What Buyers Should Check During AZS Block Preassembly？

An AZS block can match its individual drawing and still need careful checking as part of a larger assembly. For a glass furnace rebuild, discovering an orientation error, an interface mismatch or an unidentified block at the installation site can complicate an already tight schedule. Factory preassembly gives the buyer and manufacturer an opportunity to review these issues before dispatch.

Preassembled refractory blocks in the Dezhong workshop. The assembly scope should be identified against the approved drawing.

For fused cast alumina-zirconia-silica (AZS) blocks, preassembly is a check of the agreed arrangement and fit. It is not a substitute for chemical analysis or internal inspection. At Dezhong, customers can discuss the required preassembly scope together with drawings and pre-shipment acceptance requirements.

Use this checklist to prepare the inspection discussion. It is not a universal AZS acceptance standard. The drawing and agreed specification must define the applicable tolerances, methods and coverage.

Confirm whether the review covers the full supplied assembly, selected furnace sections or specific interfaces. Name anything excluded. Evidence from one section should not be presented as acceptance of all blocks in the order.

Start with the drawing revision and the reference points used for measurement. Individual block dimensions and the assembled span answer different questions. Where the drawing specifies an overall length, opening or interface, check that feature in the agreed assembly condition as well as reviewing the relevant individual measurements.

Customers reviewing refractory blocks at Dezhong. Acceptance requires agreed criteria and recorded results, not photographs alone.

Read each joint against its specified purpose. Requirements for a close-fitting joint must not be confused with a designed allowance or expansion provision. A photograph alone cannot establish a joint measurement. Use the agreed method and assess any local step or mismatch at its identified location.

For holes, notches or other special features, compare location and orientation as well as size. Mark any issue against the drawing and block ID before the assembly is dismantled. This makes a correction and its subsequent recheck easier to follow.

A well-aligned assembly demonstrates the checked arrangement; it does not reveal every internal feature of the bricks. Internal-quality requirements for critical glass-contact blocks should therefore remain a separate part of the inspection agreement. Neither a neat joint nor a smooth surface proves that a block has no internal voids.

Internal inspection at Dezhong. Internal-quality assessment and dimensional preassembly checks answer different questions.

Dezhong has internal inspection capability alongside workshop assembly review. For the order, agree on the applicable method, coverage, acceptance criteria and the records to be supplied. Link each relevant result to a block or batch reference so that it can be matched to the supplied material.

Discuss the inspection arrangement before the planned acceptance date. A useful remote review package can include an annotated assembly drawing, block identification, measured results, overall and close-up images, and a list of items awaiting resolution. Video can support the discussion, but it does not replace required measurements or agreed inspection procedures.

Before dismantling the preassembly, record its final accepted arrangement and the status of any corrections. If a block is reworked or replaced, identify which checks must be repeated and update the relevant records. A closed inspection issue should have a traceable recheck, not only a verbal confirmation.

Agree how the accepted block identities will remain recognizable after packing. A package-to-block reference can help the receiving team find the right pieces without opening every case. Confirm quantities and shipping marks, and keep the final drawing and inspection records consistent with the packing information.

Include the order reference, drawing revision, inspected scope, actual results, supporting photographs, deviations and their disposition, and the agreed approval status. Record the inspection date and responsible reviewers. Avoid describing uninspected sections as accepted.

Discuss your preassembly requirements with Dezhong

Send your AZS drawings, installation positions, quantities and acceptance requirements to zzdz@dzrefactory.com. State which sections or interfaces need preassembly and whether attendance or document review is preferred. Pre-shipment acceptance is arranged as agreed; the balance is settled before shipment and port delivery follows the contract.

The aim is to resolve fit and identification questions while the blocks are still at the factory, and to give the installation team records that match the material it receives.