GB/T1591 Q460D carbon structural steel plate

Product Introduction

01Product Overview

GB/T 1591 Q460D is a low-alloy high-strength structural steel (HSLA) — a 460 MPa-yield grade that reaches roughly 115 MPa more yield than the Q355 / Q345 family, and about 210 MPa more than plain carbon structural steel, while still welding with ordinary consumables. The name is a specification, not a marketing line: Q is the Chinese abbreviation for yield strength (qu fu), 460 is the minimum yield strength in MPa, and D is the quality grade — the letter that tells you the steel carries a guaranteed Charpy V-notch impact test at −20 °C (≥ 34 J). It sits in the Q460 family, one step tougher than Q460C and one step below Q460E.

Q460D is hot-rolled, TMCP, normalized or quenched-and-tempered plate, sheet, section and bar for heavy welded and bolted structures — construction and mining machinery, crane and lifting equipment, heavy steel structures, pressure and offshore service, and engineering vehicles. The strength comes from small additions of niobium (Nb) and vanadium (V) (plus titanium and aluminium grain refinement), not from high carbon, so it stays formable and readily weldable. One naming point worth keeping straight: GB/T 1591 was revised in 2018, but the Q460 designation is unchanged — only Q345 was renamed Q355. Q460D is the same steel in both editions; we supply and certify against whichever your drawing cites. (Q500 / Q550 / Q620 / Q690 are the new 2018 grades — Q460 was not renamed to Q500.)

550-720 MPaTensile Strengthmin-max band, not a single value

460 MPa minYield Strengthup to 16 mm; steps down with thickness

-20 °CImpact Test Temperature≥ 34 J (the 'D' grade)

Q460DUnchanged 2008 / 2018only Q345 became Q355 in 2018

02Technical Specifications

What this page publishes, and what must be confirmed on the mill certificate when you enquire.

Item	Specification
Executive Standard	GB/T 1591 (Chinese standard for hot-rolled low-alloy high-strength structural steel). The grade name Q460D is the same in GB/T 1591-2008 and GB/T 1591-2018 — the 2018 revision renamed Q345 to Q355 and added Q500/550/620/690, but left Q460 unchanged.
Steel Grade	Q460D (GB/T 1591-2008 and GB/T 1591-2018; identical designation)
Steel Category	Low-alloy high-strength structural steel (HSLA), micro-alloyed with Nb / V / Ti
Product Forms Covered	Steel Plate Sheet Section Bar hot-rolled plate and sheet on this page; Q&T plate via GB/T 16270
Thickness Range	6 – 100 mm (Q460 is published up to 100 mm; this is why the mechanical table has four thickness brackets, not six)
Width Range	1 000 – 4 000 mm
Length Range	4 000 – 12 000 mm
Production Way	Hot rolled, TMCP, normalized (N) or quenched and tempered (Q&T) — the condition is chosen with the order
Delivery Condition	AR / TMCP / N / Q&T — see section 07
Impact Requirement	-20 °C, ≥ 34 J longitudinal Charpy V-notch — this is what the “D” grade guarantees, beyond Q460C
MOQ	1 t mixed sizes negotiable
Lead Time by Quantity	1 – 10 t: 5 days · 10 – 50 t: 10 days · > 50 t: negotiable
Payment Terms	L/C T/T D/P Western Union Paypal Money Gram
Processing Services	Cutting to length and width, profiling, bevelling, bending, drilling, welding, shot blasting and painting
Certification	Mill Test Certificate to EN 10204 3.1, or 3.2 with third-party endorsement; heat analysis and mechanical test report

Two things worth clearing up about this table. First, Q460D is a low-alloy high-strength steel, not plain carbon — older listings and the site category label call it “carbon structural steel”, which is imprecise. Its strength comes from Nb/V/Ti micro-alloying, so it is heavier in manganese and carries alloying limits the plain-carbon grades do not. Second, the grade name did not change in the 2018 standard: Q460D (2008) = Q460D (2018). Only Q345 became Q355, and Q500/550/620/690 are new grades added in 2018 — Q460 was never renamed to Q500. So there is no “old vs new” Q460 name to reconcile; just state which edition your certificate must cite.

03How to Read the Grade

Every part of Q460D is a specification, not a marketing name.

