Q355MC TMCP Steel Plate GB/T 1591 Supplier

GB/T 1591 Q355MC is thermomechanical controlled process plate with 355 MPa minimum yield and 0°C impact. SHH STEEL supplies Q355MC plate mill-direct for buildings, bridges and fabrication that names the M condition. This is not hot-rolled Q355C and not normalized Q355NC.
Keywords
Q355MC, Q355MC steel plate, GB/T 1591 Q355MC, Q355MC TMCP, Q355MC supplier, EN 10025-4 S355M, ASTM A572 Gr.50, Q355C, Q355NC
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General Description
Material Specification
Chemical Composition
Mechanical Properties
Material Comparison
Equivalent Material Grades
Structural Service
Weldability
Heat Treatment and Delivery Condition
Dimensions
Tolerances
Supplementary Requirements
Applications
Supply Capability
Global Delivery and Markets
Why Choose SHH STEEL
FAQ
Conclusion

What is Q355MC TMCP Steel Plate GB/T 1591?

Q355MC, also searched as GB/T 1591 Q355MC, Q355MC steel plate, Q355MC TMCP plate and Q355 MC, is the 355 MPa quality-grade-C grade delivered by thermomechanical controlled process in GB/T 1591-2018. Q is the yield symbol, 355 is the thin-plate minimum yield in MPa, M is the delivery letter, and C is the quality letter for Charpy impact at 0°C.

The M is the point of this page. Hot-rolled GB/T 1591 Q355C has no M. Normalized GB/T 1591 Q355NC has an N. A hot-rolled certificate cannot be stamped MC. A normalized certificate cannot be stamped MC. Grade B is +20°C and is GB/T 1591 Q355MB. D is −20°C. E is −40°C. The full family sits on GB/T 1591. Do not drop a 355 MPa drawing onto a lower grade, and do not upgrade it to GB/T 1591 Q390NC without a price check.

The closest European comparison is EN 10025-4 S355M, a TMCP fine-grain grade, though that letter is tested at −20°C. EN 10025-3 S355N is normalized and closer to Q355NC. On the US side, ASTM A572 Gr.50 is 50 ksi / 345 MPa, one step lower, and it is not an MC twin. JIS G3106 SM490B is the usual Japanese comparison. Dual mark only when both books are fully met. See EN 10025-4 and high strength low alloy plates.

SHH STEEL is a global steel mill sourcing partner and steel manufacturer and exporter, mill-direct, China origin. We source Q355MC from first-line structural mills that can actually run the TMCP schedule, 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 structural steel plates and the products index.

Material Specification

Specification ElementRequirementSHH STEEL Compliance
Plate bookGB/T 1591-2018 Q355MCConfirmed
Other search namesQ355MC steel plate, Q355 MC, Q355MC TMCPCovered
Delivery conditionThermomechanical controlled processConfirmed
Yield, ≤ 16 mm355 MPa minConfirmed
Quality gradeC, impact at 0°CConfirmed
Not this pageHot-rolled GB/T 1591 Q355CDifferent condition
Not this pageNormalized GB/T 1591 Q355NCDifferent condition
EN comparisonEN 10025-4 S355MTMCP comparison, not a swap
US comparisonASTM A572 Gr.50 is 345 MPaNot a twin
Product analysisGB/T 222 column when orderedConfirmed
Supply roleGlobal steel mill sourcing partnerSHH STEEL
CertificationEN 10204 3.1 or 3.2As ordered

Nearby pages that buyers compare, but must not swap blindly, include GB/T 1591 Q355B, GB/T 1591 Q355NC and ASTM A572 Gr.50.

Chemical Composition

Heat analysis is the mill ladle table in GB/T 1591-2018 for TMCP Q355. Product analysis, when ordered, follows GB/T 222. Q355MC is a microalloyed HSLA plate. Grade C is tighter on phosphorus and sulfur than grade B, because the impact test is at 0°C. Mills may add Nb, V or Ti. The certificate shows the elements actually used. TMCP chemistry is often leaner than a normalized heat of the same yield, because the rolling schedule does part of the grain refinement.

Heat Analysis and Product Analysis — GB/T 1591 Q355MC, TMCP

ElementHeat analysis (%)Product analysis (%)
Carbon (C), max0.200.22
Silicon (Si), max0.500.55
Manganese (Mn), max1.601.70
Phosphorus (P), max0.0300.035
Sulfur (S), max0.0300.035
Niobium (Nb), max0.050.06
Vanadium (V), max0.150.16
Titanium (Ti), max0.050.06
Chromium (Cr), max0.300.35
Nickel (Ni), max0.300.35
Copper (Cu), max0.400.45
Molybdenum (Mo), max0.100.11
Nitrogen (N), max0.0150.017
Aluminium (Als), min when used0.0150.010

Carbon equivalent is limited by thickness in the standard. The M route often has a lower CEV window than hot-rolled GB/T 1591 Q355C. 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 quenched-and-tempered GB/T 16270 Q460C. A colder hot-rolled file is GB/T 1591 Q355D, not this grade.

