ASTM A662 Grade C Steel Plate | A662 Gr.C C-Mn-Si Vessel Plate supplier

ASTM A662 Grade C, also searched as A662 Gr.C, A662GRC, A662-C, A662 Gr C, ASTM A662 Gr.C and SA662 Grade C, is the highest-strength grade in ASTM A662/A662M. That book covers carbon-manganese-silicon pressure-vessel plates for moderate and lower temperature welded service where improved notch toughness matters.

The book has only three grades: A, B and C. This page is Grade C. Grade A is the lean heat, 0.14% max carbon and 400–540 MPa tensile. Grade B sits in the middle at 450–585 MPa tensile and the same 275 MPa yield as Grade A. Grade C is the only grade in the book that lifts yield to 295 MPa and tensile to 485–620 MPa. Do not stamp Grade C chemistry as Grade B. Do not treat A662 as ASTM A516 Grade 70 unless both books are fully met. Do not treat A662 as ASTM A537CL1. A537 Class 1 shares a similar tensile band but a 345 MPa yield and a different heat-treatment book. Do not treat A662 as EN 10028-2 P355GH unless both books are met.

ASME Code work uses SA-662/SA-662M. SA-662 Grade C is the same chemistry and the same tensile table. If the drawing says SA662 Gr.C, the mill still rolls ASTM A662 Grade C chemistry and prints the book the purchase order names. There is no extra “Class” under A662.

Grade C is the plate shops pick when the calculation needs the 70–90 ksi line inside the A662 family. Heat analysis carbon is 0.20% max, manganese is 1.00–1.60%, and silicon is allowed up to 0.50%. That is more manganese and more silicon than Grade B.

Heat treatment is thickness-dependent. All Grade C plate over 40 mm (1½ in) shall be normalized. Plate 40 mm and under is normally supplied as-rolled. The purchaser may order it normalized, stress-relieved, or both. Grade A does not get that thin-plate option. Grade A is normalized at every thickness.

Steel is killed and must meet the fine austenitic grain size rule in A20/A20M. General requirements follow A20. Density is 7.85 g/cm³. Typical hardness after the agreed delivery route sits around 150–190 HBW.

SHH STEEL is a global steel mill sourcing partner and steel manufacturer & exporter (mill-direct, China origin). We source A662 Gr.C from first-line Chinese mills, print heat and product analysis, record as-rolled or normalized as ordered, and ship plate to fabricators in the United States, Europe, the Middle East, Southeast Asia, Africa and South America.

Related category pages: pressure vessel steel plates, ASTM A516, ASME SA662 and carbon steel plates.

Sister grades in the same book are Grade A and Grade B. Nearby vessel pages that buyers compare, but must not swap blindly, include ASTM A515 Grade 70, ASME SA537 Class 1, EN 10028-3 P355N and GB/T 713 Q345R.

Grade C is the richest heat in A662. Ladle analysis is the mill table. Product analysis, when ordered, uses the product column in Table 1.

Heat Analysis and Product Analysis — ASTM A662 Grade C

Grade A heat carbon is 0.14% max. Grade B heat carbon is 0.19% max and manganese starts at 0.85%. Grade C is the only grade that opens silicon to 0.50% on heat analysis. If the purchase order writes product analysis, SHH STEEL prints both columns. Vacuum carbon-deoxidized steel is A20 Supplementary Requirement S17 and only applies when named.

Do not treat this chemistry as ASTM A36. A36 is structural plate, not A662 vessel plate. Do not treat it as A572 Gr.50. A572 is HSLA structural plate.

Buyers search A662 Gr.C mechanical properties, A662GRC yield, A662 Grade C tensile and SA662 Gr.C elongation.

Tensile Properties — ASTM A662 Grade C

Yield is determined by the 0.2% offset method or the 0.5% extension-under-load method. Elongation adjustments follow A20 when thickness requires them. Elongation on Grade C is one point lower than Grade A and Grade B. That is the book, not a mill option.

Grade A and Grade B both yield at 275 MPa. Grade C is the only A662 grade at 295 MPa. If the calculation needs 345 MPa yield, Grade C is still the wrong book. Move that file to A537 CL1.

Impact is not automatic. A662 exists because buyers want better low-temperature notch toughness than ordinary carbon plate, but the joules and the test temperature still have to be written on the purchase order. Typical extras are 20 J or 27 J at −20 °C, 0 °C or −46 °C, transverse, per A20 supplementary impact rules.

