Steel plate inspection

As an ISO/IEC 17025 accredited (CNAS) independent laboratory, we provide comprehensive steel plate inspection services for steel distributors, construction companies, pressure vessel manufacturers, shipyards, mining equipment fabricators and infrastructure projects in Argentina. Steel plates are fundamental materials used in building frames, bridges, storage tanks, pipelines, offshore platforms, mining chutes, and pressure vessels. Incoming and in‑process inspection of steel plates ensures that they meet specified thickness, flatness, surface quality, internal soundness, chemical composition, and mechanical properties (yield strength, tensile strength, elongation, impact toughness). Our inspection integrates non‑destructive testing (ultrasonic flaw detection, thickness measurement, magnetic particle, dye penetrant) with destructive testing (tensile, bend, impact, hardness) and dimensional checks. We follow international standards (ASTM A435, A578, A6, EN 10160, ISO 9001) and adapt to Argentine IRAM and CIRSOC requirements. Results help clients prevent material‑related failures, reduce rework, and certify steel plates for critical service conditions (seismic zones, low temperatures, sour service).

Types of Steel Plates We Inspect

Hot‑rolled carbon steel plates (grades: ASTM A36, A283, A572, IRAM‑IAS U500‑528, etc.)
Pressure vessel plates (ASTM A516 Grade 60, 65, 70; ASTM A537; EN 10028; IRAM‑IAS U500‑512)
High‑strength low‑alloy (HSLA) plates (ASTM A572 Grade 50, 65; A588 weathering steel)
Boiler plates (ASTM A285, A515; EN 10028‑2)
Shipbuilding plates (ASTM A131, ABS grades, Lloyd’s Register, DNV)
Wear‑resistant plates (AR400, AR500, Hardox, Creusabro)
Stainless steel plates (304/304L, 316/316L, duplex, 410S) for corrosive environments
Clad plates (stainless steel clad on carbon steel)
Quenched and tempered (Q&T) plates for mining and earthmoving equipment
Pre‑coated plates (primer, anti‑corrosion) – inspection of coating thickness and adhesion

Dimensional Inspection

Dimensional compliance ensures that plates fit into fabrication and assembly without excessive gaping or mismatch.

Thickness measurement – Using an ultrasonic thickness gauge (calibrated on reference blocks) or micrometer (for edges). Measurements are taken at multiple points across the plate (corners, center, quarter points). The minimum measured thickness must not fall below the nominal minus the negative tolerance (e.g., ASTM A6 allows -0.3 mm for plates ≤ 25 mm). For pressure vessel plates, 100% of the area may be scanned for thickness uniformity.
Length and width verification – Using a steel tape (calibrated) or laser distance meter. Tolerances per ASTM A6 typically ±5 mm for length and ±3 mm for width, but project specifications may be tighter.
Flatness (out‑of‑flatness) measurement – The plate is laid on a level surface. A straightedge of specified length (e.g., 1 m, 2 m) is placed on the concave side, and the maximum gap is measured with feeler gauges or a ruler. The permissible flatness deviation depends on thickness and width (e.g., ≤ 5 mm over 2 m for structural plates). Local waviness (buckle) is also checked.
Squareness (shear or cut edge perpendicularity) – Diagonal difference is measured (difference between two diagonals should be ≤ 5 mm for most plates). Edge perpendicularity to the face is checked with a square.
Edge condition (cut edges, gas cut, sheared edges) – Inspect for burrs, tears, raggedness, and cracks (especially on sheared edges). For plates to be welded, rough edges may require grinding.

Visual and Surface Inspection

Surface defects can act as stress raisers or initiate corrosion.

Surface cleanliness – Check for loose scale, rust, oil, paint, or dirt that could affect welding or coating.
Laminations and surface cracks – Look for horizontal separations (laminations) on edges and rolled‑in scale, slivers, scabs, cracks, or seams. For critical applications, magnetic particle or dye penetrant is used to confirm suspected indications.
Pitting and corrosion – Depth of pits measured; any pits deeper than the negative tolerance are cause for rejection or repair.
Surface finish (for stainless and clad plates) – Check for roll marks, scratches, gouges, and uniform passivation.
Marking and traceability – Verify that the plate is stamped or painted with heat number, grade, thickness, and manufacturer. Traceability to the mill certificate is mandatory for pressure vessel and structural plates.

Ultrasonic Flaw Detection (UT) – Internal Soundness

Internal defects such as porosity, inclusions, laminations, and cracks are detected using pulse‑echo ultrasonic testing.

Calibration – Using reference blocks (e.g., ASTM A578, EN 10160) with flat‑bottom holes (FBH) or notches. The sensitivity is set to detect defects equivalent to a 3 mm or 6 mm FBH, depending on the standard.
Scanning coverage – For structural plates, a grid scan (100 mm × 100 mm or 150 mm × 150 mm) is performed over the entire area. For pressure vessel plates, continuous scanning with 100% coverage is required.
Defect evaluation – Any indication exceeding the reference level is recorded. Laminations (indications at the backwall) and mid‑wall discontinuities are sized. Criteria: In pressure vessel plates, any lamination greater than 25 mm in diameter is unacceptable. For structural plates, isolated indications smaller than 100 mm² may be accepted if not at edges.
Thickness measurement (same UT equipment) – Also used to check for internal thinning, corrosion, or step‑down thickness changes.
Immersion or contact (direct contact) scanning – For heavy plates (> 50 mm), dual‑element probes or phased array UT may be used to improve near‑surface resolution.

