Refractory Services Information
Refractory Services Information
Refractory services manufacture, install and repair refractory shapes and monolithic refractories. Refractory shapes are hard, heat resistant materials that are suitable for applications which require high temperature strength, wear resistance, electrical or thermal insulation, or other specialized characteristics. Monolithic refractories are liners for furnaces, boilers, or other thermal processing equipment. To produce refractory shapes and monolithic liners, refractory services perform a variety of fabrication processes. Casting pours liquid into a mold and allows it to dry into a solid shape. Injection molding disperses ceramic powder in a plastic or wax binder, melts the material, and then injects the mixture into a die cavity. Sintering or firing is a thermal consolidation process that uses diffusion to bond ceramic particles together. Mechanical pressing places dry ceramic powder, usually with a wax binder or lubricant, in a die and punch set. By contrast, ramming uses wet ceramic powder or a refractory mixture with a high degree of plasticity. Gunning mixes are powdered products that are loaded with a gun into a form or onto a furnace wall to create an insulating layer. Dry refractories are fired into place. Extrusion is a process that forms stock shapes with specific cross-sectional profiles. Grinding provides very smooth, precise material finishes. Machining processes include turning, milling, and boring.
Refractory services differ in terms of basic capabilities, secondary activities, and application expertise. Basic capabilities include design assistance, research and development, material selection, prefabrication, installation and repair, inspection and testing, reverse engineering, and training. Secondary activities include assembly and bonding, brazing, glazing and coating, infiltration and sealing, and thin metal deposition. Some refractory services specialize in the manufacture, installation, and repair of refractories for chemical processing applications. Others fabricate electrical parts such as insulators and igniters for power or high voltage applications. Ceramic and refractory crucibles, tubes, stoppers, liners, spouts, permanent molds, thermocouple protection tubes, combustion gas heaters, submersible heater tubes, and die casting stalks or sleeves are used in foundries for melting and casting operations. Refractory services that provide structural components produce parts with high compressive strengths and elastic moduli. Ceramic parts are also used in automotive parts and tooling.
Refractory services fabricate refractory shapes and monolithic refractories with a variety of material types. Examples include alumina, carbon or graphite, mullite, nitride, silicate or fused silica, silicon carbide, and zirconia. Composite materials consist of a matrix material reinforced with a stronger or higher modulus second phase. The matrix may consist of a ceramic, metal, or polymeric material. The second phase may be in the form of particulates, chopped fibers or continuous fibers. Fibrous refractories or thermal insulation products are also available. These products consist of ceramic fibers in bulk, fiberboard, paper or rope form. Porous ceramics have a high degree of open or closed internal porosity to increase the thermal insulation capability of the material.
Certifications and Quality Requirements
Refractory services are located across the United States and around the world. They meet various certification and quality requirements. ISO 9001 establishes requirements for organizations whose business processes range from design and development to production, installation, and servicing. ISO 9002 establishes requirements for organizations whose business processes include production, installation, and service, but do not include design and development. QS 9000 is a quality standard for suppliers of DaimlerChrysler Corporation, Ford Motor Company, and General Motors Corporation. QS 9000 is based on the 1994 edition of ISO 9001, but contains additional requirements that are particular to the automotive industry. Refractory services that meet U.S. military specifications (MIL-SPEC) are also available.