At present, carbon steel pipe pickling method is adopted for the construction and management of the two-ring pickling and pickling inner ring.

Butt resistance welding (hereinafter referred to as butt) is the entire end face of a resistance welding method in which two workpieces of a thermal resistance are welded together at the same time. High butt productivity, easy to automate, so widely available.

Steel is the most widely used gas pipeline project. Its main advantages are: high strength, good toughness, large compressive stress, impact resistance, compactness, good plasticity, easy welding and heat treatment, thin wall thickness, saving the metal. But its poor corrosion resistance, the need to take appropriate anti-corrosion measures.

This method of welding has great advantages over other methods. The first advantage is fully automated. The second advantage, which is buried in arc welding, is its heat exchange and relatively strong performance guarantees, high quality The third advantage, due to the submerged arc welding buried in the flux, so it can be used for high current, welding efficiency is relatively high.

Due to the constraints of the production process, the high cost of seamless steel pipe production, resulting in its gradual decline in economic efficiency. As the technology advances, China's metallurgical industry, instead of hot-drawing seamless steel pipe to reduce the beginning of new products appear.

Cold-drawn tubes are generally divided into medium and low pressure boiler tubes, high pressure boiler tubes, steel tubes, stainless steel tubes, petroleum cracking tube, other steel, thin-walled carbon steel, alloy steel thin-walled, thin-walled stainless steel, special steel.

Cold drawn non-uniform thickness of the reasons for the uneven steel: 1) cutting the slope, through the big bend, the center of the hole error easily lead to uneven wall thickness. 2) When the perforation extension coefficient is too large, the roll speed is too high, rolling instability. 3) Puncher throwing steel capillary instability can easily lead to uneven thickness of the tail.

Avoiding Cold Drawn Seamless Steel Tube Uneven Wall Thickness

Seamless steel pipe classification and characteristics

3PE corrosion-resistant steel pipe buried pipe life is crucial, the same material, pipe buried in the ground for decades and some non-corrosive, leaks in a few years. Because they use different outer coating.

When hardness of steel pipe is below 500HB, which is proportional to the tensile strength and hardness. Hardness with tempering temperature decreases, but in the state as well as the quenching and tempering below 300 ℃, the hardness and tensile strength of the relationship is difficult established. When the tempering temperature at around 300 ℃, kg / m ㎡ with HRC is a correlation between that high hardness, tensile strength is high; low hardness, tensile strength is low.

Effect of remanence on welding quality and its influence Gas pipeline construction and repair welding operations, sometimes appear blowing phenomenon, affecting the welding process. The formation of a magnetic strike is due to the presence of metal residual magnetism in the pipe. Usually, the magnetic induction and remanence are divided into two processes. Magnetically-induced plants tend to produce tube links such as metal smelting, handling using electromagnetic cranes, tube parking in a strong magnetic field, non-destructive testing after magnetization, and placing the tube close to the power cord and so strongly. Magneto-electric welding often occurs during the process. When assembling and using the magnetic retainer, the fixture and the DC welding pipe are connected to each other. For example, a long contact is connected to a DC power cable, a bare wire section or a short-circuit pipe welding fixture.

Because SSAW pipe can be continuously formed by the coil width of the welding production, easy to automate the use of double-sided submerged arc welding, there are a variety of test methods to check the quality inspection of the weld. Therefore, the laying of pipelines, spiral welded pipe has been widely used. However, during the forming process, various pipe defects are generated due to process errors or due to other reasons that cause the operation to mature.

Cold drawing seamless pipe for precision mechanical structure, hydraulic equipment and good surface finish cold drawn or cold-rolled precision seamless steel tubes. High-precision drawing that diameter size accuracy (tolerance) strict, the outer surface finish, roundness, straightness, thickness uniformity is good.

Carbon Steel Weldability

UOE Pipe and JCOE Pipe

Standard and grade: ASTM a179 / ASME sa179 Delivery conditions: Annealing, normalizing, normalizing and tempering. The main tests are according to ASTM a213-09 and ASTM 1016 1. High pressure water pressure test: at least 10 maps. 2. Eddy current test, ultrasonic test Three. Mechanical test 4. OD and weight tolerance test.

Spiral submerged arc welded pipe manufacturing process: (1) strip, wire, flux of raw materials. Before entering the physical and chemical must undergo rigorous testing.

Boiler tube hardness is one of the important factors that determine the quality of high pressure boiler tubes.

Welding materials under specified conditions, the construction of components required by the design of welding methods, and to meet the intended use requirements. Through the welding material, welding, component type and the requirements of the four factors.

Cold drawing seamless pipe for precision mechanical structure, hydraulic equipment and good surface finish cold drawn or cold-rolled precision seamless steel tubes. High-precision drawing that diameter size accuracy (tolerance) strict, the outer surface finish, roundness, straightness, thickness uniformity is good.