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Solution to Rust of Double-sided Submerged Arc Welded Spiral Steel Pipe
If steel surface is polished by steel brush and other tools after rusting of double-sided submerged arc welded spiral pipe, cleaning and preheating of spiral pipe can remove loose or raised oxide scale, rust, welding slag, etc. Manual tool can reach Sa2 level, power tool can reach Sa3 level. If the surface of spiral pipe is adhered to solid oxide sheet, the effect of tool rust removal is not ideal, and the depth of anchor lines required for anti-corrosion construction can not be reached.
On the basis of traditional application, new application has been added, which makes the use of spiral steel tube more abundant, and at the same time reduces the use cost of spiral steel tube. Radio frequency inductors provide 200 volts and 50 amperes of electricity to flow smoothly through the spiral steel tube and heat the experimental samples by induction.
The spiral tube itself does not become hot, but the experimental sample has a significant fever. When the heating temperature exceeds the arc melter, the radio frequency sensor will provide more control so that scientists can adjust the specific composition of the alloy. Spiral steel pipe has strong pressure bearing capacity, good plasticity, and is easy to weld and process. Generally, spiral submerged arc welded spiral steel pipe (SY5037-83) for low pressure fluid transportation is made by double-sided automatic submerged arc welding or single-sided welding for water, gas, air and steam, etc.
Chemical Analysis of Q235B Spiral Tube Materials
The market demand of spiral steel pipe will not change fundamentally. Whether the spiral steel pipe market can maintain its rapid development depends on the change of demand. Macroeconomic regulation at the policy level will slow down the growth rate of the market in the future.
The main raw material is hot metal and scrap steel. The content of sulphur and phosphorus in steel is higher than that in high quality carbon structural steel. Generally, sulphur is less than 0.050% and phosphorus is less than 0.045%. The content of other alloying elements, such as chromium, nickel and copper, which are brought into steel by raw materials generally does not exceed 0.30%. According to the requirements of composition and properties, the grades of such steels are Q195, Q215A, B, Q235A, B, C, D, Q255A, B, Q275, etc.
Note: "Q" is the capitalized head of the yielding Chinese Pinyin character, followed by the minimum yield point (_s) value of the brand. The following symbols are classified as A, B, C and D according to the content of impurity elements (sulfur and phosphorus) in the steel from high to low and with the change of carbon and manganese elements.
According to metallurgical quality, Q235 of carbon structural steel in GB700-88 standard is divided into four grades: A, B, C and D. The Si content of each grade is 0.3%. The difference lies in the difference of carbon content and sulfur and phosphorus content. The carbon content of AB grade is 0.14%~0.22% and 0.12%~0.20%, CD grade is less than 0.18%, <0.17%, A grade is the smallest and D grade SP is the smallest.