Mechanical Properties

Buyers search Q355MC mechanical properties, Q355MC yield strength, GB/T 1591 Q355MC tensile and Q355MC impact 0°C.

Tensile and impact — GB/T 1591 Q355MC, TMCP

ThicknessYield minTensileElongation minImpact
≤ 16 mm355 MPa470–630 MPa22%0°C, grade C
> 16–40 mm345 MPa470–630 MPa22%0°C, grade C
> 40–63 mm335 MPa470–630 MPa21%0°C, grade C
> 63–80 mm325 MPa470–630 MPa21%0°C, grade C
> 80–100 mm315 MPa470–630 MPa20%0°C, grade C
> 100–150 mm295 MPa450–600 MPa20%0°C, grade C

Impact energy is the average of three longitudinal Charpy V-notch specimens, commonly 34 J minimum at 0°C. One value may fall below the table, but not below 70% of that value. Write a higher energy on the order if the owner requires it.

Yield steps down with thickness. A 355 MPa name on 12 mm plate is not the minimum on a 40 mm flange. 355 MPa is about 51.5 ksi. ASTM A572 Gr.50 is 50 ksi and is not this book. SHH STEEL quotes the thickness band and the M condition on the offer.

Density is 7.85 g/cm³. Hardness is not a design value for this grade. Z15, Z25 or Z35 through-thickness tensile is an extra, not part of the C letter.

Material Comparison

GradeBookDeliveryYield, thin plateImpactSwap?
GB/T 1591 Q355CGB/T 1591-2018Hot rolled355 MPa0°CDifferent process
GB/T 1591 Q355NCGB/T 1591-2018Normalized355 MPa0°CDifferent process
GB/T 1591 Q355MBGB/T 1591-2018TMCP355 MPa+20°CWarmer M sister
Q355MCGB/T 1591-2018TMCP355 MPa0°CThis page
Q355MDGB/T 1591-2018TMCP355 MPa−20°CColder M sister
GB/T 1591 Q390NCGB/T 1591-2018Normalized390 MPa0°CHigher yield
EN 10025-4 S355MEN 10025-4TMCP355 MPa−20°CProcess comparison
ASTM A572 Gr.50ASTM A572As rolled345 MPaDifferentLower yield

A colder hot-rolled file is GB/T 1591 Q355E. A 420 MPa file is GB/T 1591 Q420NC.

Equivalent Material Grades

There is no official one-to-one substitute for Q355MC. What buyers compare is a 355 MPa TMCP plate tested at 0°C.

EN 10025-4 S355M is the process comparison, but it is tested at −20°C. EN 10025-3 S355N is normalized and closer to GB/T 1591 Q355NC. EN 10025-2 S355J0 is 0°C and as-rolled, closer to GB/T 1591 Q355C. In the United States, ASTM A572 Gr.50 is 50 ksi / 345 MPa. ASTM A36 is 36 ksi and is well below this yield. In Japan, JIS G3106 SM490B is the usual comparison. SHH STEEL will not stamp EN 10025-4 S355M or ASTM A572 Gr.50 on a Q355MC certificate unless the purchase order names both books and both tables are met.

DesignationCountry / regionStandardNotes
Q355MCChinaGB/T 1591-2018Name on this page
GB/T 1591 Q355CChinaGB/T 1591-2018Hot rolled, not this page
GB/T 1591 Q355NCChinaGB/T 1591-2018Normalized, not this page
GB/T 1591 Q355NDChinaGB/T 1591-2018Normalized, −20°C
EN 10025-4 S355MEuropeEN 10025-4TMCP comparison
EN 10025-3 S355NEuropeEN 10025-3Normalized comparison
ASTM A572 Gr.50USAASTM A57250 ksi, lower yield
JIS G3106 SM490BJapanJIS G3106Usual Japanese comparison

Structural Service

Buyers pick Q355MC when a building, bridge member or welded fabrication wants about 355 MPa yield, a TMCP condition, and impact at 0°C. Search phrases such as Q355MC steel plate and GB/T 1591 Q355MC all point here. The family index is GB/T 1591.

