GB/T 16270 Q550F QT Carbon Steel Plate Supplier

Q550F, also searched as GB/T 16270 Q550F, Q550F QT plate, Q550F carbon steel plate, Q550F steel plate and Q550F quenched and tempered plate, is the 550 MPa quality-grade-F grade in GB/T 16270. That standard covers high-strength structural steel plate delivered quenched and tempered. Q is the yield symbol, 550 is the thin-plate minimum yield in MPa, and F is the quality letter for Charpy impact at −60°C.

Q550F is the coldest letter in the Q550 family. C is 0°C. D is −20°C. E is −40°C. F is −60°C. Buyers use it on arctic frames and any drawing that names −60°C at 550 MPa. A mill that only tested at −40°C cannot stamp F. Not every QT mill will accept F on heavy plate.

The closest European name is EN 10025-6 S550QL1. Both are about 550 MPa QT plate tested at −60°C. S550QL is −40°C and lines up with Q550E. S550Q is 0°C and lines up with Q550C. On the US side, the nearest yield comparison is ASTM A656 Grade 80, 80 ksi / 550 MPa. A656 is high-strength low-alloy plate, not this QT book, and it does not carry a −60°C letter. Dual mark only when both books are fully met. See EN 10025-6 steel plate.

SHH STEEL is a global steel mill sourcing partner and steel manufacturer and exporter, mill-direct, China origin. We source Q550F from first-line QT mills that can run a −60°C route, print heat analysis and product analysis when ordered, and ship plate to fabricators in the United States, Europe, the Middle East, Southeast Asia, Africa and South America. Related pages include high strength low alloy plates and structural steel plates.

Nearby pages that buyers compare, but must not swap blindly, include S550QL1, S550QL and A572 Gr.50.

Heat analysis is the mill ladle table in GB/T 16270. Product analysis, when ordered, follows GB/T 222. Grade F is the tightest cleanliness letter in the Q550 family, because the impact test is at −60°C. Mills add Nb, V, Ti or Al for grain refinement, and may add Ni, Cr, Mo or B by thickness. Nickel is often used on F heats to hold the cold impact. The certificate shows the elements actually used.

Heat Analysis and Product Analysis — GB/T 16270 Q550F

If the purchase order writes product analysis, SHH STEEL prints both columns and the thickness band used for the tensile test. Do not treat this chemistry as weathering plate. Do not treat it as S355JR.

Buyers search Q550F mechanical properties, Q550F yield strength, GB/T 16270 Q550F tensile and Q550F impact −60°C.

Tensile and impact — GB/T 16270 Q550F

Impact energy is the average of three longitudinal Charpy V-notch specimens. One value may fall below the table, but not below 70% of that value. A −60°C test is harder to hold than a −40°C test. Write the energy on the purchase order if the owner wants a number above the book minimum. Not every QT mill will accept F on plate over 80 mm. SHH STEEL confirms the thickness before promising the letter.

Yield steps down with thickness. A 550 MPa name on 20 mm plate is not the minimum on a 120 mm flange. ASTM A656 Grade 80 is also 550 MPa / 80 ksi minimum yield, but it does not carry this −60°C QT table. Density is 7.85 g/cm³. Hardness after temper is a mill control, not a design value. Z15, Z25 or Z35 through-thickness tensile is an extra.

There is no official one-to-one substitute for Q550F. What buyers compare is a 550 MPa QT plate tested at −60°C.

In the United States the nearest yield name is ASTM A656/A656M Grade 80. Grade 80 is 80 ksi / 550 MPa minimum yield and 90 ksi / 620 MPa minimum tensile. That matches the Q550F thin-plate yield number. It does not match the GB/T 16270 quench-and-temper route, and it does not match the −60°C quality letter. A572 Gr.65 is only 65 ksi / 450 MPa. A514 Grade Q is 100 ksi / 690 MPa QT plate, closer to Q690 than to Q550F. SHH STEEL will not stamp A656 Grade 80 or A514 on a Q550F certificate unless the purchase order names both books and both tables are met.

