirements. State the applicable test conditions and acceptance criteria under the ordered edition instead of assuming that “Grade Q” supplies a default result.

On a report, review the material identity, specimen orientation, test temperature, actual results and the required acceptance basis. Also identify any agreed specimen treatment used to represent fabrication. A lateral-expansion criterion, an energy result and a design-temperature assessment are different matters; one should not be substituted for another without the required technical basis.

Separate vessel Grade Q from structural and other vessel grades

ASTM A514 Grade Q steel plate is structural Q&T alloy plate, not A517 Grade Q. ASTM A514 Grade P steel plate belongs to that structural family as well. Similar letters or chemistry do not align the specifications, delivery requirements or material acceptance.

For other vessel-plate requirements, ASTM A537 Class 2 steel plate, ASTM A537 Class 1 steel plate and ASTM A516 Grade 70 steel plate have their own material and delivery bases. They are related purchasing topics, not an equivalent-material list for Grade Q.

Specify Q&T delivery, the complete plate schedule and the required records. Any proposed welding or later heat treatment needs an appropriate fabrication procedure and testing basis; this product description is not a preheat, quench, temper or PWHT schedule.

Buyer questions about A517 Grade Q requirements

Is Grade Q restricted to the same thickness as Grade P?

No. The official public Scope gives Grade Q a 6 in. [150 mm] ceiling, whereas Grade P is limited to 4 in. [100 mm]. A mill can offer a smaller range than the specification permits. Keep the grade ceiling, published mill reference and actual offered dimensions separate when evaluating a quotation.

Can the thicker strength band be omitted from a Grade Q enquiry?

Not where the requested thickness falls in that band. The cited mill pattern changes above 2 1/2 in. and extends to the Grade Q ceiling, subject to the ordered requirements. Identify the actual thickness and unit system so the correct strength basis is used rather than extrapolate a thin-plate value.

What does the published 16% or 14% elongation mean?

Those values are SSAB Grade Q mill restatements in a 2 in. gauge length, with the source’s A20 adjustment footnote and its product-range limitations. They are not a certified official ASTM table. Review the applicable gauge, specimen details, thickness and adjustments before comparing a test report with the requirement.

Does the heat-analysis table define product vanadium acceptance?

No. The vanadium range shown is explicitly the mill heat-analysis reference. It does not supply a finished-product tolerance, and an unexplained range from another table should not be assigned an analysis basis by guesswork. Request and assess any product-analysis results against the ordered edition and applicable provisions.

Is A514 Grade Q an acceptable alternative if its chemistry looks similar?

Not automatically. A514 is structural plate, while A517 is pressure-vessel plate with different specification and delivery requirements. The material identity and required testing must support the actual order. Any substitution or dual certification needs explicit assessment rather than reliance on a matching grade letter or appearance.