Density is 7.85 g/cm³. Hardness is not a Table 2 requirement; mills usually report about 150–190 HBW after the agreed delivery route.

There is no official one-to-one worldwide twin for A662 Gr.C. What buyers compare is a 485–620 MPa C-Mn-Si vessel plate with 295 MPa yield.

In the United States the Code name is SA-662 Grade C. See the ASME SA662 category. ASTM A516 Grade 70 shares the same tensile numbers but a lower yield name and a different chemistry table. That is why A516-70 is stocked everywhere and A662 Grade C is ordered by the drawing. ASTM A515 Grade 70 is a high-temperature carbon vessel comparison. ASTM A285 Grade C is a lower-strength vessel comparison.

In Europe compare EN 10028-2 P355GH or EN 10028-3 P355N. Dual mark only when both books are met. See EN 10028-2 and EN 10028-3.

In Japan compare JIS G3103 SB480 or JIS G3115 SPV355. In China compare GB/T 713 Q345R. Q345R yield is named 345 MPa, not 295 MPa. Dual marking only when both books are fully met.

Buyers pick A662 Gr.C when a Section VIII or similar file wants C-Mn-Si plate with improved notch toughness at the 70–90 ksi tensile line and a 43 ksi yield. Search phrases such as A662GRC, A662 Grade C, A662-C and SA662 Gr.C all point here.

It is the wrong plate for a file that needs 0.14% max carbon. That work is Grade A. It is the wrong plate for a 65–85 ksi shell that does not need 295 MPa yield. That work is Grade B. It is the wrong plate for a 345 MPa heat-treated shell. That work is A537 CL1 or ASME SA537 Class 1. It is the wrong plate for −101 °C nickel steel. That work sits on ASME SA203 or EN 10028-4. It is the wrong plate for ordinary building frames. That work sits on ASTM A36 steel plate or structural steel plates.

SHH STEEL supplies this plate to fabricators in the United States, Mexico, Argentina, Spain, the Netherlands, Germany, the UAE, Saudi Arabia, India, Singapore, Vietnam and Korea when the file actually names Grade C.

ASTM A662 Grade C is killed C-Mn-Si plate with 0.20% max heat carbon and 1.00–1.60% manganese. Treat welding as production welding for pressure equipment. Preheat, heat input and interpass have to stay inside a written WPS.

Typical consumables for this strength line are AWS A5.1 E7018, or matching GMAW / SAW wires qualified on a 70 ksi family. A procedure written for Grade B may be leaner than the heat in front of the welder. A procedure written for A516 Gr.70 is the closest everyday shop procedure, but it is still a different book. A procedure written for A572 Gr.50 is structural HSLA, not A662. After heavy cold forming, a stress relief or a normalize may be required. The fabricator owns the WPS. SHH STEEL can share mill heat data and CEV for that review.

Usual delivery from SHH STEEL for A662 Gr.C follows the thickness rule in the book.

Over 40 mm: normalized. There is no as-rolled option on thick Grade C.

40 mm and under: normally as-rolled. The purchase order may add normalize, stress relief, or both. If the order is silent, SHH STEEL will quote as-rolled for thin plate and normalized for plate over 40 mm.

Normalizing is typically 880–920 °C, soaked through, then air cooled. Fine austenitic grain per A20 is part of the manufacture clause, not an optional extra.

If the fabricator hot-forms outside the mill window, a new normalize is usually required. Simulated PWHT coupons are an extra. Write the soak temperature and time if the vessel cycle must be copied on the test piece.

The certificate lists ASTM A662 Grade C (and SA-662 Grade C when dual-marked); heat number; heat analysis and product analysis when ordered; tensile to Table 2; as-rolled or normalized as ordered; impact when ordered. Certificates may be EN 10204 3.1 or EN 10204 3.2.

Usual supply range from SHH STEEL for A662 Gr.C C-Mn-Si vessel plate:

• Thickness: commonly 6 mm – 50 mm, heavier plate by enquiry when the heat still meets Table 2
• Width: 1500 mm – 4000 mm
• Length: 3000 mm – 12000 mm

Current mill practice often stops around 50 mm because that is where most A662 vessels live. Thicker plate is possible if the composition still hits 485–620 MPa and 295 MPa yield. Cut-to-size shells and heads are available. Browse more vessel sizes on pressure vessel steel plates and the products index.