Magnetic Particle and Dye Penetrant Inspection (Surface Cracks)

For edge cracks, flame‑cut edges, and surfaces where visual inspection is insufficient.

Magnetic particle inspection (MPI) – For ferritic plates, we apply a magnetic field (yoke or coil) and sprinkle magnetic particles (wet or dry). Cracks produce flux leakage and particle accumulation. Used on edges, bevels, and around cut‑outs.
Dye penetrant testing (PT) – For non‑ferritic plates (stainless steel) or when MPI is not applicable. A penetrant is applied, dwelled, excess removed, and developer applied; red indications reveal surface discontinuities.

Mechanical Properties Testing (From Witness Coupons or Plate Samples)

When required, we cut tensile, bend, impact, and hardness specimens from the plate or from attached test coupons.

Tensile test (yield strength, tensile strength, elongation) – Specimens machined in the transverse direction (most common) or longitudinal. Tested on a universal testing machine (UTM) using an extensometer. Results compared to grade specification (e.g., A36: yield ≥ 250 MPa, tensile 400–550 MPa, elongation ≥ 20% in 200 mm).
Guided bend test (face and root bends) – For plates to be welded (especially pressure vessels and pipelines). A specimen is bent around a mandrel of specified diameter (typically 3× thickness). No cracks > 3 mm allowed.
Charpy V‑notch impact test (toughness) – For low‑temperature service or seismic zones. Specimens are tested at specified temperatures (e.g., -20°C, -40°C). Results (absorbed energy, lateral expansion, shear %) compared to requirements (e.g., 27 J average for 0°C for certain grades).
Hardness test (HB, HRB, HRC, HV) – For wear plates and quenched & tempered plates, hardness is measured on the surface (after removing scale). AR400 requires 360–440 HB.
Through‑thickness tensile (Z‑direction) test – For plates subject to high through‑thickness stress (e.g., thick flanges, offshore nodes). Reduction of area measured (Z ≥ 25% for good resistance to lamellar tearing).

Chemical Analysis (Verification of Composition)

To confirm that the plate meets the specified grade chemistry (especially for pressure vessels, sour service, or welding qualification).

Optical emission spectrometry (OES) – A small area on the plate surface is ground flat, and a spark spectrometer measures carbon, manganese, silicon, phosphorus, sulfur, chromium, nickel, molybdenum, copper, etc.
Portable XRF (handheld) – For rapid grade sorting (not for certification of low elements like C, S, P – OES is preferred for full chemistry).
Carbon equivalent (CE) calculation – Used to predict weldability. CE = C + Mn/6 + (Cr+Mo+V)/5 + (Ni+Cu)/15. For low‑carbon steels, CE < 0.45 is generally good for welding; higher CE may require preheat.

Special Tests for Specific Applications

Hydrogen‑induced cracking (HIC) test (for sour service) – When plates are used in wet H₂S environments (oil & gas), we test samples according to NACE TM0284. Crack length ratio (CLR), crack thickness ratio (CTR), and crack sensitivity ratio (CSR) are measured. Acceptable limits: CLR ≤ 15%, CTR ≤ 5%, CSR ≤ 2%.
Sulfide stress corrosion cracking (SSCC) test (NACE TM0177) – For high‑strength plates in sour service, tensile specimens are loaded in H₂S saturated solution.
Ultrasonic phased array for clad plates (bond integrity) – Checks for lack of bond between cladding and base material.
Ferrite content measurement (for stainless clad plates) – Using a ferritscope to ensure weldability and corrosion resistance.

Inspection Report and Deliverables

Each steel plate inspection report includes the following information:

Plate identification (heat number, grade, dimensions, manufacturer, quantity)
Dimensional results: measured thickness at each point, length, width, flatness, squareness, edge condition
Visual results: surface defects (type, location, depth), markings, traceability
Ultrasonic results: scan coverage, defect positions (coordinates), size, classification (e.g., lamination, inclusion), acceptance
Mechanical test results (if performed): yield strength, tensile strength, elongation, bend test result, Charpy impact values, hardness
Chemical analysis (if performed): element percentages, carbon equivalent
Conclusion: “Accept”, “Accept with repair (list)” or “Reject”.
Raw data (UT records, spectra, test curves) archived for 10 years

No statement of compliance with any external standard or regulation is made unless the client has provided specific acceptance criteria in writing. The report is intended for material certification, fabrication quality assurance, and third‑party verification.

Applications in Argentine Industry

Bridge construction (spanning large rivers and highways): Inspection of thick A572 plates for girders and trusses.
Pressure vessel manufacturing (oil & gas, chemical, petrochemical): 100% ultrasonic scanning of A516 plates and verification of Charpy impact properties.
Mining equipment (crushers, chutes, truck bodies): Inspection of wear plates (AR400/500) for hardness and flatness.
Shipbuilding and repair (Patagonian ports, navy yards): Verification of ABS grade plates, edge UT for laminations.
Wind tower fabrication (raw material for renewable energy): Dimensional and UT inspection of high‑strength plates.