U.S. imports of Refractory Nonconstructional Ceramic Goods — Other (Retorts, Muffles, Nozzles, Plugs, etc.) (HS 690390) totaled $19.1M in August 2026, imported from 36 countries.
Importers of Refractory Nonconstructional Ceramic Goods — Other (Retorts, Muffles, Nozzles, Plugs, etc.) paid $1.2M in duties in August 2026, an average duty rate of 6.29% — duty actually collected as a share of the imports that cleared customs, not the published tariff schedule. Refractory Nonconstructional Ceramic Goods — Other (Retorts, Muffles, Nozzles, Plugs, etc.) imports of $19.1M in August 2026 ran 19% above the year-to-date monthly average of $16.0M.
Last updated: August 2026 dataRefractory process components that do not qualify under the alumina/silica or free-carbon thresholds of other headings — including clay-based and specialty nonclay compositions such as silicon carbide, magnesia, or zirconia shapes — are captured here. The US schedule divides the heading between clay goods (6903900010) and nonclay goods (6903900050), making material composition the decisive classification factor. Mexico and Japan are the leading suppliers, with Germany and the United Kingdom also prominent, reflecting the engineering ceramics expertise concentrated in those markets. Silicon carbide kiln furniture and specialty nozzles for glass and ceramics processing are commercially significant product types within this heading.
AI-written summary of the official U.S. Census Bureau trade figures on this page — verify before relying on it.
568 import shipments a month
Silicon carbide kiln furniture (setters, saggers, beams, and posts) generally classifies under 6903.90 as nonclay refractory nonconstructional ceramic goods (6903900050), provided the article is not predominantly carbon by weight (which would place it in 6903.10) and is not a constructional shape. The nonclay line captures SiC and other non-alumina/silica-dominant compositions used as process support equipment in ceramics and electronics firing.
Customs may request a material composition certificate or laboratory analysis confirming whether the refractory article is clay-based (phyllosilicate minerals such as kaolinite, ball clay, or fireclay) or nonclay (SiC, magnesia, zirconia, etc.). Supplier-issued material data sheets specifying mineralogical composition and firing temperature are the standard supporting documents. Retaining these records is advisable given that the clay/nonclay split affects both classification and, potentially, applicable trade-remedy exposure.
Subheading 1 of 3 in heading 6903
Subheading 690390 · $19.1M of $37.6M
ImportsExports
Imports
$19.1MYoY · free account
Exports
$20.6MYoY · free account
12-mo low · imports
Low · free accountOver the twelve months to August 2026, the U.S. imported $184.6M of Refractory Nonconstructional Ceramic Goods — Other (Retorts, Muffles, Nozzles, Plugs, etc.) and exported $195.2M.
Through August 2026. Source: U.S. Census Bureau.
HS10 import codes under this HS6 parent, each with its own page. Source: U.S. Harmonized Tariff Schedule.
| Code | Description | Imports for consumption | Average duty rate | Dutiable Share | Duty Collected |
|---|---|---|---|---|---|
| 6903900050 | Oth Refractory Ceramic Goods NESOI, Nonclay | $17.9M | 5.71% | 45.54% | $1.0M |
| 6903900010 | Oth Refrac Ceram Gds NESOI of Clay | $1.2M | 14.72% | 71.18% | $181K |
HS10 export codes under this HS6 parent, each with its own page. Source: U.S. Schedule B export classification.
| Code | Description | Export Value |
|---|---|---|
| 6903900050 | Oth Refractory Ceramic Goods NESOI, Nonclay | $18.7M |
| 6903900010 | Oth Refrac Ceram Gds NESOI of Clay | $1.9M |
Import lines come from the U.S. Harmonized Tariff Schedule and export lines from Schedule B. The two are numbered by different agencies, so the same 10-digit code can appear in both tables describing a different product.
Trade Directory
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Imports · August 2026
origin
Mexico and Japan together supply 58% of it. Japan pays 11.9% duty; Mexico <0.1%.
customs district
destination
entry
rate provision · imports
52.8% enters free of duty; duty collected equals 6.29% of imports for consumption.