The usual European pair is S550QL1. S550QL is warmer. S550Q is only 0°C. In Japan, SM570 is a welded structural grade, not this plate.

Buyers pick Q550F when a welded frame, boom or chassis wants 550 MPa yield, QT delivery and impact at −60°C. Search phrases such as Q550F steel plate, GB/T 16270 Q550F and Q550F QT plate all point here.

It is the wrong plate for a 0°C file that can use Q550C. It is the wrong plate for a −40°C file that can use Q550E. It is the wrong plate for a US file that actually names ASTM A656 Grade 80. That work stays on A656 unless the order also accepts GB/T 16270. It is the wrong plate for a 100 ksi QT flange. That work is A514 Grade Q. It is the wrong plate for a pressure vessel. That work sits on ASTM A516 or pressure vessel steel plates.

SHH STEEL supplies this plate when the drawing names GB/T 16270 and quality grade F at 550 MPa.

Q550F is weldable QT carbon plate, but the joint must keep −60°C toughness. A procedure written for S355JR is not a Q550F procedure. A procedure qualified only at −20°C is not enough either. A procedure written for ASTM A656 Grade 80 is a useful strength check, not a finished WPS.

Typical consumables are matching 550–620 MPa low-hydrogen electrodes or wires, qualified on a QT 550 MPa family with a −60°C impact coupon. Nickel-bearing wires are common on F-grade joints. E7018-class electrodes are under-matched if the joint must develop full plate strength. A procedure written for S550QL1 is the usual starting point.

Preheat follows thickness, hydrogen and the approved WPS. Interpass temperature should stay below the mill temper range, or local yield and the −60°C result can drop. After heavy cold forming, a stress relief may be required. The fabricator owns the WPS. SHH STEEL can share mill heat data, product analysis and carbon equivalent for that review.

Usual delivery from SHH STEEL for Q550F is quenched and tempered. Austenitize typically in the 880–930°C range, quench, then temper in the window that holds 550 MPa yield and the −60°C impact. Exact temperatures stay on the mill process sheet. F-grade heats are not every mill’s standard route.

Do not order Q550F as as-rolled or TMCP unless the contract leaves GB/T 16270. ASTM A656 Grade 80 is not a QT delivery instruction for this page. Stress relief after fabrication, if used, must stay below the original temper temperature.

The certificate lists GB/T 16270 Q550F, heat number, heat analysis, product analysis when ordered, tensile by thickness band, and −60°C impact. Certificates may be EN 10204 3.1 or EN 10204 3.2. Dual marking to S550QL1 or A656 Grade 80 is available only when both books are fully met.

Usual supply range from SHH STEEL for Q550F QT carbon steel plate:

• Thickness: commonly 8 mm – 80 mm, heavier plate to 100 mm by mill confirmation
• Width: 1500 mm – 3500 mm
• Length: 3000 mm – 12000 mm

Cut-to-size webs, flanges and base plates are available. Browse more sizes on structural steel plates and the products index.

Dimensional limits for Q550F follow GB/T 709 unless the purchase order names another table.

Typical thickness tolerance idea for Q550F QT plate

Width on 1500–3500 mm plate is commonly held to about ±20–25 mm unless a tighter extra is named. Length on 3000–12000 mm plate is commonly held to about +50 / 0 mm or ±25 mm by mill practice. Flatness after QT follows the agreed class. SHH STEEL will not assume a zero-minus extra on Q550F unless the order says so.

Q550F already defines 550 MPa yield, QT delivery and −60°C impact. Extra items still have to be written on the purchase order.

Book name. Write GB/T 16270 Q550F. Do not write only Q550F.

Impact. Grade F is −60°C. Write a higher energy if the owner requires it.

US comparison. Write ASTM A656 Grade 80 only if dual mark is required.

Product analysis. Write it if the file needs the second chemistry column.

Through-thickness. Z15, Z25 or Z35 when the joint is loaded through the thickness.

NDE. UT to GB/T 2970 or the named class.

Heat-treatment record. QT temperatures when the inspector asks.

