Slide Gate Plates for Ladle & Tundish — Al-Zr-C and Magnesia-Spinel Grades

Slide gate plates are the most chemistry-sensitive item in continuous casting. Two plates of identical dimensions can differ in service life by a factor of two, purely because of which chemistry is running against which steel grade — and that is the single most common reason plate life disappoints.

Choose Chemistry by Steel Grade, Not by Habit

• Al-Zr-C (XZK-SLH-X, SLH-R) — the general long-sequence choice. Alumina body, 4% carbon, 4% zirconia for thermal shock resistance, CCS ≥100 MPa, porosity ≤10–11%.
• Magnesia-spinel (XZK-SLH-E) — 80% MgO. Specified for high-oxygen and high-manganese steels, where an alumina-carbon bore dissolves rapidly. If your plate life collapses on a particular grade, this is usually the answer.
• High-performance (XZK-SLH-M39, SLH-M) — CCS to 120 MPa with porosity at 10.0%, for the longest sequences and the most demanding duty.

Plants that run one plate chemistry across all steel grades are leaving life on the table. Matching chemistry to grade is normally the cheapest improvement available in the flow-control package.

Why Plates Crack at Start of Cast

Thermal shock, and it is worth being specific about the mechanism. A plate at ambient temperature is opened into a stream of steel at roughly 1600 °C. The bore surface heats almost instantly while the body stays cold, the gradient produces tensile stress at the bore, and the plate cracks — often before a single ton has been cast.

Two levers address this: material shock resistance (zirconia additions in the Al-Zr-C grades) and preheat practice. If you are losing plates at start of cast, inspect both before changing chemistry, because preheating is usually the cheaper fix.

Bore Erosion and Oxidation

Through the cast, the bore erodes from steel flow and slag contact. Between casts, the carbon bond oxidises if the assembly is not sealed. High crushing strength and low porosity slow the first; argon-blowing designs and good joint sealing address the second. Both are worth checking if wear is faster than expected.

Fit Is Not Negotiable

Plates are machined components, and a plate that does not seat correctly will fail regardless of chemistry. We machine to the major mechanism types, including Interstop and Vesuvius styles, and verify interface dimensions before production. Send the mechanism model or a drawing of your current set.

Supply

Quoted per set or per piece, typically 200–500 pieces minimum per item, with 20–35 day lead time from drawing approval. Dimensional inspection reports, batch test data and material certificates are supplied with every order, and third-party inspection can be arranged.

Where This Grade Sits in the Lining System

Flow-control refractories are consumed on the caster's schedule, so the specification is as much about dimensional repeatability and interchangeability with your existing mechanism as it is about composition. A plate or shroud that fits but varies by a millimetre between lots costs more in breakouts than it saves in unit price.

XZK supplies slide gate plate as one zone of a zoned package rather than as a standalone item: the grades normally zoned alongside it — among them monobloc stopper rod — are documented on the continuous casting functional refractories page, and the vessel-level architecture — where each zone starts and ends, and which mechanism actually limits the campaign — is set out on the tundish flow control and steel ladle and RH/VD pages.

For a complete vessel programme built on this class of material, including the wear survey that set the zoning, see the Colakoglu Metalurji slab caster flow control programme project reference.