ABS Grade B Shipbuilding Steel Plate Supplier

Technical Reviewer: Jack | SHH STEEL Material Solutions Department · Updated: 2026-10-27

Equivalent grades: ABS B ≈ ASTM A131 Grade B ≈ DNV NV B ≈ LR Grade B ≈ BV Grade B ≈ CCS Grade B ≈ NK KB ≈ KR RB ≈ RINA Grade B ≈ GB 712 Grade B (all class-approved, stamped by the issuing society).

ABS Grade B is an ordinary-strength hull structural steel in the ABS Rules for Materials and Welding, Part 2, Chapter 1, Section 2 (2-1-2). Minimum yield point is 235 N/mm², tensile strength 400–520 N/mm² and elongation 22 % min. Grade B is the next step up from Grade A in ordinary-strength hull steel: same 235 N/mm² yield and 400–520 N/mm² tensile, but Charpy V-notch testing at 0 °C applies where 2-1-2/15.9 Table 5 requires it (typically above 25 mm for semi-killed and in the heavier bands for killed plate). It is used for side shell, bottom shell and deck plating that must keep toughness near freezing, and for repair steel where the drawing allows A or B.

Plates that pass mill tests under ABS survey are die-stamped or stencilled AB/B and supplied with a Surveyor-endorsed certificate.

Compared with ABS Grade A, Grade B adds the 0 °C impact requirement in the thicknesses Table 5 covers; Grade A still needs no CVN up to 50 mm. Grade D (−20 °C) and Grade E (−40 °C) go further for colder service.

SHH STEEL supplies ABS Grade B plate from Chinese mills that hold ABS works approval for the grade, from stock in common sizes or from a mill rolling cycle, with ABS survey arranged at the mill. See also ABS D, ABS D and the live ABS Grade A page for the related ordinary-strength grades.

Size range. Grade B is rolled on wide plate mills in China from about 5 mm to 100 mm and more, widths 1500–3500 mm and lengths up to about 18 m depending on mill. Plates under 6 mm cut from coil need separate coil-process approval (2-1-2/3.1). Ask for confirmation for plates over 100 mm or wider than 3200 mm.

Product (check) analysis column = heat (ladle) limit adjusted by ASTM A6/A6M-19 Table A “Permitted Variations in Product Analysis”, as required by ABS Rules Part 2, 2-1-2/5.3 (maximum + “over”, minimum − “under”; row chosen by the specified upper limit); arithmetic shown in brackets.

Source: ABS Rules 2-1-2/5.1 and 15.9 Table 1. The heat (ladle) analysis is determined by the mill on each heat and must meet Table 1. Product (check) analysis on the finished plate is not routine; when required by the purchaser or Surveyor, ABS 2-1-2/5.3 applies the chemical tolerances of ASTM A6 (or another nationally recognized standard) to the Table 1 limits. Ask for product analysis at enquiry if you need it on the certificate.

Grade B is the only ordinary-strength grade with a fixed 0.80 % Mn minimum (reducible to 0.60 % when fully killed or ordered cold-flanging). Silicon is capped at 0.35 %, tighter than Grade A’s 0.50 %. Intentionally added elements must also be reported. Check actual ladle figures on the mill certificate, not a typical sheet.

Source: 2-1-2/15.9 Table 2. All four ordinary-strength grades share these tensile values. On the 200 mm gauge alternative B flat specimen, minimum elongation depends on thickness (Table 3):

Tensile tests are taken on two different plates from each heat (one test if the heat is under 50 t), and from both the thickest and thinnest plate when thicknesses in the heat differ by 9.5 mm or more. The 550 N/mm² upper tensile limit applies only to Grade A sections, not to Grade B plate.

Required average energy at 0 °C where a test applies (2-1-2/15.9 Table 4, full-size, either direction acceptable):

Note 4 of Table 4: CVN for Grade B applies only where Table 5 requires the test. One individual value may fall below the average if it is at least 70 % of it. Sub-size specimens use 5E/6, 2E/3 or E/2. If your drawing needs −20 °C or −40 °C, order Grade D or E rather than adding a special test to Grade B.

ABS applies a fixed minus tolerance of 0.3 mm on nominal thickness for hull plates regardless of thickness (2-1-1/15.3.2), much tighter than the general ASTM A6 under-tolerance. The mill demonstrates compliance by measuring each plate at defined points; Class C of ISO 7452 may be used instead with ABS agreement. Plus tolerance, flatness, width and length follow ASTM A6 or another recognised standard unless specified otherwise. For plates under 5 mm (cut from coil), tolerances follow a national standard but the minus tolerance still may not exceed 0.3 mm.

Surface defects may be ground out within the limits of 2-1-1/3; grinding areas are excluded from the thickness tolerance. If you plan to shot-blast and prime at the yard, state any surface class (for example ISO 8501-1 rust grade A or B on receipt) in the order.

Quantities are approximate and change daily; all stock plates carry AB/B marking and ABS-endorsed mill certificates. Sizes outside the table are produced in the next mill rolling cycle, typically 3–6 weeks including ABS survey (as per standard and mill certificate for exact lead time). Send your size list and we will reply with stock vs roll.

Packing. Plates are bundled by size with steel strapping, marked with heat number, grade and ABS stamp, and shipped in containers (up to about 11.8 m) or break bulk for longer plates.

These are comparisons, not substitutions. A classed hull needs plate made by a mill approved by the society that classes the vessel. Dual or multi-class certification can be arranged at the mill when the heat is surveyed by both societies.

