the-corrosion-analysis-of-direct-burial-steel-pipe

the-corrosion-analysis-of-direct-burial-steel-pipe

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Deterioration is among the major factors for the damages and also failure of hidden pipelines. For the long-distance pipeline and centralized pipeline network of natural gas transmission, the deterioration of hidden pipelines can not be straight discovered and also is troublesome for upkeep. How to prevent rust damage is an essential factor of pipeline safety design. According to the deterioration part, the rust of buried carbon steel pipe can be split right into internal rust and external deterioration.

straight funeral steel pipe

Inner Deterioration

The inner rust of pipeline is caused by harsh chemical components in the carried medium. Various tool cause various rust factors. For example, gas is high in H2S, CO2, water content and dirt, which may result in perforation as well as ruptured crashes. The interior rust of pipe is not only the result of multiple WLDSTEEL outside aspects, but additionally related to pipe product and production method, along with anxiety.

Exterior Corrosion

Soil erosion. Soil is basically a permeable gelatinous capillary with three stage states: solid, liquid as well as gas. The pores of the dirt are filled with air as well as water. A certain amount of salt in the water makes the soil have ionic conductivity. The physical as well as chemical residential properties of the soil and also the electrochemical inhomogeneity of the steel material please the electrochemical rust conditions of hidden pipes, causing rust.

Stray present rust. Roaming present is the present that corrodes and also harms steel pipes beyond the defense system style for underground circulation. Stray existing rust consists of DC stray existing corrosion and air conditioner stray current deterioration. The DC stray current primarily comes from the dc electrified train, the DC electrolytic tools grounding electrode, the anode ground bed in the cathodic protection system and so on. The roaming current circulation process develops 2 deterioration batteries established by the external potential distinction. One is that the existing drains of the rail as well as into the steel pipe. The rail is the anode of the deterioration battery, and also corrosion occurs. The other is the present draining of the pipeline back to the rail, the pipeline is the anode that rusts the battery, wears away, the rail is the cathode, does not rust.

Casing corrosion. Through casing is widely utilized in long-distance transportation pipes. The corrosion of the housing (specifically the metal housing) via the pipe area is complicated and has a shielding impact on standard cathodic defense. Casing corrosion can be separated right into conventional deterioration and also uncommon corrosion 。.

Disintegration corrosion. Due to the disintegration and also cutting of the riverbed by the river, the underwater bare pipelines are revealed in the river, causing erosion rust.

The Rust Tests Of Straight Burial Steel Pipeline.

Interior corrosion discovery.

Interior evaluation primarily consists of the geometry of the inner wall surface of the pipeline (such as ellipticity, bending, girth weld, rust reduction of wall surface density, etc.). Pipe c orrosion is generally identified by thinning of the pipeline wall surface as well as neighborhood pits and pitting. General pipeline corrosion detection is mainly to determine as well as evaluate the modifications in the term of pipeline wall surface. The internal corrosion of intricate fluid pipes is closely related to the deterioration features of the medium and also the circulation attributes of the liquid.

Outside rust detection.

Buried carbon steel pipe exterior rust defense is typically composite layer made by insulating layer and cathode security. Cathodic protection specifications can be from the damages of the pipeline defense layer, court the pipeline deterioration. Established on the basis of the concept of this method, the test specifications are mainly tube/potential measurement and also measurement of tube existing.

Currently there are 6 main type of detection approaches for external cover: Pearson detection method, alternating existing attenuation method, dc possible slope approach (DCVG), in-tube current and voltage approach (likewise called dc present and also voltage approach), variance-frequency choice technique, as well as close interval capacity technique (CIPS).

Amongst them, the first 3 techniques are generally utilized to discover the damage factor of the external cover; The center 2 approaches are generally utilized to discover the insulation resistance of the external covering layer. The last method indirectly evaluates the condition of the outer covering layer by spotting the pipe security capacity. These techniques identify the problem of the outer layer by using rated ac/dc power to the pipeline, or through the negative protection of the pipe, and also by discovering signal changes directly over the pipe.