ASTM A455 Steel Plate | A455 High-Strength Mn Vessel Plate

ASTM A455 is high-strength manganese carbon steel plate intended for welded pressure vessels. The specification is ASTM A455/A455M. There is no Grade A, Grade B or Grade 70 split. The product is one chemistry with three tensile lines by thickness, and the thickness ceiling is 20 mm (3/4 in.). As Direct Mill Supply by SHH STEEL, the plate is produced to ASTM A455/A455M.

The same plate is written A455, A455M, ASTM A455, ASME SA455, SA455, SA-455, SA455M and A/SA455. They all mean this specification. ASME SA-455/SA-455M is the Code companion used when the vessel will be stamped to ASME Section VIII.

This is thin, high-manganese carbon vessel plate. It is not SA516 Gr.70 and not A516 Gr.70. Those pages are fine-grain carbon with thick-plate capability and a different toughness habit. It is not SA515 Gr.70 or A515 Gr.70. A515 / SA515 is silicon-killed carbon for intermediate and higher temperature. It is not SA285 Gr.C or A285 Gr.C. A285 Grade C is lower-tensile carbon with a 50 mm ceiling.

It is not Mn-Mo plate like SA302 Gr.B or A302 Gr.B. It is not nickel plate like SA203 Gr.A or A203 Gr.A. It is not Cr-Mo like SA387 Gr.22 Cl.2. It is not QT 690 MPa plate like SA517 Gr.Q or A517 Gr.Q. A mill cannot recertify those heats as A455.

The steel is usually made to a semi-killed or capped deoxidation practice. Silicon-killed or aluminum-killed steel is allowed at the purchaser’s or producer’s option. That is a different melting habit from SA516 Gr.60, which is killed fine-grain carbon.

Plates are normally supplied as-rolled. They may be ordered normalized or stress-relieved, or both. Maximum thickness furnished under this specification is 20 mm. If the inquiry is 25 mm or 40 mm, A455 is the wrong book. Move the conversation to SA516 Gr.70, SA515 Gr.70 or SA537 Cl.1.

For Code work the plate is dual-marked ASTM A455 / ASME SA455. Certificates can be EN 10204 3.1 or EN 10204 3.2.

When a project is still choosing carbon vessel plate, a China mill Agent path through SHH STEEL puts A455 next to SA285 Gr.A, SA302 Gr.B and A36 steel plate, so the buyer can see whether they need thin high-Mn vessel plate, low-tensile carbon vessel plate, Mn-Mo alloy or structural carbon. Company scope: China steel Mill Agent-SHH STEEL.

This plate is a vessel product. It is not structural ASTM A36 steel plate. It is not QT alloy like SA517 Gr.Q.

Chemistry for ASTM A455 is reported as heat analysis and product analysis under ASTM A455/A455M Table 1. There is one chemistry table. Strength changes with thickness, not with a second grade name.

Heat Analysis — ASTM A455 / A455M

Product Analysis — A455 / SA455

Two footnotes change how this table is used.

When silicon is higher than 0.10%, the carbon maximum shall be 0.28%. That matters if the order asks for silicon-killed plate. Optional silicon may be 0.40% max heat and 0.45% max product. If that option is taken, carbon drops to 0.28% max.

For each reduction of 0.01 percentage point below the specified carbon maximum, an increase of 0.06 percentage point above the specified manganese maximum is permitted, up to 1.50% Mn by heat analysis and 1.60% Mn by product analysis. That is the high-manganese lever that gives A455 its name.

Compare that ladle with nearby carbon pages. SA516 Gr.70 is killed fine-grain carbon with a different C-Mn-Si table and no 20 mm ceiling. SA515 Gr.70 is silicon-killed for higher temperature. SA285 Gr.C allows 0.28% C but only 0.90% Mn max and stops at 50 mm with a lower tensile window.

If the drawing says ASTM A455 or A455M, the ladle must sit in this table. SHH STEEL reports heat analysis on every certificate and adds product analysis when A20 / SA-20 or the vessel specification requires it.

Tensile of A455 falls as thickness rises. There are three lines, all inside 20 mm.

Tensile Requirements — ASTM A455 per ASTM A455/A455M

A 8 mm plate is tested to 260 MPa yield and 515–655 MPa tensile. A 16 mm plate is tested to 240 MPa yield and 485–620 MPa tensile. Do not apply the thin-line numbers to 18 mm plate and call the heat compliant.

Elongation adjustments follow A20 / SA-20 when the specimen thickness requires them.

Density is 7.85 g/cm³. Hardness is not a default line. Charpy is not a hidden default. If the vessel needs a stated impact temperature, write it as a supplementary requirement.