It is the wrong plate when the drawing says hot rolled only. That work is GB/T 1591 Q355C. It is the wrong plate when the drawing says normalized. That work is GB/T 1591 Q355NC. It is the wrong plate for a +20°C file. That work is GB/T 1591 Q355MB, and the hot-rolled sister is GB/T 1591 Q355B. It is the wrong plate for a −20°C file. That work is Q355MD, and the normalized sister is GB/T 1591 Q355ND. It is the wrong plate for a −40°C file. That work is Q355ME, and the normalized sister is GB/T 1591 Q355NE. It is the wrong plate for a 390 MPa file. That work is GB/T 1591 Q390NB or GB/T 1591 Q390ND. It is the wrong plate for a 420 MPa file. That work is GB/T 1591 Q420NB or GB/T 1591 Q420E. It is the wrong plate for a 460 MPa file. That work is GB/T 1591 Q460D or GB/T 1591 Q460ND. 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 1591, quality grade C, and the M condition at 355 MPa.

Weldability

Q355MC is a weldable TMCP HSLA structural plate. Carbon is controlled, and many heats use Nb, V or Ti. A procedure written for ASTM A36 is not a finished WPS for thick Q355MC. Carbon equivalent on the M route is often lower than hot-rolled GB/T 1591 Q355C, which helps the root pass, but the TMCP microstructure still needs a qualified procedure. A procedure qualified only at +20°C may miss the 0°C coupon.

Typical consumables are matching 50 ksi low-hydrogen electrodes or wires. E7018-class electrodes are common when the joint does not have to develop the full plate strength. A procedure written for ASTM A572 Gr.50 is a useful strength reference after chemistry is checked. Preheat follows thickness, hydrogen and the approved WPS. Heat input should stay inside the mill window. A very high heat input can soften the TMCP zone next to the weld.

The fabricator owns the WPS. SHH STEEL can share mill heat data, product analysis and carbon equivalent for that review. Do not use a Q355MC procedure on GB/T 1591 Q355NC without checking the normalized carbon equivalent. Do not use it on GB/T 1591 Q460NE either. That plate is a different yield and a different delivery letter.

Heat Treatment and Delivery Condition

Usual delivery from SHH STEEL for Q355MC is thermomechanical controlled process. The plate is not hot rolled as GB/T 1591 Q355C and not normalized as GB/T 1591 Q355NC.

TMCP combines controlled rolling and accelerated cooling. Finish rolling is held in the non-recrystallization range, then the plate is cooled on the run-out table to a finish temperature the mill records. Do not order Q355MC as quenched and tempered. That route belongs to GB/T 16270. Stress relief after fabrication, if used, should be agreed before cutting, because a high temper can move the TMCP properties.

The certificate lists GB/T 1591 Q355MC, heat number, delivery condition, heat analysis, product analysis when ordered, tensile by thickness band, and 0°C impact. Certificates may be EN 10204 3.1 or EN 10204 3.2. Dual marking to EN 10025-4 S355M is available only when both books are fully met.

Dimensions

Usual supply range from SHH STEEL for Q355MC steel plate:

  • Thickness: commonly 6 mm – 80 mm, heavier plate to 100 mm by enquiry
  • Width: 1500 mm – 3500 mm, wider by enquiry
  • Length: 3000 mm – 14000 mm

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

Tolerances

Dimensional limits for Q355MC follow GB/T 709 unless the purchase order names EN 10029 or another table.

Typical thickness tolerance idea for Q355MC plate

Nominal thickness (mm)Usual minus (mm)Usual plus (mm)
6 – 8−0.3+0.6
8 – 15−0.3+0.8
15 – 25−0.4+0.9
25 – 40−0.5+1.1
40 – 60−0.6+1.3
60 – 80−0.7+1.5
80 – 100−0.8+1.6

Width on 1500–3500 mm plate is commonly held to about +20 / 0 mm or ±25 mm unless a tighter extra is named. Length on 3000–14000 mm plate is commonly held to about +50 / 0 mm. Flatness follows the agreed class. TMCP plate can hold a tighter flatness than a heavy normalized plate of the same thickness, but SHH STEEL will not assume a zero-minus extra on Q355MC unless the order says so.

Supplementary Requirements

Q355MC already defines 355 MPa yield, TMCP delivery and 0°C impact. Extra items still have to be written on the purchase order.

Book name. Write GB/T 1591 Q355MC. Do not write only Q355, and do not write Q355C if the mill must stamp M. The family page is GB/T 1591.

Impact. Grade C is 0°C. Write a higher energy if the owner requires it. Do not expect a −20°C result unless the grade is changed to Q355MD.

Delivery condition. Write thermomechanical controlled process. Write GB/T 1591 Q355C if hot rolled is enough. Write GB/T 1591 Q355NC if normalized is required.

EN or US comparison. Write EN 10025-4 S355M or ASTM A572 Gr.50 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.

Identification. Heat number, Q355MC, thickness and mill logo.

