Q800D QT Carbon Steel Plate GB/T 16270 Supplier

Q800D, also searched as GB/T 16270 Q800D, Q800D QT plate, Q800D carbon steel plate, Q800D steel plate and Q800D quenched and tempered plate, is the 800 MPa quality-grade-D grade in GB/T 16270. That standard covers high-strength structural steel plate delivered quenched and tempered. Q is the yield symbol, 800 is the thin-plate minimum yield in MPa, and D is the quality letter for Charpy impact at −20°C.

Q800D is the middle impact letter in the 800 MPa family. C is 0°C. D is −20°C. E is −40°C. F is −60°C. About 116 ksi on a US drawing is the same yield number. Equipment builders use it when the frame needs 800 MPa and the site sees sub-zero nights, but the specification does not call for −40°C. It is not a substitute for Q800C, and it is not a substitute for Q800E.

EN 10025-6 has no S800 grade and no −20°C letter. S690Q is 690 MPa at 0°C. S690QL is 690 MPa at −40°C. S890Q is 890 MPa at 0°C. Q800D sits between those numbers and between those temperatures. On the US side, A514 Grade Q is 100 ksi / 690 MPa, one step lower, and it does not carry a D 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 Q800D from first-line QT mills, 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 S690QL, S890Q and A514 Gr.Q.

Heat analysis is the mill ladle table in GB/T 16270. Product analysis, when ordered, follows GB/T 222. Grade D is tighter on phosphorus and sulfur than grade C, because the impact test is colder. Mills add Nb, V, Ti or Al for grain refinement, and may add Cr, Ni, Mo or B by thickness. Boron is common on 800 MPa heats. The certificate shows the elements actually used.

Heat Analysis and Product Analysis — GB/T 16270 Q800D

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 Q800D mechanical properties, Q800D yield strength, GB/T 16270 Q800D tensile and Q800D impact −20°C.

Tensile and impact — GB/T 16270 Q800D

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 typical production heat is at or above 34 J at −20°C. Write a higher energy on the order if the owner requires it.

Yield steps down with thickness. An 800 MPa name on 20 mm plate is not the minimum on a 120 mm flange. 800 MPa is about 116 ksi. ASTM A514 is 100 ksi and is not this number. SHH STEEL quotes the thickness band on the offer.

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 Q800D. EN 10025-6 jumps from 690 MPa to 890 MPa and has no −20°C letter. ASTM A514 stops at 100 ksi.

S690Q is warmer and lower. S690QL is colder and lower. S890Q is higher and warmer. A514 Grade Q is 100 ksi / 690 MPa. A572 Gr.65 is only 65 ksi. SHH STEEL will not stamp S890Q or A514 on a Q800D certificate unless the purchase order names both books and both tables are met.

Buyers pick Q800D when a welded frame, boom or chassis wants 800 MPa yield, QT delivery and impact at −20°C. Search phrases such as Q800D steel plate, GB/T 16270 Q800D and Q800D QT plate all point here.

It is the wrong plate for a 0°C-only file that can use Q800C. It is the wrong plate for a −40°C mine site. That work is Q800E. It is the wrong plate for a 690 MPa file that was sized on Q690D. It is the wrong plate for a 100 ksi US file. 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 D at 800 MPa.

Q800D is weldable QT carbon plate. The plate has already been quenched and tempered, and many heats use boron. A procedure written for S355JR is not a Q800D procedure. A procedure qualified only on Q800C at 0°C may miss the −20°C coupon.

Typical consumables are matching 800 MPa low-hydrogen electrodes or wires, qualified on a QT 800 MPa family. E7018-class electrodes are under-matched if the joint must develop full plate strength. A procedure written for S890Q is a higher-strength reference after the −20°C test temperature is checked. An A514 procedure is a lower-strength reference, not a finished WPS for this grade.

Preheat follows thickness, hydrogen and the approved WPS. Interpass temperature should stay below the mill temper range, or local yield 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 Q800D is quenched and tempered. Austenitize typically in the 880–930°C range, quench, then temper in the window that holds 800 MPa yield and the −20°C impact. Exact temperatures stay on the mill process sheet.

Do not order Q800D as as-rolled or TMCP unless the contract leaves GB/T 16270. ASTM A514 is not a delivery instruction for this page. Stress relief after fabrication, if used, must stay below the original temper temperature.

The certificate lists GB/T 16270 Q800D, heat number, heat analysis, product analysis when ordered, tensile by thickness band, and −20°C impact. Certificates may be EN 10204 3.1 or EN 10204 3.2. Dual marking to S690QL or S890Q is available only when both books are fully met.

Usual supply range from SHH STEEL for Q800D QT carbon steel plate:

• Thickness: commonly 8 mm – 60 mm, heavier plate to 80 mm by enquiry
• Width: 1500 mm – 3200 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 Q800D follow GB/T 709 unless the purchase order names another table.

Typical thickness tolerance idea for Q800D QT plate

Width on 1500–3200 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 Q800D unless the order says so.

Q800D already defines 800 MPa yield, QT delivery and −20°C impact. Extra items still have to be written on the purchase order.

Book name. Write GB/T 16270 Q800D. Do not write only Q800D.

Impact. Grade D is −20°C. Write a higher energy if the owner requires it.

EN or US comparison. Write S690QL, S890Q or A514 only if dual mark is required and both tables are met.

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, Q800D, thickness and mill logo.

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

Q800D is the plate for an 800 MPa QT file tested at −20°C. It is the wrong plate for a painted warehouse that can use S355JR. It is the wrong plate for an 890 MPa member.

SHH STEEL sources Q800D from first-line Chinese QT mills 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. 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 plate is in yard; standard QT rolling about 35–45 days; 3.2 inspection about 45–60 days.

SHH STEEL is a global steel mill sourcing partner and steel manufacturer and exporter, mill-direct, China origin. For Q800D that means mill-direct QT price, not a multi-layer stockist mark-up. We buy from mills that already run the 800 MPa quench-and-temper route, so the heat carries the −20°C impact without a second upgrade charge.

Delivery is short when the size is in rolling range: ex-stock 5–7 days, standard heat about 35–45 days, 3.2 inspection about 45–60 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 Q800D, keep the QT route, and do not ship Q800C or A514 as Q800D. We will not change D to C to save a cold test, and we will not treat Q800D as S355. If the drawing needs −40°C, we will move the inquiry to Q800E and keep the price on the right grade.

Q800D QT carbon steel plate to GB/T 16270 is 800 MPa quenched-and-tempered structural plate with impact at −20°C. S690QL is lower, S890Q is higher, and ASTM A514 is 690 MPa. None of those is a silent substitute. Whether the inquiry says Q800D, GB/T 16270 Q800D, Q800D QT plate or Q800D carbon steel plate, SHH STEEL as a global steel mill sourcing partner supplies plate with Q800D chemistry, heat and product analysis as ordered, GB/T 709 tolerances and EN 10204 3.1 or 3.2 certification.

SHH STEEL supplies Q800D 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, QT route, cutting, UT, 3.2 inspection or a worldwide quotation.

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