All ordinary-strength grades share 235 N/mm² yield and 400–520 N/mm² tensile; they differ in deoxidation and toughness. The hull steel grade for each strake is set by classification rules according to member category and thickness — check the approved drawing first. Higher-strength ABS steel plates (AH/DH/EH/FH 32–40) raise yield to 315–390 N/mm².

Choose Grade B when the approved drawing asks for 0 °C toughness at ordinary strength. Do not substitute Grade A into a B strake. Substituting D or E for B is normally accepted because they meet every B requirement plus a colder test — confirm with the Surveyor. For yield above 235 N/mm² at 0 °C, use ABS AH32 / ABS AH36 / ABS AH40.

Compared with land structural steels, Grade B differs by the 0.3 mm minus tolerance, the C + Mn/6 ≤ 0.40 cap, and class survey/stamp. For a classed barge or pontoon, only class-certified plate is accepted.

When ABS B is the right choice: typical uses are hull plating where a 0 °C toughness level is called for by the material class of the member, typically in the thicker range where Grade A is no longer accepted. The Charpy temperature (0 °C) is fixed by the letter, and the strength by the ordinary-strength level (ReH 235 N/mm²). Pick the strength from the scantling calculation and the letter from the material class and design temperature on the approved drawing. Swapping to a different letter or strength needs class approval of the drawing change, not just a new purchase order.

Typical uses: side and bottom shell in temperate service, strength deck plating, hatch coamings, repair inserts where B is drawn, inland vessels that see near-freezing winters. Offshore and port structures also use Grade B where ordinary strength with verified toughness is enough; see offshore platform steel plates for primary structure grades.

Cutting: oxy-fuel, plasma and laser cutting all work without preheat in normal thicknesses. Welding: with C + Mn/6 ≤ 0.40 %, Grade B is welded with ordinary-strength consumables approved for the required weld-metal toughness; preheat is generally unnecessary below about 25–30 mm except in cold or humid conditions — follow your approved WPS (as per standard and mill certificate for consumable grade). Forming: cold-flanging quality (S 0.020 % max., marked F) on request.

Processing notes for ABS B: cold forming and flanging of ordinary-strength plate are routine. The minimum Mn is set so that this grade can be cold-flanged where noted in 2-1-2. Keep the cut edges of plate thicker than 50 mm free of notches, because thick plate of this grade is controlled more tightly for deoxidation (killed or semi-killed ≤50 mm; killed >50 mm).

Every plate is tested and marked at the mill under ABS survey; the mill certificate lists heat number, ladle chemistry including Ni, Cr, Mo and Cu, tensile results, impact results where required, condition of supply and plate numbers, and is endorsed by the attending Surveyor. On request we add EN 10204 3.2 certificates with third-party witness by TÜV, SGS, BV or another agency, ultrasonic testing (U mark) or through-thickness testing (Z mark), and multi-class certification with ABS, DNV, LR, BV, CCS, NK, KR or RINA.

On receipt, check: AB/B stamp and heat number match the certificate; ABS endorsement is present; thickness is not below nominal minus 0.3 mm; impact temperature is 0 °C where required and energy meets Table 4.

Charpy acceptance for ABS B by thickness (from 2-1-2; actual results as per standard and mill certificate):

On receipt, check that the test temperature on the certificate is 0 °C and that the energy matches the band for the delivered thickness, not the thinnest band. Also check that the plate number on the stamp matches the certificate line, and that the ABS Surveyor endorsement is present. If UT was ordered (e.g. EN 10160 or ASTM A578 level), check the UT report as well. If the PO asked for 3.2, the inspector’s report must name the witnessed tests and plate numbers.

• Ordering B without ABS certification and receiving GB 712 / A131 only
• Assuming no impact test is ever needed — Table 5 still triggers 0 °C CVN in many bands above 25 mm
• Substituting Grade A into a B strake
• Ignoring AB/B stamp vs mill-only marking
• Ignoring the 0.3 mm minus tolerance on trader stock

Each of these is avoided by writing the requirement into the purchase order and checking it on the certificate before the plates are cut.

State the grade and rule (ABS Grade B, ABS Rules Part 2), whether multi-class certification is needed, thickness, width, length and quantity per size, condition of supply, any Z or U requirement, surface or primer requirements, certificate type (mill certificate with ABS endorsement, EN 10204 3.2), packing and destination port. Send the list to SHH STEEL for price, available stock and lead time.

Sample PO line: “Steel plate to ABS Rules Part 2 2-1-2, Grade B, delivery condition [AR/CR/N/TM], 20 × 2500 × 12000 mm, 30 pcs, marked AB/B, certificate endorsed by ABS Surveyor, EN 10204 3.2 [if required], UT [if required], CIF [port].” Each bracketed item changes price, lead time and which mills can supply, so fix them at enquiry stage.

ABS Grade B is ordinary-strength hull steel at 235 N/mm² minimum yield and 400–520 N/mm² tensile, with Charpy at 0 °C where 2-1-2 Tables 4/5 require it, and marking AB/B. Fix in the order: class certification, supply condition and impact frequency, product analysis if needed, and certificate type.

SHH STEEL supplies Grade B plate from ABS-approved Chinese mills with the AB/B stamp and Surveyor-endorsed certificates. Stock covers common sizes; other sizes are scheduled into the mill rolling cycle. EN 10204 3.2 and multi-class stamps are available on request.

Payment is T/T or L/C with inspection before balance. Mixed sizes and grades combine in one shipment. Dedicated follow-up includes photos; our workshop provides cutting, bevelling, drilling and machining.

Request a quotation: send SHH STEEL ABS B, thickness, width, length, quantity per size, destination port and any multi-class/Z/U/3.2 needs.