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

Applications

IndustryTypical components
Buildings and workshopsQ355MC columns, beams and base plates
Bridges and towersQ355MC webs and flanges from SHH STEEL
Construction machineryQ355MC frames where the drawing names M and 0°C
General fabricationQ355MC gussets and connection plates
Comparison vs EN 10025-4Q355MC next to EN 10025-4 S355M
Comparison vs ASTM A572Q355MC next to ASTM A572 Gr.50
Higher yield optionGB/T 1591 Q420ND when 420 MPa is required

Q355MC is the plate for a 355 MPa TMCP file tested at 0°C. It is the wrong plate for a painted weathering facade that needs corten. It is the wrong plate for a 690 MPa QT boom under GB/T 16270. A colder 460 MPa normalized file is GB/T 1591 Q460NC or GB/T 1591 Q460NE.

Supply Capability

SHH STEEL sources Q355MC from first-line Chinese structural 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: 6 mm, 8 mm, 10 mm, 12 mm, 16 mm, 20 mm, 25 mm, 30 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.

Global Delivery and Markets

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 M heat is in yard; standard TMCP about 25–40 days; 3.2 inspection about 35–45 days.

Why Choose SHH STEEL

SHH STEEL is a global steel mill sourcing partner and steel manufacturer and exporter, mill-direct, China origin. For Q355MC that means mill-direct structural price, not a multi-layer stockist mark-up. We buy from mills that can actually run the TMCP schedule, so the M 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 M heat about 25–40 days, 3.2 inspection about 35–45 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 1591 Q355MC, keep the TMCP route, and do not ship GB/T 1591 Q355C or GB/T 1591 Q355NC as MC. We will not drop the M to save a cooling cycle, and we will not change C to B to save a cold test. If the drawing only needs hot-rolled plate, we will move the inquiry to Q355C and keep the price on the right condition. If the drawing needs 420 MPa normalized plate, we will move it to GB/T 1591 Q420NE or GB/T 1591 Q420ND.

FAQ

What is Q355MC steel plate?
Q355MC in GB/T 1591-2018 is thermomechanical controlled process high-strength low-alloy plate with 355 MPa minimum yield on thin plate and Charpy impact at 0°C. SHH STEEL supplies this plate worldwide as a global steel mill sourcing partner.
Is Q355MC the same as Q355C?
No. Both yield at 355 MPa and both are tested at 0°C. Q355C is hot rolled. Q355MC is TMCP.
Is Q355MC the same as Q355NC?
No. Q355MC is thermomechanical rolled. Q355NC is normalized or normalizing rolled. Impact letter C is the same temperature. The process is not.
Is Q355MC the same as Q355MB?
No. Both are TMCP. Q355MB is tested at +20°C. Q355MC is tested at 0°C.
What is the European equivalent of Q355MC?
The nearest process comparison is EN 10025-4 S355M, which is TMCP but tested at −20°C. EN 10025-3 S355N is the normalized comparison. Dual mark only when both books are fully met.
What is the US equivalent of Q355MC?
There is no official ASTM twin. ASTM A572 Grade 50 is 50 ksi / 345 MPa, slightly lower, and it does not carry an MC letter. SHH STEEL does not dual-mark ASTM A572 unless both books are met.
What thickness can SHH STEEL supply?
Common supply is 6 mm to 80 mm. Plate to 100 mm is quoted by enquiry. Yield on plate over 16 mm is lower than the 355 MPa thin-plate number.
Can SHH STEEL ship Q355MC to the USA, Europe or the Middle East?
Yes. SHH STEEL quotes FOB Shanghai and CIF to US West, US Gulf, Rotterdam, Jebel Ali, Singapore and other major ports.

Conclusion

Q355MC steel plate to GB/T 1591 is 355 MPa TMCP structural plate with impact at 0°C. It is not hot-rolled GB/T 1591 Q355C and not normalized GB/T 1591 Q355NC. The nearest European process comparison is EN 10025-4 S355M. ASTM A572 Grade 50 is 345 MPa and is not a substitute. Whether the inquiry says Q355MC, GB/T 1591 Q355MC or Q355MC TMCP plate, SHH STEEL as a global steel mill sourcing partner supplies plate with Q355MC chemistry, heat and product analysis as ordered, GB/T 709 tolerances and EN 10204 3.1 or 3.2 certification.

SHH STEEL supplies Q355MC Steel Plate to the United States, Europe, the Middle East, Africa, Asia and the Americas for work that actually names the M condition. The grade family is listed on GB/T 1591.

Contact SHH STEEL for mill rolling, TMCP Q355MC, cutting, UT, 3.2 inspection or a worldwide quotation.

Q355MC, Q355MC steel plate, GB/T 1591 Q355MC, Q355MC TMCP, Q355MC supplier, SHH STEEL

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