Compare nearby pages. A516 Gr.70 is 485–620 MPa with thick-plate capability. SA537 Cl.1 is heat-treated carbon at heavier gauges. SA517 Gr.Q is QT 690 MPa alloy. A455 is thin high-Mn carbon, nothing else.

Order ASTM A455 when the drawing names A455 and thickness is 20 mm or less. SHH STEEL does not stretch this spec past 20 mm.

ASTM A455 is selected for welded vessels that need high-Mn carbon strength in thin plate. When the vessel is ASME stamped, allowable stress comes from Section II Part D for SA-455 after dual marking.

Typical use is thin shells, heads and layers inside 20 mm. It is not a creep Cr-Mo grade and not a cryogenic nickel grade. If the equipment is written to SA203 Gr.A or A203 Gr.D, this page is the wrong purchase.

Coil-origin plate furnished without heat treatment or with stress relieving only must also meet the extra A20 / SA-20 coil rules, including additional testing and reporting.

A455 is high-manganese carbon. Welding is Code welding.

Procedures for Code work are qualified to ASME Section IX. Low-hydrogen consumables such as E7018 (AWS A5.1) are the usual shop choice. Carbon can sit at 0.33% unless silicon-killed practice drops it to 0.28%. Calculate carbon equivalent from the actual ladle.

Preheat depends on thickness, restraint and hydrogen. Even at 12–20 mm, a restrained high-Mn joint should not be started cold and wet.

Do not copy a SA387 Gr.22 Cl.2 or SA517 Gr.Q procedure onto ASTM A455. The fabricator owns the WPS.

Plates are normally supplied as-rolled.

They may be ordered normalized, stress-relieved, or both.

There is no mandatory normalize-all-thicknesses rule. If the drawing is silent, as-rolled is the usual supply. SHH STEEL reports the actual delivery condition on the MTC.

Usual delivery is as-rolled high-Mn carbon vessel plate to 20 mm. Normalized or stress-relieved plate is supplied when specified.

The certificate lists ASTM A455 and, when dual certified, ASME SA455; heat number; heat analysis; product analysis when ordered; tensile results by the correct thickness line; deoxidation practice when relevant; heat-treatment condition; and supplementary tests.

Certificates may be EN 10204 3.1 or EN 10204 3.2.

Usual supply range from SHH STEEL for A455 high-strength Mn vessel plate:

• Thickness: about 5 mm – 20 mm (specification maximum)
• Width: typically up to about 2500–3000 mm from coil or plate mills
• Length: up to about 12000 mm

If the inquiry is 25 mm, this specification cannot be used. Cut-to-length shells inside 20 mm are available.

Dimensional limits follow ASTM A20 / ASME SA-20. Coil-origin plate has extra A20 rules. UT is supplementary.

Most export ASTM A455 orders add extras. SHH STEEL does not assume them.

Killed steel. Si-killed or Al-killed when specified; watch the 0.28% C cap if Si exceeds 0.10%.

Heat treatment. Normalize or stress relieve as specified.

Simulated PWHT. Same-heat coupons when the vessel cycle is known.

Charpy details. Temperature and energy as agreed.

NDE. UT to A435 / A577 / A578.

Restricted chemistry. Tighter P, S; controlled C-Mn trade-off.

Third-party. EN 10204 3.2.

For stamping, write ASTM A455 or dual A455 / SA455.

Do not use this grade as a silent stand-in for SA203 Gr.D or SA517 Gr.S.

SHH STEEL works as a China Mill Direct Exporter for plates to ASTM A455/A455M. On ASTM A455 that means mill pricing, dual A455/SA455 marking, the 0.33% carbon / 0.85–1.20% manganese table, thickness-correct tensile lines at 9.5 mm and 15 mm, the 20 mm ceiling respected, 3.1 as standard and 3.2 when specified.

We keep the order on the right specification. A455 is not SA516 Gr.55. A455 is not SA285 Gr.A. A455 is not SA517 Gr.Q. If the plate is thicker than 20 mm, we will say so before anyone tries to buy A455.

Company scope: China steel Mill Agent-SHH STEEL.

ASTM A455 Steel Plate is high-strength manganese carbon vessel plate under ASTM A455/A455M, limited to 20 mm, with three tensile lines by thickness. Whether the inquiry says A455, A455M, ASTM A455, SA455 or ASME SA455, SHH STEEL supplies plate with heat and product analysis, as-rolled or specified heat treatment, thickness-correct tensile results, and EN 10204 3.1 or 3.2 certification.

As a China mill Distributor, SHH STEEL provides ASTM A455 / A455 High-Strength Mn Vessel Plate for thin dual-certified Section VIII work.

Contact SHH STEEL for mill rolling, dual A455/SA455 marking, 3.2 inspection or a quotation.

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