Dimensional limits for ASTM A662 Grade C follow A20 / SA-20 unless the purchase order names another table. Do not apply structural A6 extras unless the order writes them.

Typical A20 thickness tolerance idea for A662 Gr.C

Width on 1500–4000 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 follows A20 unless a tighter class is written. SHH STEEL will not assume a zero-minus extra on A662GRC unless the order says so.

Grade C already defines chemistry and the 485–620 MPa table. Extra items still have to be written on the purchase order.

Book name. Write ASTM A662 Grade C. Write SA-662 Grade C if the vessel is Code work.

Delivery condition. Write as-rolled, normalized, or stress-relieved. Silent orders on plate ≤ 40 mm ship as-rolled.

Impact details. Write temperature, joules, location and orientation. A662 does not pick the temperature for you.

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

Vacuum carbon-deoxidized steel. A20 S17 only when named.

Through-thickness / Z-test. A770 or Z15/Z25/Z35 when needed.

NDE. A435, A577 or A578 as named.

HIC / NACE. Only when the process fluid needs it.

Simulated PWHT. Write soak temperature and time.

Identification and stamping. Heat number, A662 Grade C, thickness and mill logo.

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

A662 Grade C is the plate for a file that wants the top C-Mn-Si line inside A662 and improved notch toughness. It is the wrong plate for a 345 MPa heat-treated reactor. That work is A537 CL1. It is the wrong plate for a QT high-strength vessel. That work sits on ASTM A517. It is the wrong plate for a 9Ni LNG tank. That work sits on GB/T 713.4 06Ni9DR or EN 10028-4 X8Ni9.

SHH STEEL sources ASTM A662 Grade C from first-line Chinese mills and ships it on worldwide terms. Partner mills include Wuyang (Wugang), Angang, Shougang, Hanye, Anyang Iron & Steel, Baosteel, Xinyu, Xingcheng, TISCO (Taiyuan), Jiuquan (JISCO) and other qualified mills when the size or normalize route 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. Dual marking to SA-662 Grade C is available when the purchase order writes both books.

Usual stock and rolling thickness: 8 mm, 10 mm, 12 mm, 16 mm, 20 mm, 25 mm, 30 mm, 32 mm, 40 mm, 45 mm, 50 mm.

Processing: CNC or flame cutting, bevel, flattening, UT to the named A435 / A578 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 ASTM, ASME, EN, DIN, JIS and GB 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; as-rolled thin plate about 30–45 days; rolling plus normalize about 45–60 days; 3.2 inspection about 2 months.

Experience on this grade is simple: print A662 Grade C, keep carbon at 0.20% max on heat analysis, normalize everything over 40 mm, and do not silently drop the order to Grade B. SHH STEEL as a global steel mill sourcing partner and steel manufacturer & exporter (mill-direct, China origin) will not ship Grade B chemistry on a Grade C order, will not skip normalize on thick plate, and will not treat A662 as A516-70 unless both books are on the certificate.

We keep the book on the order. A662GRC is not A516 Gr.70. A662 Grade C is not A537 CL1. A662 Grade C is not Q345R unless both books are met. If the drawing says 345 MPa yield, we will move the inquiry to A537 Class 1 instead of forcing Grade C.

ASTM A662 Grade C Steel Plate is C-Mn-Si vessel plate for moderate and lower temperature welded service, with 485–620 MPa tensile, 295 MPa yield and normalize required above 40 mm. Whether the inquiry says ASTM A662 Grade C, A662 Gr.C, A662GRC, A662-C, A662 Gr C or SA662 Grade C, SHH STEEL as a global steel mill sourcing partner and steel manufacturer & exporter (mill-direct, China origin) supplies plate with Grade C chemistry, heat and product analysis as ordered, recorded as-rolled or normalized delivery, and EN 10204 3.1 or 3.2 certification.

SHH STEEL supplies ASTM A662 Grade C / A662 Gr.C C-Mn-Si Vessel 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, dual SA-662 marking, cutting, bevel, 3.2 inspection or a worldwide quotation.

ASTM A662 Grade C Steel Plate, A662 Gr.C, A662GRC, SA662 Grade C, C-Mn-Si vessel plate, A662 Grade C supplier, SHH STEEL