Every tank starts as a plate enquiry

Storage tanks and low pressure vessels do not exist until somebody rolls, welds and stands up a stack of steel plates, which means the equipment enquiry is really a plate enquiry with a shape attached. The supply side is already arranged for it. The hot rolled Q235 plate page stocks 0.3 to 200 mm thickness in 3 to 18 tonne lots, regular widths of 1000, 1250 and 1500 mm, with 6000 tonnes on the floor, and carries the sister grades Q345, ST37, Q195, Q215, SPHC, A36 and 16Mn. That thickness span is the whole story of tank construction in one line: thin enough for small atmospheric vessels, thick enough for the heaviest shell course, and the site's own writeup on hot rolled plate grades in structural fabrication counts tanks and pressure vessels among the standard end uses.

Thickness is the money, and the arithmetic is public

Steel weighs about 7.85 kg for every square metre per millimetre of thickness, so the numbers move quickly. A 10 metre diameter tank built from 2000 mm wide shell courses needs roughly 31.4 square metres of plate per ring; at 8 mm that is about 3950 kg per course, and a twelve-ring shell is nearly fifty tonnes of plate before nozzles and roof. Roughly one fifth of that weight is the annular step from 6 mm to 8 mm plate. This is also why the grade ladder matters as much as the dimension: Q345 and Q345 coil carry a higher yield strength than Q235, and in general practice the higher yield allows a thinner shell for the same hoop load, which trades a slightly dearer plate for measurably less weight to buy, roll and weld. The same trade applies through 45# plate and the coil equivalents such as ST37 coil, and the A36 construction page walks through the grade choice for exactly these structural decisions.

Cutting, forming and welding decide whether it fits

A plate that is right on the certificate can still fail the fabrication schedule, so the processing pages deserve a reading before the order. The cutting page lays out the ladder by thickness: mechanical cutting for plate under 10 mm in straight lines, hydraulic shear above 10 mm, CNC turret punch below 2 mm for chassis and cabinet work, laser for high precision complex patterns at higher cost, plasma for thick plate at speed, and waterjet where a heat affected zone is unacceptable. Shell plates are then rolled and joined, with the bending page documenting knife, two-knife and three-knife bending plus 180 degree and double-layer work governed by the bending coefficient, and the punching page noting that method choice follows thickness, aperture and batch size. The plate welding page covers the joining itself, and the surface treatment page closes the loop with rust removal by sandblast, shot blasting or pickling, protective coating to isolate air and moisture, galvanizing, polishing and heat treatment. Specifying which of these happens before delivery is cheaper than discovering afterwards that the shop expected bare mill edges.

When the product is not water, the shell changes

The moment the tank stores something corrosive, the grade question reopens. Austenitic stainless is the first step: 304 for clean products, the 316/316L coil listing where chlorides ride along, and 317LMN documented as superior to 316L and 317L in pitting and crevice corrosion when the medium concentrates. The next step up is structural as well as chemical: the 2205 page publishes yield strength about twice that of austenitic grades, which in general practice lets a designer buy a thinner wall, and it is available as duplex coil or S31803 seamless pipe for the nozzles and shell penetrations. For the harshest duties the 2507 page makes the economic argument directly, that a light gauge of 2507 can achieve the same design strength as a thicker nickel alloy with the resulting savings in weight, and S32760 adds PREN 40 with the NACE listing. Above the duplex tier sit the nickel-bearing plate grades: 904L for bleaching tanks and acid duties, Monel 400 for alkalis and hydrofluoric-adjacent service, 825 for acids and seawater, C-276 for the oxidising residues, and titanium for the internal hardware that must never be the first item replaced.

Nozzles, supports and the rest of the yard

A tank order is never only shell plate. Nozzle and manway necks come from pipe stock, with A106 seamless pressure pipe for the pressurised connections and A53 pipe for the utility side, and the large diameter thick wall listing covers the heavy stainless penetrations. Wind girders, platform clips and stair stringers roll out of the same plate or the square tube listing, while the steel structure pages supply the bund walls, pipe racks and access steel around the tank, including the Q235 IPE 450 sections and the normalised production described on the A29M H-shape page. Where the yard itself needs protection, galvanized plate and the Z275 coil handle cladding and drip protection, and the galvanized processing chain takes coil through cutting, bending and welding to finished parts.

Six lines decide the plate

An enquiry that states six things gets a quotable answer instead of a guess: the thickness range and whether it steps by course, the grade family from Q235 through Q345 to the alloy shell, the width that sets the course height, the certificate level from plain mill test report to a third-party inspection, the surface condition from mill finish to pickled or blasted, and which processing services are to be done before delivery. Every one of those six lines maps onto a page in this catalogue, which is the point. A tank is not a catalogue item, but the plate, pipe, sections and services it is made from all are, and ordering them together is how the fabrication schedule stays in one pair of hands.