Market application range of steel-clad steel steam-insulated pipes is expanding with the vigorous development of urban centralized heating and combined heat and power generation, and the technology of thermal pipeline has been widely used domestically. The direct-burial installation method is favored for its excellent insulation effect, high energy-saving efficiency; minimal land occupation, without affecting urban planning; easy installation, short construction period; long service life, and low maintenance costs. Currently, the types of external protective sleeves for direct-buried steam-insulated pipes mainly used in our country are "plastic-clad steel" and "steel-clad steel". The technical route for steel-clad steel burial is based on traditional trench laying, replacing brick or concrete trenches with steel sleeves. The sliding interface of the pipeline is the interface between the pipeline support and the inner wall of the steel sleeve. Direct-buried steam pipelines; direct burial; external fixation; internal fixation. In recent years, there have been many attempts to use direct-buried steam pipelines in northern cities. When steam pipelines cross city main roads and involve environmental beautification issues, the direct-burial laying method can effectively solve the above problems, and due to its fast construction progress, good insulation performance, low construction cost, and material saving characteristics, it has been increasingly widely used. Since steam direct-buried pipelines are a new thing, the national construction department has not yet formulated formal standards for detailed regulations on steam direct-buried pipelines.

Steel-clad steel-insulated pipe manufacturers offer direct-bury steam pipelines at competitive prices. These pipelines, as a new material in the heating industry, are gaining wider application due to their fast construction progress, excellent insulation performance, low construction cost, and material savings. Since there are no design specifications for high-temperature steam pipelines, the insulation structures and fixing methods vary among different manufacturers. This article discusses several common characteristics of direct-bury steam pipelines available in the market.