Pipes connected are for meeting certain production process demands, such as recycled-water production, fire-fighting pipeline, acid-base pipeline, steam pipeline, compressed air pipeline, living water pipelines and so on.
Anti-corrosion and Thermal Insulation Engineering
Anti-corrosion: It is to protect metal objects which are easily corroded with various methods so as to prolong its service life. The methods such as physical anti-corrosion, chemical anti-corrosion, and electrochemical anti-corrosion and so on are commonly used.
Thermal Insulation: It is a scientific, efficient and energy-saving technical measure and a measure which can slow down the conduction velocity of heat emission.
Surface Treatment
Generally, metal surfaces will be covered with dust, greasy dirt, oxide scale, rust layer, contaminants, salt or loose and old paint films. Oxide scale is a common but easily neglected part, is a dense oxide layer formed by high-temperature forging and forming of iron and steel, usually adheres firmly, is not solider than steel and it is a cathode, which accelerates metal corrosion. If these objects are not cleaned and painting g and installing directly, it must have an impact on adhesion and anti-corrosion effects of whole coating layer. According to statistics, there are about 70% of the paint problems that are caused by improper surface treatment. Therefore, proper surface treatment is very important for the performance of metal anti-corrosive painting and installation system.
Cleaning Grade
It can be called cleanliness. There are two typical international standards: One is SSPC- formulated by America in 1985, the other is Sa- formulated by Sweden in 1976 and it is divided into four grades, namely, Sa1, Sa2, Sa2.5, Sa3, which is an international working standard.Details are as follows:
Sa1: It is equivalent of SSPC-SP7 in America, and it takes the simple and general methods of brush removal and sanding by abrasive cloth and is the lowest of the four levels. Its protection for coating layer is only slightly better than that of the workpiece which has not been processed. And its technical standards of treatment: There is no greasy dirt , grease, left oxide scale, rust, left grease and other foreign matters on surface of workpiece
Sa2: It is equivalent of SSPC-SP7 in America and takes the method of blasting cleaning which is the lowest of blast-clean treatment and is the common requirement. But the protection for coating layer is much more efficient than manual cleaning. And its technical standards of treatment: There is no grease, dirt, oxide scale, rust, paint, oxide matters, corrosion matters and other foreign matters (except defect) on surface of workpiece, and the defect should be limited to not more than 33% of the surface of per square metre, including slight shadow, slight decolorization due to few defects, rust and erosion, oxide scale and paint. If there is dent on original surface of workpiece, slight corrosion and paint will be left at the bottle of dent. It can be called commodity cleaning grade(industrial grade)
Sa2.5: It is commonly used in industry and can be used as a grade for acceptance of technical requirements and standards. It can be called near-white cleaning level (near-while level or out-white level). And its technical standards of treatment: They are the same as the first half of Sa2, but the defect should be limited to not more than 5% of the surface of per square metre, including slight shadow, slight decolorization due to rust and erosion, oxide scale and paint.
Sa3: It is equivalent of SSPC-SP5 in America, and is the highest treatment grade in industry, can also be called white cleaning level (white level). And its technical standards of treatment: They are same as the Sa2.5, but there is no shadow, defects, rust and other foreign matters. [2]
With the development of modern industry, the appearance of a series of emerging industrial fields and the construction of many modern projects need higher requirements for ability to adapt to environment and service life of anti-corrosion coating. Common coating has not met these needs. The definition of “Heavy-duty Coating” defined by people is the coating which can be used in more serious corrosion environment, including matching coating of primer and finishes. Simply, heavy-duty coating can be defined it has long service life and is applicable for more serious applied environment. Generally, it can be used for 10 or 15 years in chemical atmosphere and marine environment and can be used for more than 5 years in the medium of acid, alkali, salt and solvent and under corrosion conditions with certain temperature.
Derusting Grade
Derusting by wire brush
St2 Derusting by complete handwork and power tools
There should be no grease, dirt, oxide scale, rust, paint or other foreign matters on the surface.
St3 Derusting by complete handwork and power tools
Compared with St2, the handle by St3 is cleaner and there is metallic luster on the metal substrate.
Derusting by Sand Blasting
Sa1 Slight derusting by Sand Blasting
There should be no grease, dirt, loose oxide scale, rust, paint or other foreign matters on the surface.
Sa2 Complete derusting by Sand Blasting
There should be no grease, dirt, oxide scale, rust, paint or other foreign matters and left matters should attach firmly on the surface.
Sa2.5 Extremely complete derusting by Sand Blasting
There should be no grease, dirt, oxide scale, rust, paint or other foreign matters and the marks of left matters show only slight point-shape and stripe-shape patches on the surface.
Sa3 Derusting by Sand Blasting for the cleaning on the steel surface
There should be no grease, dirt, oxide scale, rust, paint or other foreign matters and should be even metallic luster on the surface.