Part	Meaning
Q	The Chinese abbreviation for yield strength (“qu fu”). It tells you the first number is a yield value, not a tensile one.
460	The specified minimum yield strength in MPa — the whole reason the grade is called “460”. Tensile and elongation come with it, impact does not (it is set by the quality letter).
D	The quality grade: it fixes the Charpy V-notch impact temperature at -20 °C with a minimum absorbed energy of ≥ 34 J (longitudinal), and tightens phosphorus and sulphur to P ≤ 0.030 % / S ≤ 0.025 % (Q460D). C, D, E step up the impact temperature and tighten cleanliness.
GB/T 1591	The Chinese national standard for hot-rolled low-alloy high-strength structural steel. Revised in 2018, but the Q460 designation is unchanged — the 2018 edition renamed only Q345 to Q355 and added the Q500/550/620/690 grades.

The Q460 quality ladder — the letter is the impact temperature. Note there is no Q460A or Q460B.

Grade	Impact test	P max (%)	S max (%)	Position in the family
Q460C	0 °C	0.030	0.030	Mild-climate, general heavy construction
Q460D (this page)	-20 °C	0.030	0.025	Cold climates, dynamic-load and lifting structures
Q460E	−40 °C	0.025	0.020	Extreme cold, critical infrastructure

Pick the letter by the coldest service temperature. Q460D is the default for outdoor and dynamic-load structures in cold climates because it guarantees -20 °C toughness. If the structure sits in a reliably temperate environment, Q460C (0 °C) is enough and slightly cheaper; if it sees severe cold, step up to Q460E (−40 °C). The yield, tensile and thickness brackets are the same across the letters — only the impact and the P/S cleanliness change. Unlike the Q345/Q355 family, Q460 has no A or B grade.

04Equivalent Grades

Q460D is the 460 MPa yield level of the Chinese low-alloy structural family. The table maps it to its closest international grades — a similar yield figure is not a licence to substitute; check chemistry, toughness and thickness brackets before swapping. Every linked grade opens its own page.

Standard	Grade	Min. Yield	What to check before substituting
GB/T 1591 (this page)	Q460D	460 MPa	The Chinese grade — -20 °C impact, P ≤ 0.030 % / S ≤ 0.025 % (this page)
GB/T 16270	Q460D	460 MPa	The quenched-and-tempered counterpart standard — same grade name and yield, delivered in the Q&T condition rather than as hot-rolled. Closest domestic alternative when Q&T plate is required.
EN 10025-3	S460N / S460NL	460 MPa	S460N is the exact -20 °C impact match for Q460D; S460NL (-50 °C) lines up with Q460E. Note: EN 10025-2 has no 460 MPa grade — S460N/NL belong to EN 10025-3 (normalized fine-grain). Confirm chemistry and the N/NL impact class.
JIS G3106	SM570	460 MPa	The exact JIS yield match (460 MPa). A direct procurement mapping for Japanese-spec projects — confirm the impact class (SM570 has no mandatory sub-zero impact unless specified).
ASTM A572 / A572M	A572 Grade 65	450 MPa	The closest ASTM grade — 450 MPa minimum yield, within ~10 MPa of Q460D. Grade 50 (345 MPa) is too low to substitute; only Gr.65 is in the right band. Confirm impact, which A572 does not mandate.
ASTM A572 / A572M	Grade 50	345 MPa	Below Q460D by 115 MPa — a common reference grade but not an equivalent; only relevant where the design genuinely needs no more strength.
ASTM A709	Grade 50	345 MPa	The bridge-purpose version of A572 — same 345 MPa yield, mandatory Charpy. Still 115 MPa below Q460D; not an equivalent.
EN 10025-2	S355JR	355 MPa	105 MPa below Q460D — do not substitute; the JR class is a +20 °C impact, weak on cold toughness versus Q460D.
JIS G3106	SM490YA	325 MPa	135 MPa below Q460D — the JIS SM number is a tensile value, the Q/A572 number is a yield value; "490" is not stronger than "460".
GB/T 1591	Q345C / Q355C	345 MPa	115 MPa below Q460D — a lower grade in the same Chinese family; cited here only for cross-reference.

Strength proximity is not interchangeability. Chemistry limits, toughness classes, thickness brackets and delivery conditions all differ between these standards, and a substitution has to be signed off by the designer against the governing code. The two traps to name: EN 10025-2 has no 460 MPa grade — the European match is EN 10025-3 S460N (normalized, -20 °C), not an S355; and the frequently cited lower grades (S355JR 355 MPa, SM490YA 325 MPa, A572/A709 Gr.50 345 MPa) are well below Q460D and must not be used as equivalents. Where a Japanese project needs the exact yield, specify SM570; where an American project needs the closest band, specify A572 Grade 65 (450 MPa).

