The construction process and precautions of refractory plastic can be explained in combination with the following points, covering key steps and key details:
Ⅰ. Construction process
Construction preparation
● Material inspection: Confirm the plasticity of the plastic (knead it into a ball without falling apart by hand), and check the accessories such as anchor bricks and templates; if the ambient temperature is lower than 10℃, anti-cold measures need to be taken.
● Site cleaning: Clean up the debris in and around the furnace, install air compressors, scaffolding and other equipment, and inspect the steel structure and holes of the furnace body.
● Anchor device installation: The furnace wall anchor bricks need to be fixed after ramming to the designed position, and the furnace top anchor bricks need to be pre-pressed with wooden mold bricks to form tooth marks and then embedded to ensure a tight bite with the plastic.
Paving and ramming
● Layered ramming: Each layer is 50-100mm thick (bulk materials do not exceed 100mm), staggered paving of the blanks, ramming perpendicular to the construction surface, hammer heads overlap 2/3, rows overlap 1/2, and go back and forth 3-4 times.
● Holes and expansion joints treatment: Holes need to be rammed in layers and expansion joints are reserved. The longitudinal straight seams of the furnace wall are filled with polyvinyl chloride corrugated plates. The expansion joint spacing of the furnace roof is 1.2-1.5m, and the depth is 80mm4567.
● Construction interruption treatment: Cover with plastic film to prevent dehydration, leave the joint at the center line of the anchor brick, and continue construction after scraping.
Surface finishing and oven baking
● Scraping and air holes: After demolding, use nail tooth plates to scrape, and pierce air holes (depth 2/3 lining thickness, spacing 150-200mm) to promote water discharge.
● Oven baking curve: Slowly heat up in the low temperature stage (≤600℃) to avoid cracking caused by sudden loss of moisture; shrink cracks in the high temperature stage (≥1350℃), and the final strength is formed.
Ⅱ. Precautions
Material storage and handling
● Store in a cool and dry place to avoid moisture or exposure; the material needs to be trapped for more than 16 hours before construction, and the binder should be added in proportion to prevent solidification.
● If repairs are required after construction, the damaged edges must be repaired to a right angle with a thickness of ≥20mm to ensure a tight connection.
Construction environment and operating specifications
● The ambient temperature is ≥5℃, and construction is prohibited in rainy or extreme weather; the parts in contact with the castable must be waterproofed.
● The ramming must be uniform to avoid local looseness; the furnace roof must be supported during construction, and the slope section must be rammed from the lower turning point.
Safety and quality control
● Construction personnel must wear protective equipment to avoid mechanical injuries; construction records must be complete, and the density, expansion joints and anchor brick fixation must be checked during acceptance.
● If the crack width is >10mm after the furnace is baked, a refractory fiber blanket must be filled to prevent fire.
III. Key performance and applicable scenarios
● Thermal shock resistance: Alumina silicate plastics have better thermal shock resistance than sintered refractory materials due to their uniform porous structure and low expansion coefficient.
● Use temperature: ordinary clay (1300-1400℃), high aluminum (1600-1700℃), chromium (1500-1600℃).
● Application scenarios: heating furnace, soaking furnace lining, high temperature furnace burner, etc., especially suitable for complex structures or parts that require rapid construction.
The service life and safety of refractory plastics can be ensured by standardizing the construction process and strict quality control. Specific parameters need to be adjusted in combination with design requirements and material properties.