Identification. Heat number, Q550F, thickness and mill logo.

Third-party witness. EN 10204 3.2 with SGS, TÜV, BV, ABS or the inspector named.

Q550F is the plate for a 550 MPa QT file tested at −60°C. It is the wrong plate for a painted warehouse that can use S355JR. It is the wrong plate for a 100 ksi QT member.

SHH STEEL sources Q550F from first-line Chinese QT mills that can run a −60°C route and ships it on worldwide terms. Partner mills include Wuyang (Wugang), Angang, Shougang, Hanye, Anyang Iron and Steel, Baosteel, Xinyu, Xingcheng and other qualified mills when the size requires it.

Mill test certificates are issued to EN 10204 3.1 as standard. EN 10204 3.2 is arranged when the order names a third-party hold point.

Usual rolling thickness: 10 mm, 12 mm, 16 mm, 20 mm, 25 mm, 30 mm, 32 mm, 40 mm, 50 mm, 60 mm, 80 mm. Heavier plate is confirmed before order.

Processing: CNC or flame cutting, bevel, flattening, shot blast, UT to the named class.

Trade terms: FOB Shanghai main, CIF destination available. Payment: TT, LC, or TT + LC.

Ocean time from Shanghai: US West 14–18 days; US Gulf 28–35 days; Rotterdam / Antwerp 28–35 days; Jebel Ali 18–25 days; Singapore 7–12 days; other ports quoted.

Third-party: SGS, TÜV, BV, ABS, CCS, GL, VL, DNV, RINA, NK, KR, or the inspector named.

SHH STEEL is a global steel mill sourcing partner with mill partnerships in China. We supply GB, ASTM, ASME, EN, DIN and JIS steel to buyers in the United States, Europe, the Middle East, Southeast Asia, Africa and South America. Origin is mill-direct, China origin.

SHH STEEL has supplied steel plates to the USA, Mexico, Argentina, Peru, El Salvador, Spain, Netherlands, Germany, UAE, Saudi Arabia, South Africa, India, Thailand, Singapore, Vietnam, the Philippines, Japan and Korea.

Typical lead time: ex-stock 5–7 days when an F heat is in yard; standard QT rolling with −60°C test about 40–50 days; 3.2 inspection about 50–60 days.

SHH STEEL is a global steel mill sourcing partner and steel manufacturer and exporter, mill-direct, China origin. For Q550F that means mill-direct QT price, not a multi-layer stockist mark-up on a cold-impact heat. We buy from mills that can actually test at −60°C, so the letter F is on the certificate and not only in the enquiry.

Delivery is short when the size is in rolling range: ex-stock 5–7 days, standard F heat about 40–50 days, 3.2 inspection about 50–60 days. Cutting, bevel and UT can run in the same window. FOB Shanghai is the main term. CIF to US West, US Gulf, Rotterdam, Jebel Ali and Singapore is quoted on the same file.

Experience on this grade is simple: print GB/T 16270 Q550F, keep the QT route, and do not ship Q550E or ASTM A656 Grade 80 as F. We will not change F to E to save a cold test, and we will not treat Q550F as S355 or as A514. If the drawing only needs −40°C, we will move the inquiry to Q550E and keep the price on the right grade.

Q550F QT carbon steel plate to GB/T 16270 is 550 MPa quenched-and-tempered structural plate with impact at −60°C. The nearest US yield comparison is ASTM A656 Grade 80. Whether the inquiry says Q550F, GB/T 16270 Q550F, Q550F QT plate or Q550F carbon steel plate, SHH STEEL as a global steel mill sourcing partner supplies plate with Q550F chemistry, heat and product analysis as ordered, GB/T 709 tolerances and EN 10204 3.1 or 3.2 certification.

SHH STEEL supplies Q550F QT Carbon Steel Plate to the United States, Europe, the Middle East, Africa, Asia and the Americas for work that actually names this grade.

Contact SHH STEEL for mill rolling, −60°C impact, cutting, UT, 3.2 inspection or a worldwide quotation.

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