05Chemical Composition

Ladle (cast) analysis limits in weight percent, per GB/T 1591 Q460D (2008 and 2018 editions). The residual elements the old product sheet omitted are included here — product-analysis tolerances apply when ordered.

Element	Limit (% by mass)
Carbon, C	≤ 0.20
Silicon, Si	≤ 0.55
Manganese, Mn	1.00 – 1.70
Phosphorus, P	≤ 0.030
Sulphur, S	≤ 0.025 (Q460D)
Niobium, Nb	0.015 – 0.060
Vanadium, V	0.020 – 0.200
Titanium, Ti	0.020 – 0.200
Aluminium (total), Al	≥ 0.015
Chromium, Cr	≤ 0.70
Nickel, Ni	≤ 0.70
Copper, Cu	≤ 0.55
Molybdenum, Mo	≤ 0.20
Nitrogen, N	≤ 0.015
Boron, B	≤ 0.004 (when specified)

Read the certificate against this table, not against a one-line data sheet. Q460D is a micro-alloyed grade — the Nb, V and Ti rows are what deliver the 460 MPa yield without raising carbon, and they will appear on the MTC. Two notes: Q460 is a higher-strength grade, so its residual limits are wider than those of Q345 — Cr and Ni up to 0.70, Cu up to 0.55, Mo up to 0.20, N up to 0.015, with optional boron up to 0.004; the old listing omitted Cu, Mo, N and B. And the S limit for Q460D is 0.025 % (tighter than Q460C at 0.030 %), so confirm the exact grade letter on the certificate of the heat you buy.

06Mechanical Properties

Minimum room-temperature values, read against nominal thickness. Q460 is published up to 100 mm, so the full GB/T 1591 ladder is four brackets; the old product sheet listed those four but gave no elongation and no impact. Every figure is a floor the heat is tested against — not a prediction of your certificate.

Thickness (mm)	Yield R_eH min (MPa)	Tensile R_m (MPa)
≤ 16	460	550 – 720
> 16 – 35	440	550 – 720
> 35 – 50	420	550 – 720
> 50 – 100	400	550 – 720

Elongation & impact — the properties the old page omitted.

Property	Requirement
Elongation A (longitudinal)	≥ 17 % up to 40 mm; steps down (to about 15 %) at greater thickness — confirm on the certificate
Charpy V-notch, longitudinal	-20 °C, ≥ 34 J (the Q460D requirement)

Three corrections / completions against the old page. First, the yield is given in thickness bands (460 MPa up to 16 mm, stepping down to 400 MPa at 50–100 mm) — the old listing showed these four brackets, which are actually the complete GB/T 1591 Q460 ladder (Q460 is only rolled to 100 mm, so there is no fifth or sixth bracket). Second, the old sheet gave no elongation or impact; the standard requires ≥ 17 % elongation (longitudinal, up to 40 mm) and the -20 °C / ≥ 34 J impact that the “D” letter guarantees. Third, the tensile band is a single 550–720 MPa across all four brackets. Treat the table as the GB/T 1591 reference and confirm the exact band for your thickness on the certificate.

07Delivery Condition, Heat Treatment & Additional Requirements

Q460D can be supplied in several conditions; the order, not the grade, fixes the rest.

Item	Options
Delivery Condition	AR — As hot rolled (usual) TMCP N — Normalized Q&T — Quenched & tempered
Additional Conditions	UT Charpy V-notch Z15 / Z25 / Z35 Third-party test (SGS) Coated or shot blasted and painting
Surface Treatment	As rolled Shot blasted Primed Painted

What the specification sets, and what has to be added by the order.

Item	Status in GB/T 1591	How it is obtained
Delivery condition	AR / TMCP usual; N or Q&T by agreement	Normalizing or quenching & tempering can be agreed for thick plate or for a tighter, tougher microstructure (Q&T also available via GB/T 16270).
Heat treatment	Not required by the as-rolled grade	Strength comes from micro-alloying and controlled rolling; normalizing or Q&T is an agreed add-on, not a default.
Impact toughness	-20 °C / ≥ 34 J at the “D” grade	Built into the grade; third-party witnessed impact on request.
Ultrasonic testing	Not specified	GB/T 2970 or EN 10160 at an agreed acceptance level, by agreement.
Through-thickness (Z) properties	Not specified	Z15 / Z25 / Z35 by agreement where the joint pulls through the plate thickness.
Third-party inspection	Not specified	SGS, BV, TUV or Intertek at the mill before shipment.
Certificate	MTC per the specification	EN 10204 3.1 as standard, 3.2 with third-party endorsement on request.

