Hvernig til koma í veg fyrir tæringu af hífingu vélum% 3f

Hvernig til koma í veg fyrir tæringu af hífingu vélum% 3f

In recent years, with the development of my country's engineering construction, hoisting machinery has become more more widely used in modern production such as ships, aerospace, electric power, base materials, metallurgy, bridges and railways.
 

The increase in the number of cranes has brought opportunities for manufacturing companies, but also many challenges. According to authoritative statistics, while the number of cranes is increasing year by year, the number of cranes that are dismantled and scrapped each year also increases significantly, and more than 80 percent of the cranes are scrapped because of the corrosion failure of their metal structures.
 

Vegna til há hár tíðni notkunar of lyftingar véla og the tiltölulega harkalega vinnu umhverfis, þeir eru oft sett í opið loft eða in a rakt og ætandi umhverfi. The Verndandi málning lag on yfirborð af kraninn oft tapar þess verndandi virka vegna skemmda, orsaka the málmur uppbygging til vera tærð.
 

There have been two incidents of gantry cranes due to severe corrosion of the main stress-bearing components, and the use unit violated regulations and forcibly overloaded them, resulting in damage to the metal structure and accidents involving machine crashes and fatalities. Taking the United States, a developed country, as an example, according to statistics, more than 50 people are killed in crane accidents every year. Tæringin af málmi uppbyggingu efnum af lyftingum vélum ekki aðeins auðveldlega leiðir til öryggis slysa % 2c en einnig veldur risastór sóun af málmi efnum.
 

Grein 3.9 af GB6067.1-2010} "Safety Regulations for Hoisting Machinery Part 1: General Rules" clearly stipulates that when the main stress-bearing components of the crane are corroded, inspection and measurement should be carried out.

Hvenær the tæring af the section of the main force-bearing member reaches 10 percent of the design thickness, if it cannot be repaired, it should be scrapped.

Tæring hegðun og orsök greining málmur uppbygging af hífingu vélar

The main beam and other main parts of the crane are mainly made of ordinary carbon steel Q235, and the important load-bearing components of the crane metal structure are stipulated to use Q235B, Q235C, and Q235D. For the general metal structure of the crane, when the design temperature is not When it is lower than -25 degree , it is allowed to use boiling steel Q235F.

For ordinary carbon steel corrosion forms can be divided into uniform corrosion, hole corrosion and intergranular corrosion. Uniform corrosion is less harmful. Since metal components have a certain cross-sectional size, slight uniform corrosion generally does not significantly reduce the mechanical properties of the metal. But for the box-shaped metal structure (box-shaped beam, box-shaped outrigger, box-shaped arm, etc.) ACCIDENT.
 

Pore corrosion and intergranular corrosion are corrosions that occur on a localized scale in a metal body. These two kinds of corrosion will reduce the effective cross-sectional area of the component and make the parts prone to Sudden fracture. These two kinds of corrosion behavior are more harmful.
 

Rannsóknir hafa sýnt það millikorn tæring er aðallega orsakast by the leifar streita inni efnið eða the streita álag álag utan, sem leiðir til the sameinað aðgerð of streita, stofn og tæring on the efni og leiðir til
 

tæringin gangvirkið af málmur uppbygging of hífingar vélar er aðallega efnafræðileg tæring og rafefnafræðileg tæring.
 

Chemical corrosion refers to the destruction of materials caused by direct pure chemical corrosion between materials and non-conductive media, while electrochemical corrosion is the the most common important type of corrosion of metal materials through electrochemical reactions. Under normal circumstances, the steel structure of hífing vélar almennt býr til ryð á yfirborð. En in málið há há hitastig, the stál uppbygging er auðvelt til form oxíð skali. In viðbót, stál is prone to react with gas at high temperature, and the gas generated escapes from the surface the steel, and a decarburization layer is formed on the surface of the steel structure, which the performance of the lifting machinery.
 

In a harsh environment, it is easy to meet the three conditions necessary for electrochemical corrosion: the existence of a potential difference, an electrolyte solution, and contact. As long as the above three conditions are met at the same time, electrochemical corrosion can be formed, thereby destroying the metal structure of the lifting machinery.

At present, the anti-corrosion methods of crane metal structures mainly include metal structure surface coating method and sacrificial anode protection method.
 

The sacrificial anode protection method usually adds fillers (such as zinc) that are more active than steel to the paint. Through the electrochemical principle, the sacrificial anode can protect the metal structure from corrosion. Although this method does not require an external power source, it is harmful to corrosion. The quality of the coating is extremely high, and non-ferrous metals will be consumed at the same time, and the anode needs to be replaced regularly, which is costly and complicated.
 

Yfirborð húðunar aðferðir eru aðallega skipt í tvær tegundir: tæringarþolið málmur klæðning aðferð og málmlaus klæðning aðferð. Tæringarþolið málmur klæðning aðferðir almennt fela í sér rafhúðun aðferð, klæðning aðferð, hot-dip method, permeation plating method, spraying method, etc. The process requirements of these methods High, high cost, suitable for small workpieces, but for large-scale lifting machinery that has been put into practical use, it is beyond the reach of the above methods, so it has not been wide used.
 

non-metal covering method is to apply basic anti-rust paint on the metal surface. This method is low in cost and easy to operate, and is widely used in crane anti-corrosion. However, a single paint film cannot completely prevent moisture and oxygen from penetrating to the metal surface, which may cause aging and damage. In addition, the gap in the process of painting may also cause the paint to not play A Gott langtíma Árangursríkt Vernd.