Keep the condition and the code edition in the enquiry. Q460D is normally delivered hot rolled (or TMCP) and tested per heat; anything beyond that — normalized, Q&T, UT, Z-direction, third-party inspection — has to be written into the order before rolling, not added afterwards. For quenched-and-tempered plate, the same grade is supplied under GB/T 16270 Q460D. And because the grade name is unchanged between editions, just name the standard (GB/T 1591-2008 or GB/T 1591-2018) — the certificate reads Q460D either way.

08Typical Applications

Where a low-alloy 460 MPa structural steel carries the heavy load.

Construction & Mining Machinery

Excavator booms and arms, mining truck bodies and frames, loader and dozer structures — the 460 MPa yield cuts section weight where the load is high and the duty is dynamic.

Crane & Lifting Equipment

Crane jibs, boom sections, outrigger beams and lattice members — applications where -20 °C impact tolerance matters because the structure sees repeated dynamic and lifting loads.

Heavy Steel Structures & Bridges

Primary members, built-up sections and splice plates on heavy bridges and industrial structures — the -20 °C impact of Q460D lets it serve in colder-climate heavy construction where Q355 would not.

Pressure & Offshore Service

Pressure-equipment supports, offshore platform structures and drilling-rig members — high-strength, weldable plate for weight-sensitive and cold-environment service.

Engineering Vehicles & Transport

Chassis and load-bearing frames for heavy transport, trailers and engineering vehicles — strength-to-weight that trims tare weight while holding the load.

Why this grade is chosen when the design needs more than Q355 / Q345: it gives about 115 MPa more yield for a modest price step, it does it with micro-alloying rather than carbon so it still welds with ordinary consumables, and the D letter adds -20 °C toughness for cold-climate and dynamic-load service. What it does not give you is weathering (atmospheric-corrosion) resistance or the very-high-strength band of Q500–Q690 — those are different specifications or need the order to add them.

09Processing, Testing & Supply

From mill plate to a cut, certified, ready-to-fit structural item.

Cutting & Profiling

Plate and sheet cut to length and width, profiled to drawing and bevelled for weld preparation on flame, plasma or laser equipment.

Forming, Bending & Welding

Bending and rolling to radius, cold forming to the radius the thickness allows, plus welded assemblies built under a qualified procedure — preheat is generally not required up to about 30 mm, and thicker or highly restrained joints call for 100 – 150 °C with low-hydrogen consumables (higher-strength plate is less forgiving than Q355).

Surface Treatment

Shot blasting to remove mill scale, then shop primer or full paint system, followed by export marking and seaworthy packing.

Inspection & Certified Delivery

Chemical analysis and tensile testing per heat, -20 °C Charpy, UT and Z-direction testing when specified, then the MTC carrying the grade, the GB/T 1591 edition and any third-party report.

Mill Test Certificate to EN 10204 3.1, or 3.2 with third-party endorsement
MTC stating the grade (Q460D) and the GB/T 1591 edition cited (2008 or 2018 — same name)
Heat analysis and mechanical test report (yield, tensile, elongation, -20 °C Charpy)
Nb / V / Ti micro-alloy content recorded against the grade ordered
Ultrasonic testing report to the agreed acceptance level (GB/T 2970 / EN 10160)
Z-direction (through-thickness) test report where Z15/Z25/Z35 is ordered
Third-party inspection by SGS, BV, Intertek or another nominated agency
Export packing, marking and loading supervision

Quote checklist — you get a faster, comparable price if you send: thickness × width × length, quantity, product form (plate, sheet, section or bar), delivery condition (AR / TMCP / N / Q&T), the -20 °C impact requirement, UT acceptance level and any Z-direction requirement, surface treatment, MTC type, destination port and payment terms. MOQ is 1 t.

10Frequently Asked Questions

Q1What does GB/T 1591 Q460D actually mean?

Q460D is a Chinese low-alloy high-strength structural steel. Q is the abbreviation for yield strength, 460 is the minimum yield in MPa, and D is the quality grade that fixes a guaranteed Charpy V-notch impact of -20 °C, ≥ 34 J and tightens P/S to P ≤ 0.030 % / S ≤ 0.025 %. It is the -20 °C-toughness step above Q460C, and the grade standard is GB/T 1591 (the 2008 and 2018 editions share the same Q460D name).

Q2Was Q460 renamed in the 2018 standard?

No — this is a common mix-up. GB/T 1591-2018 left the Q460 designation unchanged. The 2018 revision renamed only Q345 to Q355 and added the new higher grades Q500, Q550, Q620 and Q690. Q460 was not renamed to Q500 — Q500 is a separate, stronger new grade. So Q460D is the same steel in both editions; just tell us which edition your certificate must show.

Q3What is Q460D equivalent to in EN / ASTM / JIS?

The exact European match is EN 10025-3 S460N (460 MPa, -20 °C) — note EN 10025-2 has no 460 MPa grade, so the match is in part 3, not part 2; S460NL (-50 °C) lines up with Q460E. In Japan the exact yield match is JIS G3106 SM570 (460 MPa). In the US the closest is ASTM A572 Grade 65 (450 MPa) — A572 Gr.50 (345 MPa) is too low to be an equivalent. GB/T 16270 Q460D is the quenched-and-tempered domestic counterpart. All are procurement mappings; confirm the actual values against your governing code.

Q4Is Q460D a weathering or “carbon” steel?

Neither label is quite right, and both appear on older listings. Q460D is a low-alloy high-strength steel — micro-alloyed with Nb/V/Ti, not plain carbon, and not a weathering steel (it gives no atmospheric-corrosion guarantee). If bare, unpainted outdoor exposure is the design condition, that is a different specification; ask us for a weathering grade rather than assuming Q460D will patina-protect itself.

Q5Can I substitute S355JR, A572 Gr.50, SM490 or Q345C for Q460D?

Only with the designer’s sign-off against the governing code, and for most of these the answer is no — they are too weak. S355JR (355 MPa), A572 / A709 Gr.50 (345 MPa), SM490YA (325 MPa) and Q345C / Q355C (345 MPa) are 105–135 MPa below Q460D. The grades that actually match are EN 10025-3 S460N, JIS G3106 SM570 and ASTM A572 Grade 65; even those differ in chemistry, impact class and thickness brackets, so the swap still needs design approval.

Q6How thick, how fast, what paperwork, and is the old page’s data right?

From 1 t, with typical lead times of about 5 days for 1–10 t, about 10 days for 10–50 t and negotiable above 50 t. Each heat ships with an EN 10204 3.1 mill test certificate. The figures on this page correct / complete the older listing: Q460D is a low-alloy high-strength steel (not plain carbon), the mechanical table keeps the four correct thickness brackets (Q460 is rolled only to 100 mm — there is no truncated 4-of-6 issue) but now adds the elongation and the -20 °C impact the old sheet omitted, the chemistry now includes the Cu / Mo / N / B residual limits, and we publish the key naming fact — Q460 was not renamed in 2018 (only Q345 became Q355, and Q500 is a new 2018 grade), and the Q460 family has only C/D/E, no A/B. Each change is flagged in a note box above.

More carbon and low-alloy structural grades we supply: Q460D (this page) · GB/T 16270 Q460D quenched-tempered steel plate · GB/T 1591 Q345C / Q355C low-alloy steel plate · ASTM A572 Grade 50 hot rolled sheet plate · EN 10025-2 S355JR carbon structure steel plate · JIS G3106 SM570 carbon structure steel plate · JIS G3106 SM490YA carbon structural steel plate · View all carbon and low-alloy steel plate →

Sources and limits: the figures on this page are reference information drawn from GB/T 1591 (Q460D, identical in the 2008 and 2018 editions) and published steel data sheets. Q460D is a low-alloy high-strength structural steel; the chemistry limits and the tensile / yield / elongation / -20 °C impact floors are the standard requirements, while actual heat values are recorded on the EN 10204 certificate of the lot supplied. Older listings of this grade called it “carbon structural steel” and omitted the residual chemistry (Cu, Mo, N, B), the elongation and the impact, and sometimes stated the grade was renamed in 2018 — we have corrected those against the standard: Q460 is unchanged between editions, the Q460 family is C/D/E only, and the mechanical ladder is the four brackets up to 100 mm. BBN supplies, cuts and processes the plate.

Get Your GB/T 1591 Q460D Quotation Now

Send us your standard and edition (GB/T 1591-2008 or GB/T 1591-2018 — both read Q460D), thickness, width and length, quantity, product form, delivery condition (AR / TMCP / N / Q&T), the -20 °C impact requirement and any UT / Z-direction requirement. We will reply with what the mill can roll and certify at that thickness, plate or cut-length options, mill price and production lead time — and tell you plainly if a lower Q460C would do, or if a severe-cold duty should step up to Q460E or an EN S460N / S460NL equivalent.

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